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2004 Part 2     Front Cover (2004 - Part 2)    No author information available Summary:         Table of Contents (2004 - Part 2)    No author information available Summary: Not available         Globalization and new world order: are we ready for "Scientists without Borders"?    B. Kouchner Summary: Since the end of the cold war and the fall of the Berlin wall, large scientific projects, such as the LHC and ITER, are now based on international collaborations involving most world powers. These collaborations cover not only the design, but also run the construction and operation phases. Scientists, like other cultural and economical actors, have to adapt and organize their work in this new world environment. They also need to learn how to convince public opinion, offering information and transparency. There is no good model yet on how to do that in the most efficient way and a great deal might be learned by looking at experiences outside the scientific field. Relying on my experience as founder of "Doctors Without Borders" and "Doctors of the World", as well as holder of several ministerial positions in different French governments and as former Head of the UN Interim Administration Mission in Kosovo, I share with you my view on globalization and on how to initiate and carry out large international, nonprofit technology programs.         Status report on the LHC main magnet production    G. de Rijk, M. Bajko, M. Cornelis, M. Durante, P. Fessia, J. Miles, M. Modena, G. Molinari, J. Rinn, F. Savary, K. Schirm, F. Simon, D. Tommasini, T. Tortschanoff and J. Vlogaert Summary: The LHC ring will contain 1232 main dipole and 382 main quadrupole double aperture magnets. All main magnets are superconducting and employ Nb-Ti/Cu Rutherford type cables operated at 1.9 K. The dipole production has reached the equivalent of almost three octants of cold masses and nearly four octants of collared coils. The quadrupole production has reached 75 cold masses and over 150 bare magnets. The ramping up of large scale magnet production has posed several challenges which will be discussed, like: the coil size uniformity, coil pre-stress control, cold mass welding technique and the geometrical shape issues. The magnetic measurement results at warm will be presented together with their usage for the quality control in the production. The common features and differences of the three dipole producers will be discussed. The latest version of the production schedule will be presented.         Production and measurement of the MQXA series of LHC low-/spl beta/ insertion quadrupoles    A. Yamamoto, T. Nakamoto, T. Ogitsu, N. Ohuchi, Y. Ajima, N. Higashi, M. Iida, N. Kimura, K. Ohhata, T. Shintomi, S. Sugawara, K. Sugita, K. Tanaka, A. Terashima, K. Tsuchiya, T. Fujii, E. Hashiguchi, T. Kanahara, S. Murai, W. Odajima and T. Orikasa Summary: The inner triplet quadrupole magnets (MQXA) for the LHC low-beta insertion have been developed. The quadrupoles provide a field gradient of 215 T/m at 1.9 K in a coil aperture of 70 mm diameter and with an effective magnetic length of 6.37 m. The series of 20 magnets have been produced in industry, and full testing has been done at KEK. We present an overview of the production and the results from mechanical and magnetic measurements.         Test results of LHC interaction regions quadrupoles produced by Fermilab    S. Feher, R. Bossert, J. Carson, D.R. Chichili, J. Kerby, M.J. Lamm, A. Nobrega, T. Nicol, T. Ogitsu, D. Orris, T. Page, T. Peterson, R. Rabehl, W. Robotham, R. Scanlan, P. Schlabach, C. Sylvester, J. Strait, M. Tartaglia, J.C. Tompkins, G. Velev, S. Yadav and A.V. Zlobin Summary: The US-LHC Accelerator Project is responsible for the production of the Q2 optical elements of the final focus triplets in the LHC interaction regions. As part of this program Fermilab is in the process of manufacturing and testing cryostat assemblies (LQXB) containing two identical quadrupoles (MQXB) with a dipole corrector between them. The 5.5 m long Fermilab designed MQXB have a 70 mm aperture and operate in superfluid helium at 1.9 K with a peak field gradient of 215 T/m. This paper summarizes the test results of several production MQXB quadrupoles with emphasis on quench performance and alignment studies. Quench localization studies using quench antenna signals are also presented.         Status of production of the superconducting matching quadrupoles for the LHC insertions    R. Ostojic, N.C. Lasheras, G. Kirby, J.C. Perez, H. Prin and W.V. Delsolaro Summary: Special individually powered superconducting quadrupoles are required for the LHC insertions. These units comprise quadrupole magnets of the MQM and MQY types and range in length from 5.4 m to 11.4 m. In total, 82 insertion quadrupoles will be assembled at CERN. In this paper we present the advance in construction of the magnets and report on the performance of the first series built units, including power tests and alignment of the cold masses.         Axis measurements, field quality and quench performance of the first LHC short straight sections    S. Sanfilippo, N. Smirnov, P. Schnizer, N. Sammut, P. Pugnat, L. Bottura, A. Siemko, M. Calvi, V. Chohan, A. Stafiniak, L. Walckiers, P. Hagen, E. Todesco, T. Tortschanoff, F. Simon and M. Durante Summary: The series testing at 1.9 K of the 360 Short Straight Sections (SSS) for the Large Hadron Collider have started at CERN in September 2003. The SSS contain the lattice quadrupoles and correction magnets in a common cryostat. The lattice quadrupoles feature two collared coils with 56 mm bore assembled in a common yoke. The coils are wound in two-layers from 15.1 mm wide NbTi cable, insulated with polyimide tape. The paper reviews the main test results performed in superfluid helium. The magnetic field and magnetic center position of the quadrupoles and associated correctors were measured with two independent systems, namely an automated scanner and a single stretched wire technique. The quench training, the field quality and the magnetic alignment measurements are presented and discussed in terms of the specifications and expected performances of these magnets in the LHC. We discuss in detail the field quality in terms of multipole errors measured at injection and nominal field and decomposed into geometric and persistent current magnetization errors. Warm/cold correlation for the geometric multipoles and the magnetic axis is also presented.         Field quality measurements of the LQXB inner triplet quadrupoles for LHC    G.V. Velev, R. Bossert, R. Carcagno, J. DiMarco, S. Feher, H. Glass, V.V. Kashikhin, J. Kerby, M. Lamm, A. Makulski, A. Nobrega, J. Nogiec, D. Orris, T. Peterson, R. Rabehl, P. Schlabach, J. Strait, C. Sylvester, M. Tartaglia, J.C. Tompkins and A.V. Zlobin Summary: As a part of the USLHC program, Fermilab is building half of the inner triplet quadrupole magnets for the LHC. Two identical quadrupoles (MQXB) with a dipole corrector between them in a single cryogenic unit (LQXB) comprise the Q2 optical element of the final focus triplets in the interaction regions. The 5.5 m long MQXB have a 70 mm aperture and operate in superfluid helium at 1.9 K with a peak field gradient of 215 T/m. Manufacturing of the 18 magnets is in an advanced stage. A program of magnetic field quality measurements of the magnets is performed at room temperature during magnet fabrication as well as at superfluid helium temperature during the cold qualification of each magnet. Results of the measurements are summarized in this paper.         Status of the Next European Dipole (NED) activity of the Collaborated Accelerator Research in Europe (CARE) project    A. Devred, B. Baudouy, D.E. Baynham, T. Boutboul, S. Canfer, M. Chorowski, P. Fabbricatore, S. Farinon, H. Felice, P. Fessia, J. Fydrych, M. Greco, J. Greenhalgh, D. Leroy, P. Loverige, F. Michel, L.R. Oberli, A. den Ouden, D. Pedrini, J. Polinski, V. Previtali, L. Quettier, J.M. Rifflet, J. Rochford, F. Rondeaux, S. Sanz, S. Sgobba, M. Sorbi, F. Toral-Fernandez, R. van Weelderen, P. Vedrine, O. Vincent-Viry and G. Volpini Summary: Plans for LHC upgrade and for the final focalization of linear colliders call for large aperture and/or high-performance dipole and quadrupole magnets that may be beyond the reach of conventional NbTi magnet technology. The Next European Dipole (NED) activity was launched on January 1st, 2004 to promote the development of high-performance, Nb/sub 3/Sn wires in collaboration with European industry (aiming at a noncopper critical current density of 1500 A/mm/sup 2/ at 4.2 K and 15 T) and to assess the suitability of Nb/sub 3/Sn technology to the next generation of accelerator magnets (aiming at an aperture of 88 mm and a conductor peak field of 15 T). It is integrated within the Collaborated Accelerator Research in Europe (CARE) project, involves seven collaborators, and is partly funded by the European Union. We present here an overview of the NED activity and we report on the status of the various work packages it encompasses.         R&D of Nb/sub 3/Sn accelerator magnets at Fermilab    A.V. Zlobin, G. Ambrosio, N. Andreev, E. Barzi, B. Bordini, R. Bossert, R. Carcagno, D.R. Chichili, J. DiMarco, L. Elementi, S. Feher, V.S. Kashikhin, V.V. Kashikhin, R. Kephart, M. Lamm, P.J. Limon, I. Novitski, D. Orris, Y. Pischalnikov, P. Schlabach, R. Stanek, J. Strait, C. Sylvester, M. Tartaglia, J.C. Tompkins, D. Turrioni, G. Velev, R. Yamada and V. Yarba Summary: Fermilab is developing and investigating different high-field magnets (HFM) for present and future accelerators. The HFM R&D program focused on the 10-12 T magnets based on Nb/sub 3/Sn superconductor and explored both basic magnet technologies for brittle superconductors-wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC were conducted. A series of 1-m long cos-theta dipole models based on the wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and react-and-wind technique, were also fabricated and tested. Extensive theoretical and experimental studies of electro-magnetic instabilities in Nb/sub 3/Sn strands, cables and magnets were performed and led to a successful 10 T dipole model. This paper presents the details of Fermilab's HFM program, reports its status and major results, and formulates the next steps for the program.         Mechanical analysis of the Nb/sub 3/Sn dipole magnet HD1    P. Ferracin, S.E. Bartlett, S. Caspi, D.R. Dietderich, S.A. Gourlay, C.R. Hannaford, A.R. Hafalia, A.F. Lietzke, S. Mattafirri and G. Sabbi Summary: The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has recently fabricated and tested HD1, a Nb/sub 3/Sn dipole magnet. The magnet reached a 16 T field, and exhibited training quenches in the end regions and in the straight section. After the test, HD1 was disassembled and inspected, and a detailed 3D finite element mechanical analysis was done to investigate for possible quench triggers. The study led to minor modifications to mechanical structure and assembly procedure, which were verified in a second test (HD1b). This paper presents the results of the mechanical analysis, including strain gauge measurements and coil visual inspection. The adjustments implemented in the magnet structure are reported and their effect on magnet training discussed.         Test results of HD1b, an upgraded 16 tesla Nb/sub 3/Sn dipole magnet    A.F. Lietzke, S.E. Bartlett, P. Bish, S. Caspi, D. Dietderich, P. Ferracin, S.A. Gourlay, A.R. Hafalia, C.R. Hannaford, H. Higley, W. Lau, N. Liggins, S. Mattafirri, M. Nyman, G. Sabbi, R. Scanlan and J. Swanson Summary: The Superconducting Magnet Group at Lawrence Berkeley National Laboratory has been developing high-field, brittle-superconductor, accelerator magnet technology, in which the conductor's support system can significantly impact conductor performance (as well as magnet training). A recent H-dipole coil test (HD1) achieved a peak bore-field of 16 Tesla, using two, flat-racetrack, double-layer Nb/sub 3/Sn coils. However, its 4.5 K training was slow, with an erratic plateau at /spl sim/92% of its un-degraded "short-sample" expectation (/spl sim/16.6 T). Quench-origins correlated with regions where low conductor pre-stress had been expected (3-D FEM predictions and variations in 300 K coil-size). The coils were re-assembled with minor coil-support changes and re-tested as "HD1b", with a 185 MPa average pre-stress (30 MPa higher than HD1, with a 15-20 MPa pole-turn margin expected at 17 T). Training started higher (15.1 T), and quickly reached a stable, negligibly higher plateau at 16 T. After a thermal cycle, training started at 15.4 T, but peaked at 15.8 T, on the third attempt, before degrading to a 15.7 T plateau. The temperature dependence of this plateau was explored in a sub-atmospheric LHe bath to 3.0 K. Magnet performance data for both thermal cycles is presented and discussed, along with issues for future high-field accelerator magnet development.         Design of HD2: a 15 tesla Nb/sub 3/Sn dipole with a 35 mm bore    G. Sabbi, S.E. Bartlett, S. Caspi, D.R. Dietderich, P. Ferracin, S.A. Gourlay, A.R. Hafalia, C.R. Hannaford, A.F. Lietzke, S. Mattafirri, A.D. McInturff and R. Scanlan Summary: The Nb/sub 3/Sn dipole HD1, recently fabricated and tested at LBNL, pushes the limits of accelerator magnet technology into the 16 T field range, and opens the way to a new generation of HEP colliders. HD1 is based on a flat racetrack coil configuration and has a 10 mm bore. These features are consistent with the HD1 goals: exploring the Nb/sub 3/Sn conductor performance limits at the maximum fields and under high stress. However, in order to further develop the block-coil geometry for future high-field accelerators, the bore size has to be increased to 30-50 mm. With respect to HD1, the main R&D challenges are: (a) design of the coil ends, to allow a magnetically efficient cross-section without obstructing the beam path; (b) design of the bore, to support the coil against the pre-load force; (c) correction of the geometric field errors. HD2 represents a first step in addressing these issues, with a central dipole field above 15 T, a 35 mm bore, and nominal field harmonics within a fraction of one unit. This paper describes the HD2 magnet design concept and its main features, as well as further steps required to develop a cost-effective block-coil design for future high-field, accelerator-quality dipoles.         Development of a large aperture Nb/sub 3/Sn racetrack quadrupole magnet    P. Ferracin, S.E. Bartlett, S. Caspi, D.R. Dietderich, S.A. Gourlay, C.R. Hannaford, A.R. Hafalia, A.F. Lietzke, S. Mattafirri, A.D. McInturff, M. Nyman and G. Sabbi Summary: The U.S. LHC Accelerator Research Program (LARP), a collaboration between BNL, FNAL, LBNL, and SLAC, has among its major objectives the development of advanced magnet technology for an LHC luminosity upgrade. The LBNL Superconducting Magnet Group supports this program with a broad effort involving design studies, Nb/sub 3/Sn conductor development, mechanical models, and basic prototypes. This paper describes the development of a large aperture Nb/sub 3/Sn racetrack quadrupole magnet using four racetrack coils from the LBNL Subscale Magnet (SM) Program. The magnet provides a gradient of 95 T/m in a 110 mm bore, with a peak field in the conductor of 11.2 T. The coils are pre-stressed by a mechanical structure based on a pre-tensioned aluminum shell, and axially supported with aluminum rods. The mechanical behavior has been monitored with strain gauges and the magnetic field has been measured. Results of the test are reported and analyzed.         An R&D approach to the development of long Nb/sub 3/Sn accelerator magnets using the key and bladder technology    S.E. Bartlett, S. Caspi, D.R. Dietderich, P. Ferracin, S.A. Gourlay, C.R. Hannaford, A.R. Hafalia, A.F. Lietzke, A.D. McInturff, S. Mattafirri, G. Sabbi and R.M. Scanlan Summary: Building accelerator quality magnets using Nb/sub 3/Sn for next generation facilities is the challenge of the next decade. The Superconducting Magnet Group at LBNL has developed an innovative support structure for high field magnets. The structure is based on an aluminum shell over iron yokes using hydraulic bladders and locking keys for applying the pre-stress. At cool down the pre-stress is almost doubled due to the differences of thermal contraction. This new structure allows precise control of the pre-stress with minimal spring back and conductor over-stress. At present the support structure has been used with prototype magnets up to one meter in length. In this paper, the design of a 4-meter long, 11 Tesla, wind-and-react racetrack dipole will be presented as a possible step toward the fabrication of long Nb/sub 3/Sn accelerator magnets.         Quench problems of Nb/sub 3/Sn cosine theta high field dipole model magnets    R. Yamada and M. Wake Summary: We have developed and tested several cosine theta high field dipole model magnets for accelerator application, utilizing Nb/sub 3/Sn strands made by MJR method and PIT method. With Rutherford cables made with PIT strand we achieved 10.1 Tesla central field at 2.2 K operation, and 9.5 Tesla at 4.5 K operation. The magnet wound with the MJR cable prematurely quenched at 6.8 Tesla at 4.5 K due to cryo-instability. Typical quench behaviors of these magnets are described for both types of magnets, HFDA-04 of MJR and HFDA-05 of PIT. Their characteristics parameters are compared on d/sub eff/, RRR, thermal conductivity and others, together with other historical Nb/sub 3/Sn magnets. It is suggested a larger RRR value is essential for the stability of the epoxy impregnated high field magnets made with high current density strands. It is shown that a magnet with a larger RRR value has a longer MPZ value and more stable, due to its high thermal conductivity and low resistivity.         Development of a prototype of Superconducting combined function magnet for the 50 GeV proton beam line for the J-PARC neutrino experiment    T. Nakamoto, N. Higashi, T. Ogitsu, A. Terashima, Y. Ajima, M. Anerella, R. Gupta, Y. Iwamoto, N. Kimura, Y. Makida, T. Obana, H. Ohhata, B. Parker, K. Sasaki, K. Tanaka, T. Tomaru, P. Wanderer and A. Yamamoto Summary: Superconducting combined function magnets will be utilized for the 50 GeV, 750 kW proton beam line for the J-PARC neutrino experiment and an R&D program has been launched at KEK. The magnet is designed to provide a combined function of a dipole field of 2.6 T with a quadrupole field of 19 T/m in a coil aperture of 173.4 mm. Critical magnet components including glass-fiber reinforced phenolic plastic spacers have been successfully developed. The mechanical design has been verified by a 100 mm long short-cut model, and coils have been wound for the first full-length prototype.         Radiation resistant HTS quadrupoles for RIA    R. Gupta, M. Anerella, M. Harrison, W. Sampson, J. Schmalzle, R. Ronningen and A. Zeller Summary: Extremely high radiation, levels with accumulated doses comparable to those in nuclear reactors than in accelerators, and very high heat loads (/spl sim/15 kW) make the quadrupole magnets in the fragment separator one of the most challenging elements of the proposed Rare Isotope Accelerator (RIA). Removing large heat loads, protecting the superconducting coils against quenching, the long term survivability of magnet components, and in particular, insulation that can retain its functionality in such a harsh environment, are the major challenges associated with such magnets. A magnet design based on commercially available high temperature superconductor (HTS) and stainless steel tape insulation has been developed. HTS will efficiently remove these large heat loads and stainless steel can tolerate these large radiation doses. Construction of a model magnet has been started with several coils already built and tested. This paper presents the basic magnet design, results of the coil tests, the status and the future plans. In addition, preliminary results of radiation calculations are also presented.         Optimum Integral design for maximizing the field in short magnets    R. Gupta Summary: An Optimum Integral Design is introduced for cosine(n/spl theta/) coils where the entire end-to-end length of the coil generates field with the dilution from ends practically eliminated. The benefits of such a design are particularly significant in short magnets where the overall coil length is comparable to or a few times the coil diameter. The integral field strength is further enhanced since the design allows a larger number of turns than in typical magnet coils. In this concept, the ends and body harmonics are optimized together to create an integral cosine(n/spl theta/) azimuthal current distribution. The concept was initially developed for wire/cable wound magnets where the bend radius of turns in the ends can be small. However, the benefit of this general approach can be applied to cable magnets as well. The magnetic design of a corrector dipole for the AGS helical magnet, which was recently built and tested, is presented as one of several examples. The other examples include a few sub-compact designs: a dipole with coil length less than a coil diameter, a quadrupole with coil length less than a coil radius, etc. Apart from generating a large integral field for the given length, the computed integral field harmonics in these designs are only a few parts in 10,000 at 2/3 of the coil radius.         Performance analysis of HD1: a 16 Tesla Nb/sub 3/Sn dipole magnet    S. Mattafirri, S.E. Bartlett, P.A. Bish, S. Caspi, D.R. Dietderich, P. Ferracin, S.A. Gourlay, C.R. Hannaford, A.R. Hafalia, W.G. Lau, A.F. Lietzke, A.D. McInturff, M. Nyman, G.L. Sabbi and R.M. Scanlan Summary: The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has been developing technology for high field accelerator magnets from brittle conductors. HD1 is a single bore block dipole magnet using two, double-layer Nb/sub 3/Sn flat racetrack coils. The magnet was tested in October 2003 and reached a bore peak field of 16 T (94.5% of short sample). The average quench current plateau appeared to be limited by "stick slip" conductor motions. Diagnostics recorded quench origins and preload distributions. Cumulative deformation of the mechanical structure has been observed. Quench velocity in different field regions has been measured and compared with model predictions. The results obtained during the HD1 test are presented and discussed.         Development and test of Nb/sub 3/Sn cos-theta dipoles based on PIT strands    A.V. Zlobin, G. Ambrosio, N. Andreev, E. Barzi, R. Bossert, R. Carcagno, D.R. Chichili, L. Elementi, S. Feher, V.S. Kashikhin, V.V. Kashikhin, M.J. Lamm, I. Novitski, Yu. Pischalnikov, C. Sylvester, M. Tartaglia and R. Yamada Summary: Fermilab is involved in the development of new generation high-field accelerator magnets using state-of-the-art Nb/sub 3/Sn strands produced using different technologies. Two 1-m long models-mirror configuration and dipole magnet-were fabricated recently at Fermilab based on powder-in-tube (PIT) Nb/sub 3/Sn strands with small effective filament size. This paper describes the parameters of superconducting strands and cable, the details of magnet design and fabrication procedure, and reports the results of PIT coil testing.         A high intensity Superconducting atomic beam source    M. Statera, M. Stancari, M. Capiluppi, G. Ciullo, M. Contalbrigo, P.F. Dalpiaz, F. Giordano, P. Lenisa and M. Wang Summary: A high intensity atomic beam source design, based on superconducting technology, is presented. The design requires compact sextupole magnets with a tapered bore and pole tip fields of 6-9 T, using superfluid helium if necessary. The cryostat housing these magnets, in addition to maintaining a stable magnet temperature with a minimal thickness along the inner bore, must also function as a cryopump for the atoms that are not focused.         Design concept of superconducting synchrotron magnets with pulse repetition rate up to 20 Hz    A. Kovalenko, N. Agapov, H. Khodzhibagiyan and A. Smirnov Summary: The possibilities of construction superconducting synchrotron magnets with pulse repetition rate up to 20 Hz are analyzed. Different design concepts are considered. The expected AC power losses and the magnet cooling conditions are calculated based on the data which have been obtained under design, construction and long term tests of 2 T superferric dipoles of the Nuclotron at the frequencies up to f=2 Hz. New experimental data on the investigation of the dipole at higher frequencies are presented. Hollow multifilament NbTi composite cable cooled with two-phase helium flow is used. The essential features of the test bench are described.         Construction and tests of HCX quadrupole doublet for heavy ion beam transport experiments    Chen-Yu Gung, N.N. Martovetsky, R.R. Manahan, J.V. Minervini, J.H. Schultz, G. Sabbi and P.A. Seidl Summary: A cryostat housing a pair of previously tested quadrupole magnets has been constructed as a prototype focusing cell for the High Current Experiment (HCX) project. The doublet assembly was constructed with a room temperature beam tube. The magnets were reassembled, electrically connected in series, and tested to the short sample limiting current without further training. The doublet was more sensitive to the current ramping rate as compare with the previous performance. In order to build a compact vacuum jacket for the warm bore structure, a novel radiation insulation made of aluminum coated stainless steel foil was selected. The experiences in assembly of the doublet and fabrication of the cryostat are described. The thermal performances of the cryostat are reported.         Superconducting combined function magnet system for J-PARC neutrino experiment    T. Ogitsu, Y. Ajima, M. Anerella, J. Escallier, G. Ganetis, R. Gupta, D. Hagedorn, M. Harrison, N. Higashi, Y. Iwamoto, A. Ichikawa, A. Jain, N. Kimura, T. Kobayashi, Y. Makida, J. Muratore, T. Nakamoto, T. Obana, H. Ohhata, B. Parker, K. Sasaki, M. Takasaki, K. Tanaka, A. Terashima, T. Tomaru, P. Wanderer and A. Yamamoto Summary: The J-PARC Neutrino Experiment, the construction of which starts in JFY 2004, will use a superconducting magnet system for its primary proton beam line. The system, which bends the 50 GeV 0.75 MW proton beam by about 80 degrees, consists of 28 superconducting combined function magnets. The magnets utilize single layer left/right asymmetric coils that generate a dipole field of 2.6 T and a quadrupole field of 18.6 T/m with the operation current of about 7.35 kA. The system also contains a few conduction cooled superconducting corrector magnets that serve as vertical and horizontal steering magnets. All the magnets are designed to provide a physical beam aperture of 130 mm in order to achieve a large beam acceptance. Extensive care is also required to achieve safe operation with the high power proton beam. The paper summarizes the system design as well as some safety analysis results.         A radiation resistant dipole    A.F. Zeller, J.C. DeKamp and J. DeLauter Summary: Several proposed and approved accelerator projects will need to deal with magnetic elements operating in high-radiation environments. Previous projects at LANL and PSI have relied on resistive magnets, but these new projects require the higher capabilities of superconducting magnets. A superferric dipole has been constructed using radiation resistant materials to meet these needs. The dipole uses cold iron and coils wound with materials that have high tolerance to the expected flux of high-energy neutrons. Primary insulation was polyimid and the coils were potted with CTD-422, a cyanate ester. The magnet operated at slightly greater than the manufacture's guaranteed short sample current. Quench characteristics were compared with calculations, indicating a relatively slow transverse propagation.         Magnetic field design of a Superconducting magnet for a FFAG accelerator    T. Obana, T. Ogitsu, T. Nakamoto, K. Sasaki, A. Yamamoto, T. Orikasa, M. Yoshimoto and Y. Mori Summary: A superconducting magnet for a Fixed Field Alternating Gradient (FFAG) accelerator is proposed. The static magnetic field is required to be proportional to the k-th power of the orbit radius where k is the geometrical field index of the accelerator. The left/right asymmetric coil with elliptical aperture is introduced to maximize the horizontal aperture with a compact magnet design. The 3D coil configuration is designed to meet the requirement in terms of integral magnetic field. The 3D magnetic field is evaluated and the field integral along the beam trajectory satisfies the beam optics requirement of the FFAG accelerator.         Design and test results of a BSCCO-2223 magnet for gyrotron application    R.W. McGhee, E.E. Burkhardt, A. Berryhill and D.M. Coffey Summary: A program is currently under way to develop a compact, power-efficient, robust gyrotron. Gyrotrons require a very precise magnetic field, typically generated by a NbTi superconducting magnet, to form the environment necessary for the microwave power generation. The use of high-temperature superconductor (HTS) material for a liquid cryogen-free gyrotron magnet will significantly reduce the input power requirements for the cryocooler compressor and the overall size of the magnet system. Cryomagnetics has designed, built and successfully tested a magnet wound with BSCCO-2223 tape to be used in the gyrotron. The HTS magnet was designed such that it can replace the current LTS (NbTi) cryogen-free gyrotron magnet in form, fit and function. The HTS magnet consists of 11 double-pancakes and provides stable 3.57 T operation at 37 K with a current of 120 A. Magnetic field shape, which is extremely important in gyrotron applications, was a considerable challenge since NbTi operating at 4.2 K is capable of a much higher current density than BSCCO operating at 37 K. Overall refrigeration requirements were reduced from /spl sim/8 kW in the LTS system to /spl sim/4 kW in the HTS system. A single-stage GM cryocooler was used to cool the HTS magnet. Comprehensive tests of the HTS magnet, including operation with the gyrotron tube, have been successfully completed.         Future accelerator magnet needs    A. Devred, S.A. Gourlay and A. Yamamoto Summary: Superconducting magnet technology is continually evolving in order to meet the demanding needs of new accelerators and to provide necessary upgrades for existing machines. A variety of designs are now under development, including high fields and gradients, rapid cycling and novel coil configurations. This paper presents a summary of R&D programs in the EU, Japan and the USA. A performance comparison between NbTi and Nb/sub 3/Sn along with fabrication and cost issues are also discussed.         Advances in Nb/sub 3/Sn strand for fusion and particle accelerator applications    J.A. Parrell, M.B. Field, Youzhu Zhang and Seung Hong Summary: Nb/sub 3/Sn conductor made by the internal tin route is the material of choice for the highest field superconducting magnets. These include systems ranging from solenoids used in 900MHz NMR and 20 T laboratory magnets, to large-scale applications such as ITER and possible LHC upgrades. We present our latest results on internal tin strands having critical current density (J/sub c/) values of 3000 A/mm/sup 2/ (4.2 K, 12 T), as it relates to such magnet systems. One obstacle to wider use of internal tin strand is the relatively small billet size, typically limited to 50 kg or less. As part of the R&D for the U.S. High Energy Physics National Conductor Program, we have developed a method of scaling up the distributed barrier internal tin process to billet sizes several times larger. In the past year we have successfully produced a high J/sub c/ distributed barrier strand made entirely by hot extrusion. Results are also presented on a new method of supplying Ti dopant for the Nb/sub 3/Sn that does not rely on alloying the Sn cores, matrix Cu, or the Nb filaments directly. Material made with this new doping method reached a J/sub c/ (4.2 K, 12 T) value of 2500 A/mm/sup 2/. Finally, the state of development of composites having lower AC losses is described. Such conductors are being developed for possible future fusion applications including ITER.         Voltage spike detection in high field superconducting accelerator magnets    D.F. Orris, R. Carcagno, S. Feher, A. Makulski and Y.M. Pischalnikov Summary: A measurement system for the detection of small magnetic flux changes in superconducting magnets, which are due to either mechanical motion of the conductor or flux jump, has been developed at Fermilab. These flux changes are detected as small amplitude, short duration voltage spikes, which are /spl sim/15 mV in magnitude and lasts for /spl sim/30 /spl mu/sec. The detection system combines an analog circuit for the signal conditioning of two coil segments and a fast data acquisition system for digitizing the results, performing threshold detection, and storing the resultant data. The design of the spike detection system along with the modeling results and noise analysis will be presented. Data from tests of high field Nb3Sn magnets at currents up to /spl sim/20 KA will also be shown.         Improved quench localization and quench propagation velocity measurements in the LHC superconducting dipole magnets    M. Calvi, E. Floch, S. Kouzue and A. Siemko Summary: The series tests performed on the LHC superconducting magnets at cryogenic condition give a unique opportunity to understand the mechanisms responsible for the instabilities causing the so-called training quenches. The first series production tests demonstrated that the weak points in the LHC dipoles are the coil extremities in which the majority of the quenches are located. This evidence triggered the idea of improving the resolution of the measuring system to better characterize the starting region of a quench and the beginning of its propagation. The new quench antennas equipped with sets of small, 4 cm long, and sensitive pick-up coils were designed. The system is described in detail and the first measurement results are presented. It turned out that this tool is also a reliable technique for measuring the quench propagation velocity especially in the particular regions of the superconducting coils like the crossing between the straight section of the magnet and its extremity.         Trends in cable magnetization and persistent currents during the production of the main dipoles of the Large Hadron Collider    B. Bellesia, L. Bottura, V. Granata, S. Le Naour, L. Oberli, S. Sanfilippo, C. Santoni, W. Scandale, N. Schwerg, E. Todesco and C. Vollinger Summary: The production of more than 60% of superconducting cables for the main dipoles of the Large Hadron Collider has been completed. The results of the measurements of cable magnetization and the dependence on the manufacturers are presented. The strand magnetization produces field errors that have been measured in a large number of dipoles (approximately 100 to date) tested in cold conditions. We examine here the correlation between the available magnetic measurements and the large database of cable magnetization. The analysis is based on models documented elsewhere in the literature. Finally, a forecast of the persistent current effects to be expected in the LHC main dipoles is presented, and the more critical parameters for beam dynamics are singled out.         A scaling law for the snapback in Superconducting accelerator magnets    G. Ambrosio, P. Bauer, L. Bottura, M. Haverkamp, T. Pieloni, S. Sanfilippo and G. Velev Summary: The decay of the sextupole component in the bending dipoles during injection and the subsequent snapback at the start of beam acceleration are issues of common concern for all superconducting colliders built or in construction. Recent studies performed on LHC and Tevatron dipole magnets revealed many similarities in the snapback characteristics. Some are expected, e.g. the effect of operational history. One particular similarity, however, is striking and is the subject of this paper. It appears that there is a simple linear relation between the amount of sextupole drift during the decay and the magnet current (or field) change during the ramp required to resolve the snapback. It is surprising that the linear correlation between snapback amplitude and snapback field holds very well for all magnets of the same family (e.g. Tevatron or LHC dipoles). In this paper we present the data collected to date and discuss a simple theory that explains the scaling found.         Magnetic field measurements for fast-changing magnetic fields    A. Jain, J. Escallier, G. Ganetis, Wing Louie, A. Marone, R. Thomas and P. Wanderer Summary: Several recent applications for fast ramped magnets have been found that require rapid measurement of the field quality during the ramp. (In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the accuracy typically required for accelerators.) We have built and tested a new type of magnetic field measuring system to meet this need. The system consists of 16 stationary pickup windings mounted on a cylinder. The signals induced in the windings in a changing magnetic field are sampled and analyzed to obtain the field harmonics. To minimize costs, printed circuit boards were used for the pickup windings and a combination of amplifiers and ADC's used for the voltage readout system. New software was developed for the analysis. Magnetic field measurements of a model dipole developed for the SIS200 accelerator at GSI are presented. The measurements are needed to ensure that eddy currents induced by the fast ramps do not impact the field quality required for successful accelerator operation.         Design of a 6 T, 1T/s fast-ramping Synchrotron magnet for GSI's planned SIS 300 accelerator    J.E. Kaugerts, G. Moritz, C. Muehle, A. Ageev, I. Bogdanov, S. Kozub, P. Shcherbakov, V. Sytnik, L. Tkachenko, V. Zubko, D. Tommasini, M.N. Wilson and W. Hassenzahl Summary: Gesellschaft fur Schwerionenforschung (GSI) is planning to build FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany . This facility will include SIS 300, a fast-ramping heavy ion synchrotron with a rigidity of 300 T-m, with 6 T, 100 mm coil aperture 2.6 m long superconducting dipoles, ramped at 1 T/s . The fast ramp rate requires a magnet design that minimizes AC losses and field distortions during ramping. A two layer cos /spl theta/ magnet design, using a cored Rutherford cable, has been chosen. The paper will present the features of the magnet design that is to be built, the expected AC losses and field quality, and the experimental and analytical work that supports the choice of this design.         Superconductive undulators with variable polarization direction    A. Bernhard, S. Chouhan, B. Kostka, R. Rossmanith, U. Schindler, T. Schneider, E. Steffens and M. Weisser Summary: In the past planar superconductive undulators have been successfully developed and tested with beam. They produce linearly polarized light (X-rays) and allow to tune the emitted wavelength electrically. In this paper a novel type of superconductive undulators is introduced which allows to tune electrically in addition to the wavelength the polarization direction. A short prototype was built and tested in a LHe bath.         New cryogen-free design for superconducting mini-gap undulators    A. Hobl, S. Kubsky, D. Dolling, A. Geisler, P. Komorowski, D. Krischel, U. Klein, R. Rossmanith and H.O. Moser Summary: New advanced cryogen-free superconducting mini-gap undulators are capable of supplying high-energy photons required by experiments in medium energy storage rings. ACCEL's new cryogen-free superconducting undulators pave the way for these easy-to-use high-field insertion devices. The magnet cold mass is cooled down below 4 K without even intermediate use of any cryogenic agent. The cooling power is provided exclusively by multistage cryocoolers and a sophisticated cryogenic design. The cryogenic concept as well as thermal behavior of the first industrial device delivered in January 2004 will be presented along with the field quality measurements.         Design, fabrication, and test results of undulators using Nb/sub 3/Sn superconductor    S.O. Prestemon, D.R. Dietderich, S.E. Bartlett, M. Coleman, S.A. Gourlay, A.F. Lietzke, S. Marks, S. Mattafirri, R.M. Scanlan, R.D. Schlueter, B. Wahrer and B. Wang Summary: An R&D effort is underway at Lawrence Berkeley National Laboratory (LBNL) to develop the technology of Nb/sub 3/Sn superconducting undulators (SCUs). Issues relating to the selection of the appropriate conductor are discussed. The design and fabrication of SCUs using Nb/sub 3/Sn is presented. Two prototype devices have been designed and fabricated at LBNL. The first device concentrated on basic fabrication issues and on magnet protection, a key concern due to extremely high copper current densities during a quench. Test on the first prototype demonstrated that such devices can be passively protected in a scalable manner. The second device incorporated design improvements as well as trim coils that are designed to serve as the basic element of a future active phase error correction approach. Preliminary tests on the second device are presented. The trim coils were successfully tested at a variety of field levels. Two quench runs were performed, both occurring at /spl sim/70% of short-sample J/sub c/. Stability issues associated with flux-jumps and possible epoxy cracking are discussed.         Design and development of a short-period superconducting undulator at the APS    S.H. Kim, C. Doose, R.L. Kustom, E.R. Moog and K.M. Thompson Summary: A planar superconducting undulator (SCU) with a period of 15 mm is under development at the Advanced Photon Source (APS). The SCU is designed to achieve a peak field of 0.8 T on the beam axis for an 8 mm pole gap and a current density in the coil of 1.0 kA/mm/sup 2/. Short sections of low-carbon-steel cores with 12 and 22 periods were fabricated, and coil windings were completed with NbTi superconducting wire. After "training" by means of quenches, the SCUs were able to charge up to near the critical current density j/sub c/ of 1.43 kA/mm/sup 2/. Using a thin-film heater attached to the inner surface of a vacuum chamber wall, steady-state heat fluxes were applied to the coil/pole face of the 12-period SCU in 4.2 K liquid He (LHe). The heat flux densities needed to quench the SCU were measured. At 0.998j/sub c/ and 0.8j/sub c/ the thermal stability margins were about 1.3 mW/mm/sup 2/ and 2 mW/mm/sup 2/, respectively. The thermal stability margin of the SCU was affected by the latent heat of vaporization of LHe.         Status of the superconducting magnet for the Alpha Magnetic Spectrometer    S. Harrison, S. Milward, R.S. Allen, R. McMahon, H. Hofer, J. Ulbricht, G. Viertel and S.C.C. Ting Summary: The Alpha Magnetic Spectrometer (AMS) is a particle physics experiment based on the International Space Station (ISS). At the heart of the detector is a large superconducting magnet, cooled to a temperature of 1.8 K by superfluid helium. The magnet and cryogenic system are currently under construction by Space Cryomagnetics Ltd of Culham, England. This paper describes the current status of the design and manufacture of the magnet system-including test results from the fourteen superconducting coils-and outlines the remaining work required to complete the project.         Performance of an ultra-thin superconducting solenoid for particle astrophysics    Y. Makida, T. Kumazawa, K. Tanaka, A. Yamamoto, T. Yoshida, S. Mizumaki and S. Kurita Summary: An extremely thin superconducting solenoid with a main diameter of 0.9 m and a length of 1.4 m has been fabricated for a balloon borne experiment in Antarctica to study anti-particles in cosmic rays. The solenoid has a 0.8 m diameter warm bore where a magnetic field of 0.8-1.0 T is induced. The coil was wound with mechanically advanced aluminum stabilized superconductor recently developed by using micro-alloying Ni into a pure aluminum base and by cold-work hardening, and consequently the electromagnetic force may be fully supported by the coil itself without any additional support structure. The solenoid was successfully charged up to 1.05 T without any premature quenches. Despite measured strains were beyond 1500 micro-strain, the coil behaved elastically. Because of relatively small RRR of 110, the quench energy is distributed rather unevenly, and a temperature difference of over 100 K was observed. Nevertheless, it was found to be safe to quench the magnet.         System testing and installation of the NHMFL/NSCL sweeper magnet    M.D. Bird, S.J. Kenney, J. Toth, H.W. Weijers, J.C. DeKamp, M. Thoennessen and A.F. Zeller Summary: A superconducting dipole, designed for use as a sweeper magnet in nuclear physics experiments, has been designed and built by the National High Magnetic Field Laboratory for operation at the National Superconducting Cyclotron Laboratory. The magnet operates at a peak field of 3.8 T in a 140 mm gap. A secondary beam enters the magnet from the upstream side before striking a target. The neutrons continue straight through to a neutron detector. The charged particles are swept 40 degrees on a one-meter radius into a particle spectrometer. To allow space for the exit of the downstream neutron beam, the magnet iron and coil structure are built in a modified "C" configuration. There are two coils of "D" shape, one above and one below the beam. This configuration keeps the magnet compact and removes the need for a negative curvature side. The peak field in the winding is 6.5 T. The net force on the curved leg of a single "D" is 1.6 MN. Results of system testing including cool-down, quench history, and integration with the cyclotron are presented.         The mechanical and thermal design for the MICE detector solenoid magnet system    P. Fabbricatore, S. Farinon, M. Perrella, U. Bravar and M.A. Green Summary: The detector solenoid for MICE surrounds a scintillating fiber tracker that is used to analyze the muon beam within the detector. There are two detector magnets for measuring the beam emittance entering and leaving the cooling channel that forms the central part of the experiment. The field in the region of the fiber detectors must be from 2.8 to 4 T and uniform to better than 1 percent over a volume that is 300 mm in diameter by 1000 mm long. The portion of the detector magnet that is around the uniform field section of the magnet consists of two short end coils and a long center coil. In addition, in the direction of the MICE cooling channel, there are two additional coils that are used to match the muon beam in the cooling channel to the beam required for the detectors. Each detector magnet module, with its five coils, will have a design stored-energy of about 4 MJ. Each detector magnet is designed to be cooled using three 1.5 W coolers. This report presents the mechanical and electrical parameters for the detector magnet system.         The mechanical and thermal design for the MICE focusing solenoid magnet system    S.Q. Yang, M.A. Green, G. Barr, U. Bravar, J. Cobb, W. Lau, R.S. Senanayake, A.E. White and H. Witte Summary: The focusing solenoids for MICE surround energy absorbers that are used to reduce the transverse momentum of the muon beam that is being cooled within MICE. The focusing solenoids will have a warm-bore diameter of 470 mm. Within this bore is a flask of liquid hydrogen or a room temperature beryllium absorber. The focusing solenoid consists of two coils wound with a copper matrix Nb-Ti conductor originally designed for MRI magnets. The two coils have separate leads, so that they may be operated at the same polarity or at opposite polarity. The focusing magnet is designed so that it can be cooled with a pair of 1.5 W (at 4.2 K) coolers. The MICE cooling channel has three focusing magnets with their absorbers. The three focusing magnets will be hooked together in series for a circuit stored-energy of about 9.0 MJ. Quench protection for the focusing magnets is discussed. This report presents the mechanical and thermal design parameters for this magnet, including the results of finite element calculations of mechanical forces and heat flow in the magnet cold mass.         Design, development and fabrication for BESIII superconducting muon detector solenoid    B. Wang, B. Wahrer, C. Taylor, C. Chen, T. Juang, M. Wang, Z. Zhu, H. Chen, S. Xu, C. Yi, L. Zhao, H. Yang, J. Zhou, J. Hu and B. Huang Summary: The BESIII thin superconducting solenoid will generate 1.0 T central field with a field uniformity of 5% within the drift chamber. The superconducting coil winding has an ID of 2962 mm, an OD of 3002 mm and a length of 3550 mm. The overall magnet cryostat has an I.D. of 2750 mm (warm bore), an O.D. of 3390 mm and a length of 3910 mm. Rectangular Aluminum Stabilized Nb-Ti/Cu Superconductor, 3.7 mm /spl times/ 20 mm, is employed to wind the one-layer coil inside a hoop-force support cylinder. The winding is indirectly cooled by forced-flow two-phase liquid helium. The thermal shield is also indirectly cooled by two-phase liquid nitrogen circulating in a tracing tube. The 4.5 K coil together with its support cylinder weighs 3583 kg. It is supported by twenty-four radial supports and twenty-four axial supports. The supports are designed for electromagnetic de-centering forces of 63.7 kN radial and 122.3 kN axial in addition to a 3 g axial and radial acceleration load. The 80 K thermal shields are supported by eight cold mass supports against 3 g load. The detailed magnet and cryostat design and the design of cold mass support and the coil fabrication process will be discussed.         ATLAS superconducting toroids and solenoid    H.H.J. Kate Summary: The ATLAS particle detector in the Large Hadron Collider at CERN features a hybrid system of four superconducting magnets: a Central Solenoid surrounded by 2 End-cap Toroids and a Barrel Toroid. The magnet system dimensions are 20 m in diameter and 26 m in length. With its 1.55 GJ stored energy in air, it actually is the largest superconducting magnet in the world. The construction of the magnets has started in 1998 and will end in 2006 with the completion of the installation underground. Currently, in October 2004, practically all magnet parts are manufactured and delivered to CERN for final integration. The first two out of 8 full size 25/spl times/5 m/sup 2/ size coils for the Barrel Toroid have been completed and tested while the other 6 are near to completion as well. The production of the so-called End-Cap Toroids is progressing well. The Central Solenoid is complete and ready for installation. The installation underground of the entire system including its services has commenced. In the paper the main features of the magnets, their common infrastructure and services are reviewed and the status of realization presented.         First full-size ATLAS barrel toroid coil successfully tested up to 22 kA at 4 T    A. Dudarev, J.J. Rabbers, C.P. Berriaud, S. Junker, R. Pengo, S. Ravat, L. Deront, E. Sbrissa, G. Olesen, M. Arnaud, J.-M. Rey, P. Vedrine, F. Broggi, G. Volpini, A. Foussat, Ph. Benoit, V. Stepanov, A. Olyunin, I. Shugaev, N. Kopeykin and H.H.J. Kate Summary: The Superconducting Barrel Toroid is providing (together with the two End-Cap Toroids not presented here) the magnetic field for the muon detectors in the ATLAS Experiment at the LHC at CERN. The toroid with outer dimensions of 25 m length and 20 m diameter, is built up from 8 identical racetrack coils. The coils with 120 turns each are wound with an aluminum stabilized NbTi conductor and operate at 20.5 kA at 3.9 T local field in the windings and is conduction cooled at 4.8 K by circulating forced flow helium in cooling tubes attached to the cold mass. The 8 coils of 25 m /spl times/ 5 m are presently under construction and the first coils have already been fully integrated and tested. Meanwhile the assembly of the toroid 100 m underground in the ATLAS cavern at CERN has started. The 8 coils are individually tested on surface before installation. In this paper the test of the first coil, unique in size and manufacturing technology, is described in detail and the results are compared to the previous experience with the 9 m long B0 model coil.         Electrical characterization of S/C conductor for the CMS solenoid    P. Fabbricatore, M. Greco, R. Musenich, S. Farinon, F. Kircher and B. Cure Summary: The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. The coil is wound from 20 high purity aluminum-stabilized NbTi conductors with a total length of 45 km. The main peculiarity of the CMS magnet among other existing thin detector solenoids is its sandwich-type aluminum-stabilized superconductor. This special feature was chosen in order to have a mechanically self-supporting winding structure. We measured the critical current of all the 21 finished conductors in fields up to 6 T using the Ma.Ri.S.A. test facility at INFN-Genova. We compare these results with the critical current of single strands measured by CEA-Saclay, extracted from the conductor after the co-extrusion. A comparison among the measurements provides information about the possible critical current degradation and assures an accurate quality control of the conductor production. We also qualified the method used for making the joints between the layers within a single module and between the five modules and the bus bars. Measurements on both round and straight TIG-welded samples were carried out, in Genova and at CEA-Saclay, respectively.         The mechanical and thermal design for the MICE coupling solenoid magnet    M.A. Green, S.Q. Yang, U. Bravar, W. Lau, D. Li, B.P. Strauss, S.P. Vorostek and H. Witte Summary: The MICE coupling solenoids surround the RF cavities that are used to increase the longitudinal momentum of the muon beam that is being cooled within MICE. The coupling solenoids will have a warm-bore diameter of 1394 mm. This is the warm bore that is around the 200 MHz RF cavities. The coupling solenoid is a single superconducting coil fabricated from a copper matrix Nb-Ti conductor originally designed for MRI magnets. A single coupling magnet is designed so that it can be cooled with a single 1.5 W (at 4.2 K) cooler. The MICE cooling channel has two of these solenoids, which will be hooked together in series, for a magnet circuit with a total stored-energy of the order of 12.8 MJ. Quench protection for the coupling coils is discussed. This report also presents the mechanical and thermal design parameters for this magnet, including the results of finite element calculations of mechanical forces and heat flow in the magnet cold mass.         ATLAS superconducting solenoid on-surface test    R.J.M.Y. Ruber, Y. Makida, L. Deront, Y. Doi, T. Haruyama, F. Haug, M. Kawai, T. Kondo, Y. Kondo, S. Mizumaki, G. Olesen, O.V. Pavlov, M. Pezzetti, O. Pirotte, E. Sbrissa, H.H.Jt. Kate and A. Yamamoto Summary: The ATLAS detector is presently under construction as one of the five LHC experiment set-ups. It relies on a sophisticated magnet system for the momentum measurement of charged particle tracks. The superconducting solenoid is at the center of the detector, the magnet system part nearest to the proton-proton collision point. It is designed for a 2 Tesla strong axial magnetic field at the collision point, while its thin-walled construction of 0.66 radiation lengths avoids degradation of energy measurements in the outer calorimeters. The solenoid and calorimeter have been integrated in their common cryostat, cooled down and tested on-surface. We review the on-surface set-up and report the performance test results.         Search of short circuits in the Superconducting coils of the ATLAS detector    E. Acerbi, G. Baccaglioni, G.C. Cartegni, M. Sorbi and G. Volpini Summary: The detection of a short circuit inside the superconducting coils of the ATLAS detector after their installation in the casing is mandatory for the mechanical and electrical safety during a fast discharge of the magnet. The detection of a short circuit by means of a capacitor discharge becomes very difficult once the coils are integrated inside the casing, which behaves as a short-circuited turn strongly coupled with the coils. Under these circumstances a preliminary and careful analysis of the electrical parameters of the electrically coupled system and of the discharge behavior is required in order to clearly detect a short circuit. The paper presents and discusses the results of the analysis and the measurements carried out on the 16 double pancakes of the ATLAS Barrel Toroid after their integration inside the casing.         Availability and failure modes of the BaBar Superconducting solenoid    M. Knodel, A. Candia, W. Craddock, E. Thompson, M. Racine and J.G. Weisend Summary: A 1.5 T thin superconducting solenoid has been in operation as part of the BaBar detector since 1999. This magnet is a critical component of the BaBar experiment. A significant amount of magnet operating experience has been gathered. The average availability of this magnet currently approaches 99 percent. This paper describes the historical frequency and modes of unplanned magnet ramp downs and quenches. It also describes steps that have been taken to mitigate these failure modes as well as planned future improvements.         Feasibility study of large combined function magnets for the Jefferson lab 12 GeV upgrade    P.D. Brindza, J.J. LeRose and E.M. Leung Summary: The 12 GeV upgrade at Jefferson Lab has identified two new large spectrometers as Physics detectors for the project. The first is a 7.5 Gev/c 35 m-sr. spectrometer that requires a pair of identical Combined Function Superconducting Magnets (CFSM) that can simultaneously produce 1.5 T dipole fields and 4.5 T/m quadrupole fields inside a warm bore of 120cm. The second is an 11 GeV/c 2 m-sr. spectrometer that requires a CFSM that simultaneously produces a dipole field of 4.0 T and a quadruple field of 3.0 T/m in a 60 cm warm bore. Magnetic designs using TOSCA 3D have been performed to realize the magnetic requirements, provide 3d fields for optics analysis and produce field and force information for the engineering feasibility of the magnets. A two-sector cos(/spl theta/)/cos(2/spl theta/) design with a low nominal current density, warm bore and warm iron design has been selected and analyzed. These low current densities are consistent with the limits for a cryostable winding. The current paper will summarize the requirement definition of these two magnets. The conceptual design arrived at during the feasibility study involving the choice of conductors, thermal and structural analyses will be presented. A discussion of the manufacturing approach and challenges will be provided.         An HTS insert for phase 2 of a 3-phase 1-GHz LTS/HTS NMR magnet    Haigun Lee, E.S. Bobrov, J. Bascunan, Seung-Yong Hahn and Y. Iwasa Summary: As a component of Phase-2 LTS/HTS NMR magnet of a 3-phase program to complete a 1-GHz LTS/HTS NMR magnet by 2009, an HTS insert magnet has been assembled from 48 double-pancake (DP) coils, each wound of high-strength Bi-2223/Ag/stainless steel composite tape. The paper describes the design and actual parameters; and preliminary performance results of the insert. The results include: 1) voltage vs. current data of double pancakes; and 2) splice resistances between adjacent double-pancake coils.         A 3 T magnet system for MAGNUM-PSI    H.J.N. van Eck, A. den Ouden, G.J. van Rooij, W.J. Goedheer, B. de Groot, N.J.L. Cardozo and A.W. Kleyn Summary: The FOM-Institute for Plasma Physics is preparing the construction of Magnum-psi, a magnetized (3 T), steady-state, large area (100 cm/sup 2/), high-flux (up to 10/sup 24/ H/sup +/ ions m/sup -2/s/sup -1/) plasma generator. Magnum-psi will be used to study plasma-surface interaction in conditions similar to those in the divertor of ITER and fusion reactors beyond ITER. The active magnetic field region is required to be 4 meter long, 1 meter diameter and steady state. This, together with the need for minimization of the running costs, makes the application of superconducting coils imperative. The magnet system will be unique because of its maximum transparency to provide optimal radial access to the experimental region inside the magnet bore. In this contribution we present a magnet configuration that consists of 5 cylindrical, conduction cooled NbTi coils. These generate an axial field of 3 T with a maximum field on the coils below 6 T. Two cryogenic structures are proposed: the discrete coils are either placed within separate cryostats or are supported by a single cylinder in a shared cryostat with 32 room temperature view ports. Room temperature iron rings close to the outer coils reduce the axial forces that would otherwise put severe constraints on the mechanical structure. The field will most probably be passively shielded by an iron dome at 2 meters from the cryostat.         805 MHz high power input coupler for SRF cavity in a RIA cryomodule    Quan-Sheng Shu, J. Susta, Guangfeng Cheng, T.L. Grimm, J. Popielarski, W. Hartung, S. Einarson and T.A. Treado Summary: The Rare Isotope Accelerator uses 805 MHz superconducting rf cavities in the linac. Power is transmitted capacitively into the cavities via a high power input coupler. The coupler was designed for greater than 10 kW cw with a VSWR less than 1.05. The design load to the 2 K liquid helium is less than 2 W. The external Q of the coupler is about 2/spl times/10/sup 7/. The couplers were conditioned off-line to over 200 kW pulsed before installation into a prototype cryomodule. The cryomodule was tested at 2 K to full accelerating gradients. Multipacting barriers in the coupler were quickly conditioned, and no arcs or discharges were observed during testing. Details of the power couplers performance will be presented.         Preliminary results of final test of the GHMFL 40 T hybrid magnet    A.B. Oliva, M.N. Biltcliffe, M. Cox, A. Day, S. Fanshawe, G. Harding, G. Howells, W. Joss, L. Ronayette and R. Wotherspoon Summary: The Grenoble High Magnetic Field Laboratory (GHMFL) has completed the development of a 40-T Hybrid Magnet System to support research in steady, high magnetic fields. Oxford Instruments Superconducting has carried out the design, development and construction of the superconducting outsert system for the hybrid magnet. The superconducting magnet has been successfully tested in steady conditions on its own in a bucket-dewar at 2.8 K and at fields up to 7 T. Subsequently, the magnet has then been assembled in its cryostat in Grenoble in its final position. The magnet has been cooled down to 1.8 K and an additional test is being carried out. The resistive magnet is presently being assembled. A description of the system, its manufacture processes and main test results obtained so far will be presented.         Superconducting systems for MRI-present solutions and new trends    Y. Lvovsky and P. Jarvis Summary: Over the past two decades, magnetic resonance imaging (MRI) has developed into a mature technology, and is the leading commercial large-scale application of superconductivity. This is still a rapidly evolving field, characterized by constantly emerging configurations requiring innovative technical solutions, with trends toward increasing field strength B/sub 0/ and more advanced magnetic, cryogenic and integrated system design. This paper describes the main technical approaches and challenges in MRI superconducting electromagnetic design, trade-offs in the magnet parametric design space and their effect on the superconducting design. Recent trends, advanced novel configurations and different applications are discussed. The trend toward higher fields manifests itself in the ongoing shift of clinical applications to 3 T, as well as in recent developments of whole-body MRI with field strength up to 9.4 T. Illustrations are presented from commercial and developing MRI systems.         High-T/sub c/ Superconducting receiving coils for nuclear magnetic resonance imaging    Hsu-Lei Lee, In-Tsang Lin, Jyh-Horng Chen, Herng-Er Horng and Hong-Chang Yang Summary: Nuclear magnetic resonance (NMR) microscopy poses high demands on the sensitivity of the receiver coils. We have developed high-T/sub c/ superconducting (HTS) tape receiving coils for nuclear magnetic resonance imaging. The surface receiver coil is constructed from high-T/sub c/ Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub y/ tape coil and cooled in liquid nitrogen temperature. The desired receiver surface coil is numerically simulated and optimized to have high value of the unloaded quality factor. With this HTS receiver coil we have obtained significant improvement in the unloaded Q-value, loaded Q-value and substantial gain in signal-to-noise ratio (SNR). The SNR improvement of 2.4 was achieved in the kiwi imaging and improvement of 2.7 in the braining imaging of rat at 300 K. The MRI microscopy is tested and compared the results with copper receiver.         Operation of a 930-MHz high-resolution NMR magnet at TML    T. Kiyoshi, S. Matsumoto, A. Sato, M. Yoshikawa, S. Ito, O. Ozaki, T. Miyazaki, T. Miki, T. Hase, M. Hamada, T. Noguchi, S. Fukui and H. Wada Summary: A 920-MHz high-resolution NMR spectrometer has been operating at the Tsukuba Magnet Laboratory (TML) since April 2002. It has proved its effectiveness by determining the 3-D structures of protein molecules. To accelerate studies in structural biology and solid-state NMR, a second high-field NMR magnet was developed and installed at TML. Although its basic design was the same as that of the first magnet, some improvements were made. For the innermost coil, a 16%Sn-bronze-processed (Nb,Ti)/sub 3/Sn conductor was employed. The increase in the critical current density above that of a 15%Sn-bronze-processed (Nb,Ti)/sub 3/Sn conductor made it possible to reduce the conductor size from 3.5 mm /spl times/ 1.75 mm in the first magnet to 2.80 mm /spl times/ 1.83 mm in the second. At the same operating current of the first magnet, the second magnet is expected to operate at 930 MHz. The liquid helium reservoir and the superfluid helium cooler, which were separated in the first system, were united in the same chamber in the new magnet. The latter magnet was energized up to 21.9 T without quenching in March 2004 and has operated in a persistent-mode at that field. It will be utilized mainly for solid-state NMR measurements.         Performance of the ultra wide bore 900 MHz NMR magnet at the national high magnetic field laboratory    I.R. Dixon, W.D. Markiewicz, W.W. Brey and K.K. Shetty Summary: A 900 MHz NMR magnet with a room temperature, clear bore of 105 mm was recently brought to full field at the NHMFL. The magnet was ramped to 21.1 T on its first run without incurring a quench, since installation into its final cryostat was completed. Issues on superconductor stability were present during magnet charging and are discussed. In addition, the magnet performance in terms of field uniformity and of field stability, with the implementation of a novel design concept of current injection, is presented.         Characteristics of a persistent current compensator for Superconducting NMR magnets using linear type magnetic flux pump    Yoon Do Chung, I. Muta, T. Hoshino and T. Nakamura Summary: This paper describes the characteristics of a linear type magnetic flux pump for compensating current in a superconducting coil with 10 A operating current. The linear type flux pump has been fabricated to use for compensating persistent current decay of HTS applications such as NMR and MRI systems. Pumping current of the linear type magnetic flux pump mainly can be controlled by frequency of AC current. In the experiment, it has been demonstrated that the linear type magnetic flux pump can effectively charge and discharge the current in the load coil of 543 mH for various frequencies with the DC bias of 10 A and the AC of 5 A/sub rms/. Moreover, experimental results of temperature distribution of a slow response PCS have been compared with simulation.         Superconducting 250 MeV proton Cyclotron for cancer treatment    A. Geisler, C. Baumgarten, A. Hobl, U. Klein, D. Krischel, M. Schillo and J. Timmer Summary: Starting in 2001 ACCEL Instruments GmbH has designed a superconducting cyclotron in collaboration with the National Superconducting Cyclotron Laboratory (NSCL), Michigan, USA, for proton therapy. This design is based on a proposal from NSCL from 1993. Currently two cyclotrons have been built, tested with respect to magnetic and cryogenic performance and delivered to the customer's site. Important issues taken into account when building a machine for medical use as well as design features, operating parameters and results from the in-house tests are presented.         Preparation of the ITER poloidal field conductor insert (PFCI) test    R. Zanino, S. Egorov, K. Kim, N. Martovetsky, Y. Nunoya, K. Okuno, E. Salpietro, C. Sborchia, Y. Takahashi, P. Weng, M. Bagnasco, L.S. Richard, M. Polak, A. Formisano, E. Zapretilina, A. Shikov, G. Vedernikov, D. Ciazynski, L. Zani, L. Muzzi, M. Ricci, A. della Corte, M. Sugimoto, K. Hamada, A. Portone, F. Hurd, N. Mitchell, A. Nijhuis and Yu. Ilyin Summary: The Poloidal Field Conductor Insert (PFCI) of the International Thermonuclear Experimental Reactor (ITER) has been designed in the EU and is being manufactured at Tesla Engineering, UK, in the frame of a Task Agreement with the ITER International Team. Completion of the PFCI is expected at the beginning of 2005. Then, the coil shall be shipped to JAERI Naka, Japan, and inserted into the bore of the ITER Central Solenoid Model Coil, where it should be tested in 2005 to 2006. The PFCI consists of a NbTi dual-channel conductor, almost identical to the ITER PF1 and PF6 design, /spl sim/45 m long, with a 50 mm thick square stainless steel jacket, wound in a single-layer solenoid. It should carry up to 50 kA in a field of /spl sim/6 T, and it will be cooled by supercritical He at /spl sim/4.5 K and /spl sim/0.6 MPa. An intermediate joint, representative of the ITER PF joints and located at relatively high field, will be an important new item in the test configuration with respect to the previous ITER Insert Coils. The PFCI will be fully instrumented with inductive and resistive heaters, as well as with voltage taps, Hall probes, pick-up coils, temperature sensors, pressure gauges, strain and displacement sensors. The test program will be aimed at DC and pulsed performance assessment of conductor and intermediate joint, AC loss measurement, stability and quench propagation, thermal-hydraulic characterization. Here we give an overview of the preparatory work toward the test, including a review of the coil manufacturing and of the available instrumentation, a discussion of the most likely test program items, and a presentation of the supporting modeling and characterization work performed so far.         Test results of the ITER PF insert conductor short sample in SULTAN    P. Bruzzone, M. Bagnasco, D. Bessette, D. Ciazynski, A. Formisano, P. Gislon, F. Hurd, Y. Ilyin, R. Martone, N. Martovetsky, L. Muzzi, A. Nijhuis, H. Rajainmaki, C. Sborchia, B. Stepanov, L. Verdini, R. Wesche, L. Zani, R. Zanino and E. Zapretilina Summary: A short sample of the NbTi cable-in-conduit conductor (CICC) manufactured for the ITER PF insert coil has been tested in the SULTAN facility at CRPP. The short sample consists of two paired conductor sections, identical except for the sub-cable and outer wraps, which have been removed from one of the sections before jacketing. The test program for conductor and joint includes DC performance, cyclic load and AC loss, with a large number of voltage taps and Hall sensors for current distribution. At high operating current, the DC behavior is well below expectations, with temperature margin lower than specified in the ITER design criteria. The conductor without wraps has higher tolerance to current unbalance. The joint resistance is by far higher than targeted.         DC performances of ITER NbTi conductors: models vs. measurements    D. Ciazynski, D. Bessette, P. Bruzzone, N. Martovetsky, B. Stepanov, R. Wesche, L. Zani, R. Zanino and E. Zapretilina Summary: Within the R&D program on the International Thermonuclear Experimental Reactor (ITER) Poloidal Field (PF) coils, a full size conductor sample was tested in the SULTAN facility (CRPP Villigen, Switzerland). This sample is composed of two straight ITER-like cable-in-conduit conductors, using the same NbTi strand. The two conductors are identical except that one leg has a cable containing steel wraps around the main subcables as in the ITER design, while the other has no wraps inside. The paper presents conductor DC test results compared to predictions given by various models developed within ITER-associated laboratories. These models aim to predict the DC behavior of the cable from the experimental performances of the single strand. They have to explain the observed voltage-current (V-I) or voltage-temperature (V-T) characteristics, including the thermal runaways. The lower experimental performances compared to all expectations have shown the necessity to revise the models and to introduce a possible uneven current distribution among the strands of the cables.         Effect of cyclic loading and conductor layout on contact resistance of full-size ITER PFCI conductors    Yu.A. Ilyin, A. Nijhuis, W. Abbas, P. Bruzzone, B. Stepanov, L. Muzzi, P. Gislon and L. Zani Summary: An evolution of the contact resistances (R/sub c/) of two full-size ITER (International Thermonuclear Experimental Reactor) cable-in-conduit conductors (CICC) aimed for the Poloidal Field Conductor Insert (PFCI) was studied in the Twente Cryogenic Press. The conductors are distinguished by the presence of stainless steel wraps around the last stage sub-cables in one of the conductors. The R/sub c/ and AC loss were measured on the conductors being in the "virgin" state and after they have been loaded 40,000 times with a peak force of 315 kN/m. The test results are compared with those, obtained on sections from the same conductor lengths, in the SULTAN test facility. The consequences of the cyclic loading and the sub-cable wraps on the R/sub c/ and the coupling AC loss are discussed in view of the previously published results on full- and sub-size ITER NbTi CICCs. Special emphasis was paid to the measurements of the contact resistances between individual sub-cables and the conduit, since the knowledge of them is important for proper interpretation of the DC test results. As a final goal, the test outcome will be used as a reference for calibration of the PFCI AC loss performance.         Rapid normal zone propagation observed in a 13 T-46 kA Nb/sub 3/Al cable-in-conduit conductor    N. Koizumi, K. Matsui, E. Kume and K. Okuno Summary: A quench test of a 13 T and 46 kA Nb/sub 3/Al cable-in-conduit conductor was performed. Thermo-hydraulic quench back (THQB) was observed clearly for the first time in a large magnet when the temperature was set at 0.5 K lower than the current sharing temperature and normal zone propagation velocity reached 70 m/s. These results suggest possibility of the THQB should be considered in a design of a large magnet system in case that the operating temperature is considerably close to the current sharing temperature. Calculation results by one-dimensional stability and quench simulation code are compared with the experiment. Although the calculation results show some discrepancy with the experiment they support the conclusion that the THQB took place. Some improvements of the model seem necessary.         Effect of conduit material on CICC performance under high cycling loads    N.N. Martovetsky, P. Bruzzone, B. Stepanov, R. Wesche, Chen-Yu Gung, J.V. Minervini, M. Takayasu, L.F. Goodrich, J.W. Ekin and Arend Nijhuis Summary: Recent International Thermonuclear Experimental Reactor (ITER) Model Coils and tests on Nb/sub 3/Sn Cable in Conduit Conductors (CICC) showed a significant and unexpected increase in the broadness of the transition to the normal state, resulting in degradation of superconducting properties. To investigate these phenomena, two CICC samples were built with identical 144 strand cables but different conduit materials. One sample had titanium conduit with low coefficient of thermal expansion, the other had stainless steel conduit. The purpose of this experiment was to study changes in strand properties in the cable (critical current, current sharing temperature, n-value), the effects of cycling and high electromagnetic load, and the effect of the conduit on the CICC performance.         Transverse stress effects in ITER conductors    J.H. Schultz, L. Chiesa, D.L. Harris, P.J. Lee, J.V. Minervini, B.J. Senkowicz, M. Takayasu and P. Titus Summary: The International Thermonuclear Experimental Reactor (ITER) Central Solenoid and Toroidal Field Model Coils (CSMC, TFMC) and the CSMC Insert Coils using Nb/sub 33/Sn had unexpectedly low current-sharing temperatures and cable "n-values." This paper argues that the anomalous effects can be explained by the high longitudinal strain due to transverse Lorentz loads. Simulated results of earlier experiments with A15 monoliths indicate that the transverse stress "multiplier" is actually a longitudinal strain multiplier due to transverse loading. Irreversible cyclic degradation effects in the cables with the lowest thermal contraction mismatches are explained by showing that a modest precompression is required to prevent tensile cracking of a significant number of individual filaments. Examination of filament breakage due to bending shows the possibility of a well-defined threshold for irreversible damage.         Status of the KSTAR PF6 and PF7 coil development    K. Park, W. Chung, S. Baek, B. Lim, S.J. Lee, H. Park, Y. Chu, S. Lee, K.P. Kim, J. Joo, K. Lee, D. Lee, S. Ahn, Y.K. Oh, K. Kim, J.S. Bak and G.S. Lee Summary: The KSTAR superconducting magnet system consists of 16 TF (Toroidal Field) and 14 PF (Poloidal Field) coils. Both of the TF and PF coil systems use internally-cooled Cable-In-Conduit Conductors (CICC). The PF coil system, which consists of 8 coils in the CS (Central Solenoid) coil system and 6 outer PF coils, provides 17 V-s and sustains the plasma current of 2 MA for 20 seconds inductively. PF 1-5 coils use Nb/sub 3/Sn CICC in an Incoloy 908 conduit and PF 6-7 coils use NbTi CICC in a modified stainless steel 316LN(316LN+). The fabrication of PF7L/U & PF6L/U coils is completed at present. The engineering issues and fabrication process, which are related with the KSTAR PF 6-7 coil development, are presented and discussed in this paper. TF and PF coils are in the fabrication stage for KSTAR completion in the year 2006.         Design and manufacture of a full size joint sample (FSJS) for the qualification of the poloidal field (PF) insert coil    F.H. Hurd, C. Sborchia, E. Salpietro, D. Duglue, C. Keefe, S. Bates, P. Pesenti, A. della Corte, P.L. Bruzzone and M. Polak Summary: Within the framework of the European Fusion Programme a FSJS has been designed and manufactured by European Industry using PF coil NbTi superconductor manufactured and supplied by the Russian Federation as part of the R&D for the PF Conductor Insert (PFCI) coil. In addition to the superconductor, this sample contains a number of unique features. In contrast to other samples previously manufactured in Europe, the FSJS has used the Central Solenoid Model Coil (CSMC) joint design with NbTi conductor and a thick square jacket. One leg of the FSJS has had the conductor and sub-petal steel wraps removed before jacketing to assess the difference in the conductor performances between the two configurations. This paper will report on the development and manufacture of the FSJS, in particular the use of the Central Solenoid jacketing and swaging tools for compaction of the conductor and swaging of the joints, the preparation and qualification of the manufacturing route for the joint, the jacketing of a special length without conductor wraps and the high level of instrumentation required for the testing of the joint. The sample has been instrumented with more sensors than any other previous European sample, including temperature sensors, a large number of voltage taps for quench detection and Tcs measurements, quadrupoles to detect uneven voltage distribution, hall arrays for current distribution measurements and saddle coils.         Pressure drop of the ITER PFCI cable-in-conduit conductor    C. Marinucci, P. Bruzzone, A. della Corte, L.S. Richard and R. Zanino Summary: Pressure drop in the ITER PFCI cable-in-conduit conductor (CICC) has been measured at CRPP using pressurized water at room temperature. The PFCI conductor is a dual channel CICC and the coolant flows in parallel in the central channel and in the annular bundle region. In our experiment the flow in the central channel is blocked and the longitudinal friction factor of the annular bundle region is deduced from measurements of pressure drop and mass flow rate. Two conductor samples are investigated, one with and one without subcable/outer cable wraps. The results show that the wraps have a negligible effect on the friction factor, and that the Katheder correlation overestimates the actual friction factor.         The FBI Facility-a test rig for critical current measurements on CICC as a function of strain    A. Vostner, E. Salpietro, K.P. Weiss, W.H. Fietz, A. della Corte and L. Muzzi Summary: One of the most important characteristics of Nb/sub 3/Sn strands is the strain dependence of the critical current density which has to be taken into account for every conductor design, especially for cable-in-conduit conductors (CICC) due to the additional influence of the jacket material. Therefore, a task has been launched in the framework of the European Fusion Technology Program to determine the residual thermal strain of single strands and different multi-stage conductors on absolute scale which is essential for the final optimization of the ITER TF conductor. For this purpose, an existing test rig for critical current measurements on single strands and multi-stage CICC as a function of strain and field, the FBI facility at the Forschungszentrum Karlsruhe, has been recently modified and modernized to improve the overall accuracy and resolution of the system. After a description of the facility, its capabilities and the recently performed upgrades, this paper explains the scheduled test program and the strategy to assess the impact of the cable pattern and size on the residual thermal strain. Results on Nb/sub 3/Sn strands jacketed in stainless steel are presented as well.         Reconstruction of current unbalance in full-size ITER NbTi CICC by self-field measurements    Yu.A. Ilyin, A. Nijhuis, H.H.Jt. Kate, P. Bruzzone and B. Stepanov Summary: Methods have been developed to study the distribution of the transport current among the strand bundles of cable-in-conduit conductors (CICC) by using self-field measurements with Hall probe arrays. The unbalance in the transport current is mainly caused by the unavoidable nonuniformity of the joints and can be a reason for a change in the voltage-temperature characteristic and consequently of the temperature margin. In the present study we focus on the reconstruction of the current unbalance in a full size NbTi CICC tested in the SULTAN test facility. The crucial point in the reconstruction procedure is the proper choice of the reference self-field profile corresponding to a uniform current distribution. To achieve this uniform distribution, the conductors were driven far into the current sharing regime. The self-field profile corresponding to the highest achieved voltage level was taken as a reference. This assumption is supported by the modeling of current-sharing runs in the CUDI-CICC network model. Furthermore, local redistribution effects were observed in the conductors at high currents. The current transfer associated with this redistribution is analyzed as well.         Quench detection using pick-up coils for the ITER central solenoid    Y. Takahashi, K. Yoshida and N. Mitchell Summary: At least two independent methods for quench detection should be used for the magnets of the ITER size, because of the potential severe impact of a failure. The voltage tape method and the flow meter method, which were used in the CS model coil (CSMC), are both considered for the ITER Central Solenoid (CS). The voltage tap method is primary due to its quick response. The ITER CS consists of six pancake wound modules, which are operated with individual operating current patterns in ac mode. The induced voltage in the windings must be compensated to detect the voltage due to any normal transition during the pulse operation. We have investigated the optimum configuration for pick-up coils (PC) for compensation. The results of simulations show that the compensated voltages are very low (70 mV) compared with the inductive voltage and adequate normal voltage sensitivity is obtained. The hot spot temperature in the CS during the operation was estimated from the simulation and the experimental measurements of the CSMC quench. The hot spot temperature estimated is 128-144 K, lower than the ITER design criterion (150 K). It is shown that the detection system using the PCs could be designed with a high enough detection sensitivity.         Effective resistance of the HTS floating coil of the mini-RT project    N. Yanagi, T. Mito, T. Hemmi, K. Seo, J. Morikawa, Y. Ogawa and M. Iwakuma Summary: A magnetically levitated superconducting coil device, Mini-RT, has been constructed using high temperature superconductors for the purpose of examining a new magnetic confinement scheme of high-beta plasmas. The floating coil is wound with Bi-2223/Ag tapes, and it is operated in the temperature range of 20-40 K. The excitation tests of the coil were carried out and persistent current was sustained for magnetic levitation. The decay time constant of the persistent current was measured and the effective resistance of the coil cables was evaluated. The obtained resistance shows a considerable increase than that predicted by the n-value model. This might be caused by some electromagnetic effects such as the loss generation with long-lived shielding currents. This consideration was examined by measuring the magnetization of an HTS sample coil.         DC performance analysis of NbTi and Nb/sub 3/Sn ITER relevant cable-in-conduit conductors    D. Bessette Summary: A model has been developed to analyze the DC performance of NbTi and Nb/sub 3/Sn Cable in Conduit Conductor (CICC) tested in the Sultan facility at CRPP Villigen-Switzerland. The voltage distribution along the conductor is reconstructed from the local electric field appearing on each of the cable strands as a function of temperature and magnetic field. The local heating due to the operation in the current-sharing regime is included as a heat load. The forced flow of helium is simulated by a time dependent 1-D compressible flow. The model is used for predictive s that are then compared to the experimental results of both NbTi and Nb/sub 3/Sn conductor short sample tests. The simulated tests include both ramping of the sample current at constant inlet temperature (I/sub c/ test) and ramping of the inlet temperature at constant current (T/sub cs/ test).         Current distribution measurement on the ITER-type NbTi bus bar III    R. Zanino, M. Bagnasco, F. Bellina, T. Bonicelli, A. della Corte, A. Di Zenobio, W.H. Fietz, A. Formisano, R. Heller, Y. Ilyin, V. Marchese, R. Martone, L. Muzzi, A. Nijhuis, M. Polak, P.L. Ribani, E. Salpietro, L.S. Richard, S. Turtu', L. Verdini and G.R. Zahn Summary: The Bus Bar III (BBIII), fabricated within the Toroidal Field Model Coil Task of the International Thermonuclear Experimental Reactor (ITER), was tested at the Forschungszentrum Karlsruhe, Germany, in the spring of 2004. The BBIII consists of an approximately 7 m long NbTi dual-channel conductor with a thick square stainless steel jacket, cooled by forced flow supercritical He. It was energized with currents up to 80 kA and operates in its self magnetic field (up to /spl sim/0.8 T). The BBIII was instrumented with Hall-probe heads and arrays, voltage rings and longitudinal voltage taps for electro-magnetic measurements, in order to get experimental data to be used for the validation of a recently developed hybrid thermal-hydraulic electro-magnetic code (THELMA), as well as for the assessment of the possibility of performing a reliable reconstruction of the current distribution in the conductor cross section under controlled conditions. In the tests, current ramps at different rates were applied to characterize the conductor time constants, while two different resistive heaters (one upstream of the BBIII inlet, another one directly on the BBIII jacket) were separately operated in order to approach current sharing in the conductor and to observe the related current re-distribution. In this paper, a summary of the collected experimental results is presented, with particular emphasis on those aspects more relevant for the forthcoming THELMA analysis.         Thermo-hydraulic analysis of the KSTAR central solenoid model coil    Wooho Chung, Soohwan Park, Qiuliang Wang, Sangkwon Jeong, Cheon Seog Yoon, Yeong-Kook Oh, Keeman Kim, Joo Shik Bak and G.S. Lee Summary: The Korea Superconducting Tokamak Advanced Research (KSTAR) Central Solenoid Model Coil (CSMC) has been developed to validate the design of KSATR CS coil. The thermo-hydraulic characteristics were analyzed for the KSTAR CSMC. The major thermo-hydraulic parameters of the coil are AC losses, strand temperature, coolant temperature, pressure drop and temperature margin. A numerical code has been developed for the thermo-hydaulic analysis of the KSTAR CSMC according to the operating conditions. In this paper, the description of the thermo-hydraulic analysis models and analysis results of CSMC are presented. The total energy deposition due to AC losses in CSMC winding will induce a flow reversal of supercritical helium. The minimum temperature margin is estimated approximately 0.5 K. The maximum temperature in CSMC winding is about 7.6 K.         Jacketing and repair of the KSTAR CICC    B.S. Lim, J.Y. Choi, C.S. Kim, H.T. Park, H.K. Park, S.I. Lee, W. Chung, Y. Chu, K. Pak, Y.K. Oh, K. Kim, J.S. Bak, Y. Suh, C.S. Yoon and S.Y. Kim Summary: The KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting magnet system which consists of 16 TF coils and 14 PF coils adopts a superconducting CICC (Cable-In-Conduit Conductor) type conductor. The KSTAR magnet system uses two different types of CICCs-Nb/sub 3/Sn cable with Incoloy 908 conduit and NbTi cable with 316LN stainless-steel conduit. A continuous CICC jacketing system is developed for the KSTAR CICC fabrication and the jacketing system uses the tube-mill process. It consists of forming, welding, sizing and squaring procedures. The welding condition of CICCs and the fabrication process is described. The repair of the CICC is also discussed.         Measurement of residual magnetic field by superconducting magnets of the LHD    S. Imagawa, K. Takahata, N. Yanagi and T. Mito Summary: After irregular excitations of superconducting magnets of the Large Helical Device, the residual magnetic field prevents uniform glow discharging in a plasma vacuum vessel. In order to measure the changes of residual field, fifteen Hall probes were installed at five periodic positions in three directions on the mid-plane of the inner cylinder of the cryostat. After the first excitation of the magnets in the cooling cycle, the residual field was changed by 0.1 mT at all positions. The direction was the same as the field during the excitation. After the excitation without helical coils, the residual field was clearly changed. During warm-up of the superconducting magnets, the additional residual field disappeared at the same time of the transition to a normal state. The additional residual field can be induced by magnetization of the superconducting magnets. The magnetic field by magnetization of NbTi filaments in the magnets has been calculated and compared with the measured data.         AE measurement of the LHD helical coils    T. Ishigohka, T. Tsuchiya, Y. Adachi, A. Ninomiya, N. Yanagi, K. Seo, H. Sekiguchi, S. Yamada, S. Imagawa and T. Mito Summary: The authors have measured AE signals from the helical coils of the LHD (Large Helical Device) system at NIFS (National Institute of Fusion Science, Gifu, Japan) in order to monitor the state of the superconducting coils. Four AE sensors are attached on the surface of the vessel containing the helical coils, and preamplifiers are installed close to the sensors in the area with a leakage magnetic field of about 0.02 T. The measuring system is remotely controlled by PC's via a LAN system. The AE signals are recorded and analyzed. Their relation with the balance voltage signal of the coil has been investigated. The obtained experimental result shows that (1) the AE signals have been successfully recorded despite the leakage magnetic field on preamplifier, (2) the AE signal shows a good correlation with the balance voltages, (3) the AE signal is observed only when the excitation current is changing, (4) the pattern of the observed AE signal is stable for each excitation pattern.         Conceptual design of a Superconducting 30 T solenoid using wire-in-conduit conductors    T.A. Painter Summary: A conceptual design is presented for a distributed reinforcement conductor that enables the use of presently available, high current density, round cross-sectional wire for high field superconducting magnets. One of the disadvantages of providing separate structural reinforcement on the outer diameter of layer wound coils is the inherent thermal and mechanical stresses developed at the interface between the superconductor and reinforcement. This paper proposes a new concept, a single wire in conduit (WIC), for a distributed reinforcement conductor configuration which not only eliminates the problem of interface stresses, but introduces coolant directly to the superconducting wire where it will be more effective in providing a stable operating environment. The materials required for the proposed configuration are discussed and a conceptual design for a 30 T superconducting solenoid using the WIC conductor is described. The areas of WIC conductor technology requiring development and characterization are discussed.         Cryo-permanent magnets-geometry, magnetization and cost issues    M. Sander Summary: High trapped peak magnetic fields obtained for melt-textured 123-high-temperature superconductor (HTS) bulk cylinders, make these materials highly attractive for cryo-permanent magnets (CPMs). However, to transfer the proven performances of HTS materials into practical magnetic devices with magnetizations of /spl les/5 T over /spl ges/10 cm size, issues related to geometry, magnetization and cost have to be addressed. HTS ring structures appear to be more adequate than just cylindrical bulk parts but the demands for growing, shaping and assembling the HTS materials increase. A novel process is introduced to in-situ magnetize the HTS ring using pulsed copper coils. It involves the injection of an extra current which is induced by the magnetizing pulse field. This allows flux penetration into otherwise strongly shielded rings, and thus reduces the required peak magnetic field. Concepts for "medium-size" assembled structures and results of model calculations for corresponding magnetization processes are presented. Preliminary cost comparisons with winding-based solutions are given as well.         Components of thermal and electrical insulations for the superconducting magnet systems    V. Bondarenko, S. Egorov, E. Lamzin, V. Korsunsky, I. Rodin and N. Voronin Summary: The paper reports on new approaches to design the components of the thermal and electrical insulation for superconducting magnets by the example of manufacturing and testing of the superconducting Charging Coil for the Levitated Dipole Experiment facility (LDX C-Coil) and other devices.         Superconducting and resistive tilted coil magnets for generation of high and uniform transverse magnetic field    A.M. Akhmeteli, A.V. Gavrilin and W.S. Marshall Summary: Mathematical foundation is laid for a relatively new type of magnets generating uniform transverse magnetic field-tilted coil magnets. These consist of concentric nested coils with elliptical turns tilted at a certain angle to the central axis and current flowing in opposite directions in the coils tilted at opposite angles, generating a perfectly uniform transverse field. Both superconducting wire-wound and resistive Bitter tilted coils are discussed. An original analytical method is used to prove that the wire-wound tilted coils have the ideal distribution of the axial current density-"cosine-theta". To program coil fabrication tooling, a parametric description of the helical path of the conductor within a tilted coil is given. Magnetic fields are calculated for a tilted Bitter coil magnet using an original exact solution for current density in an elliptical Bitter disk.         Structure for an LHC 90 mm Nb/sub 3/Sn quadrupole magnet    A.R. Hafalia, S. Caspi, S.E. Bartlett, D.R. Dietderich, P. Ferracin, S.A. Gourlay, C.R. Hannaford, H. Higley, A.F. Lietzke, B. Lau, N. Liggins, S. Mattafirri, A.D. McInturff, M. Nyman, G.L. Sabbi, R.M. Scanlan and J. Swanson Summary: A full-scale mechanical model of the LHC Nb/sub 3/Sn quadrupole magnet structure has been designed, built and tested. The structure will support a 90 mm bore, lm long magnet prototype as part of the US LHC Accelerator Research Program (LARP). The structure utilizes Bladder and Key Technology to control and transfer pre-stress from an outer aluminum shell to an inner coil. Axial aluminum rods take care of pre-stress at the ends-ensuring that the coil is fully constrained along all three axes. The outer aluminum shell and an inner "dummy coil" (aluminum tube) were extensively instrumented with strain gauges. The gauges were used to monitor and map the effectiveness of the stress relation between the loading structure and a "dummy" coil through varying mechanical load conditions-from bladder and key pre-stress at room temperature through cool-down. Test results of the stress distribution in the structure and the in dummy coil is reported and compared with expected results calculated with the structural analysis program ANSYS.         Novel design for a Superconducting multipole corrector magnet    V.S. Kashikhin Summary: A novel concept of a superconducting, multipole corrector magnet is presented. This magnet is assembled from 12 identical racetrack-type coils powered by separate power supplies, and can generate any combination of dipole, quadrupole, and sextupole magnetic fields. In the case of normal dipole, quadrupole, and sextupole fields the total field is symmetrical relative to the magnet median plane and there are only five, powered separately coil groups. The new type of multipole corrector magnet, which has been proposed for BTeV project at Fermilab has the following advantages: universal configuration, simple manufacture, and a high mechanical stability. The results of the magnetic design, including the field quality and magnetic forces in comparison with known shell-type superconducting correctors, are presented.         Behavior of MgB2 react & wind coils above 10 K    R. Musenich, P. Fabbricatore, S. Farinon, C. Ferdeghini, G. Grasso, M. Greco, A. Malagoli, R. Marabotto, M. Modica, D. Nardelli, A.S. Siri, M. Tassisto and A. Tumino Summary: React & wind magnesium diboride pancake coils and solenoids were constructed and tested. The solenoids (6 layers) were manufactured by winding a single length of MgB/sub 2/ tape (80 m) onto a 15 cm diameter, 15 cm high mandrel. The pancake coils were manufactured starting from a 40 meter long tape: the conductor was wound onto a 12 cm diameter coil former. The magnets were tested both in liquid helium and conduction cooled in a cryogen free apparatus. The results compared with the tape characteristics are reported.         MgB/sub 2//Cu racetrack coil winding, insulating, and testing    M.D. Sumption, M. Bhatia, M. Rindfleisch, J. Phillips, M. Tomsic and E.W. Collings Summary: A racetrack coil using MgB/sub 2//Cu strand has been fabricated and tested for transport current density at 4.2 K in self field. The monofilamentary strand was 1.0 mm OD and insulated with S-glass braid. Eighty turns of strand (42 m) were wound onto a stainless steel former with outer dimensions 25 cm/spl times/10 cm/spl times/0.86 cm. The resulting racetrack coil was heat treated at 675/spl deg/C for 30 minutes in flowing Ar. The strand, with a superconducting fraction of 26%, occupied 49% of the total coil pack cross sectional area. The coil I/sub c/ at 4.2 K and self field was 120 A (using a 1 /spl mu/V/cm criterion). This led to a J/sub c,sc/ (across the whole coil) of 6.12/spl times/10/sup 4/ A/cm/sup 2/, a J/sub e/ in the wire of 1.59/spl times/10/sup 4/ A/cm/sup 2/, and an overall winding J/sub e/ of 7.9/spl times/10/sup 3/ A/cm/sup 2/ at 4.2 K in self field. The n-values ranged from 17 to 56.         Measured strain in Nb/sub 3/Sn coils during excitation and quench    S. Caspi, S.E. Bartlett, D.R. Dietderich, P. Ferracin, S.A. Gourlay, C.R. Hannaford, A.R. Hafalia, A.F. Lietzke, S. Mattafirri, M. Nyman and G. Sabbi Summary: The strain in a high field Nb/sub 3/Sn coil was measured during magnet assembly, cool-down, excitation and spot heater quenches. Strain was measured with a full bridge strain gauge mounted directly over the turns and impregnated with the coil. Two such coils were placed in a "common coil" fashion capable of reaching 11 T at 4.2 K. The measured steady state strain in the coil is compared with results obtained using the FEM code ANSYS. During quenches, the transient strain (due to temperature rise) was also measured and compared with the calculated mechanical time response to a quench.         HTS flux pump for cryogen-free HTS magnets    M.P. Oomen, M. Leghissa, G. Ries, N. Proelss, H.-W. Neumueller, F. Steinmeyer, M. Vester and F. Davies Summary: A reliable method for persistent-current mode operation of HTS magnets is still not available. As an alternative solution to external high-current power supplies we have developed a cryogen-free operating transformer-rectifier type HTS flux pump. Using this device only small ac currents have to be supplied into the cryogenic system. Both thermally triggered HTS thin film switches as well as cryogenic MOSFET switches have been used to operate a conduction-cooled 0.5 T HTS magnet coil. This paper presents results of experimental test and modeling of the flux pump operation.         Persistent current HTS magnet cooled by cryocooler (1)-project overview    M. Igarashi, H. Nakao, M. Terai, T. Kuriyama, S. Hanai, T. Yamashita and M. Yamaji Summary: This paper describes a project overview for a persistent current HTS magnet, which has been in development for Maglev trains since 1999. The HTS magnet operates with a very small current decay rate of 0.44%/day and can be cooled by a cryocooler below 20 K. The HTS coil consists of 12 single-pancake coils, which were wound with 4 parallel Ag-sheathed Bi2223 tapes. In order to minimize the magnetic field decay rate during persistent current operation, we have made efforts not to decrease the high Tc superconductor characteristics during the winding of the single-pancake coils. The HTS coil is connected with a persistent current switch made of a YBCO thin film, and cooled by a G-M (Gifford-MacMahon) type two-stage pulse tube cryocooler. Detachable current leads were used to reduce heat leakage to the 1st stage of the cryocooler.         High-temperature Superconducting magnets for use in electron Cyclotron resonance ion sources    S. Harrison, S. Milward, R. McMahon, C. Bieth, S. Kantas and P. Sortais Summary: Ion sources using electron cyclotron resonance (ECR) require magnets to generate a particular field profile. High temperature superconducting (HTS) magnets offer advantages in power density, efficiency and the overall simplicity of the system. Space Cryomagnetics Ltd of Culham, England, has designed and manufactured HTS magnets for an ion source for Pantechnik in France, and is currently developing a second, more powerful system for the Laboratoire de Physique Subatomique et de Cosmologie (LPSC) in Grenoble, France. This paper describes the design, manufacture and test results of the first of these systems, and the current status of the design and manufacture of the second.         Design, manufacture, and test of an adiabatic demagnetization Refrigerator Magnet for use in space    S. Milward, S. Harrison, R.S. Allen, I.D. Hepburn and C. Brockley-Blatt Summary: The proposed European Space Agency (ESA) XEUS mission will use an adiabatic demagnetization refrigeration (ADR) system to cool X-ray detectors to a temperature of less than 0.1 K. The superconducting magnet for the flight standard prototype is currently under construction by Space Cryomagnetics Ltd of Culham, England. The magnet is subject to tight constraints on its mass, stray field, and power consumption. This paper describes the design, manufacture and test of the magnet.         Design and performance of a small HTS bulk reluctance motor    M. Qiu, Z. Xu, Z.H. Yao, D. Xia, L.Z. Lin, G.M. Zhang, L. Xiao, H.T. Ren, Y.L. Jiao and M.H. Zheng Summary: HTS bulks can be used as flux-focusing elements in reluctance motors. As parts of the primary study, a small prototype reluctance motor was designed and constructed by using HTS YBCO bulks. The performance was analyzed based on magnetic field calculation. An experimental investigation was carried out on the prototype motor. Computed parameters are compared with test measurements, showing good agreement. Compared with the conventional synchronous reluctance motors, higher efficiency and smaller size make these motors very attractive for the applications, such as cryogenic pumps and flywheel drives.         Manufacture and test of a 5 T bi-2223 insert coil    M. Beckenbach, F. Hornung, M. Klaser, P. Leys, B. Lott and T. Schneider Summary: With the goal of obtaining a magnetic field of 25 T in our facility HOMER II with a superconducting LTS-HTS hybrid magnet, a first prototype 5 T high temperature superconducting (HTS) insert coil has been constructed and tested. The HTS insert consists of 16 double pancakes made of stainless steel reinforced Bi-2223 tapes manufactured by American Superconductor. The HTS coil was operated at 1.8 K and produced 5.4 T at a current of 151.2 A. In a background field of 11.5 T provided by our facility HOMER I, a total field of 16.9 T was obtained several times. No training or quench of the coil was observed during the test, but after warming up a defect in the winding of one double pancake was detected, presumably due to a ballooning of the tape. The design of the coil and the results of the test are presented and discussed.         Tevatron HTS power lead test    S. Feher, R. Carcagno, D. Orris, Y. Pischalnikov, C. Sylvester, M. Tartaglia and J.C. Tompkins Summary: Two pairs of ASC 6 kA power leads developed for the Tevatron were successfully tested at Fermilab at over-current conditions. Stable operation was achieved while operating at a current of 9.56 kA for five hours and while continuously ramping between 0-9.56 kA at a ramp rate of 200 A/s for one hour. The minimum required liquid nitrogen flow rate was measured to be 1.5 g/s at 10 kA. After ramping up to 10 kA at 200 A/s, it took only 15 minutes to stabilize the upper copper section of the lead with a flow of 1.8 g/s of liquid nitrogen vapor. Testing under extreme operating conditions-270-370 kPa liquid nitrogen vapor pressure and over 0.1 T external magnetic field-demonstrated that the HTS part of the lead can safely operate in the current sharing mode and that this design has large operating margin.         Design and development of a pair of 10 kAHTS current leads for the NHMFL 45 hybrid magnet system    J.R. Miller, G.E. Miller, S.J. Kenney, D.E. Richardson and C.L. Windham Summary: During a planned replacement of one of the three superconducting coils in the outsert magnet of the 45 T Hybrid, there is an opportunity to replace the existing pair of standard helium-vapor-cooled current leads with a pair of leads incorporating high-temperature superconductor (HTS) sections. A conceptual design for these leads has been completed, and various critical components have been modeled and tested. The design includes an integral liquid-nitrogen reservoir at the interface between resistive and HTS sections, automatic liquid-nitrogen level control, a resistive heat-exchanger section cooled by nitrogen vapor, an HTS section with integral stainless-steel shunt for protection, and an interface to the low-temperature superconductor bus. A detailed design is presently underway and fabrication tooling and techniques are being developed. We present design details, projected performance, results of development testing, and plans for manufacturing and acceptance testing.         Experimental results of a 70 kA high temperature superconductor current lead demonstrator for the ITER magnet system    R. Heller, S.M. Darweschsad, G. Dittrich, W.H. Fietz, S. Fink, W. Herz, F. Hurd, A. Kienzler, A. Lingor, I. Meyer, G. Nother, M. Susser, V.L. Tanna, A. Vostner, R. Wesche, F. Wuchner and G. Zahn Summary: In the frame of the European Fusion Technology Programme, the Forschungszentrum Karlsruhe and the CRPP Villigen have designed and built a 70 kA current lead for the ITER TF Coils using High Temperature Superconductors (HTS). At the beginning of 2004 the HTS current lead was installed and tested in the TOSKA facility of the Forschungszentrum Karlsruhe. The scope of the experiment was to characterize the current lead in steady state conditions and to explore the operation limits as well. For this, the temperature profile, the contact resistances, the heat load at 4.5 K, the required 50 K He mass flow rate, and the temperature margin were evaluated. The safety margin in case of a loss of He mass flow was studied, too. The paper describes the experimental results as well as the thermal and electrical models developed.         Production LHC HTS power lead test results    M.A. Tartaglia, R.H. Carcagno, S. Feher, Y. Huang, D.F. Orris, Y. Pischalnikov, R.J. Rabehl, C. Sylvester and J. Zbasnik Summary: The Fermilab Magnet test facility has built and operated a test stand to characterize the performance of HTS power leads. We report here the results of production tests of 20 pairs of 7.5 kA HTS power leads manufactured by industry for installation in feed boxes for the LHC Interaction Region quadrupole strings. Included are discussions of the thermal, electrical, and quench characteristics under "standard" and "extreme" operating conditions, and the stability of performance across thermal cycles.         New facility for testing LHC HTS power leads    R. Rabehl, R. Carcagno, S. Feher, Y. Huang, D. Orris, Y. Pischalnikov, C. Sylvester and M. Tartaglia Summary: A new facility for testing HTS power leads at the Fermilab Magnet Test Facility has been designed and operated. The facility has successfully tested 19 pairs of HTS power leads, which are to be integrated into the Large Hadron Collider Interaction Region cryogenic feed boxes. This paper describes the design and operation of the cryogenics, process controls, data acquisition, and quench management systems. HTS power lead test results from the commissioning phase of the project are also presented.         AC transport losses calculation in a Bi-2223 current lead using thermal coupling with an analytical formula    K. Berger, J. Leveque, D. Netter, B. Douine and A. Rezzoug Summary: When a superconductor is fed with an alternating current, the temperature rise created by the losses tends to reduce the current carrying capacity. If the amplitude of the current exceeds the value of the critical current, then the losses become particularly high and the thermal heating considerable. In this paper, a numerical and an analytical model which allow to estimate AC transport losses are presented. These models, which use the expression of I/sub c/(T) and n(T), are available for any applied current (below and above I/sub c/). The results are compared and the validity of the analytical model is considered. Then, the analytical formula allows to easily obtain the thermoelectric balance point of the system, when the losses and the temperature do not vary any more. Moreover, a maximum value of the current transport, beyond which the balance point does not exist, is detected. Indeed, when this maximum value is exceeded, the system is not stable and, say, superconducting current leads may quench.         Development of a Bi2223 insert coil for a conduction-cooled 19 T superconducting magnet    K. Tasaki, M. Ono, T. Kuriyama, M. Kyoto, S. Hanai, H. Takigami, H. Takano, K. Watanabe, S. Awaji, G. Nishijima and K. Togano Summary: We designed and have been fabricating a conduction-cooled 19 T superconducting magnet consisting of a NbTi coil, Nb/sub 3/Sn coils and a Bi2223 insert coil. The insert coil is made up of 25 double-pancake coils, which are wound with the conductors composed of an Ag-sheathed Bi2223 tape and a stainless steel tape for reinforcement. The inner diameter and the outer diameter of each double-pancake coil are /spl phi/90 mm and /spl phi/180 mm, respectively. In order to investigate the mechanical and superconducting properties of the double-pancake coils, a model coil consisting of two double-pancake coils was fabricated and excited in liquid helium in the background fields up to 11 T and hoop stresses were applied to the model coil. It was found that the superconducting properties of the model coil did not change even after the hoop stress application of 52.7 MPa, which was exceeding the hoop stress applied in the 19 T superconducting magnet. The Bi2223 insert coil will be cooled by a GM-JT cryocooler to approximately 4.5 K through aluminum plates. Thermal stability analysis is very important especially for the conduction-cooled HTS coils operated at lower temperature since thermal runaway may cause the burnouts of the HTS coils. In this paper the analysis results are also discussed.         Cryocooler-cooled high T/sub c/ superconducting magnet excited by a hybrid semiconductor-HTS thermoelectric element    M. Ono, T. Kuriyama, A. Oguchi and T. Okamura Summary: This paper describes progress in a cryocooler-cooled HTS magnet excited by a thermo-electromotive force of a thermoelectric element. Since this system requires no external power sources, there are advantages in compactness and weight over conventional HTS magnet systems. Thus, it is suitable for applications in places where constraints on space and weight are severe. For improvement of this magnet system, we present a concept of the new thermoelectric element which consists of a thermoelectric semiconductor and a superconductor. This hybrid element passively utilizes a superconductor as a thermoelectric material and decreases the cryogenic heat leakage per unit current (Q/I) ideally by half. In this paper, experiments of an HTS coil excitation with a hybrid semiconductor-HTS thermoelectric element are reported. It is shown that there are some obvious merits in using the hybrid element as a substitute for a normal p- and n-type semiconductor element.         New 30 kA power system at Fermilab and its use for measuring the effects of ripple current on the performance of superconducting high field magnets    R. Carcagno, S. Feher, J. Garvey, W. Jaskierny, M. Lamm, A. Makulski, D.F. Orris, H. Pfeffer, M. Tartaglia, J. Tompkins and D. Wolff Summary: A new 30 kA, 30 V dc Power System was designed, built, and commissioned at Fermilab for testing Superconducting High Field Magnets. This system has been successfully supporting operations at the Fermilab Magnet Test Facility since April 2002. It is based on six commercial 150 kW Power Energy Industries power supply modules and the following in-house modules: six 720 Hz filters, two 15 kA/1 kV dc solid-state dump switch, and a 3 MJ/30 kA/1 kV dc dump resistor. Additional in-house electronic components were designed and built to provide precise current regulation and distribution of current and current rate of change. An industrial-type Programmable Logic Controller system was used to provide equipment interlocks and monitoring. This paper summarizes studies on the influence of characteristics of this new power system-such as ripple current-on the performance of High Field Superconducting magnets.         Correlation between strand stability and magnet performance    D.R. Dietderich, S.E. Bartlett, S. Caspi, P. Ferracin, S.A. Gourlay, H.C. Higley, A.F. Lietzke, S. Mattafirri, A.D. McInturff, G.L. Sabbi and R.M. Scanlan Summary: Magnet programs at BNL, LBNL and FNAL have observed instabilities in high J/sub c/ Nb/sub 3/Sn strands and magnets made from these strands. This paper correlates the strand stability determined from a short sample-strand test to the observed magnet performance. It has been observed that strands that carry high currents at high fields (greater than 10 T) cannot sustain these same currents at low fields (1-3 T) when the sample current is fixed and the magnetic field is ramped. This suggests that the present generation of strand is susceptible to flux jumps (FJ). To prevent flux jumps from limiting stand performance, one must accommodate the energy released during a flux jump. To better understand FJ this work has focused on wire with a given sub-element diameter and shows that one can significantly improve stability by increasing the copper conductivity (higher residual resistivity ratio, RRR, of the Cu). This increased stability significantly improves the conductor performance and permits it to carry more current.         Design and test of a hollow Superconducting cable based on keystoned NbTi composite wires    H.G. Khodzhibagiyan, E. Fischer, A.D. Kovalenko, G. Moritz, L.V. Potanina, A.K. Shikov and G.P. Vedernikov Summary: The data from the investigation of hollow superconducting cable based on keystoned NbTi wires are presented. The cable sample, consisting of 15 wires wound around a cooper-nickel tube 5 mm in diameter and cooled with two-phase helium flow has operated inside the magnet aperture at a current of 13.4 kA and the current ramp rate of 26.8 kA/s. The external magnetic field value was about 2 T and the field ramp rate of 4 T/s. The pulse repetition rate of 1 Hz was provided. The first 650 m of the new wire was manufactured based on the improved technology. A piece of hollow cable 40 m in length was fabricated. The outer cable diameter with electric insulation is 7.34 mm. A test winding for a 1.4 m superferric nucleotron-type window frame model dipole for SIS100 as part of the FAIR-project of GSI was fabricated and tested. The obtained results are discussed. The new approach to a 'cable-in-conduit' conductor cable design, based on the use of keystoned wires, is described.         Dependence of contact condition between strands on twist pitch in CIC conductor    M. Tsuda, S. Nakamura, S. Katsuda, N. Harada, T. Hamajima and K. Takahata Summary: We fabricated a model conductor using copper wire and measured the contact length by a pressure-sensitive paper, which changes color according with pressure. The contact length increased during the compression process of the model conductor due to strand displacement. The strand displacement and increase in contact length strongly depended on twist pitch in the sub-cable, strand tension in twisting process and compression method. Therefore, we fabricated four types of (3 /spl times/ 3) conductors with different combinations of twist pitches in the first and second order sub-cables to investigate the relationship between twist pitch and contact length. Smaller twist pitch in the first order sub-cable is more effective in reducing contact length. Twist pitch in the second order sub-cable did not have a strong influence on the contact length. The strand displacement in the first order sub-cable was more closely related to the twist pitch in the first order sub-cable than that of the second order sub-cable. These results imply that the smaller twist pitch in the first order sub-cable could reduce irregular coupling loss with long time constant more effectively.         Study of Nb/sub 3/Sn cable stability at self-field using a SC transformer    E. Barzi, N. Andreev, V.V. Kashikhin, D. Turrioni and A.V. Zlobin Summary: A superconducting current transformer with a maximum DC current of 28 kA has been used for Nb/sub 3/Sn cable testing at self-fields under various experimental conditions. A fast data acquisition system was developed and used for accurate measurements of the secondary current. Test results are shown for thirty cables made of MJR, RRP and PIT strands, along with a description of the SC transformer, sample preparation and test procedure. It was found that premature quenches at currents significantly lower than the expected critical currents at low fields were due to electromagnetic instabilities in the superconductor.         Sensitivity of Nb/sub 3/Sn Rutherford-type cables to transverse pressure    E. Barzi, T. Wokas and A.V. Zlobin Summary: Fermilab is developing high field superconducting magnets for future accelerators based on Nb/sub 3/Sn strands. Testing the critical current of superconducting cables under compression is a means to appraise the performance of the produced magnet. However, these cable tests are expensive and labor-intensive. A fixture to assess the superconducting performance of a Nb/sub 3/Sn strand within a reacted and impregnated cable under pressure was designed and built at Fermilab. Several Rutherford-type cables were fabricated at Fermilab and at LBNL using multifilamentary Nb/sub 3/Sn strands. The sensitivity of Nb/sub 3/Sn to transverse pressure was measured for a number of Nb/sub 3/Sn technologies (Modified Jelly Roll, Powder-in-Tube, Internal Tin, and Restack Rod Process). Results on the effect of a stainless steel core in the cable are also shown.         Critical current and instability threshold measurement of Nb/sub 3/Sn cables for high field accelerator magnets    G. Ambrosio, N. Andreev, S.E. Bartlett, E. Barzi, C.-H. Denarie, D. Dietderich, A.K. Ghosh, A.P. Verweij and A.V. Zlobin Summary: Rutherford-type cables made of high critical current Nb/sub 3/Sn strands are being used in several laboratories for developing new generation superconducting magnets for present and future accelerators and upgrades. Testing of cable short samples is an important part of these R&D programs and the instability problem found in some short model magnets at Fermilab made these tests even more significant. Fermilab in collaboration with BNL, CERN and LBNL has developed sample holders and sample preparation infrastructure and procedures for testing Nb/sub 3/Sn cable short samples at BNL and CERN test facilities. This paper describes the sample holders, sample preparation and instrumentation, and test results. Several samples made of MJR or PIT strands 1 mm in diameter have been tested. Some samples were unstable (i.e. quenched at low transport currents) at low fields and reached the critical surface at higher fields.         Cable testing for Fermilab's high field magnets using small racetrack coils    S. Feher, G. Ambrosio, N. Andreev, E. Barzi, B. Bordini, R. Bossert, R. Carcagno, V.I. Kashikhin, V.V. Kashikhin, M.J. Lamm, I. Novitski, D. Orris, Y. Pischalnikov, C. Sylvester, M. Tartaglia, R. Yamada and A.V. Zlobin Summary: As part of the High Field Magnet program at Fermilab simple magnets have been designed utilizing small racetrack coils based on a sound mechanical structure and bladder technique developed by LBNL. Two of these magnets have been built in order to test Nb/sub 3/Sn cables used in cos-theta dipole models. The powder-in-tube strand based cable exhibited excellent performance. It reached its critical current limit within 14 quenches. Modified jelly roll strand based cable performance was limited by magnetic instabilities at low fields similar to previously tested dipole models which used similar cable.         Conductor limited quenches of LHC superconducting main dipoles    M. Pojer, P. Pugnat, A. Siemko, A. Verweij and B. Vullierme Summary: In the framework of the series tests of superconducting magnets for the LHC, a special procedure was developed at CERN to perform conductor limited quenches at temperatures around 4.4 K. All results obtained on pre-series and series main dipoles tested to date will be presented with their analysis. These quenches allow fine diagnostics concerning the electrical integrity of the conductors and of the splices. They also allow the determination for each magnet of the temperature margin at nominal operating conditions of the LHC at superfluid helium. The comparison between the quench current and the critical current directly measured on short samples of superconducting cables used for the winding is discussed.         Estimation of the AC loss of a YBCO coated conductor with metal substrate by Using Numerical calculation    Hyang-beom Lee, Jikwang Lee, Hyungwoo Lim, Kwangyeon Lee, G. Cha and Chan Park Summary: The magnetization loss of the coated conductor with metal substrate is not the same with that of the coated conductor without metal substrate. Effects of the substrate on the AC loss have not been analyzed yet. In the paper, we estimated the magnetization loss in the YBCO coated conductor with metal substrate, which was exposed to the external magnetic field by using numerical calculation. The effects of magnetic property, electric property and thickness of the substrate on the AC loss of coated conductor were considered in this paper. According to the results of calculation, the existence of substrate decreased the AC loss in the coated conductor up to 39.2% at 5 mT but it increased the AC loss up to 3.7% at 100 mT.         AC loss properties of YBCO superconducting tapes exposed to external AC magnetic field    M. Iwakuma, M. Nigo, D. Inoue, T. Kiss, K. Funaki, Y. Iijima, T. Saitoh, Y. Yamada and Y. Shiohara Summary: We investigated the ac loss properties of YBCO superconducting tapes fabricated by IBAD-PLD technique. The thickness of a YBCO superconducting layer was 0.5 and 1 /spl mu/m. Sample tapes of 60 mm in length and 10 mm in width were stacked into multilayers and inserted into a saddle-shaped pickup coil. The ac loss was measured at 64 K and 77 K by applying external ac magnetic field. The magnetic field angle was changed by rotating the sample stack around its longitudinal axis. The ac loss for the smaller amplitude than the effective penetration field strongly depended on the number of stacked tapes owing to the demagnetization effect. On the other hand, the ac loss for the much larger amplitude than that was independent of the number of tapes. In addition the ac loss decreased monotonically with decreasing field angle against the wide surface for any amplitude. We proposed the theoretical expression to estimate the ac losses for any field angle by using the observed ac losses in perpendicular magnetic field and confirmed the applicability by good agreement between theory and experiment.         Analysis of AC loss characteristics of high temperature superconducting coil    S. Fukui, H. Tonsho, M. Toyoda, J. Ogawa, M. Yamaguchi, Takao Sato, M. Furuse, H. Tanaka, K. Arai, M. Umeda and T. Takao Summary: This paper reports an analytical study on AC loss characteristics of a high temperature superconducting coil wound with a Bi2223/Ag tape. The electromagnetic AC loss in the high temperature superconducting coil made by stacking pancake coils wound with the Bi2223/Ag tape was numerically calculated by using the measured DC data of the HTS tape. The calculated AC loss was compared with measured AC losses in Bi2223 HTS coils obtained in a previous study. It had been found that the measured AC losses in the coils contained large mechanical loss. For the comparison of the measured and calculated losses, the mechanical loss was subtracted from the measured total loss data to estimate the electromagnetic loss. The calculated AC losses were compared with the measured electromagnetic losses in the coils, producing rather good agreement. A possible way to reduce the AC loss in the HTS coil was also presented and discussed.         Numerical evaluation of anisotropy of magnetization losses in superconducting wires with elliptic cross section    K. Kajikawa, T. Hayashi and K. Funaki Summary: AC losses are numerically estimated in straight superconductors with an elliptic cross section exposed to a transverse magnetic field. It is assumed that the distribution of magnetic field in the superconductors is determined by Bean's critical state model, in which the critical current density is independent of the magnitude of local magnetic field. The penetration process of magnetic flux into the superconductors approximated as a group of fine rectangular bars is evaluated by means of the minimization of magnetic energy for the application of the external magnetic fields with arbitrary angles to their broadest face. By using the obtained penetration process, the AC losses are also calculated from the distribution of magnetic vector potential inside the superconductors. Furthermore, the compensation for the numerical results of AC losses enables us to obtain a universal loss property that is scarcely affected by the aspect ratio of cross section and the angle of external field.         Electromagnetic field analysis of rectangular superconductor with large aspect ratio in arbitrary orientated magnetic fields    N. Enomoto, T. Izumi and N. Amemiya Summary: An electromagnetic field analysis of high temperature superconductors with large cross-sectional aspect ratios was carried out. This analysis used a numerical model employing FEM, formulated with current vector potential and magnetic scalar potential. The model conductor with a large cross-sectional aspect ratio simulates a YBCO coated conductor. Edge basis functions and a nodal basis function were used for vector potentials and a scalar potential, respectively. The AC loss was calculated from the temporal evolution of the current distribution. AC transport current was supplied and an AC transverse magnetic field with various orientations was applied to the model conductor to calculate the AC losses at various conditions. The numerically calculated AC losses were compared with the analytical values and numerical values.         On the effect of NiW on the inductance and AC loss of HTS cables    R.C. Duckworth, M.J. Gouge, J. Caughman, J.W. Lue, J.A. Demko, J. Tolbert, C.L.H. Thieme and D.T. Verebelyi Summary: The impact of Ni-5at%W substrates on ac loss and inductance of HTS cables was examined. Two 1.2-m prototype cables were made with stainless steel laminated BSCCO tapes and were wound on a 25.4 mm diameter former. Each cable consisted of two layers of 15 BSCCO tapes wound at opposite lay angles and has an estimated critical current of 3000 A at 77 K. One cable had four additional layers of 4.8 mm wide Ni-5at%W tape co-wound with the BSCCO tapes to simulate a commercial second generation HTS cable. The Ni-5at%W tapes had the same width as the BSCCO and a thickness of 50 microns. Through the use of a coaxial copper ground, the cable inductance was measured at room temperature and liquid nitrogen (77 K) using high frequency rf measurement techniques. Experimental results for the cable inductance and ac loss were compared against numerical calculations to determine the significance of the Ni-5at%W substrate contribution. Results indicate that inductance and ac loss changes from these substrates in commercial cables should be small.         Substrate and stabilization effects on the transport AC losses in YBCO coated conductors    R.C. Duckworth, M.J. Gouge, J.W. Lue, C.L.H. Thieme and D.T. Verebelyi Summary: In support of second generation HTS conductor development for ac applications, transport ac loss measurements were conducted on a series of RABiTS-processed YBa/sub 2/Cu/sub 3/O/sub x/ (YBCO) coated conductors with different nickel alloy substrates and copper stabilization at 77 K. Each 1-cm wide sample had a critical current density between 1.0 and 2.0 MA/cm/sup 2/ and had either a 75 /spl mu/m Ni-5at%W substrate or a 75 /spl mu/m Ni-10%Cr-2%W substrate with 2-/spl mu/m nickel overlayer. Samples with copper stabilization had a 50-/spl mu/m strip of 1 cm wide copper laminated to a 3-/spl mu/m thick silver coated YBCO sample. Using thermal and electrical measurement techniques, the ac losses were measured as a function of the peak current ratio at 60 Hz. Experimental results were compared to the Norris thin strip and elliptical models to determine the influence of the ferromagnetic loss of the substrate and the copper lamination on the total ac loss.         Influence of strand deviations from nominal geometry on AC losses in multistrand Superconducting cables    M. Breschi, M. Fabbri, F. Negrini and P.L. Ribani Summary: The modeling of current distribution and ac losses in multistrand superconducting cables is strictly related to the evaluation of the cable electric parameters. A perfect knowledge of these parameters is however impossible due to the complicated manufacturing process. Strand deviations from the nominal geometry and interstrand conductance changes occur in the cable compaction process. Statistical approaches can however be applied to deal with these issues. This paper reports a sensitivity analysis aimed to determine the effects of strand deviations from the nominal geometry. The deviations, however, are not directly imposed on the mutual inductances matrix, as this approach can lead to misleading results if the final matrices do not correspond to physically possible configurations. The statistical deviations are imposed on the strands geometry, keeping the strands in physically possible locations by means of geometric constraints. A code for the electromagnetic analysis of superconducting cables is then applied to the calculation of current distribution and ac losses in the different configurations, evaluating the relevance of the main parameters variation.         Sudden flux change studies in high field superconducting accelerator magnets    S. Feher, B. Bordini, R. Carcagno, A. Makulski, D.F. Orris, Y.M. Pischalnikov, C. Sylvester, M. Tartaglia, J.C. Tompkins and A.V. Zlobin Summary: As part of the High Field Magnet Program at Fermilab many magnets have been tested which utilize multi strand Rutherford type cable made of state-of-the art Nb/sub 3/Sn strands. During these magnet tests we observed sudden flux changes by monitoring coil voltages and the magnetic field close to the magnets. These flux changes might be linked to magnet instabilities. The voltage spike signals were correlated with quench antenna signals, a strong indication that these are magnet phenomena. With a new high resolution voltage spike detection system, we were able to observe the detailed structure of the spikes. Two fundamentally different signal shapes were distinguished, most likely generated by different mechanisms.         Analysis of joint-resistance-induced, non-uniform current distribution    K. Seo, T. Mito, J.R. Miller, S. Kawabata, T. Ichihara and M. Hasegawa Summary: The observation of nonuniform current distribution (NUCD) in multi-strand cables, in particular cable-in-conduit conductors (CICC's), has been reported often. NUCD may have important effects on AC loss and stability margin in such conductors; therefore, this phenomenon must be better understood. In this study, we have used numerical simulations to study the magnetic flux changes caused by NUCD's that themselves derive from details of lap-joint construction between cables composed of hundreds of strands and twisted in specific patterns. In the steady state, a NUCD is governed by the distribution and quantitation of contact resistances between individual strands in one cable to individual strands in the other. In an otherwise well-made joint, contact resistances will be lowest between strands that approach each other across the lap-joint-interface, and a strand that has many close encounters with the interface can be expected to carry larger current in the steady-state condition than a strand that has fewer or none. The length of the joint and the cable pattern determine the number of close encounters to the lap-joint-interface by individual strands. We present the results of our simulations using different joint length, we suggest experiments to observe these effects, and we discuss their significance with regard to conductor and magnet performance.         Relation between contact resistance and twist pitches in superconducting doublets    K. Nakamura, H. Suko, T. Takao and A. Nishimura Summary: We prepared sample doublets made of two strands with three different twist pitches (25, 50 and 65 mm). One of the doublets is equally twisted to each other, and the other is a strand twisted in spiral around a straight strand. We measured the contact resistance between the strands in the doublets in liquid helium. Since not only the resistance but also mechanical properties of the strands (applied force to the strands and deformation of the doublet due to the force) were measured, the contact area could be precisely estimated, and then the surface resistance was also evaluated. As a result, the difference between the virgin-contact resistance and the contact resistance with the compressive force applied on the doublets increased when the twist pitch of the doublets became short, and the difference in the shapes of the doublets have an influence on the contact resistance. The obtained results enlarge the database used to simulate an electric circuit model of multi-stranded conductors and to estimate inter-strand coupling losses in the conductors.         Comparison of AC losses of HTS pancake winding with single tape and multi-stacked tape    Seung-wook Lee, Hee-Joon Lee, G. Cha and Ji-Kwang Lee Summary: AC losses generated in the HTS winding differ from that of the short sample because each turn of winding is magnetically affected by adjacent turns. In this paper, we calculated the AC loss of HTS pancake windings. Numerical calculation was carried out to figure out the magnetic field in the windings. During the AC loss calculation of both windings, AC losses were obtained by using the short sample AC losses data. According to the results of calculation, loss calculation by using the short sample data of multi-stacked tape was more approached to winding loss than that by using the single tape data. To prove the effectiveness of the calculations, AC losses of windings was measured and compared. Finally the single phase HTS transformer with multi-stacked tape was constructed and tested.         Magnetization loss of stacked bi-2223/Ag tapes in external magnetic field    Seyong Choi, W. Nah, Jung Ho Kim, Jinho Joo, Dae-Haing Huh, Kyung-Woo Ryu, M. Sugano, T. Kiyoshi, Myung-Hwan Sohn and Young-Kil Kwon Summary: This paper investigates the magnetization loss of stacked Bi-2223/Ag tapes. A numerical code was developed to estimate the magnetization loss of stacked tapes in parallel and perpendicular external magnetic fields. To calculate magnetization loss and current distribution across the tapes, we used magnetic field dependent current-voltage characteristics of a tape. The numerically calculated result showed good agreement with the measured magnetization loss in a tape. In a perpendicular field, it was observed that the loss per unit volume decreased as the stacking number increased because of the screening current across the tapes. In a parallel field, the loss per unit volume remained virtually unchanged as the stacking number increased. The influence of stacking effect on magnetization loss is addressed with the induced current distribution obtained from numerical calculation.         Influence of tape's critical currents and current distributions on AC loss measurement in a multi-tape conductor    K. Ryu, S.D. Hwang, S.W. Kim and S. Hahn Summary: AC loss is an important issue to design high temperature superconductor power cables, which consist of a number of Bi-2223 tapes wound on a former. In the cables, the tapes have intrinsically different critical currents, and they are electrically connected to each other and current leads. This makes loss measurements considerably complex, especially for short samples. In this work, we have prepared a multi-tape conductor composed of Bi-2223 tapes. The ac losses of the conductor have been experimentally investigated. The loss tests indicate that the effect of critical currents of each tape on AC loss measurement in the multi-tape conductor is negligible only if currents in the tapes flow uniformly. Moreover, the measured loss of the conductor is in good agreement with the sum of the transport loss in each tape. However, in the case of nonuniform current distribution, the measured AC loss considerably depends on the current distribution parameter /spl gamma/, and the positioning of a voltage lead. Thus it should be very careful to measure the AC losses in the short power cable samples.         Stability and protection of superconducting magnets-a discussion    Y. Iwasa Summary: The paper discusses stability and protection, two key issues for design and operation of superconducting magnets, both LTS and HTS. A rather optimistic view on stability is presented first, followed by discussion of protection issue, focusing on its sub-issues-overheating and internal voltage-for three types of magnets: 1) LTS cryostable magnet; 2) LTS adiabatic magnet; and 3) HTS adiabatic magnet.         Magnetic instabilities in Nb/sub 3/Sn strands and cables    V.V. Kashikhin and A.V. Zlobin Summary: This paper describes a model for calculation of magnetic instabilities in superconducting wires with transport current and reports results of instability simulations in Nb/sub 3/Sn strands from different manufacturers. The effect of magnetic instabilities on the strand and cable performance is presented and a criterion for the maximum effective sub-element size of strands for high field magnets is formulated.         Fast algorithm for computing inductive voltages in a network model of a Rutherford cable    J. McDonald and E. Barzi Summary: The fast multipole method (FMM) is applied to the electromagnetic analysis of a network model for a Rutherford cable. The FMM allows the inductive-voltage effects to be included accurately (error /spl Lt/ 1%) without the need to store, access, or invert the full inductance matrix. Applications of the resulting algorithm are discussed: relaxation of boundary-induced coupling currents, stability, and quench propagation.         Considerable stability increase in superconducting windings doped with extremely high specific heat substances    V.E. Keilin, P.A. Alekseev, A.I. Boev, I.A. Kovalev, S.S. Kozub, S.L. Kruglov, V.N. Lazukov and I.P. Sadikov Summary: The influence of some rare-earth based intermetallic compounds with extremely high specific heat capacities on the transient stability of NbTi superconducting windings was experimentally investigated. The experiments were carried out with three NbTi wire wound small round coils doped with CeCu/sub 6/, HoCu/sub 2/, and (for comparison) with boron nitride usually used as an epoxy resin filler. The intermetallic compounds, CeCu/sub 6/ and HoCu/sub 2/, were introduced as filling powders into an epoxy resin based composite in a wet winding process. Doping of about 5.7 vol.% of such compounds increases minimum quench energies several times even for short (of order of 1 ms) electromagnetic disturbances. The first results are also reported of the training history comparison in three NbTi Rutherford cable wound oval-shaped windings doped with half amount (about 2.9 vol.%) of the same compounds. It is shown that even such doping is very helpful in increasing of the first quench current. The prospects and most promising applications are briefly discussed.         Impact of void fraction on mechanical properties and evolution of coupling loss in ITER Nb/sub 3/Sn conductors under cyclic loading    A. Nijhuis, Yu. Ilyin, W. Abbas, H.H.Jt. Kate, M.V. Ricci and A. della Corte Summary: The combination of current up to 50 kA and magnetic field of 13 T in the Cable-In-Conduit Conductors (CICC) for the coils in the International Thermonuclear Experimental Reactor (ITER), cause huge local transverse forces. This results in changes in the transport properties, friction and anomalous contact resistance versus force behavior. The latest design optimizations tend to go toward a lower void fraction (VF). This has an impact on the evolution of the coupling loss and on the possible degree of strand bending and deformation. Toroidal Field Model Coil (TFMC) type of conductors with VFs of 26%, 30% and 36% respectively, are tested in the Twente Cable Press, by which a variable (cyclic) transverse force of 650 kN/m is transferred directly to a cable section of 400 mm length at 4.2 K. The AC loss of the conductor, the inter-strand and strand-bundle resistance (R/sub c/) in the cable and the associated bundle deformation are examined during mechanical cycling. The test results are discussed in view of the previous results on Nb/sub 3/Sn ITER CICCs.         AC loss characteristics of multifilamentary YBCO coated conductors    N. Amemiya, K. Yoda, S. Kasai, Zhenan Jiang, G.A. Levin, P.N. Barnes and C.E. Oberly Summary: One of the methods to reduce magnetization loss of YBCO coated conductors in a perpendicular magnetic field is subdividing the YBCO layer into filaments and twisting them as a whole. A 10 mm wide multifilamentary YBCO coated conductor with 200 /spl mu/m wide filaments was prepared by striation using the laser ablation technique. The number of filaments was 40. The sample length was varied from 100 mm to 25 mm, and their magnetization loss was measured at various frequencies. The measured magnetization losses were scaled using sample length, frequency, and field amplitude. This clarifies the magnetization loss characteristics of multifilamentary YBCO coated conductors and obtains empirical expressions for the magnetization loss. The measured loss was compared with the loss calculated numerically using a two dimensional FEM model. The experimentally confirmed effect of striation to reduce the magnetization loss was compared with theoretical predictions.         Conceptual approach to the ultimate low AC loss YBCO Superconductor    C.E. Oberly, B. Razidlo and F. Rodriguez Summary: Wide tapes of YBCO coated conductors make minimization of ac loss very difficult. Subdivision of the tape into narrow filaments does not provide complete transposition when twisted and current sharing is not equalized due to inductance differences. For ac power applications operating near 400 Hz for military aircraft power systems, equal inductance filaments and short twist pitch are very important to loss minimization. A fully transposed YBCO tape that approximates a Rutherford cable has been conceived to minimize ac loss at high frequency. Retention of optimal texture of YBCO in edge turnaround regions and filament crossovers in the Rutherford tape is essential.         Finite element modeling of thermal stability and quench propagation in a pancake coil of PbBi2223 tapes    Taotao Huang, A. Johnstone, Yifeng Yang, C. Beduz and C. Friend Summary: The initiation and propagation of quench events in a high temperature superconducting (HTS) pancake coil were modeled using finite element software package ANSYS. The nonlinear temperature dependent heat generation in HTS composite over a wide current sharing range is calculated based on power-law E-J characteristics with temperature dependence of the n-value and critical current density. Thermal properties of the HTS composite and coil sections were measured and compared with estimated values based on data for individual coil components and the fill factor of the coil construct. The effect of replacing the complex coil winding structure with an effective continuum was investigated by examining the normal zone temperature profiles and minimum quench energy (MQE). With reducing operating temperature from 77 K to 30 K, MQE reduces correspondingly from 30 J to 15 J. Simulation results are found in satisfactory agreement with experimental results from a test coil wound with PbBi2223 tape.         Quench developing process of HTS tapes under sinusoidal over-currents    Yusheng Zhou, Qingshuo Song, Fang Guo, Jingdong Li and Yuejin Tang Summary: In power systems, superconducting electric equipments inevitably suffer all kinds of dynamic processes, such as short-circuit fault. Thus they must undergo all kinds of large short-circuit currents, imbalanced currents, which might make superconducting equipments transiting from superconducting state to normal state. In this paper, the over-current faults in power systems are simulated, and a lot of experimental data are obtained, which show quench processes of HTS tapes under sinusoidal over-currents with different amplitudes. Through analysing these data in 2 cycles, the developing processes of normal state in HTS tapes are analyzed and explained. The relations of heat affecting quench developing processes are discussed, and the developing characteristics of normal state in HTS tapes are presented. Firstly, HTS tape under sinusoidal over-currents has better recovery feature when the amplitude of over-current is under two times of the critical current. Secondly, normal resistance develops rapidly as the amplitude of over-current is over three times of the critical current. Finally, quench developing is affected by liquid nitrogen cooling.         Heating development analysis in long HTS objects with cooling    V.S. Vysotsky, V.E. Sytnikov, V.V. Repnikov, E.A. Lobanov, N.V. Zmitrenko and A.L. Rakhmanov Summary: The numerical experiment to model heating development in long HTS object has been performed by use of the specially developed computer code. Cooling by liquid nitrogen was taken into account and parameters close to the real ones for HTS tapes were used in calculations. It was shown that depending on parameters' combination, particularly on current density, stable and unstable regimes can happen. At unstable regime the fast temperature runaway is combined with the strong heat localization. The safety current density levels were determined for two model tapes. The results are important for HTS power cables that should withstand large overload currents during some time in case of faults in a grid.         Normal transition and propagation Characteristics of YBCO tape    A. Ishiyama, M. Yanai, T. Morisaki, H. Ueda, Y. Shiohara, T. Izumi, Y. Iijima and T. Saitoh Summary: YBCO tape is expected to be used in future HTS applications, because it has better J/sub c/ characteristic in high temperatures and in high applied magnetic fields. It is important to consider the stability in superconducting applications. To establish the stability criterion for coated conductors, the characteristics of the transition to the normal state and normal-zone propagation in YBCO sample tapes were examined experimentally and numerically. The YBCO sample tapes were produced by IBAD/PLD method. Measurements were performed as a function of both heat input and operating current for operating temperatures of 55 K, 60 K, and 65 K in a background magnetic field of 5 T. The experimental results were compared with a simulation using a newly developed computer program based on the finite element method (FEM). In the computer program, the I-V characteristics of the YBCO sample tapes were taken into account. The computer program could simulate the normal transition and propagation phenomena and its validity was confirmed. The influence of the thickness of a Ag-stabilizer on the transient thermal behavior of YBCO tapes was examined experimentally and numerically and the results were presented here.         Thermal runaway of a 1 T cryocooler-cooled oxide Superconducting pulsed coil in Ac operation    H. Miyazaki, S. Harada, M. Iwakuma, K. Funaki, H. Hayashi and A. Tomioka Summary: We designed and fabricated a 1 T cryocooler-cooled oxide superconducting pulsed coil with Bi2223 multifilamentary flat wires. Previously we studied temperature dependence of the thermal runaway current of the pulsed coil in dc operation. The thermal runaway current was higher than the critical current that was defined as the current where the electric field 10/sup -4/ V/m was generated on average over the whole length of the conductor. In this paper, we studied the coil temperature and the ac loss dependence of the thermal runaway current in ac operation. We operated the coil at 0.5 to 5 Hz with a sinusoidal-waveform transport current. The initial coil temperature was set between 30 and 100 K. The thermal runaway current decreased monotonically with increasing temperature in a similar way to dc operation. However, in a low temperature region, the thermal runaway current was restricted to a lower level than that in dc operation due to the ac loss. We discuss the frequency dependence of thermal runaway current in ac operation.         Adiabatic normal zone development in MgB/sub 2/ Superconductors    H. van Weeren, N.C. van den Eijnden, W.A.J. Wessel, P. Lezza, S.I. Schlachter, W. Goldacker, M. Dhalle, A. den Ouden, Bt. Haken and H.H.Jt. Kate Summary: A-priori knowledge of the normal zone development in MgB/sub 2/ conductors is essential for quench protection of applications. Therefore the normal zone propagation in a monofilament MgB/sub 2//Fe conductor under near-adiabatic conditions at 4.2 K has been measured and simulated. The results show normal zone propagation velocities up to several meters per second. In addition, by including the voltage-current relation into the computational model, the influence of the n-value on the normal zone propagation is determined. The simulations show that lower n-values suppress the normal zone propagation velocity due to lower heat generation in the MgB/sub 2/ filaments.         Measurement of velocities up to 1.1 km/s and test of a very fast quench inducing system    E. Floch, G.K. Hoang, C. Kohler, P. Hiebel and J.M. Kauffmann Summary: Applications such as superconducting pulsed power transformers and fault current limiters require high propagation velocities and numerous quench starting points appearing in a short time interval (typically less than a millisecond). A few years ago, Alstom successfully tested a 500-J superconducting pulsed power transformer . In order to better model its quick transition to the normal state, an appropriate computer code was created. This paper presents this quench program and the experiment developed to validate it. The experimental set-up enabled to measure propagation velocities up to 1.1 km/s, which to our knowledge are the highest ever published. Furthermore, we took the opportunity to test a new magnetic quench inducing system. The latter revealed the possibility of inducing a quench in a few tenths of microseconds with an energy consumption at least ten times lower than a classical quench heater.         Discontinuous galerkin spectral element Simulation of quench propagation in Superconducting magnets    S. Mao, C.A. Luongo and D.A. Kopriva Summary: In this paper we simulate 1D quench propagation in superconducting magnets using cable-in-conduit conductors (CICC) by a discontinuous Galerkin (DG) spectral element method (SEM) and explicit Runge-Kutta time integration. The supercritical helium flow is considered in the modeling of quench propagation in CICC, which can be expressed by the Euler equations with additional friction and coupled heat transfer between helium and conductor and conduit. Roe's approximate Riemann solver for real gas/fluid is used to compute numerical flux and nonreflecting boundary condition is introduced in the algorithm. The method used here is highly parallelizable. Some numerical results are given and compared with those obtained by another simulation method and experimental data.         Thermal analysis of a conduction-cooled HTS coil with heat disturbances    Taozhen Dai, Jingdong Li, Yuejin Tang, Yusheng Zhou, Shijie Chen and Yuan Pan Summary: Heat disturbances, which are usually caused by nonuniformity of the conductor operating locally at overcritical currents or by resistive joints in the HTS coil, always lead to local increase in the temperature around the weak point. This may expose the coil to possible damage. Understanding the thermal behavior of the HTS coil is important when designing and operating a conduction-cooled HTS magnet. In this paper, thermal simulations were performed to analyze thermal response of the heat disturbances for a conduction-cooled HTS coil by using a model based on the heat conduction equation and solved using the finite element method. The coil is cooled by a cryocooler through a cooling plate. This study focused on the temperature profile in the coil and the heat transfer between the coil and the cooling plate. Based on the results, the issues related to thermal stability of the HTS coil are discussed.         Stability and quench protection of coated YBCO "Composite" tape    Y. Iwasa, J. Jankowski, Seung-Yong Hahn, Haigun Lee, J. Bascunan, J. Reeves, A. Knoll, Yi-Yuan Xie and V. Selvamanickam Summary: The paper presents results, experiment and simulation, of quench/recovery study of coated YBCO "composite" test samples, cooled by boiling liquid nitrogen and subjected to an over-current pulse. To operate stably and be protected from damage under adverse operating conditions of a real device, the YBCO tape must be a "composite", loaded with normal metal of a sufficient thickness that significantly increases the thickness of the original YBCO tape.         Contribution to improvement of mechanical stability in superconducting coils using DFRP bobbins    N. Sekine, S. Tada, T. Higuchi, Y. Furumura, T. Takao, A. Yamanaka and S. Fukui Summary: A moving of the superconducting wire due to an electromagnetic force induces heat, and that is one factor of instabilities in superconducting coils. There is a wire motion under a DC operation; on the other hand, there is a mechanical loss under an AC operation. To prevent those movements, it is effective to enhance the winding tension at coil-operating temperature. For that purpose, we propose the use of a Dyneema fiber reinforced plastic (DFRP), which has a negative thermal expansion coefficient, as the bobbin of the superconducting coils. To investigate a contribution to improvement of stability due to the DFRP, we performed DC and AC experiments. In the DC experiment, rates of the attainment to the critical current were evaluated by quench training measurements, and in the AC experiment, losses were measured. In both experiments, the thermal expansion characteristics of the DFRP prevented the wire's movement, therefore it was demonstrated that the use of the DFRP bobbin was effective about the improvement of stability.         Quench Characteristics in Superconducting coils fabricated by various FRP bobbins    N. Sekine, S. Tada, T. Higuchi, Y. Furumura, T. Takao and A. Yamanaka Summary: In coils using low temperature superconductor, a wire motion due to an electromagnetic force observably reduces stability. It is quite important to prevent the wire motion under a DC operation. We aim to improve stability by means of an intensification of a winding tension at cryogenic temperature. The technique is the use of the bobbins whose thermal expansion coefficients are negative. For experiments, superconducting coils were fabricated with various conditions; materials of bobbins, thermal expansion properties, and winding tensions at room temperature. And quench characteristics were measured under the DC operation. Applying a standard deviation of quench currents, we discussed about the relation between fluctuation and the amplitude of the quench currents. In the results, stable quench characteristics were obtained in the coils which were not extremely contracted in the direction of the circumference.         Calibration of inductive heater for stability test of cable in conduit conductor    K. Seo, K. Takahata, T. Mito, H. Hayashi, K. Terazono, T. Semba and K. Miyashita Summary: Stability tests employing inductive heaters are useful to evaluate stability margins of cable in conduit conductors (CICC's). The inductive heater, which consists of the resistive induction-coil and the AC or pulse power supply, can introduce eddy currents in the CICC. The frequency is more than one hundred Hz and it can introduce the heat pulse with the duration of several ms. The stability test using the inductive heaters had been reported. However, the ratio of the deposited energies to the components; superconducting strands, conduit and induction-coil, have not been discussed exactly. By the inductive heater, the coupling and eddy current losses are introduced in the strand. In addition, inter-strand coupling loss, eddy current loss in the conduit and joule and/or eddy current losses in the induction-coil itself are introduced. We evaluated these kinds of losses by both experimental and numerical methods. Finally, we evaluated the quench energy margin of the cable in conduit conductor quantitatively.         Stability study on cryocooler-cooled superconducting magnets    Hongwei Liu, Qiuliang Wang, Yunjia Yu, Ye Bai, Baozhi Zhao, Shousen Song and Keeman Kim Summary: Superconducting magnets cooled by cryocooler, without liquid helium, have been developed in recent years. This kind of magnet system is very easy and convenient to operate. The stability of the magnet depends on the balance between the cryocooler refrigeration capacity and the thermal loads. Based on thermal analysis for the magnet, study has been carried out on the stability of cryocooler-cooled superconducting magnet during current excitation.         Stability of superconducting wire with various surface conditions in pressurized He II (1)-experimental results    M. Ohya, S. Shigemasu, Y. Shirai, M. Shiotsu and S. Imagawa Summary: Stability tests were performed for two small test coils wound with NbTi/Cu composite superconducting wires with different surface conditions respectively. One is a 0.5 mm-diameter bare wire with the copper ratio of 1.3. Another is the same wire with chemically oxidized copper surface. The stable limit current under constant magnetic field greatly increased by shifting to He II cooling from He I cooling for both wires, but stationary normal zones were observed in wide current area lower than the stable limit currents for the oxidized wire. The characteristic of the stability of a superconducting wire is more deeply dependent on the conductor surface condition cooled by He II than that in case of He I cooling.         Stability of Superconducting wire with various surface conditions in pressurized He II (2)-numerical analysis    S. Shigemasu, M. Ohya, Y. Shirai, M. Shiotsu and S. Imagawa Summary: We developed a computer code to analyze the stability of a superconducting wire in He II based on the one-dimensional heat equation. We applied to this code our experimental data on heat transfer characteristics of He II, such as Kapitza conductance, critical heat flux and heat transfer curve in film boiling. Using this code, we simulated the recovery or quench process of a normal zone that was initiated by a thermal disturbance for the liquid helium temperatures from 1.8 K to 2.0 K at atmospheric pressure. The numerical solutions agreed with our experimental data for the same characteristics of the wire (bare and oxidized surfaces) and corresponding experimental conditions. We clarified the influences of the surface insulation and the liquid helium temperature on the stability of the superconducting wire.         Experimental evaluation of loss generation in HTS coils under various conditions    T. Hemmi, N. Yanagi, K. Seo, R. Maekawa, K. Takahata and T. Mito Summary: To develop the high performance HTS coil operated in persistent-current mode, loss mechanisms of the HTS coil have been studied. We consider that the loss generation is associated with the shielding current and its temporal variations. To investigate the shielding current characteristics, the decay of shielding currents were measured under various conditions, and we evaluated these effects in simple experiments.         Electrical coupling parameter reconstruction from system model in multistrand superconducting cables    Bing Lu and Cesar Luongo Summary: Current distribution in multistrand superconducting cables has substantial influence on stability. Any analysis of current distribution requires knowledge of the electrical coupling parameters, (e.g., self and mutual inductances, and the interstrand contact conductance). In this paper, a new approach that reconstructs the parameters from distributed parameter circuit model of multistrand superconducting cable is proposed. The strand currents are measured by experiment and treated as known conditions. The unknown parameters are then extracted from the partial differential equations that describe the current distribution. The desired results are found to be the minimum norm least squares solution that best fit the system equations and minimize errors. A code is developed to implement this reverse identification process. The results are validated by substituting the reconstructed parameters to the system equations for simulation and then comparing with current distribution experiments. The parameters are also compared with those from conventional experimental methods, (e.g., DC four-point method to measure interstrand conductance). This method, using parametric identification theory, provides a way to evaluate the electrical coupling parameters in multistrand superconducting cables under different conditions (current density and frequency, mechanical loads, etc.). The calculated parameters can be used in analysis of current distribution and cable stability.         Development and testing of 30 m HTS power transmission cable    Jeonwook Cho, Joon-Han Bae, Hae-Jong Kim, Ki-Deok Sim, Ki-Chul Seong, H.-M. Jang and Dong-Wook Kim Summary: To obtain realistic data on HTS power cable, single-phase 30 m long, 22.9 kV class HTS power transmission cable system have been developed by Korea Electrotechnology Research Institute (KERI) and LG cable Ltd. that is one of 21st century frontier project in Korea. The HTS cable consists of Ag/Bi-2223 tapes, high voltage insulation paper which is impregnated by LN/sub 2/. The cable is rated at 22.9 kV, 50 MVA, 60 Hz and is cooled with pressured liquid nitrogen at temperature from 70 to 80 K. This paper describes the results of design, fabrication and evaluation of the single-phase, 30 m HTS power cable system.         Development of the 22.9-kV class HTS power cable in LG cable    Do-Woon Kim, H.-M. Jang, Chi-Ho Lee, Ji-Hwan Kim, Che-Wung Ha, Yoon-Hyuk Kwon, Dong-Wook Kim and Jeon-Wook Cho Summary: Since 2001, LG Cable has been developing the HTS cable system as a member of national DAPAS project. In 2003, 30 m long cold dielectric HTS cable with 22.9 kV, 1260 A/sub rms/ with single core was fabricated to validate the design concept and long-term performance for 4 months. In this year, 30 m long cable with 3 cores in 1 cryostat has been fabricated and installed to conduct long-term reliability test. At this time, the evaluation of basic properties has been completed and long-term test is in progress. Also, a termination to connect with other conventional power equipment and a cryogenic refrigeration system has been developed concurrently. This paper describes the design, fabrication, and evaluation processes of these two cable systems and gives a chance to take the interim examination of this project through the analysis of test results. In next stage, LG cable plant to develop a splice for a long length cable, a cooling system with high efficiency and capacity, and 154 kV HTS cable system.         Insulation studies and experimental results for high Tc superconducting power cable    H.J. Kim, D.S. Kwag, J.W. Cho, K.C. Seong, K.D. Sim and S.H. Kim Summary: In this paper, we studied electric insulation characteristics of synthetic Laminated Polypropylene Paper (LPP) in liquid nitrogen (LN/sub 2/) for the application to high temperature superconducting (HTS) cable. And, we selected the insulation paper/LN/sub 2/ composite insulation type for the electric insulation design of a HTS cable. Furthermore, we compared the breakdown characteristics of the butt gap and bent mini-model cable that comes into being in this kind of cryogenic insulation type. It is necessary to understand the winding parameter of insulation paper/LN/sub 2/ composite insulation.         A study on the composite dielectric properties for an HTS cable    D.S. Kwag, V.D. Nguyen, S.M. Baek, H.J. Kim, J.W. Cho and S.H. Kim Summary: In order to optimize the insulation design of a cold dielectric high temperature superconducting (HTS) cable, the composite insulation system has been investigated according to the arrangement of laminated polypropylene paper (LPP) and kraft paper in liquid nitrogen. LPP is a prominent insulating material with a high dielectric strength and low dielectric loss, which has been used previously as a HTS cable insulating materials. In addition kraft paper has been used for oil-field (OF) cable as insulating materials for a long time. In this paper, the dielectric properties on composite insulation system according to the arrangement of LPP and kraft paper was compared. The economic and dielectric performances of two insulating materials were considered and applied toward a HTS cable. Furthermore, from an economic satisfaction point the most suitable arrangement, and compared the dielectric properties of the mini-model cables were examined.         Influence of pitch length and winding direction on four-Layer HTSC power transmission cable with a shield Layer    Sung-Hun Lim, Seong-Woo Yim, Si-Dole Hwang and Byoung-Sung Han Summary: The design for even current sharing in high-T/sub C/ superconducting (HTSC) power transmission cable is required to increase the current transmission capacity and decrease the AC loss. Increasing the contact resistance of each layer is effective method for achieving the uniform current distribution among conducting layers. However, this method increases the power loss and causes the efficiency of HTSC cable system to decrease. Another method to adjust the pitch length and the winding direction of each layer is complicated, which is difficult for the cable designer to find a simple solution for the uniform current distribution. In this paper, we investigated the current distribution of HTSC cable dependent on the pitch length and the winding direction of each layer for two cases: four-layer HTSC cable with a shield layer and four-layer HTSC cable without a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC cable could contribute to the improvement of current distribution of each layer at the specific pitch length and winding direction. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.         Application of IPTs to HTS cable conductor for uniform current distribution between their layers    Young-Sun Choi, Seong-Woo Yim, Jungwook Sim, Hye-Rim Kim, Song-Ho Sohn and Si-Dole Hwang Summary: Multi-layer HTS cables are apt to experience unequal current distribution among their layers, which is a main reason of the occurrence of ac losses. In this study, the application of IPTs, which are known to control the impedance among paths of a circuit using a magnetic shield effect, were proposed to solve the problems of HTS cables. A 2 layer HTS cable conductor and IPTs were fabricated using Bi-2223/Ag tapes with a 115 A critical current. The inner layer of the HTS cable conductor was composed of 10 HTS tapes with a pitch length of 18 cm and the tapes of the outer layer were placed straightly without winding pitch. Applying various magnitudes of currents to IPTs, we investigated the current sharing performance between layers of the HTS cable conductor. The applied current was distributed uniformly into the layers successfully. In addition, the performance of IPTs was examined under various conditions for the practical application in detail. From the results, the application of IPTs to HTS cables was considered to be a useful method to reduce ac losses.         Surface spark-over voltage on solid insulator in sub-cooled liquid nitrogen    M. Chiba and T. Nitta Summary: Surface spark-over voltages on solid insulators in boiling and sub-cooled liquid nitrogen are studied under ac, dc and impulse voltage. The insulator structure used is a model of a power cable end. In the structure, static capacitance is formed between outer surface and inner conductor of the insulator. The spark-over voltages for several insulators were measured at gap length 60 mm or less under each voltage waveform. The spark-over voltages increase slightly with increasing gap length in boiling and sub-cooled liquid. In range of shorter gap length spark-over voltages in sub-cooled liquid are higher than those in boiling liquid nitrogen. The differences between spark-over voltages in both liquids are caused by bubbles generated due to discharge at low voltage. The spark-over voltage for the insulator with the larger static capacitance is lower than that for one with the small capacitance.         Analysis of shielding layers in HTS cable taking account of spiral structure    T. Nakamura, H. Kanzaki, K. Higashikawa, T. Hoshino and I. Muta Summary: Analysis code for shielding layers of HTS cable, which was taken account of spiral structure of Bi-2223/Ag tape conductors, was developed based on finite element method. The 66 kV class HTS cable, which was fabricated and successfully tested in cooperation of Tokyo Electric Power Co. (TEPCO) and Sumitomo Electric Industries, Ltd. (SEI), was subjected in this study. Electric field vs. current density property was expressed based on percolation depinning model (Yamafuji-Kiss model). Multifilamentary structure of the tapes and spiral structure of the conductors were directly modeled in order to analyze precisely. Systematic analysis results were presented and discussed.         An investigation of the current distribution in the triaxial cable and its operational impacts on a power system    M.A. Young, M.J. Gouge, M.O. Pace, J.A. Demko, R.C. Duckworth, J.W. Lue and A. Fathy Summary: An investigation of the current distribution in a three-phase triaxial superconducting cable is underway to study phase imbalances under steady-state operation and to assist in the construction of a transient model to study operational impacts of the cable in a power grid. The triaxial cable consists of three superconducting concentric phases inside a copper shield, with each phase composed of multiple layers of BSCCO tape wound helically in opposite directions. Current distribution among the phases of the cable is determined by using an electric circuit (EC) model containing the self and mutual inductances resulting from both axial and tangential fields. An ac loss term is also included in the model. Building on the EC model, a lumped cable model is used to investigate the effects of the triaxial cable on a power grid when faults are applied to the system. Cable lengths practical for future applications (/spl sim/10 km) are considered.         Testing of a 1.5-m single-phase short-sample cable made with copper laminated HTS tapes at ORNL    J.A. Demko, J.W. Lue, R.C. Duckworth, M.A. Young, M.J. Gouge, D. Lindsay, J. Tolbert, M. Roden, D. Willen and C. Traeholt Summary: The use of high temperature superconducting (HTS) materials for power transmission cable applications is being realized in several utility demonstration projects. Tape testing on short-sample cables is conducted to determine the suitability of HTS tapes for use in different cable designs. Testing includes determining the DC critical current, ac loss and overcurrent behavior in a wound cable configuration. The short-sample cable configuration is similar in physical respects, such as winding diameter, winding pitch, application of dielectric, to a practical length cable. With more attention being paid to the short-circuit fault protection, the over-current pulse behavior of the cable will be tested thoroughly. The temperature history of the cable in the radial direction and the re-cooling of the cable will be monitored and compared with a model calculation. This paper describes the testing and results from one such series of tests of a short-sample cable made with copper laminated HTS tapes for use in future projects.         Feasibility study of low-Voltage DC Superconducting distribution system    M. Furuse, S. Fuchino, N. Higuchi and I. Ishii Summary: This paper describes the advantages of using superconducting cables in low-voltage DC distribution systems, focusing on total cost reduction. Demand for DC electric power has been rapidly increasing, requiring reductions in total costs and power supply system losses. The effects of using superconducting cables were investigated by changing parameters such as the current and length of cables, and it is shown that DC superconducting distribution systems are feasible even for small-capacity power systems and savings can be obtained beyond the extra cost of the superconductors and refrigeration systems. In this study, a test model of a DC superconducting distribution system, constructed by modification of an AC superconducting power transmission system, is presented and evaluated.         Manufacturing and installation of the world's longest HTS cable in the Super-ACE project    S. Mukoyama, N. Ishii, M. Yagi, S. Tanaka, S. Maruyama, O. Sato and A. Kimura Summary: The 500 m high temperature superconducting cable (HTS cable) is 77 kV 1 kA single-core cable with LN2-impregnated paper insulation. Demonstration and verification test of 500 m HTS cable has been started from March 2004 and many useful results can be obtained in the test for future practical uses. Furukawa Electric has mainly taken charge of designing, manufacturing and installation of the 500 m cable. In the manufacturing process, the cable could be fabricated without Ic degradation in Ag/Bi-2223 tapes. Moreover, various factory tests were carried out for the 500 m cable. The result of tests showed that the cable has sufficiently satisfied the quality requirement. In the installation, the cable was successfully pulled into a cable duct of 170 m long like actual underground cable installations.         Dielectric properties of 500 m long HTS power cable    T. Takahashi, H. Suzuki, M. Ichikawa, T. Okamoto, S. Akita, S. Maruyama and A. Kimura Summary: The 500-m high temperature superconducting (HTS) cable has been constructed in the Yokosuka area, CRIEPI, by CRIEPI, The Furukawa Electric Co. and Super-GM. Its design voltage is 77 kV and the thickness of the electrical insulation layer should be 8 mm made of semi-synthetic paper (polypropylene laminated paper). During cooling, the capacitance and dielectric loss tangent were measured periodically. After cooling, which means that the HTS cable was fully filled with liquid nitrogen (LN/sub 2/), the initial voltage withstand test was carried out. This paper describes the design method of the electrical insulation layer including determination of the testing voltage and the result of the initial voltage withstand test, and the permittivity calculated from the capacitance, and dielectric loss tangent.         Thermomechanical characteristics of 500-m HTS power cable    M. Ichikawa, M. Kanegami, T. Okamoto, S. Akita, M. Yagi and A. Kimura Summary: A 500-m single-core high temperature superconducting (HTS) cable system has been constructed and tested in Yokosuka area, CRIEPI, by CRIEPI, The Furukawa Electric and Super-GM. In the actual power grid, the HTS cable distance extends sometimes several km. And has to be cooled down from about room temperature to liquid nitrogen temperature. As, the HTS cable is contracted and suffers mechanical stress. In the case of the long distance HTS cable, it remains a major development issue. The HTS cable constructed in this test system has an offset section for absorbing the thermal contraction. In this paper, we describe the validity of that offset section and the thermomechanical characteristics on the cooldown and warm-up test. The offset functioned successfully as designed.         Current distribution analysis in tri-axial HTS cable considering three phases    T. Hamajima, T. Yagai, M. Tsuda and N. Harada Summary: High Temperature Superconducting (HTS) cables have been recently studied because of low loss and compactness, compared with conventional copper cables. We, so far, analyzed current distributions in a single-phase coaxial cable with and without shield current. Three-phase cables are usually composed of the three single-phase cables. However, a tri-axial cable, composed of concentric three phases, has more advantages compared with the three coaxial cables, because of reduced HTS tapes and leakage field. We derive equations governing layer current and current density distributions in the tri-axial cable considering other phases. The current and current density distributions are described as explicit functions of cable construction parameters, such as radius, twist pitch and twist direction. We calculate the homogeneous current and current density distributions by choosing adequate cable construction parameters.         Phase shifts of parallel currents in a single-Layer model of Superconducting cables    F. Gomory, L. Frolek, J. Souc and F. Grilli Summary: To reach large current carrying capability and mechanical flexibility, superconducting cables consist of many single conductors connected in parallel. Distribution of ac current into these parallel paths is controlled by their impedances, which often are not identical. We have found that, even in the case of a cable model made from straight Bi-2223 tapes placed in just one single layer, the nonuniformity of contact resistances causes a dispersion in the amplitudes and phases of ACs in individual tapes. Two models, one analytical and other a Finite Element Model, were used to predict the influence of phase shifts on ac loss and its measurement by an electrical method. Due to phase shifts of local magnetic fields, the purely inductive component of voltage taken by an arbitrary pair of taps is not exactly out-of-phase regarding the total cable current. Then, its product with the cable current is evaluated as a false loss-contributing component. Fortunately, with the use of voltage taps and wires regularly distributed around the cable, true value of ac loss can be recovered.         A novel method of controlling the effective impedance of a cold-dielectric, very low impedance, superconducting cable    T.L. Baldwin, M. Steurer and Yazhou Liu Summary: Cold-dielectric superconducting cables with a shield made of superconductors have the characteristic of very low impedance. This characteristic is beneficial in developing flexible ac transmission networks. The use of low impedance cables result in unequal distribution of power flows with parallel circuits of superconducting cables and conventional transmission lines. This work addresses a method of controlling the effective impedance of a cold-dielectric superconducting cable utilizing the shield current to provide control over the power flows. This control requires only a simple circuit or power electronic device as compared with the more traditional method of using a phase angle regulator.         Development and demonstration of a long length HTS cable to operate in the long island power authority transmission grid    J.F. Maguire, F. Schmidt, F. Hamber and T.E. Welsh Summary: The US Department of Energy is currently funding the design, development and demonstration of the first long length, transmission level voltage, cold dielectric, high temperature underground superconductor power cable. The cable is designed for permanent installation in the Long Island Power Authority (LIPA) grid and is being designed to carry 574 MVA at a voltage of 138 kV. The project is led by American Superconductor and the team is comprised of Nexans, Air Liquide and LIPA. This paper describes the goals of the project, and an overview of the cable design, refrigeration system and site system requirements. It also includes a discussion of the influence of transmission network requirements, such as fault currents, on the design of the cable.         Overview of the underground 34.5 kV HTS power cable program in albany, NY    C.S. Weber, C.T. Reis, A. Dada, T. Masuda and J. Moscovic Summary: A team consisting of SuperPower, Inc. (HTS systems manufacturer), The BOC Group (global industrial gases company), Sumitomo Electric Industries (cable manufacturer), and Niagara Mohawk (electric utility) is developing a 34.5 kV HTS cable for installation in the distribution network in downtown Albany, NY. Energization is projected for the winter of 2005. The cable will be rated for 800 Arms, with all three electrical phases in one cryostat. The 350 m long cable will be pulled through a duct that includes a 90/spl deg/ bend. A field installed underground cable joint will allow for the replacement of a 30 m section of the original first generation HTS cable with a section manufactured utilizing second generation superconductor, in 2006. This paper will summarize the progress made to date and outline future development work.         Cryogenic refrigeration system for HTS cables    R.C. Lee, A. Dada and S.M. Ringo Summary: The cost and reliability of cryogenic refrigeration is key to successful commercialization of High Temperature Superconducting (HTS) cables. This paper describes the design and initial test results of the Cryogenic Refrigeration System (CRS) that will be used in the 350 m HTS cable demonstration at Albany NY. The 34.5 kV/800 A HTS cable will be installed in the distribution power grid of Niagara Mohawk. The CRS will provide a nominal 6 kW closed cycle refrigeration at 77 K, and will have a lower operating temperature of 66 K. The CRS has a core heat exchanger that will accept any mechanical refrigeration unit (cryocooler), and is designed to provide unlimited back-up refrigeration capability. Following the completion of the testing reported in this paper, the CRS will be installed and commissioned at the Albany site beginning late 2004. Once onsite, the CRS will be continuously monitored throughout the HTS cable demonstration using BOC's remote operations infrastructure.         Dielectric characteristics of HTS cables based on partial discharge measurement    N. Hayakawa, M. Nagino, H. Kojima, M. Goto, T. Takahashi, K. Yasuda and H. Okubo Summary: We have discussed dielectric characteristics of liquid nitrogen (LN/sub 2/)/polypropylene (PP) laminated paper composite insulation system for the practical electrical insulation design of high temperature superconducting (HTS) cables. Focusing on the partial discharge (PD) inception characteristics and mechanism, the volume effect and its saturation on PD inception electric field strength (PDIE) was evaluated at atmospheric and pressurized condition. PD inception characteristics under lightning impulse voltage application were also investigated using an electrical and optical PD measuring system, and compared with those under ac voltage application.         Design and experimental results for Albany HTS cable    T. Masuda, H. Yumura, M. Watanabe, H. Takigawa, Y. Ashibe, C. Suzawa, T. Kato, Y. Yamada, K. Sato, S. Isojima, C. Weber, A. Dada and J.R. Spadafore Summary: The Albany Project plans to install a 350 m High Temperature Superconducting (HTS) cable in the power grid of the Niagara Mohawk Power Company to carry 800 Arms at 34.5 kV. The type of the cable has 3 HTS cores in one cryostat with Bi-2223 used for HTS conductor and shield layers. The three cores are housed within double SUS corrugated pipes which provides thermal insulation. The tapes are manufactured with a new innovative sintering method with controlled over pressure (CT-OP) technology. Polypropylene laminated paper (PPLP) is used as electrical insulation. The cable will be installed in long underground conduit. A cable joint will be made in an underground vault to connect a 30 m length of the cable with the remaining 320 m. The original Bi-2223 30 m cable will be replaced with a 30 m YBCO cable after long-term operation. The terminations at both ends of the cable will have three bushings in a cryogenic vessel. Typical performance evaluation experiments, such as cable bending tests, voltage tests, and fault current tests, have been conducted with sample cables to check the design. Voltage tests for 69 kV AC and 200 kV impulse were successfully applied to a 5 m cable in accordance with the Association of Edison Illuminating Companies (AEIC) code of 35 kV class cable. The cable will be manufactured and installed in 2004 and 2005, then, long-term operation will be started.         The SuperCable: dual delivery of chemical and electric power    P.M. Grant Summary: We consider the general design of an "Energy SuperCable" capable of efficient simultaneous transmission of chemical and electric power over long distances. The electrical component consists of wires or tapes of high temperature ceramic superconductors or MgB/sub 2/, while the chemical element comprises liquid or cold gaseous hydrogen or liquid methane. In principle, hydrogen or methane can also serve as cryogens, although for the latter, practical superconducting wire does not yet exist that is able to operate at the required temperature. On the other hand, liquid hydrogen would suffice for present HTSC wire, but one could also consider a "hybrid" design whereby liquid nitrogen is the primary refrigerant and the chemical agent is liquid methane or cold hydrogen gas under pressure. We point out that hydrogen in the SuperCable can perform the dual function of energy delivery and electricity storage on the scale of a pumped hydro facility, the realization of which would revolutionize the marketing of electric power.         Introduction of China's first live grid installed HTS power cable system    Ying Xin, Bo Hou, Yanfang Bi, Haixia Xi, Yong Zhang, A. Ren, Xicheng Yang, Zhenghe Han, Songtao Wu and Huaikuang Ding Summary: China's first HTS power cable project was started in the second half of 2002 and on site system installation was finished at Puji Substation of China Southern Power Grid in March, 2004. This cable system consists of three 33.5 m, 35 kV/2 kA/sub rms/ cables, six terminations, and a closed cycle liquid nitrogen cooling station. The conductors of the cables were made of 4 layers of BSCCO 2223 HTS tapes. Off grid field testing and live grid trial operation has been carried out since the completion of the installation. In this paper, we will report the key technical parameters of the system. Descriptions of the installation site, demonstration of the system installation, and results of testing and trial operation will also be presented and discussed.         R & D of superconductive cable in Japan    A. Kimura and K. Yasuda Summary: Super-ACE (Superconducting AC Equipments) project was started in 2000 fiscal year as a national project to research and develop superconducting AC power equipment. This project goal to develop basic technologies for high temperature superconducting (HTS) cable, HTS fault current limiter (FCL), HTS magnet for reactor and transformer. Main subjects of the cable study are development of: HTS conductor having 3 kA rated current with 1 W/m AC loss, cooling technologies for a 500 m HTS cable with 1 kA rated current, and analytical study of integrated HTS power system. This paper describes major results of studies on the HTS superconductors, and outline and some results of verification test of 500 m cable.         Demonstration and verification tests of 500 m long HTS power cable    T. Takahashi, H. Suzuki, M. Ichikawa, T. Okamoto, S. Akita, S. Mukoyama, N. Ishii, A. Kimura and K. Yasuda Summary: A high-temperature superconducting (HTS) power transmission cable is considered as one of the next-generation power transmission technologies. The introduction of HTS cables into the actual power grid requires a long-distance cooling tube, due to the location of the cooling stations at intervals of several kilometers along the cable length. Therefore, it is essential to understand the flow property of the liquid nitrogen as a coolant for the HTS cable, the current flow properties, electrical insulation characteristics, thermal insulation properties and mechanical behavior for the HTS cable taking into account its long length. This paper provides a brief summary of the HTS cable test system with a length of 500 m constructed in the Yokosuka area of CRIEPI.         Tests of tri-axial HTS cables    M.J. Gouge, D.T. Lindsay, J.A. Demko, R.C. Duckworth, A.R. Ellis, P.W. Fisher, D.R. James, J.W. Lue, M.L. Roden, I. Sauers, J.C. Tolbert, C. Traeholt and D. Willen Summary: The Ultera/ORNL team have built and tested 3-m and 5-m triaxial cables rated at 3 and 1.3 kA-rms, respectively. The three concentric superconducting phases are made of BSCCO-2223 HTS tapes, separated by layers of cold-dielectric tapes. A copper braid is added as the grounding shield on the outside of the three active phases. Tests of these cables were performed at temperatures ranging from 70 to 84 K. AC loss data reconfirmed the previous result on a 1.5-m prototype cable that the total 3-phase ac loss is about the sum of the calculated ac losses of the three concentric phases. These and other test results of the 1.3 and 3 kA cables will be used to construct a second 5-m triaxial cable rated at 3 kA-rms, 15 kV. Preliminary test results supporting this new cable and the associated termination are summarized.         The reliability and quench process of superconductor cable    Weizhi Gong, Ying Xin, Yong Zhang and Yang Wan Summary: Two superconductor cable samples were tested under overload current and the quench behavior of the cables was investigated. The results showed that the quench first began at the weakest spot on the cable and propagated depending on the surrounding thermal conditions. Local thermal runaways, which could permanently damage the cable, would occur if heat is accumulated in small areas. The phase shift angle between the current and voltage could be used as a quench indicator to avoid the thermal runaway, because this angle is especially sensitive to resistance changes in the cable. The cable was quite strong to withstand overload inrush current. The overload current, double of the critical current and lasting 3 s, will not degenerate the performance of the cable. However, too much overload current does impair the cable, or causes its critical current to decrease.         Over-current testing of HTS tapes    J.W. Lue, M.J. Gouge and R.C. Duckworth Summary: High-temperature superconducting (HTS) transmission cables are subjected to short-circuit fault currents 10 to 30 times the normal operating current and lasting up to 15 cycles. These over-currents will drive the HTS conductor normal and generate heat during the fault. A concern is whether the fault current will either electromechanically or thermally damage the HTS conductor and degrade it or burn-out the tape altogether. Electromechanical and thermal limitations of over-current pulses were measured on BSCCO and YBCO tapes in a liquid nitrogen bath. With pulse lengths as short as 35 ms, it is found that single BSCCO and YBCO tapes can be pulsed to at least 1 to 1.2 kA without being damaged electromechanically. Longer pulses at moderate (450-750 A) over-currents indicated that HTS tapes can be heated transiently to over 400 K without suffering degradation. Thus, it is likely that other considerations of the cable rather than the HTS tape itself would set the limit for short-circuit fault protection.         Optimization of transformer winding considering AC loss of BSCCO wire    Jong-Tae Kim, Woo-Seok kim, Sung-Hoon Kim, Kyeong-Dal Choi, Gye-Won Hong, Hyeong-Gil Joo and Song-Yop Hahn Summary: AC loss is one of the important parameters in HTS (High Temperature Superconducting) AC devices. Among the HTS AC power devices, the transformer is an essential part in electrical power system. But, AC loss is one of the most serious problems of the HTS transformer, especially with pancake windings, because high alternating magnetic field is applied perpendicularly to the surface of BSCCO wire in HTS windings of that, comparing with the other HTS AC power devices. For the reason above the calculation of AC loss generated in the HTS windings should be carried out in advance when designing the HTS transformer. In the paper we performed study for optimization of winding design to minimize the magnetization loss of HTS winding such as the spaces between pancake windings and operating temperature of HTS wire. The calculation of the AC loss was accomplished by 2-dimensional Finite Element Method.         Low-cost dielectrics for power distribution transformers    T. Bodziony, T.L. Baldwin, S. Pamidi and S.J. Dale Summary: With the continuing improvements in HTS conductors, the application to power distribution transformers becomes possible as well as economical. To realize a viable design, many system aspects must be addressed including the thermal and dielectric characteristics of the winding insulation. This work reports on the study of cellulose-based dielectric insulation and transformer-board for dry-type (conduction cooled), 50 kVA to 5000 kVA, medium-voltage, high-temperature superconductor transformers. Results of electric-field strength studies and tests are presented.         Tests of a Bi/Y transformer    P. Tixador, Y. Cointe, T. Trollier, E. Maher and A. Usoskin Summary: In the context of a European project (READY) we designed, constructed and tested a single phase transformer. The primary winding uses a PIT-Bi-2223 tape. The secondary is wound with two lengths (2 /spl times/ 8 m) of YBCO coated conductor. With these two lengths in series, the secondary characteristics are 75 V-50 A at 77 K. We designed the transformer with an integrated refrigerator. The cooler is a high cooling capacity (100 W at 80 K) single stage coaxial pulse tube cooler (PTC) developed by Air Liquide. We chose a cold magnetic circuit with low iron loss FeSi sheets. The cryostat is then very simple with metallic vessels and only one interface with the PTC, and the cooling fluid is helium in order to investigate a wide temperature range (40-80 K). About 30 hours are required to reach 70 K from 300 K using only the PTC. This paper presents the transformer layout and some electrical tests (no load and short circuit tests). The ac losses are high in the PIT coil, but in good agreement with numerical simulations. In the YBCO coil the ac losses are lower and in good agreement with the Norris formula.         Active damping of inrush and DC-currents for high temperature Superconducting (HTS)-transformers on rail vehicles    M. Meinert and A. Binder Summary: The 1-MVA-HTS-transformer made by Siemens promises a high-efficient drive component as has been reported-even if a converter is used and additional AC-losses occur. HTS-transformers on rail vehicles have to meet different demands on the energizing to the grid. Due to the small resistance, the damping of DC-components of inrush currents or due to the bouncing of pantographs is insufficient. Additional damping devices, especially a switched resistor, promise a well-working solution. On the other hand, additional costs and mounting space will be caused. But what would be possible, if we would consider the use of already implemented on-board equipment like traction converter to fulfill the given demands on the inrush current? The DC-components may be damped by an active switching of the installed converters. Investigations, results and influences on the transformers behavior of the mentioned operations by using the on-board converters to meet the demands of railroad companies will be presented here.         Influence of the shape in the losses of solenoidal air-core transformers    P. Suarez, A. Alvarez, B. Perez, D. Caceres, E. Cordero and J.-M. Ceballos Summary: The losses in an HTS tape depend strongly on the perpendicular magnetic field. In order to avoid this magnetic field component in an air core transformer, a toroidal geometry was proposed and studied in previous work. Due to the difficulties that one finds in constructing toroidal coils, the straight solenoidal geometry is now under study. In this case, the magnetic field close to the ends of the coil is not parallel to the axis and a perpendicular component appears. In the present work, the losses due to this component are studied as a function of the coil geometry-i.e., the ratio between length and diameter-and a practical formulation is found.         Recovery characteristics after current limitation of high temperature superconducting fault current limiting transformer (HTc-SFCLT)    C. Kurupakorn, H. Kojima, N. Hayakawa, M. Goto, N. Kashima, S. Nagaya, M. Noe, K.-P. Juengst and H. Okubo Summary: Superconducting Fault Current Limiting Transformer (SFCLT) is one of the promising superconducting power apparatus, since it has both functions of superconducting transformer in normal condition and superconducting fault current limiter in fault condition. In this paper, current limiting and the recovery tests of high temperature SFCLT (HTc-SFCLT) with MCP-BSCCO2212 bulk coils were performed at liquid nitrogen temperature. Experimental results revealed that the HTc-SFCLT could successfully recover into the superconducting state by itself immediately after the fault clearance. Moreover, the recovery criterion of HTc-SFCLT as a function of load current was clarified.         Insulation test of reciprocal and concentric winding arrangement for a HTS transformer    S.M. Baek, D.S. Kwag, H.J. Kim, M.S. Yun and S.H. Kim Summary: In Korea, the Hyosung Industrial, Korea Polytechnic University and Gyeongsang National University are developing a power distribution and transmission class HTS transformer that is one of the 21st century superconducting frontier projects. For the development, it is necessary to establish the dielectric technology at cryogenic temperature such as insulating design, cooling system, manufacture, compact, and so on. Also, verification of insulating stability is an important dielectric technology. Therefore, we prepared two models, one is concentric arrangement, the other is reciprocal arrangement, from Kapton insulated Cu tape for a small simulated HTS transformer and measured their insulation characteristics such as PD, ac (50 kV, 1 min) and impulse (154 kV, 1.2/spl times/50 /spl mu/s) withstand test. Before manufacture of each model, we have analyzed insulation composition and investigated electrical characteristics such as breakdown of LN/sub 2/, polymer and surface flashover on FRP in LN/sub 2/. We are going to compare with measured each value and apply the value to most suitable insulating design of the HTS transformer.         Design of the 3 phase 60 MVA HTS transformer with YBCO coated conductor windings    Chanjoo Lee and Bok-Yeol Soek Summary: In this paper, a 3 phase 60 MVA high temperature superconducting (HTS) transformer was designed with YBCO coated conductor windings and its characteristics were analyzed. First, an automatic calculation program for HTS transformer design was developed, in which the Ic-B characteristics of HTS tape was considered. Using the calculation program, basic dimensions of windings and iron core were determined and electromagnetic field analysis was performed for the loss computation. Finally, efficiency, weight and wire length of HTS transformer with coated conductor winding were calculated. The efficiency was over 99.9%, which is higher than that of any conventional transformer. The weight of the HTS transformer was about 16.6 tons and the length of HTS wire was about 47 km when the voltage per turn is 89.7234. Moreover, the magnetization AC loss of coated conductor winding was very small compared with that of BSCCO-2223 winding. To reduce the AC losses, we introduced the low current density winding method in all windings and the magnetization loss was reduced to about 66% of that of general winding.         A study on mitigation method of perpendicular magnetic field in HTS superconducting coils for power transformer    Bok-Yeol Seok and Chanjoo Lee Summary: Methods to mitigate a perpendicular magnetic field component on the surface of a high temperature superconducting (HTS) tape in HTS coils by arranging low current density (LCD) coils in the edges were studied analytically. Four types of winding arrangement with and without the LCD coils at both edges of the superconducting winding, which are used to model a three-phase 40 MVA HTS transformer, were proposed. The results of magnetic field analysis in the proposed winding arrangements reveal that (1) the maximum perpendicular magnetic field (B/sub /spl perp/max/) on the surface of the HTS tape is influenced markedly by the LCD coils arrangements and that (2) the winding arrangement which is LCD coils installed in both edges of top and bottom in the LV and the HV winding is very effective in reducing the B/sub /spl perp/max/ in both edges of top and bottom.         Fabrication of inner secondary winding of high-T/sub C/ superconducting traction transformer for railway rolling stock    H. Kamijo, H. Hata, H. Fujimoto, K. Ikeda, T. Herai, K. Sakaki, H. Yamada, Y. Sanuki, S. Yoshida, Y. Kamioka, M. Iwakuma and K. Funaki Summary: We studied the possible application of high-T/sub C/ superconducting traction transformer to railway rolling stock, and designed an iron core type two-leg 4 MVA superconducting traction transformer for Shinkansen. This traction transformer has a primary winding, four secondary windings and a tertiary winding. The four secondary windings are independent of each other. Two secondary windings are arranged around each leg of the iron core and placed inside and outside the primary and tertiary windings. In this study, we fabricated a high-T/sub C/ superconducting coil whose form and dimension are the same as those of the inner secondary winding. This coil can be used as the inner secondary winding of the experimental high T/sub C/ superconducting traction transformer that will be fabricated in the future. The inner secondary winding has 96 turns and a layer with eight parallel Bi2223 superconducting tapes. Transposition among the superconducting tapes is performed 15 times every six turns. We measured the voltage-current and AC loss characteristics when it was cooled in saturated and sub-cooled liquid nitrogen.         Transient thermal characteristics of cryocooler-cooled HTS coil for SMES    A. Ishiyama, M. Yanai, T. Morisaki, H. Ueda, S. Akita, S. Kouso, Y. Tatsuta, H. Abe and K. Tasaki Summary: Thermal behavior of high-temperature super-conducting (HTS) coil is exceedingly different from that of low-temperature superconducting (LTS) coil. Therefore for the sake of the application of HTS coil to practical use, establishment of a new stability criterion for coil design becomes indispensable. In this study, a small-sized cryocooler-cooled HTS coil wound with Bi-2223/Ag tape was constructed and tested to evaluate the electromagnetic and thermal characteristics in the cryocooler-cooled HTS coil. We carried out experiments subjected to pulse current operation supposing SMES for power system stabilization. The simulation by a newly developed computer program based on the finite element method (FEM) agreed well with experimental results. In the computer program, short-sample data concerning the E-J characteristics, which depend on the orientation of applied magnetic field to the wide face of Bi-2223Ag tape, was adopted. By using the computer program, we also evaluate the thermal behavior of HTS coil graded according to the magnetic field distribution.         Control design of STATCOM with superconductive magnetic energy storage    Hui Li, D. Cartes, M. Steurer and Haibin Tang Summary: This paper describes the control design of a SMES power conditioning system for static reactive power compensation at distribution voltage levels. This system comprises a five-level voltage source inverter and a five-level two-quadrant chopper fed from SMES. Due to the high order nonlinear nature of multilevel converters, a multivariable control method is proposed to enable high-bandwidth control of power transfer to and from the SMES coil. Theoretical analysis of the controller design and the simulation results are presented.         Frequency response characteristics of a 100 MJ SMES coil - measurements and model refinement    M. Steurer and W. Hribernik Summary: Operating the coil of a superconducting magnetic energy storage (SMES) system through a switching type electronic power supply may excite resonances within the coil, thus potentially leading to internal over voltages. The latter may cause degradation of the dielectric insulation over time or, in severe cases, even damaging of the insulation. This paper complements theoretical investigations of these frequency selective voltage amplifications previously published by the authors by comparing them with measurements taken on the assembled 100 MJ/100 MW low-T/sub C/ SMES coil stack at room temperature. It has been found that surrounding metal structures such as the temporary mounting plane cause additional damping of resonances. Incorporating the latter into the theoretical model still results in internal voltage amplifications of up to two per units which have been verified by measurements. It is concluded that even with additional damping effects the potential problem of over voltages within large SMES coils persists and that it can be avoided by a careful design of the power electronic interface utilizing a comprehensive computer model of the system.         Stability evaluation of a conduction-cooled prototype LTS pulse coil for UPS-SMES    A. Kawagoe, F. Sumiyoshi, T. Mito, H. Chikaraishi, R. Maekawa, K. Seo, T. Baba, T. Henmi, K. Okumura, M. Iwakuma, K. Hayashi and R. Abe Summary: The stability of a prototype conduction-cooled LTS pulse coil for UPS-SMES of 100 kJ was evaluated. This coil has been developed as a first step of a project to develop a 1 MW, 1 UPS-SMES to protect semiconductor chip production equipment and nuclear fusion experimental devices, etc, from momentary voltage drop and power failure. The winding conductor is an NbTi/Cu Rutherford cable, which is extruded with aluminum. This conductor has both low AC losses and high stability under specified orientation of changing transverse magnetic fields. The 100 kJ-coil are wound by the new winding method. In order to improve the heat conduction properties in the coil, Dyneema FRP and Litz wires are used as spacers. Litz wires were connected with the cryocooler as cooling paths. On the pulse operation, the operating current is reduced from 1000 A to 707 A in 1 s. In this paper, the thermal properties of the 100 kJ-coil are calculated by finite element method under pulse operation. In order to estimate the stability, a calibration experiment was carried out. Results indicated that our prototype LTS pulse coil has high stability to enable to allow over 10 times as large heat as AC losses.         Design of bi-2223/Ag coil based on genetic algorithm and finite element method    K. Higashikawa, T. Nakamura, T. Hoshino and I. Muta Summary: We designed Bi-2223/Ag coils based on genetic algorithm and finite element method. The winding geometry as well as the operating current of the coil was optimized for the minimization of its loss, on condition that its operating temperature, stored energy and total length of the conductor were constant. The loss was calculated with the use of the analytical expressions that could quantitatively describe the current transport characteristics in high T/sub c/ superconductor including their magnetic anisotropy and temperature dependence. Some optimized results were shown and discussed in this paper.         Design and preliminary results of a prototype HTS SMES device    C.J. Hawley and S.A. Gower Summary: The University of Wollongong (UOW) has developed the design for a 20 kJ high transition temperature Superconducting Magnetic Energy Storage (SMES) device, and constructed a nominally 2.5 kJ prototype. The coil for the prototype was wound using High Temperature Superconducting (HTS) BSCCO-2223 tape. It was refrigerated to 20 K using a gaseous helium cold head cryocooler. The SMES device has been constructed as a prototype for a larger commercially realizable system, and hence is capable of supplying a 3-phase load during voltage sags or short (<1 s) power interruptions. This paper discusses the modeling and design of the electromagnetic and thermal aspects of the coil, the Power Control Circuit (PCC), current leads and cryogenic system. Also presented are preliminary results of the SMES coil, cryogenics, and system energy storage and delivery capabilities.         A 150 kVA/0.3 MJ SMES voltage sag compensation system    Xiaohua Jiang, Xiaoguang Zhu, Zhiguang Cheng, Xiaopeng Ren and Yeye He Summary: To protect a 110 kVA critical load from voltage sags, a demonstration SMES-based voltage sag compensator has been developed and tested. This system consists of a 150 kVA IGBT (Insulated Gate Bipolar Transistor) current source converter, a 0.3 MJ NbTi magnet and three phase-shift inductors. Experiments were carried out to test the compensation performances for both balanced and unbalanced voltage sags with a 110 kW load of resistance. The results show that the load voltage recovers in less than one cycle (20 ms) whenever a three-phase or single-phase voltage sag occurs.         Design of a 800 kJ HTS SMES    P. Tixador, B. Bellin, M. Deleglise, J.C. Vallier, C.E. Bruzek, S. Pavard and J.M. Saugrain Summary: In the context of a DGA (Delegation Generale pour l'Armement) project, we have designed and are going to build a 800 kJ SMES. It is based on Bi-2212 PIT tapes from Nexans operating at 20 K. Their engineering current densities exceed 300 MA/m/sup 2/ at 20 K and 5 T making them excellent candidates. The coil consists in 26 stacked pancakes (O = 814 mm; h = 182 mm). The conductor is made of 4 soldered tapes or 3 soldered tapes + one stainless steel tape depending on its location inside the coil. The stainless steel significantly reinforces the conductor. The conductor is insulated by Kapton. To make the cryogenics very transparent and easy for the SMES user, the coil is conduction cooled using a large capacity Gifford-McMahon cycle cryocooler. The SMES design is presented as well as some qualification tests (critical stresses, connections, etc.) for the key issues of the project.         Construction of a 7-T force-balanced helical coil    S. Nomura, Y. Ohata, T. Hagita, H. Tsutsui, S. Tsuji-Iio and R. Shimada Summary: Force-Balanced Coil (FBC) is a helically wound toroidal coil that can minimize the required mass of its structure by selecting an optimal number of poloidal turns per toroidal turn. A 7-T Force-Balanced Coil (7-T FBC) was designed in order to demonstrate the feasibility of the FBC concept for high field superconducting magnets. The 7-T FBC with an outer diameter of 0.53 m will have 270-kJ stored magnetic energy at maximum magnetic field of 7.0 T. This coil is a hand-made coil using NbTi superconductor. The maximum working stress of the 7-T FBC is lower than the elastic limit of the Cu matrix so that the 7-T FBC can be excited up to the rated magnetic field of 7.0 T without reinforcing materials for the NbTi strand. The winding form is made of aluminum alloy and slots are cut on its surface with the shape of the helical winding with a numerically controlled (NC) lathe. The experiments will be conducted with pool boiling liquid helium cooling in order to measure the quench properties of the 7-T FBC and evaluate the working stresses in the helical windings.         A hybrid energy storage with a SMES and secondary battery    T. Ise, M. Kita and A. Taguchi Summary: An energy storage device with high energy density and high power density is desired for compensation of fluctuating loads such as railway substations and distributed generations such as wind turbines. Typically, a SMES (Superconducting Magnetic Energy Storage) has higher power density than other devices of the same purpose, and secondary batteries have higher energy density than SMES. In this study, the authors propose a hybrid energy storage system composed of a superconducting magnet and secondary battery for an energy storage system with high energy density and high power density. The sharing method of power for each storage device using a Fuzzy control and filters, simulation for the compensation of railway loads and the power of wind turbines are presented.         Characteristic test of HTS pancake coil modules for small-sized SMES    Ji Hoon Kim, Woo-Seok kim, Song-Yop Hahn, Jae Moon Lee, Myung Hwan Rue, Bo Hyung Cho, Chang Hwan Im and Hyun Kyo Jung Summary: In this paper, 16 HTS pancake coil modules made with 32 double pancake coils were designed, analyzed, built, assembled, and tested to show feasibility of small sized HTS SMES (/spl mu/-SMES). Rated current is 200 A and operating temperature is 20 /spl sim/ 30 K. Evolution strategy was used for coil optimization and FEM was used for magnetic field calculation. After building the modular toroid coils, a vacuum chamber was built to contain the coil. Three GM cryocoolers were used to reach the operating temperature. Bridge type converter was used to supply the current to the SMES coil modules. Operation showed a close agreement with the calculated result.         On-line steady state security assessment of power systems by SMES    Yong Min, Zifeng Lin, Jiageng Qiao and Xiaohua Jiang Summary: The response-based on-line steady state security assessment method of power systems can prevent influences of inaccuracy of models and parameters used in theoretical calculations and numerical simulations. With the aid of a grid model SMES system producing the specially designed disturbance signals, experiments were carried out in a simple power system to demonstrate the feasibility of the method. The results of experiments are then compared with that of calculations and simulations. The study indicates that the response signal of the power system being disturbed contains information of low-frequency oscillation modes and can be used as an index to the degree of steady state security of power systems.         An optimal configuration design method for HTS-SMES coils    S. Noguchi, A. Ishiyama, S. Akita, H. Kasahara, Y. Tatsuta and S. Kouso Summary: Recently, the properties of high temperature superconducting tapes have been in advance and high temperature superconducting magnets have been constructed and demonstrated. However, the high temperature superconducting tapes have different thermal characteristics compared with low temperature superconducting wires. Therefore, it is necessary to consider these characteristics of high temperature superconducting tapes at the magnet design stage. We proposed an optimal design method for superconducting coils wound with Bi2223/Ag tapes. In this paper, the configuration of 72 MJ SMES coils wound with Bi2223/Ag tapes are optimized.         Development of MVA class HTS SMES system for bridging instantaneous voltage dips    K. Shikimachi, H. Moriguchi, N. Hirano, S. Nagaya, T. Ito, J. Inagaki, S. Hanai, M. Takahashi and T. Kurusu Summary: A SMES system of MVA class for bridging instantaneous voltage dips has been developed using Bi-2212 wire. The Bi-2212 wire has high-performance conductive characteristics that do not deteriorate at a low temperature in high magnetic fields beyond 10 T. These characteristics enable a compact design of a SMES system of the Bi-2212 wire. In addition, coils of the Bi-2212 wire can be adequately insulated due to a high temperature margin. Therefore, the SMES system designed by using the coils has advantages to enhance dielectric strength and output power of the system. In our previous study, a SMES system consisting of 4 unit coils was constructed and the various properties were examined. Up to the present, the total 18 unit coils were stacked to make a coil system (outer diameter: 700 mm, height: 554 mm, stored energy: 984 kJ) and installed into a SMES system of 1 MVA for bridging instantaneous voltage dips. Also, the cooling system of the HTS SMES has been improved. The characteristics of the conduction cooled HTS coils of 1 MJ class were investigated in the operations of 1 MVA SMES system for bridging instantaneous voltage dips. Thermal reliability was verified during each operations of exciting, standby, bridging and current damping. Moreover, the repetitive bridging operations even worked out every 5 minutes. Advantages of the conduction cooled HTS coils for SMES were verified.         Prototype development of a conduction-cooled LTS pulse coil for UPS-SMES    T. Mito, A. Kawagoe, H. Chikaraishi, K. Okumura, R. Abe, T. Henmi, R. Maekawa, K. Seo, T. Baba, M. Yokota, Y. Morita, H. Ogawa, K. Yamauchi, M. Iwakuma and F. Sumiyoshi Summary: We are planning to develop a 1 MW, 1 sec UPS-SMES for a protection from a momentary voltage drop and an instant power failure. As the first step, we have been developing a 100 kJ class prototype UPS-SMES, using a low temperature superconducting coil because of its better cost and performance over the high temperature superconducting coil. However, the difficulty to utilize a pool-boiling LTS pulse coil is the reliability of operation. To solve this problem, a conduction-cooled LTS pulse coil has been designed and fabricated as a key component of the UPS-SMES. The reduction of AC loss and high stability are required for the SC conductor for the conduction-cooled coil because of a limited cooling capacity. The SC conductor of a NbTi/Cu compacted strand cable extruded with an aluminum is designed to have the anisotropic AC loss properties to minimize the coupling loss under the specified orientation of the time varying magnetic field. The coil was wound with a new twist-winding method in which the variation of twist angle of the conductor was controlled with the winding machine designed specifically for this purpose. The fabrication technique and performance of a conduction-cooled prototype LTS pulse coil are described.         Eddy current heating in micro-SMES bus-bars    J.M. Pfotenhauer, J.P. Blanchard and C.J. Martin Summary: Results from numerical models and theoretical analyses are presented that describe the development of eddy current heating in copper bus bars, both with and without superconducting elements, in response to the rapid decay of current in a nearby superconducting magnet such as in micro-SMES systems. The analysis differs from those available in the open literature in that the change of magnetic field is neither instantaneous, nor sinusoidal. We especially investigate eddy current heating in the regime where the field decay time is on the order of the current diffusion time constant. It is found that the self-inductance of the copper bus bar contributes significantly to the time dependent heat generation. Analytical results are compared to experimental data in the form of subsequent temperature excursions of a liquid helium cooled copper bus, in response to field ramp rates on the order of 1.5 tesla/second.         A multilevel power conditioning system for superconductive magnetic energy storage    Hui Li, T.L. Baldwin, C.A. Luongo and Da Zhang Summary: The introduction of multilevel converters makes possible the use of pulse width modulation (PWM) converters and fast switching medium power devices like insulated gate bipolar transistors (IGBTs) for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS). This paper proposes a five-level voltage source inverter (VSI)-chopper for a superconductive magnetic energy storage (SMES) power conditioning system (PCS). The circuit topology and operation principles are presented. The advantages of the proposed power conditioning system have been investigated and compared with present PCS including a traditional transformer coupled multi-pulse VSI-chopper topology. The validity of the system is verified by computer simulation.         Research and development of high-T/sub c/ SMES    A. Ichinose, H. Kasahara, H. Sakaki, S. Akita, A. Ishiyama, A. Maruyama and S. Koso Summary: High-T/sub c/ superconducting technology is thought to provide many merits for SMES systems. For example, a cryocooled system can be used as a cooling system for High-T/sub c/ superconducting coils, indicating that an operation temperature can be selected from a wide-temperature range below critical temperatures. Refrigerator cooling operation temperature for High-T/sub c/ SMES can be elevated more than 20 K from conventional 4.2 K. As a result, the heat capacity of coil system becomes much larger than that at 4.2 K, indicating that thermal diffusion time constant becomes much longer. If we could absorb transient heat generation with heat capacity of the coil, SMES systems can be designed under the over current state of critical current for a short duration. As a cooling capacity for an average heat load will be enough to cool High-T/sub c/ superconducting coil system for SMES, the refrigerator system cost can be much lower than that for a SMES system using Low-T/sub c/ superconductors. Moreover, we are developing high critical current superconducting wire for SMES system. The Bi2212 Rutherford conductors can carry 4 kA at 26 K under cryocooling. We also estimate the superconducting wire cost of the whole coil system, which is designed to minimize the superconductor volume. The conclusion is that the cost of High-T/sub c/ SMES system will be reduced by using the low-cost YBCO superconducting wires in the future.         Wind farms linked by SMES systems    S. Nomura, Y. Ohata, T. Hagita, H. Tsutsui, S. Tsuji-Iio and R. Shimada Summary: The objective of this paper is to introduce the concept of wind farms linked by SMES systems. In this work, the SMES system is applied to a wind farm that is interconnected with a grid through a back-to-back DC link for the variable speed operation of the wind turbines. This system enables the output power leveling of the wind farm depending on the power demand and can reduce the capacity of the converter system by selecting an optimal discharge/charge rate of the SMES. By using the stored energy of the SMES, this system can also compensate the inertia of the blades so that the wind turbine speed can be rapidly controlled depending on the wind condition. This paper describes the design condition of the SMES for the output power leveling of the wind farm and discusses the SMES configuration for a 100-MW class wind farm.         CURL 10: development and field-test of a 10 kV/10 MVA resistive current limiter based on bulk MCP-BSCCO 2212    J. Bock, F. Breuer, H. Walter, S. Elschner, M. Kleimaier, R. Kreutz and M. Noe Summary: Within the German project CURL 10 a full scale three-phase resistive current limiter was developed and successfully tested up to the nominal voltage and power (10 kV, 10 MVA). This is up today the largest HTS current limiter world wide. The device is based on bifilar coils of MCP-BSCCO 2212 bulk material and operates at T=66 K. Per phase 30 components are connected in series in order to obtain the required resistance. The electrical stabilization is based on a metallic shunt contacted continuously to the superconductor and allows electrical fields up to 0.6 V/cm. We report on the development of the superconducting components and their large-scale manufacturing processes including material, contacts, mechanical stabilization, high voltage insulation and quality control. In a series of preliminary small scale tests at different temperatures as well as in the final tests with the full scale prototype reliable current limitation could be demonstrated in the full range of prospective fault currents, also in the particular dangerous small load regime. Since April 2004 the demonstrator has been installed within a field test in the grid of RWE.         System technology and test of CURL 10, a 10 kV, 10 MVA resistive high-Tc superconducting fault current limiter    R. Kreutz, J. Bock, F. Breuer, K.-P. Juengst, M. Kleimaier, H.-U. Klein, D. Krischel, M. Noe, R. Steingass and K.-H. Weck Summary: A full scale three-phase resistive high-Tc superconducting fault current limiter (SCFCL) designed for 10 kV, 10 MVA, has been developed, manufactured, and tested within a publicly funded German project called CURL 10. The device is based on 90 bifilar coils of MCP BSCCO-2212 bulk material. The operating temperature of 66 K is achieved by cooling of liquid nitrogen using two Stirling cryocoolers. Until today, this is the largest HTS fault current limiter world wide. We report on the design features, the composition, and the operation parameters of the SCFCL system. From April 2004 on CURL 10 is installed and tested within the network of the utility RWE at Netphen near the city of Siegen, Germany. The results of the laboratory test and the field test of CURL 10 are given.         Design and manufacturing of the large scale high-T/sub c/ superconducting DC magnet for the 2.3 MVA SFCL    Duck Kweon Bae, Hyoungku Kang, Min Cheol Ahn, Yong Soo Yoon and Tae Kuk Ko Summary: To develop a High-T/sub c/ superconducting (HTS) magnet that is applicable to the high voltage electric device applications, it is necessary to consider several important factors such as large critical current, reliable electric insulation system, stable cryogenic status, expected economic benefits, and so on. This paper deals with the skills to design and manufacture the high voltage HTS DC magnet accepting large pulse input current. The multi-stacked HTS solenoid winding was suggested for the HTS magnet having large critical current. To protect the HTS winding, when quenched, the copper layer was suggested as a buffer sharing the large pulse current. The thin grooves on the GFRP bobbins not only guide the HTS winding but also play the role of electrical insulation for the high voltage application. With regard to the thermal stability of the magnet, sub-cooled liquid nitrogen cooling system was used for the cooling system of the HTS DC magnet. To reduce the resistance of the normal conducting parts in the HTS magnet, several HTS tapes were additionally attached on these parts. Based on this study, the HTS DC magnet for the 2.3 MVA class high-T/sub c/ superconducting fault current limiter (HTSFCL) was successfully manufactured and tested. The HTS DC magnet developed by this study endured 2.53 MJ (18.66 MW/sub max/) without any evidence of quench.         Fundamental Characteristics of Y123 thin film for switching surge current to design SCFCL    J. Baba, T. Higata, M. Chiba and T. Nitta Summary: Superconducting Fault Current Limiters (SC-FCLs) have been expected not only to reduce fault current but also to improve power system stability. For introducing them, various kinds of characteristics, such as trigger current level, must be examined. They should be designed not to be triggered by switching surge that comes from out of the target section. In this paper, fundamental characteristics of SCFCL for surge current have been studied. Y123 thin films with Au protection layer on sapphire substrate have been prepared, and the voltage-current characteristics have been measured. The measurements have been carried out by use of the impulse and sinusoidal currents to evaluate the characteristics of Y123 thin film for switching surge. The relation between operational current levels and their operational times and the relation between operational current levels and the wave front times are shown in the paper. These characteristics are useful for designing the SCFCL which will not to be triggered by switching surge.         Semi-empirical correlation for quench time of inductively coupled fault current limiter    Y.S. Cha Summary: Experimental results on the quench time of an inductively coupled fault current limiter are presented. The quench time is defined as the period between the initiation of the fault and the time when the device begins to limit the current. The experimental results show that the fault current limiter begins to limit the current well before the superconductor is fully quenched. A semi-empirical model, based on a lumped-parameter circuit analysis, is developed to predict the quench time. The model assumes that the average power dissipated in the fault current limiter is used to heat up the superconductor. The derived equation indicates that the quench time depends on the properties of the superconductor, the design parameters of the fault current limiter, and the system parameters. There is very little dissipation in the superconductor when the system voltage is less than the critical voltage of the superconductor. Therefore, the overvoltage (system voltage minus the critical voltage), instead of the system voltage, should be used in calculating the quench time. The quench time calculated from the semi-empirical correlation agrees well with experimental data.         Research & development of superconducting fault current limiter in Japan    K. Yasuda, A. Ichinose, A. Kimura, K. Inoue, H. Morii, Y. Tokunaga, S. Torii, T. Yazawa, S. Hahakura, K. Shimohata and H. Kubota Summary: R&D of fundamental technologies for superconducting AC Power equipment (Super-ACE project) started as a national project, for a five-year plan since fiscal 2000 by MITI and NEDO. This project is to research and develop the basic technology of super-conductive cable, fault current limiter and transformer. This paper summarizes the research and development of following 2 types FCL. The R&D of the SN transition resistive type superconducting thin film fault current limiter aims to establish large-current/high-voltage technology by arranging films in multi-parallel/series, and increasing the current-carrying capacity through widening the area of the thin film of the current limiting element. The R&D of the reactor for a rectifier-type fault current limiter using coils of superconducting wire of the Ag sheath Bi2223 tape, aiming to apply it to high-voltage systems.         Proof-of-concept prototype test results of a superconducting fault current limiter for transmission-level applications    Xing Yuan, K. Tekletsadik, L. Kovalsky, J. Bock, F. Breuer and S. Elschner Summary: SuperPower, Inc. and Nexans SuperConductors GmbH have partnered to develop a superconducting fault current limiter for transmission level applications. The device employs SuperPower's Matrix Fault Current Limiter (MFCL) technology and BSCCO-2212 bulk material manufactured by Nexans' melt cast processing technique. The development program has been underway since June 2002 and is divided into a series of prototype demonstrations of progressive capability, culminating in a Beta prototype that will be installed at a host utility on a 138 kV line. This paper describes the test results of the first major program milestone, a proof-of-concept prototype at distribution level voltage. The test results show the expected current limiting performance of the MFCL technology to provide fast current limiting and dynamic resistance development before the first peak of the fault. The fault current evenly distributes among the elements of the MFCL array, which employs a resistive-inductive approach for limiting the current. The results also show the excellent electric field performance of the BSCCO-2212 material.         Test of a 1 kA superconducting fault current limiter for DC applications    H.-P. Kraemer, W. Schmidt, B. Utz, B. Wacker, H.-W. Neumueller, G. Ahlf and R. Hartig Summary: A low voltage fault current limiter (FCL) having a nominal current of 1 kA has been set up using switching elements based on YBCO thin films fabricated by reactive thermal co-evaporation. The films showed critical current densities exceeding 1 MA/cm/sup 2/ @ 77 K. After patterning and contacting the films, the elements have been assembled in a closed cryostat for operation in a liquid nitrogen bath. The FCL model was successfully tested using prospective fault currents from 25 kA to 150 kA. The electric data show a peak current of 2.7 kA within 1 ms and a limitation to approximately nominal current within 5 ms. Due to this fast response of the YBCO switching elements, FCL coupled grids can be instantaneously decoupled during a fault, leaving the faultless part of the grid practically unimpaired.         Test of YBCO thin films based fault current limiters with a newly designed meander    L. Antognazza, M. Decroux, M. Therasse, M. Abplanalp and Y. Fischer Summary: To facilitate the up scaling of thin film based fault current limiters (FCL), a complete control of the localization of the dissipated power is needed. This control can be achieved by a new design where constrictions, which are regularly located along the YBCO/Au meander, have the aim of localizing and homogenizing this dissipated power at the beginning of a short circuit. To minimize the initial power peak, the resistivity of the constrictions has to be as small as possible whereas the resistivity of the connecting paths should be increased in order to lower the long-term power. We have tested these expected improvements on 5 kW (340 V, 16 A) FCL, on 2'' wafers, in AC conditions. The observed behavior of the FCL during short circuits, initiated at fault angles, confirm that the dissipated power is minimized and distributed, in a controlled way, along the meander. Finally we present measurements of the self-restoring time of the FCL and test on a 10 kW FCL made of two wafers connected in parallel.         A new low-loading HTS current switch triggered by RF signals    Jianwei Liu, R.R. Mansour and M.M.A. Salama Summary: A new low-loading HTS Superconductive-Normal (S-N) current switch using a YBCO thin film stripe is introduced in this paper. Low cost 2.45 GHz microwave signal is applied as the triggering method. Two configuration patterns, cavity layout and transmission line layout, have been tested in the experimental environment. Reliable 100 ms S-N switching is observed with transmission line layout where the loading current is set below 5% of the critical current (Ic). This work demonstrates that a high frequency RF signal is an applicable approach for S-N switch development.         3-D finite element Simulations of strip lines in a YBCO/Au fault current limiter    J. Duron, L. Antognazza, M. Decroux, F. Grilli, S. Stavrev, B. Dutoit and O. Fischer Summary: Geometrical aspects of the design of fault current limiters (FCL) have a great impact on their performances. Recently, the University of Geneva have made certain optimizations by splitting the FCL into many small dissipative lengths in order to achieve a distributed transition along the device. For this paper, we have performed new 3D finite element method (FEM) simulations for studying the behavior of strip lines of a YBCO/Au FCL in an AC nominal use (sinusoidal current at industrial frequency) up to 3 I/sub c/. The very large aspect ratio of the device needs a particular attention to the modeling and meshing process. The numerical results show that presence of sharp corners can influence the performance of the device. Due to the high value of the electric field in these areas, the local losses are much higher than in the case of smooth corners, and this may lead to burning and cracking the wafer. Irreversible damage experiments have confirmed these locations. In this paper we proposed new geometries, taking into account the length of the connecting path and the corners optimization in order to decrease the risk of very high localized losses in the meander.         Flux flow resistance in Bi2223 generated by pulse currents    K. Mutsuura, H. Shimizu, Y. Yokomizu and T. Matsumura Summary: We have proposed a current limiting element using the flux flow resistance in a high temperature superconductor (HTS) for a pulse over-current such as a magnetizing inrush current in a transformer. We experimentally investigated the generation process of flux flow resistance in a Bi2223 bulk with an inrush current. The voltage-current density characteristics and their dependence on the joule heat generated in the Bi2223 bulk were measured. Comparing the results with the characteristics for the ac over-current, we made it clear that the both have almost the same characteristics.         Fundamental characteristics of a 200A-class HTS reactor    M. Inaba, A. Ninomiya, T. Ishigohka, H. Tanaka, M. Furuse, K. Arai and M. Umeda Summary: In order to develop a reactor for a LC resonance-type fault current limiter, we have been studying a pancake-type HTS coil with a low loss and a high current capacity. Double-pancake coils wound by Bi2223 tape wire are adopted as a unit coil for the reactor. In the double-pancake coil, two Bi2223 tapes are wound in parallel to each other to obtain a high current capacity. Besides, a stainless steel wire is co-wound with the Bi2223 tapes in order to increase the mechanical strength. The reactor is designed as an air-core type one to obtain a constant inductance. 12 unit double-pancake coils are manufactured. They are located in a toroidal shape in order to obtain symmetry. 12 unit coils are connected in "3-parallel/4-series" mode. The critical current, the AC loss, and the current sharing ratio between the unit coils are measured. From the experimental results, it has been confirmed that the current sharing among the 3 parallel circuits is uniform, in spite of some deviations between the critical currents of each unit coil.         Quench properties of superconducting fault current limiters with a protective coating    Hye-Rim Kim, Jungwook Sim and Ok-Bae Hyun Summary: We investigated the quench development in resistive superconducting fault current limiters (SFCLs) with a protective coating. The protective coating is needed to protect the SFCL from moisture in the air, but should not have an adverse effect on the quench properties of the films. The 300 nm thick YBCO film coated in situ with a gold layer was first patterned into meander lines by photolithography, and then coated with teflon by spin-coating. The SFCL was subjected to simulated AC fault currents for quench measurements. It was immersed in liquid nitrogen during the experiment for effective cooling. The coating retained its form throughout repeated quenches in liquid nitrogen. Moreover, quench properties did not change for thin coatings. The quench resistance of SFCLs with a protective coating was similar to that without a coating. This enables one to use a protective coating without compromising the performance of SFCLs. The quench development in SFCLs with a coating of different thickness was explained with the concept of heat transfer to the coating and the liquid nitrogen.         Generating performance of limiting impedance in flat type of fault current limiter with high Tc superconducting plate    T. Matsumura, M. Sugimura, Y. Yokomizu, H. Shimizu, M. Shibuya, M. Ichikawa and H. Kado Summary: We have proposed a flat type of the superconducting fault current limiter (FCL) which is a modified version of a magnetic shielding type of the fault current limiter. The new FCL basically consists of a doughnut-like form high Tc superconductor (HTS) plate and spiral coil, each of which works as a secondary one-turn winding and a primary winding, respectively. The FCL modules can be easily built up to make a large scale FCL. This simple construction may enable us to reduce the manufacturing costs. We made two small modules of the flat type FCL with Bi2223 bulk plate and YBCO thin film plate and investigated the generation of the limiting impedance due to an excess current. Higher ratio of the limiting impedance to normal one was produced by the YBCO thin film plate than by the Bi2223 bulk plate.         Research on a combined device SMES-SFCL based on multi-object optimization    Guiping Zhu, Zanji Wang and Guoqiang Zhang Summary: A multi-function superconducting equipment SMES-SFCL is proposed in this paper. It mainly consists of diodes, power condition system, control circuit and a superconducting coil. Its circuit topology is also presented in the paper. Proved by previous simulation and experiment, the combined device can work as SMES or SFCL separately and effectively. Further research on the performance of the device when it fulfills the two functions simultaneously is proposed in this paper. Control strategy based on multi-object optimization is adopted, which is proved to be applicable by simulation by MATLAB. At the end of the paper, the authors give some suggestion on the device structure and control strategy.         Measurement of lateral current redistribution of fault current limiter using YBCO thin film    M. Miyashita, S. Umeda, S. Nagao, N. Amemiya, H. Kubota, Y. Kudo and K. Inoue Summary: The current redistribution during the limiting phase of a FCL element using YBCO thin film was studied. The FCL element which we have been studying consists of YBCO thin film and nickel film shunt resistor and they are connected in parallel by indium bridges. When a normal zone appears in YBCO thin film due to the over-current, the current transfers from YBCO thin film to nickel film shunt resistor through indium bridges. We measured the change in the distribution of magnetic flux produced by the current carried by the FCL element using an array of pick-up coils. From the pick-up coil signals, the change in the lateral current distribution in the FCL element was calculated assuming an electrical circuit model of the FCL element.         6.6 kV resistive superconducting fault current limiter based on YBCO films    Ok-Bae Hyun, Hye-Rim Kim, Jungwook Sim, Young-Ho Jung, Kwon-Bae Park, Jong-Sung Kang, B.W. Lee and Il-Sung Oh Summary: We present the fabrication and short circuit tests of a three-phase 6.6 kV resistive superconducting fault current limiter (SFCL) demonstrator based on YBCO films. The SFCL is operated at three-phase 6.6 kV/sub rms/ and has the quench development current of 200 Arms in the liquid nitrogen temperature. Individual components were YBCO films of 300 nm thickness covered by 140 nm thick Au on the sapphire substrates of 4'' diameter. The films were patterned into bi-spiral lines of width 5 mm. The wafers have the operating voltage 600 V/sub rms/ and the critical current 47 A in average. Eight wafers were connected in series to make a unit of rated voltage 4.8 kV/sub rms/, and six units were connected in parallel to complete a single phase SFCL. Equal shunt resistors across the wafers in series have been adopted to induce the simultaneous quenches of the components for equal voltage applications. Voltage enhancement of single unit is to handle asymmetric faults such as a line-to-line fault. Short circuit tests for line to ground, line to line and 3 phases fault showed that the SFCL is highly reliable for the current limiting capability. The SFCL successfully suppressed the fault current up to 10 kA below 900 A. Particularly, the current limitation was found to be independent of the maximum fault current. Detailed study on the fabrication and short circuit tests will be presented.         Design and testing of 230 V inductive type of Superconducting Fault Current Limiter with an open core    J. Kozak, T. Janowski, S. Kozak, H. Malinowski, G. Wojtasiewicz and B. Kondratowicz-Kucewicz Summary: A single-phase, 230 V Superconducting Fault Current Limiter using two Bi2223 HTS tubes with the total critical current 2.5 kA situated in vacuum insulated cryostat has been described in this paper. We designed and manufactured the inductive SFCL with an open core as core shielded type acquired the optimal design parameters by using Finite Element Method. We tested the limiter performances at liquid nitrogen temperature 77 K. We proved that the performances of properly designed limiter with open core could be comparable to the limiter with closed core.         Responses of resistive superconducting-fault-current-limiters to unbalanced faults    Hyo-Sang Choi, Sung-Hun Lim, Dong-Chul Chung, Byoung-Sung Han, Ok-Bae Hyun, Tae-Hyun Sung and Jong-Sun Hwang Summary: We analyzed the unsymmetrical fault characteristics of resistive superconducting-fault-current-limiters (SFCL) based on YBCO thin films with the unbalanced faults such as a single line-to-ground fault, a double line-to-ground fault, and a line-to-line fault in a three-phase system. The unsymmetrical rates of fault phases were 6.4, 9.2, 8.8 at the fault onset, but decreased by 1.4, 1.5, 3.7 after 50 ms in the fault types, respectively. The positive sequence current I/sub 1/ was the highest in a double line-to-ground fault, immediately after the fault onset, but that of a line-to-line fault was the highest after 50 ms. This means the current limiting effect was the worst in a line-to-line fault, due to the unbalanced quench between the SFCL units. The negative sequence currents I/sub 2/ of a single and double line-to-ground faults were relatively low, except for the quench instant, because of the rapid interruption of fault currents by the SFCL. The zero sequence current I/sub 0/ was similar to the behavior of the negative sequence current. Finally, the positive sequence resistance Z/sub 1/ was reduced remarkably immediately after the fault but gradually approached the balanced positive sequence resistance prior to the system fault, except during a line-to-line fault. The simultaneous quench between the SFCL units was important for low line-to-line fault currents.         Impedance variation of a flux-lock type SFCL dependent on winding direction between coil 1 and coil 2    Sung-Hun Lim, Hyo-Sang Choi, Dong-Chul Chung, Seokcheol Ko and Byoung-Sung Han Summary: The flux-lock type superconducting fault current limiter (SFCL) uses the magnetic coupling between two coils connected in parallel with each other. This SFCL has the merit that both the resistance of high-T/sub C/ superconducting (HTSC) element and the limiting current capacity can be simultaneously increased through the application of magnetic field into HTSC element. However, unlike other types SFCLs, the different fault current limiting characteristics can appear according to the winding direction between the two coils. In this paper, the relation of the impedance of the flux-lock type SFCL with the resistance of HTSC element was derived from its equivalent circuit using the current and the voltage relationship between the two coils. The limiting impedances of the flux-lock type SFCL due to the winding direction through the discrete fourier transform (DFT) analysis for the voltage and the current data obtained from the fault current limiting experiments were extracted and analyzed from the point of view of the limited line current and the resistance of HTSC element.         Analysis of operational characteristics of flux-lock type SFCL combined with power compensator    Sung-Hun Lim, Seong-Ryong Lee, Hyo-Sang Choi and Byoung-Sung Han Summary: The flux-lock type superconducting fault current limiter (SFCL) combined with a power compensator was proposed in this paper. This SFCL consists of a flux-lock reactor and a power compensator. The former, which has coil 1 and coil 2 wound in parallel through high-T/sub C/ superconducting (HTSC) element, can perform the fault current limiting operation during a fault period. The latter is composed of a current-controlled inverter and an AC/DC converter between coil 3 and grid, which can be operated as the power compensator for nonlinear load during a normal operation. The specification for a test model was determined and its operational characteristics were analyzed through computer simulation using PSIM program. It was confirmed that the suggested flux-lock type SFCL, combined with the power compensator, could protect the system from over-current by a short circuit accident and compensate the reactive power due to a nonlinear load during a normal operation as well.         Switches based on high-temperature superconducting thin films    V. Meerovich, V. Sokolovsky and I. Vajda Summary: Switches based on high-temperature superconducting (HTS) thin films have been developed for the application in fault current limiters and various controlling devices. HTS thin film structures needed for this purpose have usually been fabricated as long multi-layered elements, in which HTS thin film is deposited on a dielectric substrate with high heat conductivity and covered by a thin layer with high electric conductivity. The main challenge has been to provide the fast and simultaneous transition of the whole of switch from the superconducting to the normal state. We experimentally investigated, under DC and AC conditions, the superconducting-normal state (S-N) transition in switches fabricated from parallel and series-connected YBCO thin films. The films were deposited on a sapphire substrate of 0.5 mm in thickness and covered by 100 nm Au layer. The appearance and propagation of normal zones in the films were determined by measuring the voltage drop across their different sections. The results were compared with ones obtained for a single film. The conditions providing a simultaneous S-N transition of the whole of the switch are discussed. It is shown that shunting the film by a resistor improves both the film protection from overheating and the homogeneity of S-N transition in the switch.         Inductive type fault current limiter using Bi-2223 thick film on MgO cylinder with Bi-2212 buffer Layer    H. Kado, M. Ichikawa, M. Shibuya, M. Kojima, M. Kawahara and T. Matsumura Summary: We have been developing an inductive type superconducting fault current limiter with a superconducting cylinder. For practical use, a high critical current density (Jc) is needed in a large diameter. To achieve these items, we have developed a Bi-2223 thick film on a MgO substrate, with a Bi-2212 buffer layer. This cylinder was 450 mm in diameter and 120 mm in length. We describe the superconductive characteristics of this cylinder, and the limiting properties of the fault current limiter using these cylinders.         Fault current limiting Characteristics of resistive type SFCL using a transformer    Sung-Hun Lim, Hyo-Sang Choi, Dong-Chul Chung, Yeong-Ho Jeong, Yong-Huei Han, Tae-Hyun Sung and Byoung-Sung Han Summary: A transformer is expected to be an useful component of resistive type superconducting fault current limiter (SFCL) using high-T/sub C/ superconducting (HTSC) element with constant critical current for easier adjustment of both the limiting impedance and the initial limiting current level. Therefore, the analysis for the fault current limiting characteristics of the resistive type SFCL using a transformer considering the resistance variance of HTSC element is needed because the resistance of HTSC element during a fault period is affected by the design condition of the transformer. In this paper, we investigated the limiting impedance and the initial limiting current level of the resistive type SFCL using a transformer as a function of the turn numbers' ratio between the primary winding and the secondary winding. The limiting impedance of SFCL was extracted by applying discrete Fourier transform (DFT) equation for the measured voltage and current data of SFCL. It was confirmed from the analysis that the transformer design with the lower turn numbers' ratio of the primary winding for the secondary winding was advantageous for the larger load current capacity of SFCL and that the transformer with the higher ratio design condition, on the other hand, was favorable for the larger fault current limiting capacity of SFCL.         66 kV/1 kA high-T/sub c/ superconducting fault current limiter magnet    T. Yazawa, Y. Ootani, M. Sakai, T. Kuriyama, M. Urata, Y. Tokunaga and K. Inoue Summary: One of the items included in the Super-conductive AC Equipment (Super-ACE) project, being performed from 2000 to 2004, is development of a 66 kV/1 kA class high-Tc superconducting (HTS) fault current limiter (FCL) magnet. This research focuses on fundamental technical items essential for a 66 kV class fault current limiter, that is, high current-capacity, high voltage-insulation, and sub-cooled nitrogen cooling. This paper describes the design of the magnet and the test results obtained. The magnet mainly consists of a vacuum vessel, a nitrogen bath, a pair of current leads, cryocoolers, and six sets of coils wound with Bi2223 tape. The rated current of the magnet is 750 Ap. The insulation voltage of the magnet is of the 66 kV class. In the final year of the project, all six sets of the coils are set connected in the cryostat and evaluation tests have been implemented. In the cooling test, sub-cooled nitrogen of 65 K was obtained, with homogenous temperature distribution in the cryogen. The rated current of 750 Ap was successfully obtained for both direct and alternating current tests. In addition, the magnet passed the simultaneous current and voltage application test. Finally, the dielectric test results showed that the magnet satisfied the insulation for 66 kV apparatus in the Japanese Electrotechnical Committee Standard (JEC) standard.         Non-inductive variable reactor design and computer simulation of rectifier type superconducting fault current limiter    T. Hoshino, I. Muta, T. Nakamura, K.M. Salim and M. Yamada Summary: A rectifier type superconducting fault current limiter with noninductive reactor has been proposed by the authors. The concept behind this SFCL is that the high impedance generated during superconducting to normal state of the trigger coil limits the fault current. In the hybrid bridge circuit of the SFCL, two superconducting coils: a trigger coil and a limiting coil are connected in anti-parallel. Both the coils are magnetically coupled with each other and could have the same value of self inductance so that they can share the line current equally. At fault time when the trigger coil current reaches a certain level, the trigger coil changes from superconducting state to normal state. This super to normal transition of the trigger coil changes the current ratio of the coils and therefore the flux inside the reactor is no longer zero. So, the equivalent impedance of both the coils is increased and limits the fault current. We have carried out computer simulation using PSCAD/EMTDC and observed the results. Both the simulation and preliminary experiment shows good results. The advantage of using hybrid bridge circuit is that the SFCL can also be used as circuit breaker.         Simulations and electrical testing of superconducting fault current limiter prototypes    L. Martini, M. Bocchi, M. Levati and V. Rossi Summary: The Superconducting Fault Current Limiter (SFCL) is a device of particular interest to electricity companies since it is aimed to maintain fault current levels on electricity networks to acceptable values, i.e. within electrical component design limits. The use of high temperature superconductors (HTS) allows the fabrication of effective SFCL devices with different configurations. In this work, we report on simulations and electrical testing of resistive-type SFCL prototypes. Short-circuit testing of several HTS windings has been carried out at CESI facility. Prospective symmetrical and asymmetrical fault currents 40 times larger than the nominal current value have been applied for 40-160 ms on single-phase devices. As a result, the prospective peak short-circuit current of 4,5 kA has been effectively reduced to 300 A-800 A depending of applied voltage. Time evolution of limited current, voltage across SFCL prototypes, dissipated energy and heating phenomena are reported and discussed.         Inrush-current-limiting with high T/sub c/ Superconductor    H. Shimizu, K. Mutsuura, Y. Yokomizu and T. Matsumura Summary: We propose an inrush-current-limiting element as a new application of high-temperature superconductor (HTS). The inrush-current-limiting element is required to recover automatically to superconducting state without any current interruption after the current limiting operation. The limiting element proposed suppresses the inrush current using the flux-flow resistance generated in the HTS. Since the flux-flow resistance is small as to be neglected when the instantaneous value of the current in the HTS is below its critical-current, the limiting element may satisfy the above requirement for the inrush-current-limitation. To verify the performance of the inrush-current-limiting element, we performed the current-limiting tests by a limiting element made of bulk Bi2223. As a result, it was confirmed that the limiting element suppressed the magnetizing inrush current of a transformer and self-recovered to superconducting state.         Analysis of magnetic field and geometry effects for the design of HTS devices for AC power applications    F. Grilli, L. Martini, S. Stavrev, B. Dutoit and R. Brambilla Summary: The performance of HTS devices is strongly influenced by local values of the current and field distributions. In this paper, we investigate the influence of the magnetic field and the geometrical configuration on the loss behavior of a 200 kVA FCL prototype, composed by Bi-2223/Ag tapes wound around a cylindrical support. The investigation is performed by means of finite element computations, with the use of an axisymmetric 2D A-V formulation for taking into account the cylindrical geometry. The electrical behavior of the superconductor is described by means of a B-dependent E-J power-law relation, derived from experimental measurements with a field of different orientation. Several geometrical configurations are analyzed and compared, in order to find the ones with the lowest AC loss.         Temperature dependent equivalent circuit of a magnetic-shield type SFCL    M. Fabbri, A. Morandi, F. Negrini and P.L. Ribani Summary: In order to investigate the reciprocal interaction between a SFCL and the Power System an equivalent circuit of the device needs to be introduced in a power system simulator. In this paper the equivalent circuit of a magnetic shield type SFCL, consisting of two coupled electric and thermal networks, is obtained starting from the integral formulation of the coupled electromagnetic-thermal problem inside the device. The numeric waveforms of current and voltage across an SFCL during a fault are calculated and compared with the experimental ones.         High voltage design, requirements and tests of a 10 MVA superconducting fault current limiter    M. Noe, K.-P. Juengst, S. Elschner, J. Bock, F. Breuer, R. Kreutz, M. Kleimaier, K.-H. Weck and N. Hayakawa Summary: In recent years the development of superconducting fault current limiters (SCFCLs) has made significant progress. Within the frame of the German project CURL10 a 10 kV, 10 MVA demonstrator of a resistive SCFCL, using MCP-BSCCO 2212 bifilar coils, has been developed and successfully tested. A world-wide first field test of a resistive SCFCL started in 2004. This paper reports about the high voltage design aspects and summarizes the high voltage tests performed within this project. The different tests confirm that the design requirements of 28 kV AC voltage and 75 kV lightning voltage are fulfilled. Even at worst case conditions of a quench and a lightning pulse at the same time no breakdown was observed.         Improvement of functionality and reliability by inductive HTS fault current limiter units    A. Gyore, S. Semperger, L. Farkas and I. Vajda Summary: The inductive type high temperature superconducting fault current limiter (HTS FCL) is one of the prospective and developing applications of HTS materials. A transformer type FCL build up of YBCO rings using a magnetic core with an adjustable air gap has been built and studied. For the practical applications of HTS FCLs in industrial environments we have investigated various connections of individual FCL units, viz. series, parallel and matrix (combination of series and parallel) arrangements of FCL groups to increase the fault power capacity as well as the reliability of HTS FCLs. A modeling method and a respective simulation have been developed, which include the hysteresis and heating of the HTS and the nonlinear characteristics of the magnetic core. Simulation results were verified by tests. We propose an important application viz. a self-limiting transformer using HTS YBCO rings, which is a combination of a transformer and a fault current limiter in one unit. The theory and the build-up of such a transformer is described, test results with respect to the operation of the self-limiting transformer are presented.         A generic real-time computer Simulation model for Superconducting fault current limiters and its application in system protection studies    J. Langston, M. Steurer, S. Woodruff, T. Baldwin and J. Tang Summary: A model for the SCFCL suitable for use in real time computer simulation is presented. The model accounts for the highly nonlinear quench behavior of BSCCO and includes the thermal aspects of the transient phenomena when the SCFCL is activated. Implemented in the RTDS real-time simulation tool the model has been validated against published BSCCO characteristics. As an example for an application in protection system studies, the effect of an SCFCL on a utility type impedance relay has been investigated using a real time hardware-in-the-loop (RT-HIL) experiment. The test setup is described and initial results are presented. They illustrate the effect of how the relay misinterprets the dynamically changing SCFCL impedance as an apparently more distant fault location. It is expected that the new real-time SCFCL model will provide a valuable tool not only for further protection system studies but for a wide range of RT-HIL experiments of power systems.         Thermal runaway and resistive properties of a Bi2223 pancake coil subjected to overcurrent    H. Tanaka, M. Furuse, K. Arai, M. Umeda and S. Fuchino Summary: Various kinds of superconductivity-based fault current limiters (FCL's) have been studied. One type uses a superconductive reactor or magnet that loses its superconductive properties when subjected to excessive current flow. We examined the characteristics of a Bi2223 double pancake coil subjected to overcurrent. DC or AC overcurrent was passed through the coil cooled by saturated liquid nitrogen, and the resultant temperature difference was measured between the coil surface and the saturated liquid nitrogen. We then theoretically and experimentally investigated the starting conditions of the resultant thermal runaway. Our results confirmed that these conditions are decided by the product of critical heat flux and cooling area, and that the angle of the coil is important if the cooling channels are narrow.         Experimental and numerical analysis of energy losses in resistive SFCL    S. Kozak, T. Janowski, B. Kondratowicz-Kucewicz, J. Kozak and G. Wojtasiewicz Summary: The resistive SFCL (superconducting fault current limiter) is a superconducting device which may operate both in superconducting state and in normal conducting (resistive) state. The paper presents FEM numerical model (in FLUX2D) of resistive SFCL made using Bi-2212 bifilar coil (NEXANS) cooled by pool boiling cooling technique (liquid nitrogen, 77 K). Real geometry of resistive SFCL is replaced by equivalent, due to energy and current density, geometry of numerical model. The electro-thermal numerical model of resistive SFCL can be used to estimate the energy and maximum temperature in limiter and the time to switch off the current to protect against damage.         The short-circuit characteristics of a DC reactor type superconducting fault current limiter with fault detection and signal control of the power converter    Min Cheol Ahn, H. Kang, Duck Kweon Bae, Dong Keun Park, Yong Soo Yoon, Sang Jin Lee and Tae Kuk Ko Summary: In general case of DC reactor type superconducting fault current limiter (SFCL), a fault current gradually increases during the fault. It takes above 5 cycles to cut off the fault in the existing power system installed the conventional circuit breakers (CBs). Therefore, the fault current increases during the fault even if the SFCL is installed. This paper proposes a technique for decaying the fault current with the function of the fault detection and control of power converter of the SFCL. Using the proposed method, the fault current can decay after 1-2 cycles when the fault occurs. To analyze this technique, three-phase 6.6 kV/200 A SFCL was fabricated. The SFCL has just one DC reactor, an AC to DC power converter which has thyristors as the rectifying device, and a three-phase transformer, which is called magnetic core reactor (MCR). The short-circuit tests of this SFCL were performed successfully. Comparing the result using the proposed technique with the typical result, the fault current is decreased effectively by the proposed technique. This result shows that this SFCL using the fault detection and control of power converter can be applied to the existing power system which has conventional CBs.         Current limiting characteristics of transformer type superconducting fault current limiter    H. Yamaguchi, K. Yoshikawa, M. Nakamura, T. Kataoka and K. Kaiho Summary: The transformer type superconducting fault current limiter is composed of a series transformer and a superconducting current limiting device. The primary winding of the transformer is connected in series to the power transmission line, and the secondary winding is short-circuited through the superconducting current limiting device whose normal resistance plays an important role in limiting the fault current. According to our previous investigations, the basic characteristics and the design indexes of the transformer type superconducting fault current limiter were clarified. In this paper, the results of the current limiting test of a 5 kVA class transformer type superconducting current limiter are analyzed in detail, and the limiting characteristics such as the dependency of the initiation current of the limiting operation on the fault phase angle are shown.         Repetitive operation of three-phase superconducting fault current limiter in a model power system    Y. Shirai, A. Mochida, T. Morimoto, M. Shiotsu, T. Oide, M. Chiba and T. Nitta Summary: Superconducting fault current limiters (SCFCLs) are expected to improve reliability and stability of power systems. To introduce an SCFCL to power systems, the repetitive operation at the severe continuous faults is one of the important function. The recovery time of the proposed 3-phase FCL was confirmed experimentally to be sufficiently short for the repetitive operation. This paper shows the experimental results and discussion on the repetitive current limiting operation of the 3-phase SCFCL, which was demonstrated in a model power system. The test condition was that the fault line is open at the fault within 100 ms and is re-closed within 930 ms, but the fault is not cleared during the interval while the fault line is open. It was confirmed that the SCFCL started to limit the fault current immediate after the fault and recover to the stand-by mode during the interval, and limited the fault current again at the re-closure without any degradation of the trigger current level and the limiting impedance.         Performances of small fault current limiting breaker model with high Tc Superconductor    T. Matsumura, T. Aritake, Y. Yokomizu, H. Shimizu and N. Murayama Summary: This paper describes the breaking ability of a small model of a fault current limiting circuit breaker (FCLCB), which consists of an air relay unit and a flux flow resistive type of a superconducting FCL unit with a high Tc B2223 bulk. Two Bi2223 elements were connected in series as an elementary FCL unit. Current carrying tests were performed for the elementary FCL unit to find the generating aspects of the flux flow resistance and the contact resistance. Current limiting and breaking performances were measured for the small model of the FCLCB that was constructed by connecting the elementary FCL unit with the relay contactor. It is confirmed that the apparent capability of the breaker unit is elevated by combination with the FCL unit. The FCL unit for the 6.6 kV power distribution systems was also designed.         Optimized current path pattern of YBCO films for resistive uperconducting fault current limiters    B.W. Lee, J.S. Kang, K.B. Park, H.M. Kim and I.S. Oh Summary: High critical current density, high n value and fast recovery characteristics of YBCO thin films are attractive characteristics for developing resistive type fault current limiters (FCLs). In order to get desirable resistance during quench state, it is important to design optimum current path etched on the surface of YBCO films, Therefore it is needed to determine the optimum current path patterns of YBCO thin films in order to prevent the distortion caused by both localized heat caused by excessive fault currents and breakdown occurred from intensification of electric field during quench period. In this study, to clarify the optimum current path design of YBCO films, electromagnetic analysis of various current paths including meander pattern, spiral pattern, and bi-spiral pattern were considered and to verify the analysis results, experimental tests including quench test, and insulation tests were performed. From the analytical and the experimental results, it was concluded that bi-spiral pattern of YBCO thin film was rather effective for quench and insulation than the other patterns. Finally, this bi-spiral current path pattern was adopted for YBCO thin film design for developing 6.6 kV/200 A 3 phase resistive fault current limiters, and it was possible to get satisfactory results.         Equal current distribution in parallel circuits of resistive superconducting fault current limiters using multiple superconducting inter-phase transformers    Jungwook Sim, Yong-Sun Choi, Hye-Rim Kim and Ok-Bae Hyun Summary: Differences in impedances of the superconducting parallel circuits during normal operations cause unequal distribution of currents in the circuits, resulting in quench or loss in certain superconducting parts. However, those impedances are so small that they are hardly controllable. To solve this problem, attempted were such measures as inserting resistors or inductors into each of the parallel circuits in series. This leaves extra losses due to resistance or reactance. In this study, we proposed a multiple superconducting inter-phase-transformers (SIPT) for the equal current distribution in superconducting parallel circuits and investigated their performance. SIPTs were fabricated using double pancake windings of BSCCO-2223 HTS tapes and were applied to parallel circuits of resistive superconducting fault current limiters (SFCLs). Results showed that the SIPTs effectively made the current distribution uniform in superconducting parallel circuits that had unequal resistances. In addition, the secondary loop configuration with air-core SIPTs was suggested as the most efficient for the SFCLs.         Performance comparison of a DC hybrid type FCLI with other types    Hongtian Shao, M. Yamaguchi, S. Fukui, J. Ogawa, Takao Sato and H. Ishikawa Summary: Fault current limiting and interrupting performances of three types of fault current limiting interrupter (FCLI) are compared; a DC reactor type, a DC S/N transition type and a DC hybrid type, which are made of the Bi-2223 tape and bulk. The DC hybrid type FCLI can limit a fault current by means of the inductance of HTS coil and the normal resistance of high temperature superconducting bulk (HTSB). In the case of an accident, the normal transition of the bulk can be accelerated by the magnetic field of the HTS coil. In this paper, performances of the DC hybrid type three-phase FCLI are compared analytically with the DC reactor type and the DC S/N transition type. Features derived from the combination of a reactor coil and an S/N transition element for the DC hybrid type are discussed and as an example it is applied to 6.6 kV-2000 A power distribution system.         Applications of superconducting fault current limiters in electric power transmission systems    L. Kovalsky, Xing Yuan, K. Tekletsadik, A. Keri, J. Bock and F. Breuer Summary: The introduction of new generating facilities by independent power producers and increasing load demand can result in fault-current over-duty on existing transmission system protective equipment. Conventional solutions to fault current over-duty such as major substation upgrades, splitting existing substation busses or multiple circuit breaker upgrades could be very expensive and require undesirable extended outages and result in lower power system reliability. Less expensive solutions such as current limiting reactors may have unwanted side effects, such as increase in system losses, voltage regulation problems or possibly could compromise system stability. This paper discusses the benefits of superconducting Fault Current Limiters (FCLs) which can be economically competitive with expensive conventional solutions. Superconducting FCLs are invisible in normal operation and do not introduce unwanted side effects. The performance of a particular type of limiter, the Matrix Fault Current Limiter (MFCL) is presented and examples are provided on how it could relieve fault current over-duty problems. The use of this device in a particular application in the American Electric Power (AEP) 138 kV transmission grid is also discussed.         Operation tests for SN transition superconducting fault current limiter in the power system simulator    S. Torii, H. Kameda, T. Kumano, H. Sakaki, H. Kubota and K. Yasuda Summary: One of important problems to be solved in Japanese trunk transmission systems is the reduction of short-circuit capacity. As one solution, double buses are split into two buses in some substations. In recent years, dispersed generators have been introduced in lower voltage classes due to the deregulation of the electricity. A fault current exceeding the capacity flows during a short-circuit fault by the connection of dispersed generators. One of the key technologies for solving the above problem is the fault current limiter. We are presently conducting research on the effect of the introduction of fault current limiters into a power system. In this paper, we describe the results of operation tests of the SN transition superconducting fault current limiter (SCFCL) using 3 phases of SCFCL modules against various kinds of system faults or inrush current in the power system simulator installed at Central Research Institute of Electric Power Industry (CRIEPI).         Very low impedance (VLI) superconductor cables    M.J. McCarthy Summary: High Temperature Superconductor (HTS) cable is regarded as one of the most promising new technologies to address grid bottlenecks. Among HTS cable designs, one in particular-shielded cold dielectric cable-offers performance advantages particularly well suited to today's siting, reliability and performance challenges. Shielded cold dielectric HTS transmission cables feature lower electrical losses; the virtual elimination of stray EMF; and significantly lower impedance than conventional cables and lines. Of particular importance, the very low impedance (VLI) inherent in cables of coaxial design makes it possible to control power flows over VLI circuits. In addition, variable impedance may be cost-effectively added to VLI circuits with relatively small angle, conventional phase angle regulators. Thus, VLI circuits can function like fully controllable DC circuits. The introduction of VLI cable enables new approaches to important challenges in grid management. The strategic insertion of relatively short segments of VLI cable to bridge bottlenecks can offload flows from overburdened conventional circuits, thereby expanding grid capacity, extending the useful life of conventional network elements, and raising overall asset utilization. With power markets in turmoil and transmission increasingly the center of attention, VLI cable is a breakthrough technology that has great potential as a cost-effective solution for many of the industry's most pressing problems.         Applications of high temperature superconductors to direct current electric power transmission and distribution    B.W. McConnell Summary: For several reasons, the application of superconductors to both the transmission and distribution of electric power is a desire that is best accomplished by using direct current. The inherent low loss, high current capability of dc superconducting cables allows the replacement of ultra-high voltage apparatus and the associated high cost and inversion-rectification difficulties with a compact potentially lower cost, low profile, high current, cable system. This paper discusses the history of dc transmission and distribution applications and the reasons that high temperature superconductors, modern cryogenic systems, and cryogenic power electronics are the potential enabling technologies. The economic and performance enhancements that follow from the integration of these high current, superconducting dc systems into the electric grid are presented together with the expected potential operational benefits. Possible cable and rectifier-inverter configurations are summarized along with the technical and economic challenges that must be overcome to achieve a significant penetration of dc cable technology on both the transmission and distribution grids. Finally, the steps needed to achieve large-scale applications of high-current dc transmission and dc distribution in the future electric grid are summarized.         Superconductor synchronous condenser for reactive power support in an electric grid    S.S. Kalsi, D. Madura and M. Ingram Summary: High Temperature Superconductor (HTS) SuperVAR dynamic synchronous condensers (DSC) developed by American Superconductor have a small foot print, are readily transportable, and are expected to be an economic option for providing peak and dynamic reactive compensation to a power system. HTS DSC machines are also inherently stable to close in faults and can provide up to twice their nominal rating for about one minute (peak rating) during depressed voltage events. Last, but not least, HTS DSC machines use less than half of the energy of a conventional synchronous condenser and about the same amount of energy as a modern Flexible AC Transmission System (FACTS) device consumes. It is expected to be highly reliable. The first HTS DSC machine is being operated at an arc furnace where it is being tested for its ability to mitigate flicker and provide dynamic power factor compensation. This location also exposes the machine to a large number of transients providing an excellent accelerated age test of the device. This paper describes features and test results of the HTS DSC.         Conduction cooling of a compact HTS motor for aeropropulsion    J.E. Pienkos, P.J. Masson, S.V. Pamidi and C.A. Luongo Summary: Thermal aspects of a novel high temperature superconducting motor design are examined for use in the propulsion of an aero-vehicle. To simplify the refrigeration, focus is on conduction cooling of the superconducting material directly from the cold head of the cryocooler. A brief description of the motor is followed by an analysis of the conduction cooling apparatus. An experimental setup has been developed, including a cryocooler, a cryostat, and a mockup of the HTS motor, to validate the system model.         Experimental determination of dynamic parameters for a superconducting machine    S. Woodruff, M. Steurer and H. Boenig Summary: Superconducting electrical machines are increasingly of interest for diverse applications such as generators, synchronous condensers and motors. These machines' dynamic behavior differs from that of conventional machines in significant ways due to certain time constants and reactances being very different. These differences can present difficulties when conventional testing procedures are applied. A 5 MW superconducting rotor machine designed and built by American Superconductor Corporation is currently being tested in the Advanced Test Facility of the Center for Advanced Power Systems at Florida State University. A variety of test procedures are being applied to determine the machine's dynamic performance and the effectiveness of these tests when applied to a superconducting machine is being assessed. In this paper, two means of analysing test data and extracting machine parameters are described.         Concept of multiply connected Superconducting tapes    G.A. Levin and P.N. Barnes Summary: The possibility of a substantial reduction of weight and size of electrical generators is the main incentive behind the effort to develop superconducting armature windings based on Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 6+x/ (YBCO) coated conductors in the form of wide tapes with large aspect ratio. The main obstacle to the application of coated superconductors in stator windings is the large losses incurred due to the ac magnetic field produced by the rotor's dc coils of the field windings. In the range of frequencies typical for aircraft generators, the hysteretic losses in wide tapes are unacceptably high. They can be reduced by dividing the YBCO layer into multiple filaments separated by non-superconducting barriers. However, the lack of current sharing between the filaments makes the conductor vulnerable to the localized defects, so that a single blockage can impede the flow of transport current through the whole length of a given filament. We present estimates of reliability as well as the magnetization losses in multiply connected superconductors. In this type of superconducting tape, a sparse network of superconducting bridges, which allows for current sharing, connects the filaments. The trade-off between the different types of losses and the connectivity requirement imposes restrictions on the number of filaments and properties of the network of bridges.         AC losses in a high temperature superconducting generator    K. Sivasubramaniam, Xianrui Huang, D. Ryan, K. Weeber, J.W. Bray, E.T. Laskaris, L. Tomaino, J.M. Fogarty and S. Ashworth Summary: As part of the DOE-SPI funded project a commercial HTS utility-size generator is being developed based on GE's iron core superconducting generator technology. The iron core concept has significant advantages over air core designs. The rotor consists of a cold superconducting field coil and coil supports and a warm iron core, which takes the torque and transmits to the shafts. Heat load due to AC losses in the cold mass of the rotor are a key design constraint. Analyses have been performed both at the component and system levels. AC loss tests have been conducted on an HTS generator. This paper presents and discusses the analytical and test results.         Study of practical applications of HTS synchronous Machines    N. Maki, T. Takao, S. Fuchino, H. Hiwasa, M. Hirakawa, K. Okumura, M. Asada and R. Takahashi Summary: A small research and study committee, composed of corporations in the industrial/governmental/academic fields, was established, and a feasibility study of HTS synchronous machines (HTSMs) was carried out. Promising application fields for HTSMs were considered and their applicability was studied. Fundamental designs of these HTSMs were then carried out using a specially developed design program, and their merits and demerits were clarified. As key components, HTS field coils and refrigeration systems were examined closely, and technological problems related to their development were studied.         Fundamental studies of helical-type seawater MHD generation system    M. Takeda, Y. Okuji, T. Akazawa, Xiaojun Liu and T. Kiyoshi Summary: A new MHD (magnetohydrodynamics) generator based on electromotive force using seawater, that is, a helical-type seawater MHD generator with a 7 T solenoid superconducting magnet, is designed, constructed and tested. The constructed generator contains a helical insulation wall made of polyvinyl chloride 140 mm long and 100 mm in diameter, an anode rod made of SUS316 1350 mm long and 10 mm in diameter, and a cathode pipe made of SUS316 260 mm long and 100 mm in diameter. In the experiment, electromotive force and generator output are measured in terms of average flow velocity (0-5.6 m/s) and magnetic field (0-7 T) using artificial seawater (3.4% NaCl aqueous solution). As a result of the experiment, it was found that the electromotive force increases proportionally to average flow velocity and magnetic field, and that the generator output increases quadratically to average flow velocity and magnetic field over certain points. Experimental values are discussed by comparing the theoretical values and computed values.         Disk-shaped Superconducting rotor under a rotating magnetic field: speed dependence    A. Alvarez, P. Suarez, D. Caceres, E. Cordero, J.-M. Ceballos and B. Perez Summary: As part of the design of small axial-flux induction motors using disk-shaped rotors made from YBCO bulks, in previous work we studied the behavior of such disks under a rotating 2-pole magnetic field and gave an explanation of the results. That work yields information on such internal parameters as pinning forces and pull-out torque, and good estimates of the damping and Magnus coefficients. As in conventional motors, one expects to find dependence of these parameters on the magnetic field speed-the synchronous speed. In the present work, this dependence is studied and the previous model is improved.         Torque-speed characteristics of superconducting synchronous reluctance motors with DyBCO bulk in the rotor    S.D. Chu and S. Torii Summary: Several kinds of superconducting motors have been proposed, Among them the superconducting synchronous reluctance motor (SCSynRM) is expected to develop. The maximum output characteristics of traditional synchronous reluctance motor are basically determined by the relation between the reluctances on d-q axes of the compound rotor. In the conventional synchronous reluctance motor, it is achieved by using the compound rotor of magnetic and nonmagnetic materials. In the SCSynRM nonmagnetic materials are replaced by DyBCO bulk, which possesses diamagnetic properties. Therefore its output characteristics will be improved. In this paper, toward the same stator, we made four types of rotors, which are a salient rotor, an aluminum rotor, a plastic rotor, and a DyBCO rotor. The stator has laminated iron core and three-phase copper windings in the twelve slots. Each rotor has 38 mm diameter and 35 mm axial length, in which the slot, the aluminum, the plastic, or the DyBCO occupies about 37% of total rotor volume. The torque-speed characteristics under the same condition were measured. Through comparison of four motors, the output characteristics of SCSynRM were discussed.         Construction of a 100 kVA high temperature superconducting synchronous generator    M.K. Al-Mosawi, C. Beduz and Y. Yang Summary: This paper reports on the design and construction of the 100 kVA High Temperature Superconducting generator which is successfully built at the University of Southampton. The generator is a 2-pole synchronous machine with a conventional 3-phase stator and a HTS rotor which is constructed from stacks of 9 wt% Ni steel plates. The rotor winding is made of ten single vacuum impregnated pancake coils connected in series and operated in the temperature range 73-77 K. The relatively high operating temperatures are made possible by the use of metallic core as well as flux diverters between the coils. These coils have been successfully manufactured and tested over several cooling cycles. These provide the necessary mechanical support whilst minimizing the heat intake to the rotor core. The coils generate an air gap flux density of about 0.6 T at 77 K, while producing a perpendicular magnetic field of only 0.038 T to board face of the superconducting tape. Furthermore, the design and construction of two novel fiberglass torque tubes is also presented.         Theoretical study of a new kind HTS motor    D. Netter, J. Leveque, E. Ailam, B. Douine, A. Rezzoug and P.J. Masson Summary: This paper describes the design of a new kind HTS motor. Superconducting plates used as magnetic screen that cause a spatial variation of the flux density. It is theoretically possible to obtain an air gap flux density variation greater than 3 T. We perform a dimensionless study of the device showing that the torque depends on shape parameters and is limited by the maximum field on the superconducting wire. In the last section, we discuss the performance of the device in term of torque density.         Investigation of on-board hybrid pulse tube cryocooler for high temperature superconducting rotor    Jung-Won Nam, Sangkwon Jeong, Hongseong Kim, Jeheon Jung and Young-Kil Kwon Summary: This paper discusses the practical realization of an advanced cooling method for superconducting rotor; on-board cryocooler. A hybrid pulse tube cryocooler was designed and tested in the rotating system. A Stirling cryocooler precooled the regenerator of the pulse tube cryocooler to produce lower temperature at the cold end of the pulse tube cryocooler. Based on adiabatic model and loss mechanism analysis, the pulse tube cryocooler was designed and fabricated. The hybrid cryocooler was aligned in the test rotor to have a concentric centerline with the rotation axis. Even if the performance of the rotating hybrid pulse tube cryocooler was not satisfactory, achieving 55 K, the feasibility of on-board cryocooler method for superconducting rotor was confirmed.         Development of a 100 hp synchronous motor with HTS field coils    Y.K. Kwon, M.H. Sohn, S.K. Baik, E.Y. Lee, J.M. Kim, T.S. Moon, H.J. Park, Y.C. Kim and K.S. Ryu Summary: A 3-phase, 100 hp, 4 pole, 1800 rpm superconducting synchronous motor built and tested in Korea Electrotechnology Research Institute(KERI). This machine consists of HTS rotor and air-core stator. The HTS field windings are composed of the double-pancake coils wound with AMSC's stainless steel-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. The open circuit, no-load, and short circuit characteristic were obtained. Also, load tests in motor mode driven by inverter and generator mode connected to resister load bank were conducted. This paper will present design, construction, and experimental test results of the 100 hp HTS machine.         Preliminary test results of radial-type sintered Sm-123 bulk motor    H.-J. Jung, T. Nakamura, H. Miyake, I. Muta and T. Hoshino Summary: We designed and fabricated a radial-type motor with a high temperature superconducting bulk rotor. The fabricated motor has 3-phase and 4-pole armature winding, and then generates rotating magnetic field at the speed of 1800 rpm under the condition of 3-phase, 60 Hz electric power. Sintered Sm-123 bulk was utilized for the solid rotor in this study. The performance of the sintered Sm-123 bulk motor was evaluated by no-load, locked-rotor and load test. Test results showed that the motor generated a little torque and rotated with large slip, even if the motor was applied 165 V/sub rms/ of the phase voltage (the stator current is 18 A/sub rms/). Because of small magneto-motive-force and spatial harmonic components in the air-gap, magnetic flux was prevented from penetrating into the HTS bulk rotor. Therefore, the screening current in the rotor flowed only at the surface of the rotor and generated torque is remained in a little value.         Design considerations for 1 MW class HTS synchronous motor    S.K. Baik, M.H. Sohn, E.Y. Lee, Y.K. Kwon, Y.S. Jo, T.S. Moon, H.J. Park and Y.C. Kim Summary: A 1 MW class superconducting synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1 MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS (High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30 K (-243/spl deg/C) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron-cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.         The performance of a 5 MW high temperature superconductor ship propulsion motor    G. Snitchler, B. Gamble and S.S. Kalsi Summary: A 5 MW, 230 RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor is presently under test at the Center for Advance Power Systems (CAPS). This paper provides a summary of the key design features of the motor, predicted performance, factory test results and extended test results to date at CAPS. This motor was designed and built under the U.S. Navy's Office of Naval Research (ONR) funding (Contract #N00014-02-C-0190) to address the next generation of electric ship propulsion systems. HTS motors are characterized by high power density, quiet operation and high efficiency. HTS air-core motors have unique electrical characteristics and therefore require dynamic testing to validate all modes of operation. The test program at CAPS is designed to address dynamic performance and simulation of this class of propulsion motor. The motor has been operated at 5 MW load for over 3 hours at CAPS.         Design and operational testing of a 5/10-MVA HTS utility power transformer    C.S. Weber, C.T. Reis, D.W. Hazelton, S.W. Schwenterly, M.J. Cole, J.A. Demko, E.F. Pleva, S. Mehta, T. Golner and N. Aversa Summary: High temperature superconducting transformers offer many economic, operational, and environmental benefits over conventional power transformers for utility applications. To establish the technical and economic feasibility and benefits of HTS transformers of medium-to-large (>10 MVA) ratings, a team that includes Waukesha Electric Systems (transformer manufacturer), SuperPower Inc. (HTS systems manufacturer), Oak Ridge National Lab, and Energy East has designed, built and tested a prototype 5/10 MVA superconducting transformer. The transformer's 4.5-ton cold mass has been successfully maintained at temperatures of 30-50 K for several months, without full-time operator attendance. The transformer has reached its full three-phase operating current, and has been tested to 1.4 times operating current (limited by available power supplies) in single-phase mode. It is now undergoing long-term tests at various current levels, high-voltage tests, and transient overcurrent tests at the Waukesha site. This paper summarizes the manufacturing, cooldown, and the test results achieved to date.         Characteristic tests of a 1 MVA single phase HTS transformer with concentrically arranged windings    Sung-Hoon Kim, Woo-Seok kim, Kyeong-Dal Choi, Hyeong-Gil Joo, Gye-Won Hong, Jin-Ho Han, Hee-Gyoun Lee, Jung-Ho Park, Hee-Suck Song and Song-Yop Hahn Summary: A 1 MVA single phase high temperature superconducting (HTS) transformer was manufactured and tested. The rated voltage of primary and secondary of HTS transformer are 22.9 kV and 6.6 kV respectively. BSCCO-2223 HTS tape was used for HTS windings of 1 MVA HTS transformer. In order to reduce AC loss generated in the HTS winding, the concentrically arranged winding was adopted to 1 MVA HTS transformer. Single HTS tape for primary windings and 4 parallel HTS tapes for secondary windings were used considering the each rated current of the HTS transformer. A core of HTS transformer was fabricated as a shell type core made of laminated silicon steel plate. And a GFRP cryostat with a room temperature bore was also manufactured. The characteristic tests such as no load test, short circuit test and several insulation tests were performed at 65 K using sub-cooled liquid nitrogen. Through these test results, the validity of design of HTS transformer was ascertained.         HTS motors in aircraft propulsion: design considerations    P.J. Masson, D.S. Soban, E. Upton, J.E. Pienkos and C.A. Luongo Summary: Current high temperature superconducting (HTS) wires exhibit high current densities enabling their use in electrical rotating machinery. The possibility of designing high power density superconducting motors operating at reasonable temperatures allows for new applications in mobile systems in which size and weight represent key design parameters. Thus, all-electric aircrafts represent a promising application for HTS motors. The design of such a complex system as an aircraft consists of a multi-variable optimization that requires computer models and advanced design procedures. This paper presents a specific sizing model of superconducting propulsion motors to be used in aircraft design. The model also takes into account the cooling system. The requirements for this application are presented in terms of power and dynamics as well as a load profile corresponding to a typical mission. We discuss the design implications of using a superconducting motor on an aircraft as well as the integration of the electrical propulsion in the aircraft, and the scaling laws derived from physics-based modeling of HTS motors.         An axial gap-type HTS bulk synchronous motor excited by pulsed-field magnetization with vortex-type armature copper windings    H. Matsuzaki, Y. Kimura, I. Ohtani, M. Izumi, T. Ida, Y. Akita, H. Sugimoto, M. Miki and M. Kitano Summary: We studied a high-temperature superconducting synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk field magnets. The motor is an axial gap-type, brushless synchronous motor with eight rotating bulk field magnet poles. Liquid nitrogen is circulated to cool down the rotor components. Pulsed field magnetization was performed to excite the bulk field magnets by using a pair of the vortex-type armature copper windings under the zero-field cooling. The trapped peak field density on the surface of the bulk was varied from 0.5 T to 0.8 T. The trapped peak magnetic field 0.5 T on the surface of the bulk magnets provided the motor performance of 3.1 kW with 720 rpm. The field density distribution on the pole bulk magnet surface is anisotropic and different from the ideal conical shape. The optimized pulsed current waveform applied to the armature and the employing of a composite of bulk crystal magnets leading to a spatially homogeneous flux trapping are promising methods for reinforcement of the field flux from the rotor and the motor torque.         High power density superconducting motor for all-electric aircraft propulsion    P.J. Masson and C.A. Luongo Summary: NASA conducts and funds research to advance the state of the art in aeronautics, including improvements in aircraft design leading to enhanced performance in areas such as noise, emissions, and safety. A particular initiative involves development of an all-electric aircraft requiring significant improvements in certain technologies. NASA has started a new project with one of the objectives being the development of enabling technologies for an all-electric aircraft. Electrical aeropropulsion requires the design of more compact and efficient electrical motors. In order to increase the power density, the weight/size must be minimized and the air gap flux density must increase significantly: the use of superconducting materials is an obvious choice. Existing HTS motors are proof-of-principle demonstrators and exhibit power densities lower than 1 HP/lb, which is too low to be considered in mobile systems. This paper deals with a preliminary electromagnetic design of a 200 HP high temperature superconducting motor optimized in terms of power density. The presented configuration is a synchronous motor with a nonconventional topology enhanced by HTS bulk material. The design targets the Cessna 172 propulsion requirements that are 200 HP at 2700 RPM.         Lift and restoring force characteristics evaluation of levitating X-Y transporter using HTS bulks    Y. Kudou, H. Ueda and A. Ishiyama Summary: We have been developing an X-Y (two-dimensional) magnetic levitating transporter, which is composed of the HTS bulks and permanent magnets. To accomplish the design of a real levitation system, we have to investigate the influence of permanent magnet arrangement on levitating characteristics. In this study, we prepared several types of permanent magnets and evaluated how magnetic flux distribution influences the levitating characteristics through lift and restoring force measurements and numerical simulation. For the simulation, we developed a computer program based on the 3D hybrid finite and boundary element (FE-BE) methods, taking into account the anisotropic and nonlinear I-V characteristics of HTS bulks. The simulation results agreed well with experiments. Therefore, we designed and constructed a levitating transporter model, which can levitate a load of 200 kg with a gap of 16 mm, using the developed computer program.         Operational characteristics of linear synchronous actuator with field-cooled HTS bulk secondary    A. Sato, H. Ueda and A. Ishiyama Summary: It is expected that HTS bulk materials will be applied to various electric devices. We have fabricated and tested a linear synchronous actuator with double-sided primary and HTS bulk secondary. The linear actuator consists of a field-cooled YBCO bulk for secondary (mover) and copper windings with iron core as a primary. The primary, which was excited by a three-phase VVVF power source to generate sinusoidal traveling magnetic field, was divided into two sections: 1) the starting section in which the secondary is accelerated as an induction machine; and 2) the synchronous section in which the secondary moves with a specified synchronous speed. As the secondary, two field-cooled bulks were arranged in certain interval. In this paper, for various intervals of bulks, we experimentally investigated the static characteristic in points of synchronous thrust force and the pull-in characteristics. And we developed a simulation program based on the finite element method (FEM) to investigate electromagnetic behavior within the bulk exposed to the magnetic field generated by the primary winding. We investigated the influence of the size, the number, and the interval of bulks on the static characteristic in points of synchronous thrust force by using the developed computer program.         Basic study of a magnetically levitated conveyer using superconducting magnetic levitation    M. Komori and G. Kamogawa Summary: This paper discusses a newly developed conveyer that uses superconducting levitation. The conveyer is composed of a levitated stage with a permanent magnet (PM) and a superconductor with an electromagnet and a Hall sensor. The gap between the PM stage and the superconductor is detected by using the Hall sensor and the current of the electromagnet coil. In order to suppress vibrations of the PM stage, PD (proportional & differential) control using adoptive control method is applied to the system. Control forces are produced by the electromagnet under the superconductor. The dynamics of the levitated stage are discussed in the case that PD control and only D (differential) control are applied to the system.         Axial stiffness of journal bearings in zero-field and field-cooled modes    A. Rastogi, T.A. Coombs, A.M. Campbell and R. Hall Summary: Superconducting journal bearings have been investigated for use in flywheel systems. We report on the zero-field cooled and field-cooled stiffness of these bearings. They are made up of radial magnet rings with alternating polarities, a pole pitch of 11 mm and a surface field of 0.1 T. Field-cooled stiffness of the journal bearings increased four times over the zero-field-cooled stiffness.         Application of superconducting magnetic bearings to a 10 kWh-class flywheel energy storage system    T. Ichihara, K. Matsunaga, M. Kita, I. Hirabayashi, M. Isono, M. Hirose, K. Yoshii, K. Kurihara, O. Saito, S. Saito, M. Murakami, H. Takabayashi, M. Natsumeda and N. Koshizuka Summary: Radial type superconducting magnetic bearings have been developed for a 10 kWh-class flywheel energy storage system. The bearings consist of an inner-cylindrical stator of YBCO bulk superconductors and an outer-rotor of permanent magnets. The rotor is suspended without contact via the pinning forces of the bulk superconductors that are arranged such that the c-axis of each superconductor is aligned parallel to the radial direction of the cylinder. In this paper, we describe the implementation of the stator part and report the SMB test results, namely that the rotor was successfully rotated at up to 7,500 rpm. Thus we succeeded in energy storage of 2.24 kWh.         Design and characteristics of a superconductor bearing    Y.H. Han, J.R. Hull, S.C. Han, N.H. Jeong, T.H. Sung and Kwangsoo No Summary: A high-temperature superconductor (HTS) journal bearing was designed for a flywheel energy storage system. A rotor was supported at top and bottom by two HTS bearings. The rotor weight is 4 kg and the length and diameter of shaft were about 300 mm and 40 mm, respectively. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Static properties of the bearing were calculated by frozen image method and verified by experiments. The vertical stiffness of the bearing was 38.9 N/mm. The rotational drag and vibration were measured up to 8000 rpm. The loss coefficient was linear up to 8000 rpm and the final value was 7.5/spl times/E-6. The average of vibration was about 10 micrometer (zero/spl I.bar/peak) except the resonance speed range. Rotation tests were conducted over the same speed range at several chamber pressures. Chamber pressure of 0.4 mtorr is sufficiently low to minimize windage loss.         Halbach array superconducting magnetic bearing for a flywheel energy storage system    G.G. Sotelo, A.C. Ferreira and R. de Andrade Jr. Summary: In order to develop a new magnetic bearing set for a flywheel energy storage prototype, it was designed and simulated some configurations of Permanent Magnetic Bearings (PMB) and Superconducting Magnetic Bearings (SMB). The bearings were assembled with Nd-Fe-B permanent magnets and the simulations were carried out with the Finite Element Method (FEM). The PMB was designed to reduce the load on SMB and provide radial positioning of the whole set. SMB were designed with YBCO superconductors and an assembly of permanent magnets. Several configurations of permanent magnets were simulated, trying to maximize the magnetic flux gradient in direction orthogonal to the movement and flux density in the surface of the superconductors. Early experiments have shown an increasing stiffness and levitation force with increasing field gradient and intensity. It was also a goal to reduce the stray field outside the bearing. The levitation force of the SMB using a flux shapers configuration was measured and compared with FEM simulation, showing very good agreement. The simulation of a SMB using Halbach array configuration shows that it increases the levitation force and reduces the stray field.         Numerical evaluation of rotational speed degradation in the superconducting magnetic bearing for various superconducting bulk shapes    I. Masaie, K. Demachi, T. Ichihara and M. Uesaka Summary: In constructing the 100 kWh flywheel energy storage systems, the performance of the Superconducting Magnet Bearing (SMB) needs to be calculated to get better technical and practical results. The SMB system mainly consists of the Superconducting (SC) stator and the Permanent Magnet (PM) rotor. The SMB has the advantage that the rotational dragging force between the PM rotor and the SC stator is greatly smaller compared with the usual bearing systems. However, the magnetic friction becomes large enough to cause significant rotational speed degradation. The rotational speed degradation, which cuts down the stored energy, occurring in the PM rotors is one of the most significant problems for the practical use of the SMBs. It is caused mainly by the Lorentz force due to the inhomogeneous magnetic field of the SC stator and the induced eddy current in the PM rotor. In this study, we tried up various shapes of the SC stator to smooth the magnetic field and decrease the energy loss and then evaluated the levitation force, the magnetic field of the SC stator and the energy loss.         Improving the dynamics of two types of flywheel energy storage systems with SMBs    M. Komori and Y. Uchimura Summary: This paper describes two types of energy storage systems (I and II) with a flywheel rotor supported by superconducting magnetic bearings (SMBs). Both systems I and II are composed of a rotor and superconducting magnetic bearings (SMBs) at both ends of the rotor. The rotors of systems I and II are driven by using an air turbine and a brushless motor, respectively. The superconductors of the systems I and II are field-cooled by using liquid nitrogen and a cryogenic refrigerator, respectively. In this paper, a new method for improving the dynamics of the passive type SMBs for two types of flywheel energy storage systems is discussed. The method is performed by changing relative displacements between the SMBs and the rotor PMs after field-cooling process.         Voltage sags compensation using a superconducting flywheel energy storage system    R. de Andrade Jr., A.C. Ferreira, G.G. Sotelo, J.L.S. Neto, L.G.B. Rolim, W.I. Suemitsu, M.F. Bessa, R.M. Stephan and R. Nicolsky Summary: This paper presents a voltage sag compensator, which uses a flywheel energy storage system with superconducting magnetic axial thrust bearing (SMB) and a permanent magnet radial bearing (PMB). The SMB was built with Nd-Fe-B magnet and YBCO superconducting blocks, refrigerated with liquid Nitrogen. The magnets are assembled with magnetic flux shapers in order to increase the levitation force and the stiffness. The radial PMB is used to positioning the vertically arranged switched reluctance machine (SRM) used as motor/generator. Simulations of the power electronics and SRM show that the system can work up to 30,000 rpm supplying the required energy during disturbances.         Supply of rotational energy to a levitated magnet by applying alternating transverse magnetic field    T. Sugiura and Y. Matsuzaki Summary: This research investigates generation of spin torque acting on a permanent magnet, freely levitated above a high-T/sub c/ superconductor, under alternating transverse magnetic field. Numerical results of 6-d.o.f. motion show that the magnet increases its velocity of rotation around its cylindrical axis and finally obtains steady-state rotation. This velocity depends on the frequency of the input coil current. A simplified 2-d.o.f. system with only essential terms was introduced in order to discuss the mechanism of nonlinear coupling which generates spinning in alternating magnetic field. Experimental results were in good agreement with numerical ones. These results show possibility of supplying rotational energy to a levitating magnet by applying alternating magnetic field.         Design consideration of a high temperature superconductor Maglev vehicle system    J.S. Wang, S.Y. Wang, C.Y. Deng, Y.W. Zeng, H.H. Song, Jun Zheng, Xinzhi Wang, H.Y. Huang and Fu Li Summary: The design consideration of the superhigh speed HTS Maglev vehicle system of 1000 m test line is presented on the basis of the experiment results of HTS Maglev vehicle in the years before last. The gross weight of NdFeB of test line guideway is 6750 kg. The low temperature rectangle-shape liquid nitrogen vessel on board has high mechanical strength at 77 K of the temperature. The vessel has 5 mm of bottom thickness and 12 hours of continuous working time. There are two seats in the HTS Maglev vehicle. The total load of the Maglev vehicle is 500 kg including 150 kg of weight of two passengers in the weight. The vehicle body is the quasiellipsoidal shape, and the outside outline size of the vehicle with shell is about 2.3 m of length 0.95 m of height, and 1.2 m of width. The vehicle is driven by a linear motor which is controlled by a ground controlling system. Drive acceleration is 5 g (about 49 m/s/sup 2/), and the acceleration section length is 300 m. The maximum speed of the vehicle is over 600 km/h when there is no onboard man, and the manned speed is still up to 100 km/h.         Experiment and numerical calculation of high temperature superconducting Maglev    Suyu Wang, Jun Zheng, Honghai Song, Xinzhi Wang and Jiasu Wang Summary: The results of the levitation force and the guidance force of Y-Ba-Cu-O bulk above a Nd-Fe-B permanent magnetic guideway (PMG) are reported. These results include both experimental and numerical calculation. The experimental results are measured by high temperature maglev measurement system, and the calculation based on the critical state model using FORTRAN language. The results include the levitation force and the guidance force in the field-cooling (FC) and the zero field-cooling (ZFC), the influence of the shape and the size of HTS bulk on levitation and guidance force, the levitation properties of a YBCO bulk with a different hollow hole, the phenomena of YBCO bulk array above a PMG, the influence of field-cooling height on the levitation force and the lateral force above a PMG, and so on.         Experimental and numerical analysis of lift force in magnetic levitation system    T. Takao, A. Niiro, S. Suzuki, M. Hashimoto, H. Kamijo and H. Fujimoto Summary: A new type of magnetic levitation system using the shielding effect of the HTS bulk is studied. The system includes a permanent magnet and three HTS bulks as a vehicle, and a ferromagnetic bar as a guide way. The simple structure of the guide way reduces large amount of construction costs. The system also provides stable lift force without any active control system. The characteristics of lift force are numerically analyzed using IEM(Integral Element Method). Experiment was performed using a small model. The two results are compared.         Persistent current HTS magnet cooled by cryocooler (2) - magnet configuration and persistent current operation test    S. Kusada, M. Igarashi, K. Kuwano, K. Nemoto, S. Hirano, T. Okutomi, M. Terai, T. Kuriyama, K. Tasaki, T. Tosaka, K. Marukawa, S. Hanai, T. Yamashita, Y. Yanase, H. Nakao and M. Yamaji Summary: An high temperature superconducting (HTS) magnet, consisting of an HTS coil, a persistent current switch, a GM type two-stage pulse tube cryocooler, and YBCO current leads was developed. Detachable current leads were adopted to reduce heat leakage during persistent current operation. The HTS coil was cooled to approximately 10 K and persistent current mode operation tests were carried out at various currents up to 532 A, which is the rated current. Current decay at each persistent current mode operation was investigated by measuring the magnetic field at the center of the coil. The current decay rate at the 532 A operation was found to be approximately 0.44%/day.         Persistent current HTS magnet cooled by cryocooler (3)-HTS magnet characteristics    K. Tasaki, T. Tosaka, K. Marukawa, T. Kuriyama, S. Hanai, M. Yamaji, K. Kuwano, M. Igarashi, K. Nemoto, S. Hirano, T. Okutomi, H. Nakao and M. Terai Summary: We fabricated a persistent current HTS magnet wound with conductors composed of four Ag-sheathed Bi2223 wires and an insulated stainless-steel tape. The HTS magnet is composed of 12 racetrack formed single-pancake coils and impregnated with epoxy resin. The magnet is the same size as a magnet for a Maglev train. The stored energy of the magnet is 0.34 MJ and the central magnetic field is 1.3 T at the rated current operation of 532 A. Cooling the magnet to less than 20 K, I-V characteristics in persistent current operations and AC losses in charging and discharging the magnet were investigated.         Persistent current HTS magnet cooled by cryocooler (4) - persistent current switch characteristics    T. Tosaka, K. Tasaki, K. Marukawa, T. Kuriyama, H. Nakao, M. Yamaji, K. Kuwano, M. Igarashi, K. Nemoto and M. Terai Summary: We developed a persistent current high temperature superconducting (HTS) magnet for Maglev train. The HTS magnet mainly consists of an HTS coil, a persistent current switch (PCS), a GM type two-stage pulse tube cryocooler. A PCS is one of the most important components to maintain persistent current operation. A YBCO thin film was adopted for a PCS conductor because it has a high resistivity over a critical temperature and a high critical current density at lower temperatures. Persistent current mode operation tests were successfully carried out with the PCS. The current decay rate at the rated current operation of 532 A was 0.44%/day which was investigated by measuring the magnetic field at the center of the coil.         A six-meter long prototype of the Mag-Lev cryogen transfer line    Q.S. Shu, G.F. Cheng, J. Susta, Deqing Li, J.R. Hull, J.A. Demko, C.P. Britcher, J.E. Fesmire, S.D. Augustynowicz, F. Werfel and E.C. Bonnema Summary: An innovative six-meter long prototype of the magnetic levitation suspended cryogen transfer line has design, constructed and tested to demo potentials of extending many missions by saving cryogens, or reducing the overall launch mass to accomplish a given mission. The use of magnetic levitation by permanent magnets (PM) and high temperature superconductors (HTS) provides support without mechanical contact and thus, the conduction part of the heat leak can be reduced to zero, which is ultimately the most serious heat leak after thermal radiation has been minimized. The configurations of HTS & PM, the levitation force in different arrangements, the mechanical design of the transfer line, the support/release structures, and the cryogenic testing results are also discussed.         Superconductively levitated transport system - the SupraTrans project    L. Schultz, O. de Haas, P. Verges, C. Beyer, S. Rohlig, H. Olsen, L. Kuhn, D. Berger, U. Noteboom and U. Funk Summary: SupraTrans is an innovative transportation concept based on the principle of superconductive magnetic levitation. The aim of the project is to create a fully working prototype, which proves its ability for passenger transport by explicit consideration of the compatibility between systems for propulsion, safety, positioning, power supply, transport logistics and the levitation system itself. The SupraTrans technology uses the flux pinning in high temperature superconductors (HTS) to stabilize the lateral and vertical position of the vehicle on the magnetic track. This self-stabilizing system is the main advantage of the superconductive levitation in comparison to all other levitation systems, which need electronic control and power to keep a constant distance between the train and the track.         Encapsulated HTS bearings: technical and cost considerations    F.N. Werfel, U. Floegel-Delor, T. Riedel, R. Rothfeld, D. Wippich and B. Goebel Summary: Thermal encapsulation of HTS is one way to fabricate high-efficient HTS magnetic bearings for flywheels, motors and generators. We have been designed, manufactured and tested 200 mm axial and radial bearings for loads close to 300 kg. The maximum load to bearing weight is in the 10 to 1 ratio. At 77 K, a vacuum cryostat around the HTS reduces basic thermal losses to 6.4 W with very small rotational ac losses of 0.1 W/1000 rpm. The encapsulation reduces the cryogenic threshold in the application and allows a convenient adaptation of cryo-coolers. Basic elements are the melt textured YBCO single crystals, appropriately machined and glued in a copper ring in the center of the vacuum cryostat combined with an intrinsic cryo-sorption pump. Ten axially stacked 200 mm PM rings comprise the magnetic excitation system of the rotor. The coefficient of friction is about 10/sup -4/ at ambient and 10 times lower at reduced pressure. For higher loads the manufacturing effort of HTS bearings, becomes comparable with mechanical bearings, increasing the chances of replacing mechanical bearings.         Superconducting micro-bearings    T.A. Coombs, I. Samad, D. Ruiz-Alonso and K. Tadinada Summary: This paper presents research into superconducting Micro-Bearings for MEMS systems. Advanced silicon processing techniques developed for the Very Large Scale Integration (VLSI) industry have been exploited in recent years to enable the production of micro-engineered moving mechanical systems. These devices commonly known as Micro-ElectroMechanical Systems (MEMS) have many potential advantages. In many respects the effect of scaling a machine from macro-sized to micro-sized are either neutral or beneficial. However in one important respect the scaling produces a severely detrimental effect. That respect is in the tribology and the subsequent wear on the high speed rotating machines. This leads to very short device lifetimes. This paper presents results obtained from a MEMS motor supported on superconducting bearings. The bearings are self-positioning, relying on, the Meissner effect to provide a levitation force which moves the rotor into position and flux pinning to provide stability thereafter. The rotor is driven by a simple electrostatic type motor in which photo resist is used to pattern the motor poles directly onto the rotor.         Magnetic field inhomogeneity and torque in high temperature superconducting magnetic bearings    T. Matsumura, S. Hanany, J.R. Hull, B. Johnson and T. Jones Summary: We give experimental evidence for the connection between magnetic field inhomogeneity of a permanent magnet and torque on the rotor in a high temperature superconducting bearing. Spin-down measurements below 14 Hz are used to demonstrate a high degree of correlation between variations in the angular speed of the rotor within a single period of rotation with the measured spatial structure of the magnetic field of the rotor. At frequencies below /spl sim/1 Hz the fractional speed variation within a single period of rotation is inversely proportional to the square of the mean frequency of rotation. We propose that a dipole-dipole interaction gives rise to the torques that lead to speed variations and we show that this interaction explains the observed functional dependence on frequency. At frequencies above /spl sim/1 Hz the measured magnitude is about 1% of the mean frequency of rotation, consistent with the noise level in the experiment. The results imply that arcminute accuracy angular encoding of the rotor can be achieved with a single measurement of angle in each period.         Compact HTS cryogen-free magnet for magneto-optics research setup    Y. Wolfus, A. Friedman, F. Kopansky, Y. Yeshurun, Z. Bar-Haim, Z. Ron and N. Pundak Summary: Small working distances between the objective lenses and the inspected samples in magneto-optical (MO) setups limit the volume available for external magnetic field generation coils. Air or water-cooled copper coils are commonly used for field generation, however these coils usually make it possible to attain limited fields of the order of 10-50 mT, in continuous operating mode. HTS coils offer a unique and cost effective solution in such cases of limited space. A compact, 0.4 T, cryogen-free, HTS magnet has been designed, built and tested in a MO setup. The magnet is made of 3, 100 turns single pancakes, mounted on the second stage of a two-stage cryocooler. The HTS coil operates at about T=45 K and generates 0.4 T in a warm bore of 30 mm diameter. Minimization of metal components in the coil makes it possible to attain field ramp rates of 7.4 T/sec with a coil charging voltage of 20 V. Initial cool-down time of the magnet takes less than 5 hours. The magnet design and performances are described in detail and serve as an example for solutions that HTS technology may offer in limited space applications.         An integrated micro HTS system for energy storage and attitude control for three-axis stabilized nanosatellites    Eunjeong Lee, Bongsu Kim, Junseok Ko, Chi Young Song, Seong-Jin Kim, Sangkwon Jeong and S.S. Lee Summary: This paper presents the development of an integrated micro high-temperature superconductor system for energy storage and attitude control of three-axis stabilized nano satellites. The micro HTS system consists of a flywheel/rotor, motor/generator, motor electronics, and a cooling system. The flywheel/rotor has been fabricated by using sintered NdFeB and the stator for motor/generator has been fabricated by micro fabrication technology. An alternative stator has been fabricated by cutting a 50 micron-thick copper film for comparison. A servo amplifier to drive the DC brushless motor of the integrated HTS system has been developed and successfully tested. A cooling system has been developed to test the system. It has been observed that the micro fabricated stator can make the flywheel rotate at a constant velocity of up to 12,000 rpm whereas the other stator generates a constant velocity of up to 2,500 rpm. Experiments show that the micro fabricated stator can significantly reduce the motor/generator losses.         Loss evaluation and simulation of superconducting magnetic bearings    Z. Kohari, V. Tihanyi and I. Vajda Summary: Static and dynamic behaviors of axial flux SC magnetic bearings are very important for motor-generator design. Stability and losses were investigated both theoretically and experimentally, and spin down curves were calculated and measured. We derived the dynamic mechanical equations for axial SC bearings, and gave a mathematical frame which can include different spin-down models and loss components in which only macroscopic factors were taken into account. The elasticity of the bearings (lateral displacement) was taken into account on the basis of static force measurements. We suggested a mathematical description for the deceleration also, where each loss component was described by one appropriate coefficient. We also made a rather simple but effective superconductor model, which can be used in 2D or 3D finite difference or finite element methods. In this the superconductor was characterized by a maximum flux density gradient which has a close relation to the pinning forces, and is equivalent with a J/sub c/ value in 1D.         Development of conduction-cooled high temperature superconducting magnet    Qiuliang Wang, Yingming Dai, Hui Huang, Shouseng Song, Bo Zhang, Keeman Kim and Sangjun Oh Summary: We are carrying out a National High Technology Program in China to fabricate a magnetic separator by using a conduction-cooled Bi-based high temperature superconducting (HTS) magnet. The magnet is made of Bi-2223 pancakes, and has the inner and outer coil diameters of 120 mm and 211.2 mm and coil height of 202.8 mm. The operating current is about 80 A. This magnet is cryocooler-cooled with no liquid helium and should generate a magnetic field of 3 T at a temperature of 20 K. In the paper, we report the design and fabrication technique of the HTS magnet.         Magnetic separation of industrial waste waters as an environmental application of superconductivity    T. Hartikainen, J.-P. Nikkanen and R. Mikkonen Summary: Open gradient magnetic separation enables continuous operation of the separator without the need of matrix-elements. Such a separator consisting of liquid helium cryostat and an interchangeable pair of NbTi and Nb3Sn coils were designed and constructed for testing the separation of various substances. As an environmental application, synthetic and genuine steel mill waste waters were purified with the separator. Synthetic waste water contained dissolved Cr while genuine steel mill waste water contained Cr, Fe, Ni and Mo both in particle and in ionic form. Chemical treatment was needed to make the dissolved metals susceptible for magnetic field; this was achieved with the help of an adsorbent and ferromagnetic magnetite. Separated sludge was collected by attached pipeline. Cleaned waste water was first pH-treated and then analyzed by AAS-spectroscopy. Results showed that open gradient separator is a promising alternative for matrix-type separators.         Numerical evaluation of separation characteristics of open gradient magnetic separation using quadrupole magnetic field    M. Takahashi, T. Umeki, S. Fukui, J. Ogawa, M. Yamaguchi, T. Sato, H. Imaizumi, M. Oizumi, S. Nishijima and T. Watanabe Summary: Numerical study on the open gradient magnetic separation using the quadrupole magnetic field is presented in this paper. The characteristics of separating multiple kinds of magnetic particles with different magnetic susceptibility are numerically evaluated by the model to analyze the transient diffusion process developed in our previous study. We consider two methods for the separation of multiple kind particles. In the first method, the numerical results show that the two kinds of particles with different magnetic susceptibility can be selectively separated. The second method is one of the field flow fractionation which is called the magnetic chromatography. The calculated time evolutions of the particle concentration in the thin cylindrical channel show the flow velocity difference of the particle transport corresponding to the difference of the magnetic susceptibility. It is considered that the open gradient quadrupole magnetic field can be applied for the magnetic chromatography.         Characteristics of an improved coil structure for the magnetic stereotaxis system    Ye Bai, Qiuliang Wang, Ming Yang, Yunjia Yu, Hongwei Liu and Keeman Kim Summary: The Magnetic Stereotaxis System (MSS) is a unique medical device designed to deliver drugs and other therapies directly into deep brain tissues. This approach uses superconducting coils to manipulate a small permanent magnet pellet attached to a catheter through the brain tissues. The movement of the small pellet is controlled by a remote computer and displayed on a fluoroscopic imaging system. The magnets of the previous generations were composed of three pairs of orthogonal superconducting solenoid coils. The control strategies are complex because of the magnetic field distribution of solenoids. The high inductance values of solenoid coils can severely slow down the ratio of current change and therefore do harm to the control precision of a magnet pellet. This paper presents a novel type of spherical coils that can generate linear gradient fields over a large spherical volume. This type of modified spherical coils with a constant current distribution model is easy to fabricate in engineering and manufacture. A prototype of this spherical magnet has already been constructed with copper conductors at the Applied Superconductivity Laboratory, CAS. We have also completed the design of superconducting spherical coils with NbTi conductors. Simulation and test results of this magnet are also presented.         A digital flux injector for NMR magnets    R. Mai, Seung-Yong Hahn, Haigun Lee, J. Bascunan and Y. Iwasa Summary: By periodically injecting a quantified amount of flux in a "slightly" resistive NMR magnet, a digital flux injector (DFI) enables the magnet to effectively operate in persistent mode. This paper presents: 1) parameters of the first full-scale DFI, specifically designed and built to operate with an LTS/HTS NMR magnet; and 2) its preliminary results when coupled to an LTS insert magnet in a bath of liquid helium.         A "persistent-mode" magnet comprised of YBCO annuli    Y. Iwasa, Seung-Yong Hahn, M. Tomita, Haigun Lee and J. Bascunan Summary: A new type of "persistent-mode" magnet, assembled from YBCO annuli, appears promising for "microcoil" NMR, in which compactness and simple manufacturability are vital. To develop an annular magnet for micro NMR, a YBCO-annulus Helmholtz coil was studied. The paper describes the new magnet concept and results of our study on the Helmholtz coil.         Solenoidal Bi-2223/Ag induction heater for aluminum and copper billets    I. Hiltunen, A. Korpela and R. Mikkonen Summary: Induction heating is widely used to heat up aluminum and copper billets before extrusion. Resistive induction heating systems, which typically have the total efficiency of 50-60%, are generally used with ac current. By utilizing superconductivity, the total efficiency of induction heating system can be increased to approximately 90%. If the heating power of conventional induction heaters can be reached with a superconducting device, resistive systems could be replaced by superconducting ones, and remarkable savings would develop in the long run. In this paper the feasibility of Bi-2223/Ag induction heater is studied. A solenoidal magnet for induction heating of aluminum and copper billets is designed. Ac losses are a considerable problem in Bi-2223/Ag magnets. Thus, dc current is utilized and the eddy currents are generated by rotating the billets. Coil design aimed to maximize the heating power by maximizing the radial gradient of the magnetic flux density in the heating area. In the design procedure the optimization algorithm Sequential Quadratic Programming was coupled with electromagnetic field computation by means of Finite Element Method. The quench current of the coil was determined based on the stability analysis of conduction-cooled Bi-2223/Ag magnets.         Discharge and current limiting characteristics of a superconducting fuse    Hyo-Sang Choi, Sung-Hun Lim and Dong-Chul Chung Summary: We investigated the basic properties of a superconducting fuse (SF) based on YBCO/Au films. The SF consists of YBCO stripes covered with Au layers for current shunt. The fault current was limited to a designed value within 0.4 msec by resistance generated in YBCO/Au after its quenching. This enabled the SF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, which is short enough to do self-interruption. Under the source voltage of 100 V/sub rms/, the longer the current limiting time was, the shorter its discharge time was. The current limiting time and its discharge time were reduced as the applied voltages increased in the range of 200-300 V/sub rms/. We thought that this was because the quench propagation was limited by local melting generated from higher voltage. The superconducting fuse could be designed in small size and compact structure using the characteristic of its high current density compared with the conventional fuse. The superconducting fuse was not harmful to the environment because it was immersed in liquid nitrogen.         Superconducting hybrid power electronics for military systems    T. Curcic and S.A. Wolf Summary: Cryogenic and superconducting technologies will likely be present on board future battle ships and aircraft, primarily in motors and generators. Motivated by this prospect, DARPA has sponsored a study to investigate the impact of expanding cryogenics to the power conversion equipment as well. An overview of the results of this study and future prospects are the subject of this paper.         Improving performance of cryogenic power electronics    P. Haldar, Hua Ye, H. Efstathiadis, J. Raynolds, M.J. Hennessy, O.M. Mueller and E.K. Mueller Summary: Cryogenic Power Electronics (CPE) provides promising benefits for power conditioning system compared to their room-temperature counterparts in terms of reduced size and weight (increased power density), improved efficiency, improved switching speed, and improved reliability. Active devices such as semiconductor switches can exhibit performance improvements such as reduced conduction losses, higher switching speed, reduced diode reverse recovery, greater device gain, higher over-current capability, and increased power levels. Passive devices (inductors, capacitors, interconnects) will also improve by the lowered resistance of their constituent metal conductors or the use of superconductors. This paper aims to review the present status of CPE and to provide an outlook on emerging device technologies that are gaining in interest. Advanced power electronic packaging/interconnect methods that adapt well to cryogenics and help further improve system performance is discussed. Given improved and known device and interconnect properties, the system designer can develop the best circuit topologies for maximum CPE system performance.         Investigation of potential benefits of MOSFETs hard-switching and soft-switching converters at cryogenic temperature    Hui Li, D. Liu and C.A. Luongo Summary: This paper presents an investigation of potential advantages of MOSFETs hard-switching and soft-switching converter at liquid nitrogen temperature (LNT). Circuits are proposed, analyzed and built to demonstrate the different switching performance at room temperature and reduced temperature. The experimental results showed both hard-switching and soft-switching operation of MOSFETs in a boost converter is improved at 77 K. The gate drive circuit needs to be designed specially for MOSFETs to work well at liquid nitrogen temperature.         A new technique for the measurement of AC loss in second-generation HTS tapes    R.J. Soulen Jr., M.S. Osofsky, M. Patten and T. Datta Summary: The successful application of superconductivity to motors and other power system components depends on several factors. One of these involves characterization and minimization of the ac loss in the superconductor used for fabrication of the component. Previous electrical measurements of ac loss have been complicated by the presence of large, undesirable voltages due to stray inductances in the circuit. Their effect was minimized by the addition of a compensation circuit. We have developed a much simpler circuit that significantly reduces this problem to the extent that no compensation is necessary. We report on measurements of the ac loss of several commercial YBaCuO samples immersed in liquid nitrogen using this circuit. We also propose a definition for characterizing the quality of the tapes.         Inductor design for cryogenic power electronics    J.H. Claassen Summary: The core losses of a number of ferrite compositions as well as several metallic ferromagnetic materials have been measured at 78 K. From these measurements we can estimate the power dissipation of a conventional inductor (copper windings, magnetic core) at low temperature. It is found that the magnetic losses generally increase on cooling; this counteracts the reduction in copper losses, and the dissipation would not be much different than its room temperature value. If superconducting windings are substituted for the copper, there remains a tradeoff between losses in the core and in the superconductor. Optimization of this combination will require extensive modeling; it may be that the best solution involves no magnetic core at all.         Large superconducting radio frequency construction projects    C.H. Rode Summary: The SRF achievements of the last two decades will be reviewed; concentrating on the CEBAF, LEP, and SNS projects. The near term new SRF initiatives will also be presented.         New directions in superconducting radio frequency cavities for accelerators    T.L. Grimm, A. Aizaz, M. Johnson, W. Hartung, F. Marti, D. Meidlinger, M. Meidlinger, J. Popielarski and R.C. York Summary: Superconducting radio frequency (SRF) cavities used in present-day accelerators for the acceleration of charged particles near the speed of light are based on the axially symmetric TM010 mode of a pillbox cavity. Future accelerators such as the Linear Collider require high accelerating gradients to limit the length of the linac. Two techniques to improve the gradient are being explored: a cavity that is half reentrant to improve the electromagnetic characteristics, and improved heat transfer via cooling channels and surface modification at the helium interface. These changes could potentially increase the gradients and reduce the cryogenic losses. For other applications more important criteria are simplicity, acceleration of high beam current, or the ability to use advanced materials such as Nb/sub 3/Sn or high-T/sub c/ superconductors. A new type of cavity based on the TM01p pillbox mode with p>0 offers such improvements.         First results of testing 3.9 GHz TM/sub 010/ superconducting cavity    N.A. Solyak, L. Bellantoni, T.G. Berenc, H.T. Edwards, I.V. Gonin and T.N. Khabiboulline Summary: Fermilab is developing third a harmonic 3.9 GHz superconducting cavity to improve performances of A0 and TTF photoinjectors. In the frame work of this project we have built and tested two nine-cell copper models and one 3-cell niobium cavity. Properties of the high order modes were carefully studied in a chain of two copper cavities at room temperature. In this paper we discuss results of cold tests of the 3-cell cavity before and after surface treatment.         Facility for chemical polishing of superconducting niobium RF cavities    C. Boffo, L. Elementi and Y. Terechkine Summary: Chemical polishing of surfaces of Nb RF cavities is an important part of cavity fabrication process. Because of the dangerous nature of the chemicals involved in the process, safety considerations require careful design of the facility and of the process. This report describes the major features of the facility prototype at FNAL and a description of the process and the control systems.         Magnetostrictive fast tuners for SRF cavities    A. Mavanur, Chiu-Ying Tai, C.H. Joshi, E. Daly and K. Davis Summary: Energen, Inc. has demonstrated new tuners based on magnetostrictive actuators to address SRF cavity fast tuning requirements for next-generation particle accelerators. Prototype fast tuners were fabricated and delivered to DESY, Argonne National Lab and Jefferson Lab. Results are reported from tests at Jefferson Laboratory, which were done under realistic operating conditions. In these tests, Energen's fast tuner was found to have a tuning range double the required 1200 Hz and provided precise, nanometer-resolution motion. Slow tuner results have been reported in earlier papers.         Author Index (2004 - Part 2)    No author information available Summary: Not available         Upcoming Special Conference Issues (2004 - Part 2)    No author information available Summary: Not available

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