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Detection of the magnetic signature of ships can be avoided by using a degaussing system; a set of on-board copper coils that compensates for the magnetic signature. High temperature superconductors (HTS) are currently investigated as a replacement for copper degaussing coils. By using HTS, we have to deal with higher currents and therefore with higher power supply losses. Also, large current leads are needed which introduces extra losses. This paper investigates different possible solutions to minimize these losses. Four H-bridge-based MOSFET topologies are presented that were designed to reduce the power supply and current lead losses. The first topology uses an H-bridge configuration so that the degaussing current can freewheel through the low-resistance MOSFETs. The second topology places the H-bridge inside the cryostat so that the current leads can be made smaller. The third topology includes a smoothing capacitor in the cryostat so that the current leads and input current are even smaller. The fourth topology uses a transformer so that the current leads can be eliminated. Measurements were done to determine the MOSFETs and capacitor performance in liquid nitrogen. The simulated losses of the four topologies are compared to determine the most energy-efficient option for supplying current to the HTS coils. It was found that by submerging multiple parallel MOSFETs in liquid nitrogen, the on-state resistance is decreased and the current supply can be made more efficient. Also, by placing a smoothing capacitor inside the cryostat, the current lead losses can be minimized significantly. The benefits of using a transformer do not outweigh the transformer losses.

A key component in superconducting magnetic energy storage (SMES) system design is the cooling system. A well-designed cooling apparatus allows a SMES to work with higher critical currents, have less AC losses and work in a stable way. Acknowledging the importance of cooling systems in a SMES and that there have been many different designs presented in the bibliography, we hereby analyze various thermal designs that utilize cryocoolers, and we estimate the total volume of the superconducting coils used in their experiments. This review article focuses on recent high temperature superconducting (HTS) materials, and presents the cooling methods employed to cool the coil in conjunction with other important characteristics, such as the coil geometry, the operating temperature of the magnet, the thermal insulation temperature and the cooling power of the cryocoolers. From the presented analysis, the authors propose a procedure to devise a proper cooling scheme for a SMES design. Additionally, a qualitative comparative assessment of the analyzed designs in literature, in eight assessment criteria, is presented. [ABSTRACT FROM AUTHOR]

In the scope of the Future Circular electron positron Collider study (FCC-ee), the IDEA detector is developed. It comprises a superconducting solenoid with free bore of 4 m, 6 m long and a central magnetic field of 2 T. The positioning of the magnet between the inner tracker and the electronic calorimeter heavily constrains the magnet design, as it is required to have the lowest possible radiation length, so minimum thickness and lowest density material. With respect to the classical solution of a solenoid enclosing the calorimeters, a cost reduction of about 50% is expected due to size reduction. An optimization of the different components of the magnet system has been carried out, resulting in the development of a new composite high-strength conductor that can be used to build a 30 mm thin solenoid. The quench analysis of the solenoid will be presented as it is of critical importance given the high energy density in the magnet of 21 kJ/kg. A cryostat made of concentric aluminium shells would account for about 50% of the radiation length of the magnet and most of this material is used in the outer vacuum shell of the cryostat to prevent buckling. In order to further reduce the radiation length, two fundamentally different approaches are being analysed. The first method focuses on reducing drastically the outer shell thickness. This leads to use honeycomb composites, reinforcing bars and corrugated shells for the outer shell of the cryostat. The second approach consists of supporting very thin cryostat shells directly on the solenoid cold mass using proper support. This can be achieved by replacing the thick walls and MLI insulation by a material that can sustain 1 atm while having low radiation length and low thermal conductivity. Cryogel Z has shown promising properties and its suitability for this project is being analysed. This novel approach has never been used so far for superconducting magnets. [ABSTRACT FROM AUTHOR]

A cryogen recondensing cooling system was designed for a 7 T superconducting solenoid magnet in an electron beam ion source (EBIS) system. In an EBIS system, it is difficult to access the apparatus due to strong X-ray emission when in full operation. The proposed cooling system was adapted for liquid-helium recondensation. An EBIS is a typical ion source that is feasible for highly charged ion production. Thus, the EBIS system can meet various requirements of end applications, and the development of such a system is strongly required. Estimations of the thermal and structural stability levels are very important during the design of a cryostat; therefore, these values were calculated by means of a numerical analysis. In the thermal analysis, the heat loads were calculated according to the temperature gradient after calculating the temperature distribution. The cooling margins were estimated at the first and second stages of the cryocooler, respectively, with respect to the calculated heat load. It was also estimated that the thermal stress due to the temperature gradient. Finally, it was confirmed that the proposed cryostat design was thermally and structurally stable and suitable for application to a superconducting magnet for an EBIS system. [ABSTRACT FROM AUTHOR]

The rare isotope science project (RISP) was established at the Institute for Basic Science, Daejeon, South Korea to construct a heavy ion acceleration facility for rare isotope beam production. The separators include two pre- and main separators. The central purpose of the preseparator is to remove the primary and unwanted isotope beams; radiation heating and shielding are the major design considerations. For a warm ion, the hightemperature superconducting (HTS) dipole magnet will be used in the front region of the preseparator, and six HTS quadrupole magnets will be installed consecutively. In this paper, we present the electromagnetic design details and the specifications of the consecutive HTS quadrupole magnets for the preseparator at the RISP. Metal (Stainless steel 316) insulated magnets were designed to include iron cores. Using the finite-element method tool, six HTS magnets were modeled and simulated. The operational characteristics including the field gradient, effective length, and uniformity of each magnet were analyzed and presented as well. The research outcomes will be useful for the actual construction of a heavy ion acceleration facility in South Korea. [ABSTRACT FROM AUTHOR]

The cryostat chiefly consists of external vacuum housing, 60 K shield screens, liquid helium vessel with an SC multipole magnet inside, vacuum chamber (beam duct) with copper liner inside, and four two-stage cryocoolers with a stage temperature of 4.2 K/60 K. Current leads have heat in-leak interception in vacuum using cryocoolers. The helium vessel is suspended with four vertical and four horizontal CFRP (T300) tension rods connected to the external cryostat vessel. These tension rods pass throughout the 60 K shield screens and attach to bolts on the external housing walls and are used for precise alignment of the vertical magnet position. [ABSTRACT FROM AUTHOR]

A superconducting magnet is operated under cryogenic conditions. To effectively design a cryostat for hightemperature superconducting (HTS) magnets, thermal loads-- including conduction and radiation--should be minimized. These heat loads are closely related to the shape of both cryostat and HTS magnets, metal current lead, and cooling method used. A 300-kW-class superconducting induction heater (SIH) is being developed to design an effective cryostat. This paper presents two different cryostat designs (with different shapes) for conductioncooled HTSmagnets. The thermal stability of the HTSmagnet was analyzed by considering heat generation and temperature increase and how these were related to quench phenomena. The cooling characteristics of single- and two-stage cryocoolers were analyzed and compared using the finite-element method. The study results will be applied to the fabrication of the 300-kW-class SIH. [ABSTRACT FROM AUTHOR]

A conduction-cooled cryostat has been developed for NbTi superconducting magnet used in a cryogenic probe station. In a cryogenic probe station, a sample stage for transient measurement is located in the bore of a low-temperature superconducting (LTS) magnet and thermally connected to the second-stage cold head of a cryocooler to cool the sample down to the liquid helium temperature. Two separate structures exist in order to maintain isolation between the LTS magnet and sample stage. The system is cooled by a two-stage cryocooler, and the LTS magnet is charged and generates the designed magnetic field. When the magnet is charged and maintains a certain magnetic field, the temperature of sample stage is varied depending on the amount of heating. The thermal linkage between the LTS magnet and second-stage cold head as well as the sample stage and second-stage cold head is investigated in terms of the stability of LTS magnet, magnetic field, and temperature of sample stage. The mechanical module including the thermal link to control the sample stage is integrated into the system and the results of the performance test are reported. [ABSTRACT FROM AUTHOR]

Recent progress on the development of very low noise high purity germanium ionization spectrometers has produced an instrument of 1.2 kg mass and excellent noise performance. The detector was installed in a low-background cryostat intended for use in a direct detection search for low mass, WIMP dark matter. This transaction reports the thermal characterization of the cryostat, specifications of the newly prepared 1.2 kg p-type point contact germanium detector, and the spectroscopic performance of the integrated system. The integrated detector and low background cryostat achieved full-width-at-half-maximum noise performance of 98 eV for an electronic pulse generator peak and 1.9 keV for the 1332-keV 60Co gamma ray. [ABSTRACT FROM AUTHOR]

Direct-drive superconducting generators are attracting wide interest in wind power generation. Cryostats are usually required in superconducting electric machines to keep low temperature for the superconducting coils. The characteristics of superconducting machine should be taken into account in the cryostat design. In this paper, a conceptual design of the cryostat for a low temperature superconducting (LTS) direct-drive wind generator is presented. Different cooling methods for the superconductors are discussed and a conductive cooling method is employed. A cryostat supporting structure is proposed and the structural analysis is performed according to the performance of the superconducting electric machine. The thermal loads are estimated by empirical formula and finite element analysis (FEA), and the detailed design is also presented. [ABSTRACT FROM PUBLISHER]

The range of temperature measurements have been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new two-stage, closed-cycle helium cryostat which has an extended sample temperature range from <40 to >450~K, with long-term controlled stability of <0.5~K. The system was designed to maintain compatibility with an existing ultrahigh vacuum chamber (base pressure <10^-7~Pa) that can simulate diverse space environments. These existing capabilities include controllable vacuum and ambient neutral gases conditions (<10^-8\-10^-1~Pa), electron fluxes (5–30-keV monoenergetic, focused, and pulsed sources over 10^-4\-10^10~nA\-cm^-2), ion fluxes (<0.1\-5~keV monoenergetic sources for inert and reactive gases with pulsing capabilities), and photon irradiation (numerous continuous and pulsed monochromated and broad band IR/VIS/UV [0.5\-7~eV] sources). The new sample mount accommodates one to four samples of 1–2.5-cm diameter in a low-temperature carousel, which allows rapid sample exchange and controlled exposure of the individual samples. Custom hemispherical grid retarding field analyzer and Faraday cup detectors, custom high speed, high-sensitivity electronics, and charge neutralization capabilities used with <50~pA, <5~\mus, and <3\times 10^3 electrons/pulse pulsed-beam sources permit high-accuracy electron emission measurements of extreme insulators with minimal charging effects. In situ monitoring of surface voltage, arcing, and luminescence (250–5000 nm) have recently been added. [ABSTRACT FROM AUTHOR]

This paper presents progress on the development of a cryostat intended to improve upon the low-energy threshold (below 0.5 keV) of p-type point contact germanium gamma-ray spectrometers. Ultra-low energy thresholds are important in the detection of low-energy nuclear recoils, an event class relevant to both dark matter direct detection and measurement of coherent neutrino-nucleus scattering. The cryostat design, including a thermal and electrical-field model, is given. A prototype cryostat has been assembled and data acquired to evaluate its vacuum and thermal performance. [ABSTRACT FROM PUBLISHER]

An automated system was developed to image the 3-D distribution of fluorescent magnetic nanoparticles in tissue samples. It enables easy measurement of magnetic nanoparticle distributions, for small and large tissue samples (currently up to a maximum size of 25\ mm\times 25\ mm\times 25\ mm), in 3-D, with about 70 \mum resolution in plane and 1 \mum in the vertical direction. There is a linear correlation between particle concentration and fluorescence intensity, hence the system provides a quantitative measure of the nanoparticle distribution, but the tissue sample is destroyed during the imaging process. The system was demonstrated by measuring the particle distribution in rat ear and brain samples. [ABSTRACT FROM AUTHOR]

This paper presents the design of an AC loss experiment using nitrogen boil-off method. This experiment is aimed at exploring the AC loss of HTS double race-track coils which will be installed on the rotor of a wind turbine generator. The operating environment is simulated by designing a cryostat with rotating magnetic field windings. Apart from the fact that the alternating magnetic field causes most of AC loss on the HTS coils, we also believe that the DC background field would be another important factor causing AC loss if the HTS coil is experiencing by both alternating magnetic field in the perpendicular direction and DC background field in the parallel direction. In order to perform the boil-off measurement, we present the method to estimate the heat leakage in the cryostat which might cause errors to the measurement . [ABSTRACT FROM PUBLISHER]

The new AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) Experiment has the main goal to measure the Earth's gravitational acceleration of antihydrogen atoms. Two high-homogeneity superconducting 1 T and 5 T solenoids are placed on the same axis and provide the magnetic field required for the cylindrical Penning traps to catch and to accumulate antiprotons delivered by the Antiproton Decelerator of CERN. The solenoids have a free bore of 250 mm and 160 mm respectively and the overall system length is 3 m. The 1 T and 5 T solenoids are equipped with a set of superconducting correction coils charged by individual power supplies. In addition, there is a shielding coil to minimize the stray magnetic field in the measurement area. The solenoids and their sets of correction coils are constructed and tested at CERN. Before system integration the single coils are tested separately in a vertical cryostat. To guarantee smooth precooling of the impregnated coils a small volume of liquid nitrogen is placed inside the solenoid bore without direct thermal contact to the solenoid cold mass. The heat exchange and therefore the cool down rate are controlled by regulating the helium gas pressure in the cryostat. The final magnet control system is used for coil energizing and quench protection. [ABSTRACT FROM PUBLISHER]

One of the critical matters yet to be solved for commercial applications of extra high voltage superconducting devices is the optimum design and development of high voltage cryogenic bushings which could withstand both severe insulation requirements and a steep temperature gradient due to the cryogenic environment. Neither conventional extra high voltage bushings insulated by SF6 gas nor composite materials are directly applicable to cryogenic bushings due to an extremely low temperature environment. In order to obtain suitable dielectric performance of bushings in the cryogenic environment, we focused on an alternative insulation gas instead of SF6 such as CF4, which shows excellent dielectric performance under extremely low temperatures, and also on the optimum design of cryogenic bushings, which have a longer creepage distance compared to conventional bushings. In this paper, design factors of cryogenic bushings were discussed, and test results of 60 and 100 kV extra high voltage prototype bushings were discussed in detail. Consequently, it was possible to obtain satisfactory results to verify the insulation level of newly designed extra high voltage cryogenic prototype bushings for superconducting electric power applications. [ABSTRACT FROM PUBLISHER]

The development of a 5 T high temperature superconducting (HTS) insert magnet system is underway at the Korea Basic Science Institute (KBSI). The objective of the program is the design and fabrication of HTS insert magnet system for high field superconducting magnet applications. Since the HTS magnet system should be inserted into the conduction-cooled 15 T background magnet with 102 mm room-temperature bore, several ancillary requirements such as space restriction and cryostat structure need technical attention. The design and fabrication of the HTS insert cryostat are completed now. In this paper, the design of the cryostat for the 5 T HTS insert magnet is presented, taking into account the cryogenic loads and inventory of cryogenic liquid. In addition, the structure of the cryostat, minimizing thermal flow from room-temperature to cryogenic-temperature, is described in detail. The preliminary results of performance test of the HTS insert cryostat are also discussed. [ABSTRACT FROM PUBLISHER]

High temperature superconducting devices utilize liquid nitrogen (LN2) both for cryogenic liquids and insulating media. Regarding the insulating performance of LN2, it shows excellent characteristics comparable to insulating oil which is widely used for conventional electric equipment. But, detailed complex insulating structure in LN2 composed of cryogenic liquids, solid insulating material and conductor material has not been fully considered yet. In order to commercialize superconducting devices, insulating characteristics of LN2 should be analysed and confirmed to the level of insulating oil. In this work, we focused on the breakdown characteristics of LN2 especially for different electrode materials. Aluminum, Stainless steel, and Copper electrode systems were fabricated and tested in LN2 to verify uniform and non-uniform characteristics of LN2 according to the electrode materials. AC withstand voltage test and lightning impulse test has been performed. From the test results, it was revealed that the breakdown voltages were significantly changed according to the electrode materials. Especially for Stainless steel, it shows prominent enhancement of breakdown voltage compared to copper and aluminum electrode in LN2. Consequently, it was deduced that optimum choice of conductor materials in LN2 is another critical factor to determine complex insulating performance of superconducting devices. [ABSTRACT FROM PUBLISHER]

Based on a small GM cryocooler, a cryogen-free insert cryostat for physics experiment in a pulsed high magnetic field has been designed. The GM cryocooler is used as the cooling source. The sample is cooled by liquid helium for the low temperatures and by helium gas for the high temperatures. The inner diameter of the cryostat is 8 mm and the outer diameter of the tail is 16 mm, thus it can be inserted into a 60 T pulsed magnet. Experimental results show that the temperature can be controlled from 1.5 K to 300 K easily. In the sample region, stability of the temperature is obtained: \pm0.1 K at 20 K–300 K, \pm0.2 K at 5 K–20 K and \pm0.02K at 1.5 K–5 K. The system may be used for electrical transport and magnetization measurements in a pulsed high magnetic field. [ABSTRACT FROM PUBLISHER]

The new AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) Experiment will be installed in the Antiproton Decelerator hall at CERN. The main goal is to measure the Earth's gravitational acceleration of antihydrogen atoms. The experiment consists of two high-homogeneity solenoids placed on the same axis. The 5 T magnet is part of a cylindrical Penning trap to catch and to accumulate antiprotons delivered by the decelerator. The antihydrogen is then produced in the 1 T region where sub-kelvin antiproton temperatures provided by the dilution refrigerator are required to form a slowly-moving beam of antihydrogen. The helium bath cooled superconducting magnets; the different traps and the dilution refrigerator are integrated in a common cryostat with an internal vacuum barrier between the insulating cryogenic vacuum and the very high beam vacuum. In addition, the magnet system has to guarantee a smooth transition between the 5 T and the 1 T magnetic field areas required for a loss-free transfer of antiprotons and positrons from the trapping region to the antihydrogen production area. In this paper the design of this AEGIS magnet system is presented and discussed. [ABSTRACT FROM AUTHOR]

The Korea Basic Science Institute (KBSI) has initiated the development of a 5 T HTS insert magnet system. The objective of this program is the design and fabrication of HTS insert magnet for GHz class LTS/HTS NMR applications. Compact and efficient HTS magnet system is designed to be inserted into 15 T conduction-cooled superconducting magnet with 100 mm room-temperature bore. In this paper, the status of the HTS insert magnet development in KBSI is presented. The design issues of the 5 T HTS insert magnet including 2G HTS conductor properties with additional reinforcement and insulation, coil configuration with supporting structures, magnetic winding and bending stress-strain, detect and activate protection, and spatial and temporal field performance are discussed. In addition, the design of cryostat for 5 T HTS insert magnet is presented. [ABSTRACT FROM AUTHOR]

The first production focusing lens for the HINS beam line at Fermilab has been assembled into a cryostat and tested. A total of 5 devices will be tested before they are installed in the low energy section of the HINS beam line, which uses copper Crossbar-H (CH) style RF cavities. One of the tested CH-section lens assemblies includes a pair of weak orthogonal steering dipoles nested within a strong focusing solenoid, and has six vapor cooled power leads. The other device has only the strong focusing solenoid, and utilizes a single pair of HTS power leads. The production test program is designed to measure the thermal performance of the cryostat, minimum cooling requirements for the HTS leads, quench performance of all superconducting components, and precise determination of the magnetic axis and field angles. Results and future plans for the first production device tests are presented. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) is designing a series-connected hybrid magnet, which has a 40 mm diameter vertical warm bore with a cylindrical profile. The magnet will generate a 36 T field with 13 MW power for a high homogeneity version (1 ppm homogeneity) or >40 T for a high field version. This hybrid shares the design of superconducting coil with another SCH designed for Berlin, Germany. The cryostat design is quite different however. In this paper the design of the NHMFL cryostat is presented. The main features are described at first followed by the discussion of the FEA models and results. [ABSTRACT FROM AUTHOR]

The Facility for Rare Isotope Beams to be built at Michigan State University will be capable of providing beams of any element at energies of at least 200 MeV/u at beam powers of 400 kW. The fragment production target is in close proximity to the superconducting quadrupole magnets. These magnets have to operate in the high-radiation environment, with calculated radiation doses of more than 10 MGy per year. The design of a large bore, superferric quadrupole magnet that provides high field gradient of 15 T/m and effective length of 0.6 m is presented. The current design is “warm-iron” with a nominal yoke length of 520 mm and a pole radius of 135 mm. A coil design based on spinel insulated cable-in-conduit conductor that provides ample current margin provides significant long lifetime against radiation damage. The major challenges are the tight geometry, high forces and remote handling of an irradiated magnet. This paper presents the magnet design including coil forces and coil restraint system. In addition, coil properties, conductor stability and full mechanical details are also presented. [ABSTRACT FROM AUTHOR]

The International Thermonuclear Experimental Reactor (ITER) superconducting magnet system requires current supplies from 10 kA to 68 kA. The components relating the electrical power and cryogens through the warm-cold barrier to the ITER magnets are the so-called feeders. In total there are 31 such feeders for the ITER magnet system, 9 of them necessary for the toroidal field magnet system are called TF feeders. Each feeder consists of three main units: the In-Cryostat Feeder (ICF), the Cryostat Feed-Through (CFT) and the S-Bend Box (SBB)/Coil Terminal Box (CTB) assembly. This paper presents the latest design of the TF feeder components. [ABSTRACT FROM AUTHOR]

The High Magnetic Field Laboratory, Chinese Academy of Sciences is developing a 40 T hybrid magnet. The hybrid magnet cryostat consists of two separate but attached cryostats. The main function of the cryostats is to provide a thermal barrier between the ambient temperature experimental hall and the supercritical helium forced cooled superconducting magnet. It also provides feed-through penetrations for all the connecting elements inside and outside the cryostat. The Outsert Magnet Cryostat is a large vacuum vessel with cylindrical shell, standard elliptical top, and flat bottom. The structural analyses, including buckling, for the cryostat vessel have been carried out using finite element code. Stress analysis results show that the maximum Von Mises stress will be below the allowable value. In this paper, we focus on the structural analyses and design of the cryostat. [ABSTRACT FROM AUTHOR]

The National High Magnetic Field Laboratory (NHMFL) is designing two series-connected hybrid magnets, one for the Helmholtz Center Berlin (HZB) and the other for the NHMFL. The one for HZB has a horizontal, conical warm bore with a 30 degree opening angle for neutron scattering experiments. The one for the NHMFL has a 40 mm diameter vertical warm bore with a cylindrical profile. The design of the HZB cryostat will be completed this year. In this paper the design of the HZB cryostat is presented. The results of a structural analysis performed for normal operation and for fault scenario are discussed. The main features of the NHMFL cryostat are described shortly in the introduction section. [ABSTRACT FROM AUTHOR]

A collaboration between NSCL and Jlab has developed the reference design and coil winding for Jlab's Super High Momentum Spectrometer (SHMS) horizontal bend magnet. A warm iron "C" type superferric dipole magnet will bend the 12 GeV/c particles horizontally by 3° to allow the SHMS to reach angles as low as 5.5°. This requires an integral field strength of up to 2.1 T.m. The major challenges are the tight geometry, high and unbalanced forces and a required low fringe field in primary beam path. A coil design based on flattened SSC Rutherford cable that provides a large current margin and commercially available fiberglass prepreg epoxy tape has been developed. A complete test coil has been wound and will be cold tested. This paper present the modified magnet design includes coil forces, coil restraint system and fringe field. In addition, coil properties, quench calculations and the full mechanical details are also presented. [ABSTRACT FROM AUTHOR]

This report summarizes current status of an R&D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process. [ABSTRACT FROM AUTHOR]

Fermi National Accelerator Laboratory is involved in the development of a 60 MeV superconducting linac. This linac is part of the High Intensity Neutrino Source (HINS) R&D Program. The initial beam acceleration in the front end section of the linac is achieved using room temperature spoke cavities, each of which is combined with a superconducting focusing solenoid. These solenoid magnets are cooled with liquid helium at 4.5 K, operate at 250 A and have a maximum magnetic field strength of 7.5 T. A prototype solenoid cryostat was built and tested at the Fermilab Magnet Test Facility. This paper discusses the test results of the prototype and compares the measured and estimated performance of the cryostat. We also present the methods and results for measuring and fiducializing the axis of the solenoid lens. [ABSTRACT FROM AUTHOR]

The paper describes a multipurpose facility and the results of experimental studies of magnetization, trapped flux mapping, flux creep and low amplitude external AC magnetic field effects for YBCO monocrystal pellets, as well as the technique and results of measuring the volt-ampere characteristics of YBCO thin-wall cylinder at 77, 73 and 66 K. The facility features with placing the pellets in separate demountable liquid nitrogen cryostats, and using the set of Hall probes for studies of the evolution of the trapped magnetic field. [ABSTRACT FROM AUTHOR]

The characteristic of the superconducting magnetic energy storage (SMES) system is more fast response, long life time, more economical, and environment-friendly than other uninterruptible power supply (UPS) using the battery. So, the SMES system can be used to develop methods for improving power quality where a short interruption of power could lead to a long and costly shutdown. Recently, cryogen free SMES is developed briskly based on BSCCO wire. We fabricated and tested the conduction cooling system for the 600 kJ class HTS SMES. The experiment was accomplished for simulation coils. The simulation coils were made of aluminum, and have inner and outer coil diameters of 460 mm and 728 mm and coil height of 237 mm. The mass of coil is 171.6 kg, it is equivalent to thermal mass of 600 kJ HTS SMES coil. The coil is cooled with two GM coolers through the copper conduction bar. In this paper, we report the test results of cool-down and heat loads characteristics of the simulation coils. [ABSTRACT FROM AUTHOR]

The air-core Barrel Toroid of the ATLAS Detector at the CERN Large Hadron Collider, is the largest superconducting magnet ever built. This muon-spectrometer magnet consists of 8 discrete coils, arranged symmetrically around the beam axis. The average field is 0.5 T, and the stored energy 1.1 GJ. The windings are 25 m long, S m wide and 0.4 m thick. Each coil cold mass consists of 2 double pancakes of aluminum-stabilized NbTi conductor securely fixed in an aluminum alloy casing. Before assembly, each coil is tested individually in the presence of a magnetic mirror to simulate the magnetic forces exerted on the tie rods. This mirror is composed of several iron plates made of magnetically non-linear material. Each coil is enclosed in a separate, stainless-steel cryostat with relative magnetic permeability slightly larger than 1. In this paper the magnetic field distribution and Lorenz forces between the magnetic mirror and the coil in centered and shifted positions are presented. The magnetic influence of the cryostat on the field distribution is also discussed. [ABSTRACT FROM AUTHOR]

Collaboration exists between NSCL and JLab to developing the reference design of JLab's Super High Momentum Spectrometer (SHMS) horizontal bend magnet. A Superconducting "C"type, superferric dipole magnet that allows the SHMS to reach small forward angles without restricting the SHMS's acceptance, degree of motion or range of particle energy is presented. Spatial requirements for the coexistence of the SHMS at forward angles of -5.5° along with the existing High Momentum Spectrometer (HMS) at 12° to the primary beam line give rise to close tolerances on design parameters. The bending of 12 Gev/c particles by 3° requires an integral field strength up to 2.1 T.m. The current design is "warm-iron" with a nominal yoke length of 600 mm and a minimum pole gap of 350 mm. Choice of superconducting conductor, between surplus re-flattened SSC NbTi Rutherford cable that provides plenty of current margin and cost savings and Nb3 Sn cable, noted for its temperature margin will be highlighted. Coil forces, coil restraint system, energy margins, hot spot and final temperatures, beam radiated heating and superconducting stability will also be presented. [ABSTRACT FROM AUTHOR]

SMES is a potential solution for power quality issues. The development of a 1 M J/0.5 MVA SMES is now at its final stage and the device will be put into operation in a live power grid of 10 kV in late of 2006 at a substation in the suburb of Beijing, China. The design and analysis of the SMES coil has been completed and magnetic flux density distribution of and electromagnetic force on the coil has been analysed by means of FEM. The cryogenic system adopts bath cooling method and employs four cryo-coolers to re-liquefy the evaporated helium. And HTS current leads are utilized to reduce heat loss. [ABSTRACT FROM AUTHOR]

Superconducting magnetic energy storage (SMES) is more fast response, economical, and environment-friendly than uninterruptible power supply (UPS) using the battery. And the SMES not only has the ability to control active and reactive power simultaneously, but also has a long life time because the superconducting magnet does not have degradation problem which the battery has. Therefore, the SMES is a candidate for instead of the UPS using the battery. The SMES needs cryogenic system without exception. A conduction cooling system that has a simple, light and small structure is well adapted to high temperature superconducting (HTS) SMES. The cryogenic conduction cooling system is needed some technologies such as insulation, vacuum, and thermal analysis. Conduction heat is mainly transferred by cooler port, access port, support bar, etc., and radiation heat is transferred by vacuum chamber, thermal shield and HTS coil surface. The heat loads through the conduction and radiation of cryostat are calculated. Radiation shield heat load, temperature of HTS coil and conduction copper plate are estimated and measured. A cryopumping effect of cooled radiation shield was observed. A current lead and HTS coil heat load was evaluated to maintain HTS coil temperature was under 20 K. [ABSTRACT FROM AUTHOR]

In this study, electrical insulation design for the development of 13.2 kV/630 A bifilar winding type high temperature superconducting (HTS) fault current limiter (FCL) with YBCO coated conductor (CC) wire was conducted. At first, operating conditions of the temperature and the pressure were determined considering the effects of bubble suppression and breakdown withstand voltage in quench state. The electrical insulation design for HTS coil was performed based on electric field calculation under normal and quench states. Furthermore, new concept of cryostat which is beneficial to the sub-cooling and the electrical insulation was proposed. Finally, two high voltage lead designs were evaluated taking into account the insulation environment of the HTS FCL and the new cryostat design. [ABSTRACT FROM AUTHOR]

The first full-scale prototype magnet system assembled with the cryostat for the J-PARC proton beam line of neutrino experiment was successfully developed and tested. Two superconducting combined function magnets have been installed into the cryostat. The magnets were successfully cooled down to 4.5 K by forced flow supercritical helium and excited up to the current of 7345 A which is the nominal current of 50 GeV proton beam. The spot heater quench test showed that the quench characteristics in the supercritical helium were very similar to that in the liquid helium at 4.2 K, 1 atm. The quench protection scheme with both cold diodes and quench protection heaters was tested, and it has been verified that the magnet can be protected with safe margin. [ABSTRACT FROM AUTHOR]

A compact three-pole superconducting magnet with an aluminum warm beam duct was designed and fabricated as an X-ray source in a 1.5 GeV Taiwan Light Source (TLS) or the 3 GeV Taiwan Photon Source (TPS). Three pairs of racetrack NbTi superconducting coils were connected to one main power supply to create a central field of over 6.5 T. Two low current trim power supplies were connected in parallel to the two side pairs of the coil to eliminate the first and second field integrals. The wavelength shifter magnet was cooled in a pool boiling helium bath. Helium boils off at 1.3 L/hr. The vapor-cooled current lead is used to pass the 350 A excitation current. The magnetic field strength was measured at room temperature using a Hall probe and a stretched wire system. The magnet was tested successfully to 308 A, at which the central field exceeded 6.5 T, and the peak field on coil was 8.2 T. The design and construction of the magnet and the cryostat, the quenching protection, and field measurement results will be presented and discussed. [ABSTRACT FROM AUTHOR]