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Sample records for advanced superconducting magnets

  1. Advanced Manufacturing of Superconducting Magnets

    NASA Technical Reports Server (NTRS)

    Senti, Mark W.

    1996-01-01

    The development of specialized materials, processes, and robotics technology allows for the rapid prototype and manufacture of superconducting and normal magnets which can be used for magnetic suspension applications. Presented are highlights of the Direct Conductor Placement System (DCPS) which enables automatic design and assembly of 3-dimensional coils and conductor patterns using LTS and HTS conductors. The system enables engineers to place conductors in complex patterns with greater efficiency and accuracy, and without the need for hard tooling. It may also allow researchers to create new types of coils and patterns which were never practical before the development of DCPS. The DCPS includes a custom designed eight-axis robot, patented end effector, CoilCAD(trademark) design software, RoboWire(trademark) control software, and automatic inspection.

  2. Superconducting magnets

    SciTech Connect

    Not Available

    1994-08-01

    This report discusses the following topics on superconducting magnets: D19B and -C: The next steps for a record-setting magnet; D20: The push beyond 10 T: Beyond D20: Speculations on the 16-T regime; other advanced magnets for accelerators; spinoff applications; APC materials development; cable and cabling-machine development; and high-{Tc} superconductor at low temperature.

  3. A Novel superconducting toroidal field magnet concept using advanced materials

    NASA Astrophysics Data System (ADS)

    Schwartz, J.

    1992-03-01

    The plasma physics database indicates that two distinct approaches to tokamak design may lead to commercial fusion reactors: low Aspect ratio, high plasma current, relatively low magnetic field devices, and high Aspect ratio, high field devices. The former requires significant enhancements in plasma performance, while the latter depends primarily upon technology development. The key technology for the commercialization of the high-field approach is large, high magnetic field superconducting magnets. In this paper, the physics motivation for the high field approach and key superconducting magnet (SCM) development issues are reviewed. Improved SCM performance may be obtained from improved materials and/or improved engineering. Superconducting materials ranging from NbTi to high- T c oxides are reviewed, demonstrating the broad range of potential superconducting materials. Structural material options are discussed, including cryogenic steel alloys and fiber-reinforced composite materials. Again, the breadth of options is highlighted. The potential for improved magnet engineering is quantified in terms of the Virial Theorem Limit, and two examples of approaches to highly optimized magnet configurations are discussed. The force-reduced concept, which is a finite application of the force-free solutions to Ampere's Law, appear promising for large SCMs but may be limited by the electromagnetics of a fusion plasma. The Solid Superconducting Cylinder (SSC) concept is proposed. This concept combines the unique properties of high- T c superconductors within a low- T c SCM to obtain (1) significant reductions in the structural material volume, (2) a decoupling of the tri-axial (compressive and tensile) stress state, and (3) a demountable TF magnet system. The advantages of this approach are quantified in terms of a 24 T commercial reactor TF magnet system. Significant reductions in the mechanical stress and the TF radial build are demonstrated.

  4. Superconducting magnet

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

  5. Superconducting magnet

    DOEpatents

    Satti, John A.

    1980-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  6. New generation of cryogen free advanced superconducting magnets for neutron scattering experiments

    NASA Astrophysics Data System (ADS)

    Kirichek, O.; Brown, J.; Adroja, D. T.; Manuel, P.; Kouzmenko, G.; Bewley, R. I.; Wotherspoon, R.

    2012-12-01

    Recent advances in superconducting technology and cryocooler refrigeration have resulted in a new generation of advanced superconducting magnets for neutron beam applications. These magnets have outstanding parameters such as high homogeneity and stability at highest magnetic fields possible, a reasonably small stray field, low neutron scattering background and larger exposure to neutron detectors. At the same time the pulse tube refrigeration technology provides a complete re-condensing regime which allows to minimise the requirements for cryogens without introducing additional noise and mechanical vibrations. The magnets can be used with dilution refrigerator insert which expands the temperature range from 20mK to 300K. Here we are going to present design, test results and the operational data of the 14T magnet for neutron diffraction and the 9T wide angle chopper magnet for neutron spectroscopy developed by Oxford Instruments in collaboration with ISIS neutron source. First scientific results obtained from the neutron scattering experiments with these magnets are also going to be discussed.

  7. Recent advances in the technology of superconducting accelerator magnets

    SciTech Connect

    Taylor, C.E.

    1985-05-01

    Recent progress in technology of high-current-density cables for SSC model magnets is summarized. NbTi cable with J/sub c/ up to 50% higher than Tevatron cable can be expected. Magnetization effects can be predicted and corrected with several new techniques. Development of Superconductor with 2 to 3 ..mu..m filament diameter and high J/sub c/ is expected. 15 refs., 3 figs.

  8. High field superconducting magnets

    NASA Technical Reports Server (NTRS)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  9. Hybrid superconducting magnetic suspensions

    SciTech Connect

    Tixador, P.; Hiebel, P.; Brunet, Y.

    1996-07-01

    Superconductors, especially high T{sub c} ones, are the most attractive materials to design stable and fully passive magnetic suspensions which have to control five degrees of freedom. The hybrid superconducting magnetic suspensions present high performances and a simple cooling mode. They consist of a permanent magnet bearing, stabilized by a suitable magnet-superconductor structure. Several designs are given and compared in terms of forces and stiffnesses. The design of the magnet bearing plays an important part. The superconducting magnetic bearing participates less in levitation but must provide a high stabilizing stiffness. This is achieved by the magnet configuration, a good material in term of critical current density and field cooling. A hybrid superconducting suspension for a flywheel is presented. This system consists of a magnet thrust bearing stabilized by superconductors interacting with an alternating polarity magnet structure. First tests and results are reported. Superconducting materials are magnetically melt-textured YBaCuO.

  10. Stacked magnet superconducting bearing

    SciTech Connect

    Rigney, T.K. II; Saville, M.P.

    1993-06-15

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines.

  11. Rapid cycling superconducting magnets

    NASA Astrophysics Data System (ADS)

    Fabbricatore, P.; Farinon, S.; Gambardella, U.; Greco, M.; Volpini, G.

    2006-04-01

    The paper deals with the general problematic related to the development of fast cycled superconducting magnets for application in particle accelerator machines. Starting from the requirements of SIS300 synchrotron under design at GSI and an envisaged future Super-SPS injector at CERN, it is shown which developments are mandatory in the superconducting wire technology and in the magnet design field.

  12. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Cui, Z. Q.; Chen, Z. J.; Xie, X. F.; Peng, X. Y.; Hu, Z. M.; Du, T. F.; Ge, L. J.; Zhang, X.; Yuan, X.; Fan, T. S.; Chen, J. X.; Li, X. Q. E-mail: guohuizhang@pku.edu.cn; Zhang, G. H. E-mail: guohuizhang@pku.edu.cn; Xia, Z. W.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  13. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak.

    PubMed

    Cui, Z Q; Chen, Z J; Xie, X F; Peng, X Y; Hu, Z M; Du, T F; Ge, L J; Zhang, X; Yuan, X; Xia, Z W; Hu, L Q; Zhong, G Q; Lin, S Y; Wan, B N; Fan, T S; Chen, J X; Li, X Q; Zhang, G H

    2014-11-01

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  14. Light weight, high field, stable, superconducting magnets for advanced transportation systems

    SciTech Connect

    Lubell, M.S.; Dresner, L.; Kenney, W.J.; Lue, J.W.; Luton, J.N.; Schwenterly, S.W.

    1991-01-01

    Although the Guideway may be the most expensive component of a MAGLEV system, the importance of a suitable magnet system should not be underestimated. The reliability of operation of MAGLEV depends on the superconducting magnets performing to their specifications in a reliable manner (i.e., without training or quenching). Besides reliability the magnets should produce high field, be sufficiently stable to withstand reasonable perturbations, be light weight, be protected in the event of a quench, and be economical (although performance should outweigh cost). We propose to develop superconducting magnets that have these features. Our magnet designs are based on internally cooled, cable-in-conduit superconductor with Polymer Matrix Composites (PMC) as the structural reinforcement. Although the initial work is with metallic superconductors such as NbTi, the processes being developed will be applicable to the High Temperature Ceramic Superconductors when they become suitable for magnet applications.

  15. Superconducting magnets 1992

    SciTech Connect

    Not Available

    1993-06-01

    This report discusses the following topics on Superconducting Magnets; SSC Magnet Industrialization; Collider Quadrupole Development; A Record-Setting Magnet; D20: The Push Beyond 10T; Nonaccelerator Applications; APC Materials Development; High-T{sub c} at Low Temperature; Cable and Cabling-Machine Development; and Analytical Magnet Design.

  16. Preliminary investigation of force-reduced superconducting magnet configurations for advanced technology applications

    SciTech Connect

    Bouillard, J.X.

    1992-12-01

    The feasibility of new high-field low specific weight superconducting magnet designs using force-free fields is being explored analytically and numerically. This report attempts to assess the technical viability of force-free field concepts to produce high-field, low specific weight and large bore volume magnets, which could promote the use of high temperature superconductors. Several force-free/force-reduced magnet configurations are first reviewed, then discussed and assessed. Force-free magnetic fields, fields for which the current flows parallel to the field, have well-known mathematical solutions extending upon infinite domains. These solutions, however, are no longer force-free everywhere for finite geometries. In this preliminary study, force-free solutions such as the Lundquist solutions truncated to a size where the internal field of the coil matches an externally cylindrical magnetic field (also called a Lundquist coil) are numerically modeled and explored. Significant force-reduction for such coils was calculated, which may have some importance for the design of lighter toroidal magnets used in thermonuclear fusion power generation, superconducting magnetic energy storage (SMES), and mobile MHD power generation and propulsion.

  17. Superconducting multipole corrector magnet

    SciTech Connect

    Kashikhin, Vladimir; /Fermilab

    2004-10-01

    A novel concept of superconducting multipole corrector magnet is discussed. This magnet assembled from 12 identical racetrack type coils and can generate any combination of dipole, quadrupole and sextupole magnetic fields. The coil groups are powered from separate power supplies. In the case of normal dipole, quadrupole and sextupole fields the total field is symmetrical relatively the magnet median plane and there are only five powered separately coil groups. This type multipole corrector magnet was proposed for BTeV, Fermilab project and has following advantages: universal configuration, simple manufacturing and high mechanical stability. The results of magnetic design including the field quality and magnetic forces in comparison with known shell type superconducting correctors are presented.

  18. Magnetically leviated superconducting bearing

    DOEpatents

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  19. Experimental validation of advanced regulations for superconducting magnet cooling undergoing periodic heat loads

    NASA Astrophysics Data System (ADS)

    Lagier, B.; Rousset, B.; Hoa, C.; Bonnay, P.

    2014-01-01

    Superconducting magnets used in tokamaks undergo periodic heat load caused by cycling plasma operations inducing AC losses, neutrons fluxes and eddy currents in magnet structures. In the cryogenic system of JT60-SA tokamak, the Auxiliary Cold Box (ACB) distributes helium from the refrigerator to the cryogenic users and in particular to the superconducting magnets. ACB comprises a saturated helium bath with immersed heat exchangers, extracting heat from independent cooling loops. The supercritical helium flow in each cooling loop is driven by a cold circulator. In order to safely operate the refrigerator during plasma pulses, the interface between the ACB and the refrigerator shall be as stable as possible, with well-balanced bath inlet and outlet mass flows during cycling operation. The solution presented in this paper relies on a combination of regulations to smooth pulsed heat loads and to keep a constant refrigeration power during all the cycle. Two smoothing strategies are presented, both regulating the outlet mass flow of the bath: the first one using the bath as a thermal buffer and the second one storing energy in the loop by varying the cold circulator speed. The bath outlet mass flow is also controlled by an immersed resistive heater which enables a constant evaporation rate in the bath when power coming from the loops is decreasing. The refrigeration power is controlled so that the compensating power remains within an acceptable margin. Experimental validation is achieved using the HELIOS facility. This facility running at CEA Grenoble since 2010 is a scaled down model of the ACB bath and Central Solenoid magnet cooling loop of the JT60-SA tokamak. Test results show performances and robustness of the regulations.

  20. Experimental validation of advanced regulations for superconducting magnet cooling undergoing periodic heat loads

    SciTech Connect

    Lagier, B.; Rousset, B.; Hoa, C.; Bonnay, P.

    2014-01-29

    Superconducting magnets used in tokamaks undergo periodic heat load caused by cycling plasma operations inducing AC losses, neutrons fluxes and eddy currents in magnet structures. In the cryogenic system of JT60-SA tokamak, the Auxiliary Cold Box (ACB) distributes helium from the refrigerator to the cryogenic users and in particular to the superconducting magnets. ACB comprises a saturated helium bath with immersed heat exchangers, extracting heat from independent cooling loops. The supercritical helium flow in each cooling loop is driven by a cold circulator. In order to safely operate the refrigerator during plasma pulses, the interface between the ACB and the refrigerator shall be as stable as possible, with well-balanced bath inlet and outlet mass flows during cycling operation. The solution presented in this paper relies on a combination of regulations to smooth pulsed heat loads and to keep a constant refrigeration power during all the cycle. Two smoothing strategies are presented, both regulating the outlet mass flow of the bath: the first one using the bath as a thermal buffer and the second one storing energy in the loop by varying the cold circulator speed. The bath outlet mass flow is also controlled by an immersed resistive heater which enables a constant evaporation rate in the bath when power coming from the loops is decreasing. The refrigeration power is controlled so that the compensating power remains within an acceptable margin. Experimental validation is achieved using the HELIOS facility. This facility running at CEA Grenoble since 2010 is a scaled down model of the ACB bath and Central Solenoid magnet cooling loop of the JT60-SA tokamak. Test results show performances and robustness of the regulations.

  1. Superconducting magnetic quadrupole

    SciTech Connect

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  2. Superconducting magnets for MRI

    SciTech Connect

    Williams, J.E.

    1984-08-01

    Three types of magnets are currently used to provide the background field required for magnet resonance imaging (MRI). (i) Permanent magnets produce fields of up to 0.3 T in volumes sufficient for imaging the head or up to 0.15 T for whole body imaging. Cost and simplicity of operation are advantages, but relatively low field, weight (up to 100 tonnes) and, to a small extent, instability are limitations. (ii) Water-cooled magnets provide fields of up to 0.25 T in volumes suitable for whole body imaging, but at the expense of power (up to 150 kW for 0.25 T) and water-cooling. Thermal stability of the field requires the maintenance of constant temperature through periods both of use and of quiescence. (iii) Because of the limitations imposed by permanent and resistive magnets, particularly on field strength, the superconducting magnet is now most widely used to provide background fields of up to 2 T for whole body MRI. It requires very low operating power and that only for refrigeration. Because of the constant low temperature, 4.2 K, at which its stressed structure operates, its field is stable. The following review deals principally with superconducting magnets for MRI. However, the sections on field analysis apply to all types of magnet and the description of the source terms of circular coils and of the principals of design of solenoids apply equally to resistive solenoidal magnets.

  3. A superconducting magnetic gear

    NASA Astrophysics Data System (ADS)

    Campbell, A. M.

    2016-05-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844-46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further.

  4. Superconducting magnet system for the TPX Tokamak

    SciTech Connect

    Hassenzahl, W.V.; Chaplin, M.R.; Heim, J.R.

    1993-09-15

    The Tokamak Physics Experiment (TPX) will be the first Tokamak using superconducting magnets for both the poloidal and toroidal field. It is designed for advanced Tokamak physics experiments in steady-state and long-pulse operation. The TPX superconducting magnets use an advanced cable-in-conduit conductor (CICC) design similar to that developed in support of the International Thermonuclear Experimental Reactor (ITER). The toroidal field magnets provide 4.0 T at 2.25 m with a stored energy of 1.05 GJ. The poloidal field magnets provide 18.0 V-s to ohmically start and control long burns of a 2.0 MA plasma.

  5. Superconducting Magnetic Projectile Launcher

    NASA Technical Reports Server (NTRS)

    Jan, Darrell L.; Lawson, Daniel D.

    1991-01-01

    Proposed projectile launcher exploits Meissner effect to transfer much of kinetic energy of relatively massive superconducting plunger to smaller projectile, accelerating projectile to high speed. Because it operates with magnetic fields, launcher not limited by gas-expansion thermodynamics. Plunger energized mechanically and/or chemically, avoiding need for large electrical power supplies and energy-storage systems. Potential applications include launching of projectiles for military purposes and for scientific and industrial tests of hypervelocity impacts.

  6. Development of an alternating integrator for magnetic measurements for experimental advanced superconducting tokamak.

    PubMed

    Liu, D M; Wan, B N; Zhao, W Z; Shen, B; He, Y G; Chen, B; Huang, J; Liu, H Q

    2014-11-01

    A high-performance integrator is one of the key electronic devices for reliably controlling plasma in the experimental advanced superconducting tokamak for long pulse operation. We once designed an integrator system of real-time drift compensation, which has a low integration drift. However, it is not feasible for really continuous operations due to capacitive leakage error and nonlinearity error. To solve the above-mentioned problems, this paper presents a new alternating integrator. In the new integrator, the integrator system of real-time drift compensation is adopted as one integral cell while two such integral cells work alternately. To achieve the alternate function, a Field Programmable Gate Array built in the digitizer is utilized. The performance test shows that the developed integrator with the integration time constant of 20 ms has a low integration drift (<15 mV) for 1000 s.

  7. Development of an alternating integrator for magnetic measurements for experimental advanced superconducting tokamak

    SciTech Connect

    Liu, D. M. Zhao, W. Z.; He, Y. G.; Chen, B.; Wan, B. N.; Shen, B.; Huang, J.; Liu, H. Q.

    2014-11-15

    A high-performance integrator is one of the key electronic devices for reliably controlling plasma in the experimental advanced superconducting tokamak for long pulse operation. We once designed an integrator system of real-time drift compensation, which has a low integration drift. However, it is not feasible for really continuous operations due to capacitive leakage error and nonlinearity error. To solve the above-mentioned problems, this paper presents a new alternating integrator. In the new integrator, the integrator system of real-time drift compensation is adopted as one integral cell while two such integral cells work alternately. To achieve the alternate function, a Field Programmable Gate Array built in the digitizer is utilized. The performance test shows that the developed integrator with the integration time constant of 20 ms has a low integration drift (<15 mV) for 1000 s.

  8. Superconducting Magnets for RIA

    NASA Astrophysics Data System (ADS)

    Zeller, A. F.

    2004-06-01

    The highest priority for new construction for the nuclear physics community is the Rare Isotope Accelerator. This project's goal is to produce up to 400 kW of beams from protons to uranium. Beam transport at the high-energy end has to deal with high radiation fields and high beam rigidities. Superconducting magnets are being designed to fulfill both these requirements. The quadrupoles in the fragment separator will use superferric design with pole tip fields of up to 2.5 T to produce the required gradients in the large apertures. Several techniques are presented that deal with making the magnets radiation resistant.

  9. Downsized superconducting magnetic energy storage systems

    NASA Astrophysics Data System (ADS)

    Palmer, David N.

    Scaled-down superconductive magnetic energy storage systems (DSMES) and superconductive magnetic energy power sources (SMEPS) are proposed for residential, commercial/retail, industrial off-peak and critical services, telephone and other communication systems, computer operations, power back-up/energy storages, power sources for space stations, and in-field military logistics/communication systems. Recent advances in high-Tc superconducting materials technology are analyzed. DSMES/SMEPS concepts are presented, and design, materials, and systems requirements are discussed. Problems ar identified, and possible solutions are offered. Comparisons are made with mechanical and primary and secondary energy storage and conversion systems.

  10. Superconducting magnetic coil

    DOEpatents

    Aized, Dawood; Schwall, Robert E.

    1996-06-11

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  11. Superconducting magnetic coil

    DOEpatents

    Aized, Dawood; Schwall, Robert E.

    1999-06-22

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

  12. Superconducting magnetic coil

    DOEpatents

    Aized, D.; Schwall, R.E.

    1999-06-22

    A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.

  13. Superconducting magnet development in Japan

    SciTech Connect

    Yasukochi, K.

    1983-05-01

    The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb/sub 3/Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting ..mu.. meson channel and ..pi.. meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration.

  14. Protection circuits for superconducting magnets

    SciTech Connect

    Parsons, W.M.; Wood, R.J.

    1980-01-01

    As the technology of controlled nuclear fusion progresses, plans for new experimental reactors include much longer duty cycles than those of earlier experiments. Many of the magnet systems for these reactors must be superconducting due to the prolonged or continuous high current levels required. The large initial investment of a superconducting magnet system justifies a protective dump circuit. This circuit must operate if the magnet goes normal or in the event of failure of some of the critical auxiliary equipment. This paper examines two applications of superconducting magnet protection for fusion experiments. A novel dc interrupter being developed especially for this purpose is also discussed.

  15. Freely oriented portable superconducting magnet

    SciTech Connect

    Schmierer, Eric N.; Prenger, F. Coyne; Hill, Dallas D.

    2010-01-12

    A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

  16. Superconducting energy storage magnet

    NASA Technical Reports Server (NTRS)

    Boom, Roger W. (Inventor); Eyssa, Yehia M. (Inventor); Abdelsalam, Mostafa K. (Inventor); Huang, Xianrui (Inventor)

    1993-01-01

    A superconducting magnet is formed having composite conductors arrayed in coils having turns which lie on a surface defining substantially a frustum of a cone. The conical angle with respect to the central axis is preferably selected such that the magnetic pressure on the coil at the widest portion of the cone is substantially zero. The magnet structure is adapted for use as an energy storage magnet mounted in an earthen trench or tunnel where the strength the surrounding soil is lower at the top of the trench or tunnel than at the bottom. The composite conductor may be formed having a ripple shape to minimize stresses during charge up and discharge and has a shape for each ripple selected such that the conductor undergoes a minimum amount of bending during the charge and discharge cycle. By minimizing bending, the working of the normal conductor in the composite conductor is minimized, thereby reducing the increase in resistance of the normal conductor that occurs over time as the conductor undergoes bending during numerous charge and discharge cycles.

  17. Fast superconducting magnetic field switch

    SciTech Connect

    Goren, Y.; Mahale, N.K.

    1995-12-31

    The superconducting magnetic switch or fast kicker magnet is employed with an electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater than the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. Magnetic switches and particularly fast kicker magnets are used in the accelerator industry to quickly deflect particle beams into and out of various transport lines, storage rings, dumps, and specifically to differentially route individual bunches of particles from a train of bunches which are injected or ejected from a given ring.

  18. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  19. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Y.; Mahale, N.K.

    1996-08-06

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.

  20. A Beamline for High-Pressure Studies at the Advanced Light Sourcewith a Superconducting Bending Magnet as the Source

    SciTech Connect

    Kunz, Martin; MacDowell, Alastair A.; Caldwell, Wendel A.; Cambie, Daniella; Celestre, Richard S.; Domning, Edward E.; Duarte,Robert M.; Gleason, Arianna E.; Glossinger, James M.; Kelez, Nicholas; Plate, David W.; Yu, Tony; Zaug, Joeseph M.; Padmore, Howard A.; Jeanloz,Raymond; Alivisatos, A. Paul; Clark, Simon M.

    2005-06-30

    A new facility for high-pressure diffraction and spectroscopy using diamond anvil high-pressure cells has been built at the Advanced Light Source on Beamline 12.2.2. This beamline benefits from the hard X-radiation generated by a 6 Tesla superconducting bending magnet (superbend). Useful x-ray flux is available between 5 keV and 35 keV. The radiation is transferred from the superbend to the experimental enclosure by the brightness preserving optics of the beamline. These optics are comprised of: a plane parabola collimating mirror (M1), followed by a Kohzu monochromator vessel with a Si(111) crystals (E/DE {approx}7000) and a W/B4C multilayers (E/DE {approx} 100), and then a toroidal focusing mirror (M2) with variable focusing distance. The experimental enclosure contains an automated beam positioning system, a set of slits, ion chambers, the sample positioning goniometry and area detectors (CCD or image-plate detector). Future developments aim at the installation of a second end station dedicated for in situ laser-heating on one hand and a dedicated high-pressure single-crystal station, applying both monochromatic as well as polychromatic techniques.

  1. A BEAMLINE FOR HIGH PRESSURE STUDIES AT THE ADVANCED LIGHT SOURCE WITH A SUPERCONDUCTING BENDING MAGNET AS THE SOURCE

    SciTech Connect

    Kunz, M; MacDowell, A A; Caldwell, W A; Cambie, D; Celestre, R S; Domning, E E; Duarte, R M; Gleason, A; Glossinger, J; Kelez, N; Plate, D W; Yu, T; Zaug, J M; Padmore, H A; Jeanloz, R; Alivisatos, A P; Clark, S M

    2005-04-19

    A new facility for high-pressure diffraction and spectroscopy using diamond anvil high-pressure cells has been built at the Advanced Light Source on Beamline 12.2.2. This beamline benefits from the hard X-radiation generated by a 6 Tesla superconducting bending magnet (superbend). Useful x-ray flux is available between 5 keV and 35 keV. The radiation is transferred from the superbend to the experimental enclosure by the brightness preserving optics of the beamline. These optics are comprised of: a plane parabola collimating mirror (M1), followed by a Kohzu monochromator vessel with a Si(111) crystals (E/{Delta}E {approx} 7000) and a W/B{sub 4}C multilayer (E/{Delta}E {approx} 100), and then a toroidal focusing mirror (M2) with variable focusing distance. The experimental enclosure contains an automated beam positioning system, a set of slits, ion chambers, the sample positioning goniometry and area detectors (CCD or image-plate detector). Future developments aim at the installation of a second end station dedicated for in situ laser-heating on one hand and a dedicated high-pressure single-crystal station, applying both monochromatic as well as polychromatic techniques.

  2. Improved superconducting magnet wire

    DOEpatents

    Schuller, I.K.; Ketterson, J.B.

    1983-08-16

    This invention is directed to a superconducting tape or wire composed of alternating layers of copper and a niobium-containing superconductor such as niobium of NbTi, Nb/sub 3/Sn or Nb/sub 3/Ge. In general, each layer of the niobium-containing superconductor has a thickness in the range of about 0.05 to 1.5 times its coherence length (which for Nb/sub 3/Si is 41 A) with each copper layer having a thickness in the range of about 170 to 600 A. With the use of very thin layers of the niobium composition having a thickness within the desired range, the critical field (H/sub c/) may be increased by factors of 2 to 4. Also, the thin layers of the superconductor permit the resulting tape or wire to exhibit suitable ductility for winding on a magnet core. These compositions are also characterized by relatively high values of critical temperature and therefore will exhibit a combination of useful properties as superconductors.

  3. Superconductivity in magnetic multipole states

    NASA Astrophysics Data System (ADS)

    Sumita, Shuntaro; Yanase, Youichi

    2016-06-01

    Stimulated by recent studies of superconductivity and magnetism with local and global broken inversion symmetry, we investigate the superconductivity in magnetic multipole states in locally noncentrosymmetric metals. We consider a one-dimensional zigzag chain with sublattice-dependent antisymmetric spin-orbit coupling and suppose three magnetic multipole orders: monopole order, dipole order, and quadrupole order. It is demonstrated that the Bardeen-Cooper-Schrieffer state, the pair-density wave (PDW) state, and the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state are stabilized by these multipole orders, respectively. We show that the PDW state is a topological superconducting state specified by the nontrivial Z2 number and winding number. The origin of the FFLO state without macroscopic magnetic moment is attributed to the asymmetric band structure induced by the magnetic quadrupole order and spin-orbit coupling.

  4. Novel Design of Superconducting Helical Dipole Magnet

    NASA Astrophysics Data System (ADS)

    Meinke, R.; Senti, M.; Stelzer, G.

    1997-05-01

    Superconducting helical dipole magnets with a nominal field of 4 Tesla are needed for the spin physics program at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The magnets are required to operate at a relatively low current of 400 A since many of these magnets have to be independently controlled. The Advanced Magnet Lab, Inc., in Palm Bay, FL has designed and built two prototype magnets using advanced computer controlled coil winding technology. The AML design is extremely cost effective since it avoids magnet specific tooling despite the required complex coil pattern and any precision machined inserts or spacers. It is the first time an accelerator magnet of this technology has reached a field above 4 Tesla. Results from the prototype testing at BNL are presented.

  5. Magnetic and Superconducting Materials at High Pressures

    SciTech Connect

    Struzhkin, Viktor V.

    2015-03-24

    transitions from magnetic to nonmagnetic phases in a broad pressure-temperature range; using X-ray methods including the newly developed RIXS high-pressure technique to explore pressure-tuned electronic excitations in strongly correlated 3d-materials; and advancing transport and magnetic techniques for measurements on small samples at very high pressures in a wide temperature range, with the application of focused ion beam technology and photolithography tailored to the design of microcircuits down to a nanoscale size, thus expanding the horizon in the search for novel physical phenomena at ultrahigh pressures. Apply new optical magnetic sensing techniques with NV- centers in diamond to detect superconductivity and magnetic transitions with unprecedented spatial resolution.

  6. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, R.C.; McConnell, B.W.; Phillips, B.A.

    1996-07-02

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit. 6 figs.

  7. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, Robert C.; McConnell, Benjamin W.; Phillips, Benjamin A.

    1996-01-01

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit.

  8. A superconducting large-angle magnetic suspension

    NASA Astrophysics Data System (ADS)

    Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.

    1992-12-01

    SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.

  9. A superconducting large-angle magnetic suspension

    NASA Technical Reports Server (NTRS)

    Downer, James R.; Anastas, George V., Jr.; Bushko, Dariusz A.; Flynn, Frederick J.; Goldie, James H.; Gondhalekar, Vijay; Hawkey, Timothy J.; Hockney, Richard L.; Torti, Richard P.

    1992-01-01

    SatCon Technology Corporation has completed a Small Business Innovation Research (SBIR) Phase 2 program to develop a Superconducting Large-Angle Magnetic Suspension (LAMS) for the NASA Langley Research Center. The Superconducting LAMS was a hardware demonstration of the control technology required to develop an advanced momentum exchange effector. The Phase 2 research was directed toward the demonstration for the key technology required for the advanced concept CMG, the controller. The Phase 2 hardware consists of a superconducting solenoid ('source coils') suspended within an array of nonsuperconducting coils ('control coils'), a five-degree-of-freedom positioning sensing system, switching power amplifiers, and a digital control system. The results demonstrated the feasibility of suspending the source coil. Gimballing (pointing the axis of the source coil) was demonstrated over a limited range. With further development of the rotation sensing system, enhanced angular freedom should be possible.

  10. Superconductivity from Emerging Magnetic Moments.

    PubMed

    Hoshino, Shintaro; Werner, Philipp

    2015-12-11

    Multiorbital Hubbard models are shown to exhibit a spatially isotropic spin-triplet superconducting phase, where equal-spin electrons in different local orbitals are paired. This superconducting state is stabilized in the spin-freezing crossover regime, where local moments emerge in the metal phase, and the pairing is substantially assisted by spin anisotropy. The phase diagram features a superconducting dome below a non-Fermi-liquid metallic region and next to a magnetically ordered phase. We suggest that this type of fluctuating-moment-induced superconductivity, which is not originating from fluctuations near a quantum critical point, may be realized in spin-triplet superconductors such as strontium ruthenates and uranium compounds. PMID:26705649

  11. Superconductivity from Emerging Magnetic Moments

    NASA Astrophysics Data System (ADS)

    Hoshino, Shintaro; Werner, Philipp

    2015-12-01

    Multiorbital Hubbard models are shown to exhibit a spatially isotropic spin-triplet superconducting phase, where equal-spin electrons in different local orbitals are paired. This superconducting state is stabilized in the spin-freezing crossover regime, where local moments emerge in the metal phase, and the pairing is substantially assisted by spin anisotropy. The phase diagram features a superconducting dome below a non-Fermi-liquid metallic region and next to a magnetically ordered phase. We suggest that this type of fluctuating-moment-induced superconductivity, which is not originating from fluctuations near a quantum critical point, may be realized in spin-triplet superconductors such as strontium ruthenates and uranium compounds.

  12. Accelerator magnet designs using superconducting magnetic shields

    SciTech Connect

    Brown, B.C.

    1990-10-01

    Superconducting dipoles and quadrupoles for existing accelerators have a coil surrounded by an iron shield. The shield limits the fringe field of the magnet while having minimal effect on the field shape and providing a small enhancement of the field strength. Shields using superconducting materials can be thinner and lighter and will not experience the potential of a large de-centering force. Boundary conditions for these materials, material properties, mechanical force considerations, cryostat considerations and some possible geometrical configurations for superconducting shields will be described. 7 refs., 3 figs., 3 tabs.

  13. Superconducting magnet wire

    DOEpatents

    Schuller, Ivan K.; Ketterson, John B.; Banerjee, Indrajit

    1986-01-01

    A superconducting tape or wire with an improved critical field is formed of alternating layers of a niobium-containing superconductor such as Nb, NbTi, Nb.sub.3 Sn or Nb.sub.3 Ge with a thickness in the range of about 0.5-1.5 times its coherence length, supported and separated by layers of copper with each copper layer having a thickness in the range of about 170-600 .ANG..

  14. Superconducting magnet technology for accelerators

    SciTech Connect

    Palmer, R.; Tollestrup, A.V.

    1984-03-01

    A review article on superconducting magnets for accelerators should first answer the question, why superconductivity. The answer revolves around two pivotal facts: (1) fields in the range of 2 T to 10 T can be achieved; and (2) the operating cost can be less than conventional magnets. The relative importance of these two factors depends on the accelerator. In the case where an upgrade of an accelerator at an existing facility is planned, the ability to obtain fields higher than conventional magnets leads directly to an increase in machine energy for the given tunnel. In the case of a new facility, both factors must be balanced for the most economical machine. Ways to achieve this are discussed.

  15. Superconducting magnet cooling system

    DOEpatents

    Vander Arend, Peter C.; Fowler, William B.

    1977-01-01

    A device is provided for cooling a conductor to the superconducting state. The conductor is positioned within an inner conduit through which is flowing a supercooled liquid coolant in physical contact with the conductor. The inner conduit is positioned within an outer conduit so that an annular open space is formed therebetween. Through the annular space is flowing coolant in the boiling liquid state. Heat generated by the conductor is transferred by convection within the supercooled liquid coolant to the inner wall of the inner conduit and then is removed by the boiling liquid coolant, making the heat removal from the conductor relatively independent of conductor length.

  16. Superconducting bulk magnets for magnetic levitation systems

    NASA Astrophysics Data System (ADS)

    Fujimoto, H.; Kamijo, H.

    2000-06-01

    The major applications of high-temperature superconductors have mostly been confined to products in the form of wires and thin films. However, recent developments show that rare-earth REBa 2Cu 3O 7- x and light rare-earth LREBa 2Cu 3O 7- x superconductors prepared by melt processes have a high critical-current density at 77 K and high magnetic fields. These superconductors will promote the application of bulk high-temperature superconductors in high magnetic fields; the superconducting bulk magnet for the Maglev train is one possible application. We investigated the possibility of using bulk magnets in the Maglev system, and examined flux-trapping characteristics of multi-superconducting bulks arranged in array.

  17. Superconducting magnet for the Maglev transport system

    NASA Astrophysics Data System (ADS)

    Nakashima, Hiroshi

    1994-07-01

    Magnetically levitated vehicles (Maglev) using superconducting magnets have been under development in Japan for the past 23 years. The superconducting magnets for the Maglev system are used in a special environment compared to other applications. They have to work stably subject to both mechanical and electromagnetic disturbances. The brief history of the Maglev development in Japan, the planning of new test line, the superconducting magnet's stability and the on-board refrigeration system will be presented.

  18. Magnetism and Superconductivity in Iron Pnictides

    SciTech Connect

    Singh, David J

    2012-01-01

    The discovery of high temperature superconductivity in iron pnictides and chalcogenides has resulted in surprising new insights into high temperature superconductivity and its relationship with magnetism. Here we provide an overview of some of what is known about these materials and in particular about the interplay of magnetism and superconductivity in them. Similarities and contrasts with cuprate superconductors are emphasized and the superconducting pairing is discussed within the framework of spin fluctuation induced pairing.

  19. Superconducting magnet and fabrication method

    NASA Technical Reports Server (NTRS)

    Israelsson, Ulf E. (Inventor); Strayer, Donald M. (Inventor)

    1994-01-01

    A method of trapping a field in a block of superconductor material, includes providing (i) a block of material defining a bore, (ii) a high permeability core within the bore that defines a low reluctance path through the bore, (iii) a high permeability external structure on the exterior of the block of material that defines a low reluctance path between opposite ends of the core, and (iv) an electromagnet configured to apply a magnetic field around the high permeability core. The method proceeds by energizing the electromagnet to produce an applied magnetic field around the high permeability core, cooling the block of material sufficiently to render the block of material superconducting, de-energizing the electromagnet to result in a trapped magnetic field, and at least partially removing the low reluctance path defined by the core and the external structure in order to increase the magnetic flux density of the trapped magnetic field.

  20. BNL Direct Wind Superconducting Magnets

    SciTech Connect

    Parker, B.; Anerella, M.; Escallier, J.; Ghosh, A.; Jain, A.; Marone, A.; Muratore, A.; Wanderer, P.

    2011-09-12

    BNL developed Direct Wind magnet technology is used to create a variety of complex multi-functional multi-layer superconducting coil structures without the need for creating custom production tooling and fixturing for each new project. Our Direct Wind process naturally integrates prestress into the coil structure so external coil collars and yokes are not needed; the final coil package transverse size can then be very compact. Direct Wind magnets are produced with very good field quality via corrections applied during the course of coil winding. The HERA-II and BEPC-II Interaction Region (IR) magnet, J-PARC corrector and Alpha antihydrogen magnetic trap magnets and our BTeV corrector magnet design are discussed here along with a full length ILC IR prototype magnet presently in production and the coils that were wound for an ATF2 upgrade at KEK. A new IR septum magnet design concept for a 6.2 T combined-function IR magnet for eRHIC, a future RHIC upgrade, is introduced here.

  1. Freely Oriented, Portable Superconducting Magnet

    NASA Astrophysics Data System (ADS)

    Schmierer, E. N.; Charles, B.; Efferson, R.; Hill, D.; Jankowski, T.; Laughon, G.; Prenger, C.

    2008-03-01

    A high-field low-temperature superconducting solenoidal magnet was developed that is portable and can be operated in any orientation relative to gravity. The design consists of several features that make this feasible; 1) bulk liquid cryogen storage occurs in a separate Dewar rather than as part of the magnet assembly, which allows single-person transport due to each component of the system having low relative weight, 2) vapor generated pressurization that circulates cryogenic fluid to and from the magnet with flexible transfer lines allowing operation in any orientation, and 3) composite, low-conducting structural members are used to suspend the magnet and shield layers within the vacuum vessel that provide a robust low heat loss design. Cooling is provided to the magnet through fluid channels that are in thermal contact with the magnet. The overall design of this magnet system, some of the analyses performed that address unique behavior of this system (pressure rise during a magnet quench and transient cooldown), and test results are presented.

  2. Superconducting magnet needs for the ILC

    SciTech Connect

    Tompkins, J.C.; Kashikhin, Vl.; Parker, B.; Palmer, M.A. /; Clarke, J.A.; /Daresbury

    2007-06-01

    The ILC Reference Design Report was completed early in February 2007. The Magnet Systems Group was formed to translate magnetic field requirements into magnet designs and cost estimates for the Reference Design. As presently configured, the ILC will have more than 13,000 magnetic elements of which more than 2300 will be based on superconducting technology. This paper will describe the major superconducting magnet needs for the ILC as presently determined by the Area Systems Groups, responsible for beam line design, working with the Magnet Systems Group. The superconducting magnet components include Main Linac quadrupoles, Positron Source undulators, Damping Ring wigglers, a complex array of Final Focus superconducting elements in the Beam Delivery System, and large superconducting solenoids in the e{sup +} and e{sup -} Sources, and the Ring to Main Linac lines.

  3. A superconducting large-angle magnetic suspension

    NASA Technical Reports Server (NTRS)

    Downer, James; Goldie, James; Torti, Richard

    1991-01-01

    The component technologies were developed required for an advanced control moment gyro (CMG) type of slewing actuator for large payloads. The key component of the CMG is a large-angle magnetic suspension (LAMS). The LAMS combines the functions of the gimbal structure, torque motors, and rotor bearings of a CMG. The LAMS uses a single superconducting source coil and an array of cryoresistive control coils to produce a specific output torque more than an order of magnitude greater than conventional devices. The designed and tested LAMS system is based around an available superconducting solenoid, an array of twelve room-temperature normal control coils, and a multi-input, multi-output control system. The control laws were demonstrated for stabilizing and controlling the LAMS system.

  4. Concerning superconducting inertial guidance gyroscopes inside superconducting magnetic shields

    SciTech Connect

    Satterthwaite, J.C.; Gawlinski, E.T.

    1997-12-01

    Superconductors can in theory be used to detect rotation by Josephson interference or by detection of the London field, a magnetic induction that fills the interior of any rotating bulk superconductor. One might hope to use these properties of superconductors to build a practical inertial guidance gyroscope. A problem arises from the necessity of surrounding the device with superconducting magnetic shielding: the London field generated by a co-rotating shield eliminates the response of the superconducting device within the shield. The present article demonstrates this point more rigorously than has been done before, discussing solutions of Ampere`s law for rotating and nonrotating superconductors and paying careful attention to boundary conditions. Beginning with a supercurrent density derivable from either the Ginzburg-Landau or the London theory of superconductivity, the article shows: (1) that a superconducting device cannot distinguish between rotation and an applied magnetic field; (2) that a superconducting device surrounded by a co-rotating superconducting shield cannot detect rotation. The term `superconducting gyroscope` in this article refers only to a device whose working principle is the response of the superconductor itself to rotation, not to any device in which superconducting electronic components are used to detect some other effect. {copyright} {ital 1997 American Institute of Physics.}

  5. Space applications of superconductivity - High field magnets

    NASA Technical Reports Server (NTRS)

    Fickett, F. R.

    1979-01-01

    The paper discusses developments in superconducting magnets and their applications in space technology. Superconducting magnets are characterized by high fields (to 15T and higher) and high current densities combined with low mass and small size. The superconducting materials and coil design are being improved and new high-strength composites are being used for magnet structural components. Such problems as maintaining low cooling temperatures (near 4 K) for long periods of time and degradation of existing high-field superconductors at low strain levels can be remedied by research and engineering. Some of the proposed space applications of superconducting magnets include: cosmic ray analysis with magnetic spectrometers, energy storage and conversion, energy generation by magnetohydrodynamic and thermonuclear fusion techniques, and propulsion. Several operational superconducting magnet systems are detailed.

  6. Field quality aspects of CBA superconducting magnets

    SciTech Connect

    Kahn, S.; Engelmann, R.; Fernow, R.; Greene, A.F.; Herrera, J.; Kirk, H.; Skaritka, J.; Wanderer, P.; Willen, E.

    1983-01-01

    A series of superconducting dipole magnets for the BNL Colliding Beam Accelerator which were manufactured to have the proper field quality characteristics has been tested. This report presents the analysis of the field harmonics of these magnets.

  7. High-field superconducting nested coil magnet

    NASA Technical Reports Server (NTRS)

    Laverick, C.; Lobell, G. M.

    1970-01-01

    Superconducting magnet, employed in conjunction with five types of superconducting cables in a nested solenoid configuration, produces total, central magnetic field strengths approaching 70 kG. The multiple coils permit maximum information on cable characteristics to be gathered from one test.

  8. Superconducting magnets. Citations from NTIS data base

    NASA Astrophysics Data System (ADS)

    Reimherr, G. W.

    1980-10-01

    The cited reports discuss research on materials studies, theory, design and applications of superconducting magnets. Examples of applications include particle accelerators, MHD power generation, superconducting generators, nuclear fusion research devices, energy storage systems, and magnetic levitation. This updated bibliography contains 218 citations, 88 of which are new entries to the previous edition.

  9. Advanced composite materials and processes for the manufacture of SSC (Superconducting Super Collider) and RHIC (Relativistic Heavy Ion Collider) superconducting magnets used at cryogenic temperatures in a high radiation environment

    SciTech Connect

    Sondericker, J.H.

    1989-01-01

    Presently, BNL work on superconducting magnets centers mainly on the development of 17 meter length dipoles for the Superconducting Super Collider Project, approved for construction at Waxahatchie, Texas and 9.7 meter dipoles and quadrupoles for the Relativistic Heavy Ion Collider, a BNL project to start construction next year. This paper will discuss the role of composites in the manufacture of magnets, their operational requirements in cryogenic and radiation environments, and the benefits derived from their use. 13 figs.

  10. Field errors in superconducting magnets

    SciTech Connect

    Barton, M. Q.

    1982-01-01

    The mission of this workshop is a discussion of the techniques for tracking particles through arbitrary accelerator field configurations to look for dynamical effects that are suggested by various theoretical models but are not amenable to detailed analysis. A major motivation for this type of study is that many of our accelerator projects are based on the use of superconducting magnets which have field imperfections that are larger and of a more complex nature than those of conventional magnets. Questions such as resonances, uncorrectable closed orbit effects, coupling between planes, and diffusion mechanisms all assume new importance. Since, simultaneously, we are trying to do sophisticated beam manipulations such as stacking, high current accelerator, long life storage, and low loss extraction, we clearly need efficient and accurate tracking programs to proceed with confidence.

  11. Superconducting Materials, Magnets and Electric Power Applications

    NASA Astrophysics Data System (ADS)

    Crabtree, George

    2011-03-01

    The surprising discovery of superconductivity a century ago launched a chain of convention-shattering innovations and discoveries in superconducting materials and applications that continues to this day. The range of large-scale applications grows with new materials discoveries - low temperature NbTi and Nb3 Sn for liquid helium cooled superconducting magnets, intermediate temperature MgB2 for inexpensive cryocooled applications including MRI magnets, and high temperature YBCO and BSSCO for high current applications cooled with inexpensive liquid nitrogen. Applications based on YBCO address critical emerging challenges for the electricity grid, including high capacity superconducting cables to distribute power in urban areas; transmission of renewable electricity over long distances from source to load; high capacity DC interconnections among the three US grids; fast, self-healing fault current limiters to increase reliability; low-weight, high capacity generators enabling off-shore wind turbines; and superconducting magnetic energy storage for smoothing the variability of renewable sources. In addition to these grid applications, coated conductors based on YBCO deposited on strong Hastelloy substrates enable a new generation of all superconducting high field magnets capable of producing fields above 30 T, approximately 50% higher than the existing all superconducting limit based on Nb3 Sn . The high fields, low power cost and the quiet electromagnetic and mechanical operation of such magnets could change the character of high field basic research on materials, enable a new generation of high-energy colliding beam experiments and extend the reach of high density superconducting magnetic energy storage.

  12. Present Status of the KSTAR Superconducting Magnet System Development

    NASA Astrophysics Data System (ADS)

    Kim, Keeman; H, K. Park; K, R. Park; B, S. Lim; S, I. Lee; M, K. Kim; Y, Chu; W, H. Chung; S, H. Baek; J Y, Choi; H, Yonekawa; A, Chertovskikh; Y, B. Chang; J, S. Kim; C, S. Kim; D, J. Kim; N, H. Song; K, P. Kim; Y, J. Song; I, S. Woo; W, S. Han; D, K. Lee; Y, K. Oh; K, W. Cho; J, S. Park; G, S. Lee; H, J. Lee; T, K. Ko; S, J. Lee

    2004-10-01

    The mission of Korea Superconducting Tokamak Advanced Research (KSTAR) project is to develop an advanced steady-state superconducting tokamak for establishing a scientific and technological basis for an attractive fusion reactor. Because one of the KSTAR mission is to achieve a steady-state operation, the use of superconducting coils is an obvious choice for the magnet system. The KSTAR superconducting magnet system consists of 16 Toroidal Field (TF) coils and 14 Poloidal Field (PF) coils. Internally-cooled Cable-In-Conduit Conductors (CICC) are put into use in both the TF and PF coil systems. The TF coil system provides a field of 3.5 T at the plasma center and the PF coil system is able to provide a flux swing of 17 V-sec. The major achievement in KSTAR magnet-system development includes the development of CICC, the development of a full-size TF model coil, the development of a coil system for background magnetic-field generation, the construction of a large-scale superconducting magnet and CICC test facility. TF and PF coils are in the stage of fabrication to pave the way for the scheduled completion of KSTAR by the end of 2006.

  13. Superconducting magnets for fusion applications

    SciTech Connect

    Henning, C.D.

    1987-07-02

    Fusion magnet technology has made spectacular advances in the past decade; to wit, the Mirror Fusion Test Facility and the Large Coil Project. However, further advances are still required for advanced economical fusion reactors. Higher fields to 14 T and radiation-hardened superconductors and insulators will be necessary. Coupled with high rates of nuclear heating and pulsed losses, the next-generation magnets will need still higher current density, better stability and quench protection. Cable-in-conduit conductors coupled with polyimide insulations and better steels seem to be the appropriate path. Neutron fluences up to 10/sup 19/ neutrons/cm/sup 2/ in niobium tin are achievable. In the future, other amorphous superconductors could raise these limits further to extend reactor life or decrease the neutron shielding and corresponding reactor size.

  14. Improved thermal isolation for superconducting magnet systems

    NASA Technical Reports Server (NTRS)

    Wiebe, E. R.

    1974-01-01

    Closed-cycle refrigerating system for superconductive magnet and maser is operated in vacuum environment. Each wire leading from external power source passes through cooling station which blocks heat conduction. In connection with these stations, switch with small incandescent light bulb, which generates heat, is used to stop superconduction.

  15. Superconducting magnetic shielding apparatus and method

    DOEpatents

    Clem, John R.; Clem, John R.

    1983-01-01

    Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.

  16. Discoveries in Superconductivity, Persistent-Switch Magnets, and Magnetic Cooling

    NASA Astrophysics Data System (ADS)

    Adams, E. Dwight

    2016-07-01

    A historical review of developments in superconducting magnets begins with Kamerlingh Onnes' construction of the first one in 1914 and extends to the invention of the superconducting persistent switch reported in 1963. A section on magnetic cooling includes refrigeration by paramagnetic salts and by nuclei in metals, as well as direct nuclear demagnetization in which only the nuclei are cooled.

  17. Discoveries in Superconductivity, Persistent-Switch Magnets, and Magnetic Cooling

    NASA Astrophysics Data System (ADS)

    Adams, E. Dwight

    2016-11-01

    A historical review of developments in superconducting magnets begins with Kamerlingh Onnes' construction of the first one in 1914 and extends to the invention of the superconducting persistent switch reported in 1963. A section on magnetic cooling includes refrigeration by paramagnetic salts and by nuclei in metals, as well as direct nuclear demagnetization in which only the nuclei are cooled.

  18. Innovative insulation systems for superconducting fusion magnets

    NASA Astrophysics Data System (ADS)

    Humer, K.; Bittner-Rohrhofer, K.; Fillunger, H.; Maix, R. K.; Prokopec, R.; Weber, H. W.

    2006-03-01

    Glass fibre reinforced plastics (GFRPs) are usually employed as insulating materials for the superconducting coils of large fusion magnets, e.g. of the International Thermonuclear Experimental Reactor (ITER). Both the radiation spectrum and the stresses at the magnet location significantly influence the mechanical behaviour of the magnet insulation and, therefore, impose high demands on the material performance. During the last few decades, advanced epoxy based GFRPs with improved mechanical properties and radiation hardness were introduced into fusion technology. More recently, cyanate ester (CE) matrix systems have become of special interest. In this paper, various magnet insulation systems containing boron-free R-glass fibre reinforcements in commercial and new epoxies as well as in pure CE and CE/epoxy blended matrix systems are presented. All systems were irradiated in a fission reactor at ambient temperature (~340 K) to a fast neutron fluence of 1 × 1022 m-2 (E>0.1 MeV). The mechanical properties were assessed at 77 K in tension as well as in interlaminar shear prior to and after irradiation under static and dynamic conditions.

  19. Magnet design for superconducting open gradient magnetic separator

    NASA Astrophysics Data System (ADS)

    Ahoranta, Maria; Lehtonen, Jorma; Mikkonen, Risto

    2003-04-01

    The use of superconductivity opens new applications for magnetic separation because very high magnetic fields become available. In this paper the magnet design for a laboratory scale superconducting open gradient magnetic separator is presented. The separator will be used to optimize the separation parameters for different kinds of applications, such as the foundry sand purification. Therefore, the goal of the magnet design is to obtain a constant magnetic force density distribution inside the working volume. The high magnitude of magnetic force density is required because the materials to be separated have low magnetic susceptibilities. The maximum achievable force density is determined by the critical current in superconducting magnets. The advantages and drawbacks of solenoid, racetrack and saddle coil geometries are compared. Ways for improving the performance of the system is discussed. Finally, the influence of the stray field on the slurry flow outside the working volume is studied.

  20. A parasitic magnetic refrigerator for cooling superconducting magnet

    SciTech Connect

    Nakagome, H.; Takahashi, M.; Ogiwara, H.

    1988-03-01

    The application of magnetic refrigeration principle at a liquid helium temperature (4.2K) is very useful for cooling a superconducting magnet for its potential of high efficiency. The magnetic refrigerator equipped with 14 pieces of GGG (gadolinium-gallium-garnet) single crystal unit (30mm in diameter 10mm in length) in the rotating disk operates along the gradient of the magnetic field produced by a racetrack superconducting magnet, whose maximum magnetic field is 4.5 Tesla and the minimum field is 1.1 Tesla. The final goal of their program is to liquefy gaseous helium evaporated from a liquid helium vessel of the racetrack superconducting magnet by the rotating magnetic refrigerator which operates by using the magnetic field of the superconducting magnet. A 0.12W refrigeration power in the 0.72rpm operation has been achieved under condition of 4.2K to 11.5K operation. The helium evaporation rate of this magnet system is estimated as the order of 10mW, and the achieved refrigeration power of 0.12W at 4.2K is sufficient for cooling the superconducting magnet.

  1. Advanced Beamline Design for Fermilab's Advanced Superconducting Test Accelerator

    SciTech Connect

    Prokop, Christopher

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) at Fermilab is a new electron accelerator currently in the commissioning stage. In addition to testing superconducting accelerating cavities for future accelerators, it is foreseen to support a variety of Advanced Accelerator R&D (AARD) experiments. Producing the required electron bunches with the expected flexibility is challenging. The goal of this dissertation is to explore via numerical simulations new accelerator beamlines that can enable the advanced manipulation of electron bunches. The work especially includes the design of a low-energy bunch compressor and a study of transverse-to-longitudinal phase space exchangers.

  2. Advanced beamline design for Fermilab's Advanced Superconducting Test Accelerator

    NASA Astrophysics Data System (ADS)

    Prokop, Christopher R.

    The Advanced Superconducting Test Accelerator (ASTA) at Fermilab is a new electron accelerator currently in the commissioning stage. In addition to testing superconducting accelerating cavities for future accelerators, it is foreseen to support a variety of Advanced Accelerator R&D (AARD) experiments. Producing the required electron bunches with the expected flexibility is challenging. The goal of this dissertation is to explore via numerical simulations new accelerator beamlines that can enable the advanced manipulation of electron bunches. The work especially includes the design of a low-energy bunch compressor and a study of transverse-to-longitudinal phase space exchangers.

  3. Interplay between superconductivity and magnetism in iron-based superconductors

    SciTech Connect

    Chubukov, Andrey V

    2015-06-10

    fermions, understand what sets the upper scale for attractive interaction, compute T_c, and then obtain and solve matrix non-linear gap equation for spin-mediated pairing and study various feedbacks from the pairing on fermions on ARPES spectra, optical and thermal conductivity, and other observables, The problems I have chosen are quite generic, and the understanding of magnetically-mediated superconductivity in the strong-coupling regime will not only advance the theory of superconductivity in FeSCs, but will contribute to a generic understanding of the pairing of fermions near quantum-critical points -- the problems ranging from s-wave pairing by soft optical phonons to to color superconductivity of quarks mediated by a gluon exchange.

  4. Stable superconducting magnet. [high current levels below critical temperature

    NASA Technical Reports Server (NTRS)

    Boom, R. W. (Inventor)

    1967-01-01

    Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

  5. A superconducting magnet for Stanford University

    NASA Astrophysics Data System (ADS)

    Parmer, J. F.; Magnuson, G. D.; Jones, R. G.; Taylor, W. D.; Peck, S. D.; Waszczak, J. P.; Williams, J. E. C.; Bobrov, E. S.

    1981-01-01

    Three MHD superconducting magnets are being developed for coal power generation. A rectangular saddle magnet uses a nonmetallic substructure for conductor support; a circular magnet contains the radial Lorentz forces by interlayer bands instead of a superstructure; and a circular saddle magnet supports conductors with a metallic substructure. A substructure support provides conductor movement within the winding controlled by the limits of frictional heating of the conductor and reacts with a significant part of the magnetically induced loads. During a seismic event or MHD channel-induced vibration of the winding, eddy currents induced in the vacuum vessel provide damping for the controls of resonant amplitude.

  6. The superconducting magnet of AMS-02

    NASA Astrophysics Data System (ADS)

    Blau, B.; Harrison, S. M.; Hofer, H.; Milward, S. R.; Ross, J. S. H.; Ting, S. C. C.; Ulbricht, J.; Viertel, G.

    The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to search for anti-matter, dark matter and the origin of cosmic rays in space. The detector will be installed on the International Space Station (ISS). The planned duration of the experiment is 3 years. The magnetic dipole field is achieved by an arrangement of 14 superconducting coils. The magnet system consists of a pair of large Helmholtz coils together with two series of six racetrack coils, circumferentially distributed between them. This arrangement was mainly chosen to minimize the stray field outside of the magnet. It generates a magnetic field of 0.87 T in the center of the magnet with a bending power of 0.78 Tm 2. All superconducting coils are indirectly cooled by pressurized superfluid helium at 1.8 K. This cooling loop is thermally connected with a 2500 l vessel for superfluid helium which serves as a cold reservoir. In order to ensure the 3 year endurance without refilling, the magnet design was optimized with respect to very low heat losses. This paper describes the main features of the AMS superconducting magnet and the principle concept of the cryogenic system.

  7. Thermo-magnetic instabilities in Nb3Sn superconducting accelerator magnets

    SciTech Connect

    Bordini, Bernardo

    2006-09-01

    The advance of High Energy Physics research using circulating accelerators strongly depends on increasing the magnetic bending field which accelerator magnets provide. To achieve high fields, the most powerful present-day accelerator magnets employ NbTi superconducting technology; however, with the start up of Large Hadron Collider (LHC) in 2007, NbTi magnets will have reached the maximum field allowed by the intrinsic properties of this superconductor. A further increase of the field strength necessarily requires a change in superconductor material; the best candidate is Nb3Sn. Several laboratories in the US and Europe are currently working on developing Nb3Sn accelerator magnets, and although these magnets have great potential, it is suspected that their performance may be fundamentally limited by conductor thermo-magnetic instabilities: an idea first proposed by the Fermilab High Field Magnet group early in 2003. This thesis presents a study of thermo-magnetic instability in high field Nb3Sn accelerator magnets. In this chapter the following topics are described: the role of superconducting magnets in High Energy Physics; the main characteristics of superconductors for accelerator magnets; typical measurements of current capability in superconducting strands; the properties of Nb3Sn; a description of the manufacturing process of Nb3Sn strands; superconducting cables; a typical layout of superconducting accelerator magnets; the current state of the art of Nb3Sn accelerator magnets; the High Field Magnet program at Fermilab; and the scope of the thesis.

  8. Structure and Magnetism in Superconducting Iron Chalcogenides

    NASA Astrophysics Data System (ADS)

    Thampy, Vivek

    Iron superconductors are unique in that they provide a wide range of control parameters such as structure, chemical composition, pressure and impurities that can be tuned to provide insight into the underlying mechanisms of cooper pairing. In this dissertation, we will discuss the relationship of superconductivity with a) crystal structure, b) magnetic order, c) impurities, and d) low energy magnetic excitations in the structurally simplest iron superconductors, (Fe 1+yTe1-xSex). We use thin films of FeTe0.5Se0.5, in which the structural parameters are modulated using different growth conditions, to demonstrate the importance of the Te/Se height to superconductivity and show that it is consistent with the s± pairing symmetry. The proximity of magnetism and superconductivity in the iron superconductors is delved into for the iron chalcogenide superconductors by tracking the evolution of magnetic order and superconductivity with dopant (Se) concentration. We elucidate the pivotal role played by iron impurities, occupying interstitial sites in Fe1+yTe0.62Se0.38, in the microscopic origin of the quasi-static magnetism at (½,0). We used polarized and unpolarized neutron scattering, simulations of the scattering function based on structural data, and a semi-metallic 5-band model with super-exchange interactions with the interstitial iron to show the formation of magnetic polarons around the interstitial iron atoms which seed the observed (½,0) magnetism. Though the quasi-static magnetism occurs at (½,0), the low energy spin dynamics are dominated by the (½,½) fluctuations, like other iron based superconductors. We examine the characteristics of the signature feature in the low energy inelastic neutron scattering spectrum - the so-called spin resonance, and try to glean its microscopic origin by studying the effect of magnetic fields on the resonance.

  9. Levitating a Magnet Using a Superconductive Material.

    ERIC Educational Resources Information Center

    Juergens, Frederick H.; And Others

    1987-01-01

    Presented are the materials and a procedure for demonstrating the levitation of a magnet above a superconducting material. The demonstration can be projected with an overhead projector for a large group of students. Kits to simplify the demonstration can be purchased from the Institute for Chemical Education of the University of Wisconsin-Madison.…

  10. Superconducting Magnetic Energy Storage and Applications

    NASA Astrophysics Data System (ADS)

    Rao, V. Vasudeva

    2008-10-01

    This paper gives an Introduction to Superconducting Magnetic Energy Storage (SMES) systems and their applications along with an overview of their present status. Further a brief description to a Micro SMES/UPS system of 0.5 MJ capacity that was developed/tested at IIT, Kharagpur is also included.

  11. Superconducting magnetic spectrometer for cosmic ray nuclei.

    NASA Technical Reports Server (NTRS)

    Smith, L. H.; Buffington, A.; Wahlig, M. A.; Dauber, P.

    1972-01-01

    This paper describes the design, calibration, and operation of a magnetic spectrometer for particle astronomy. The spectrometer consists of a superconducting magnet, optical spark chambers, scintillation detectors, and associated electronics. The instrument has been flown in a balloon gondola to 4.8 g/sq cm residual atmosphere, where it was used to analyze the charge and differential rigidity spectra of primary nuclei from 5 to 100 GeV/c.

  12. Superconductivity and magnetism in naturally occurring minerals

    NASA Astrophysics Data System (ADS)

    Wang, Renxiong; Saha, S. R.; Wang, Xiangfeng; Greene, R. L.; Paglione, J.; Santelli, C.; Post, J.

    2014-03-01

    In a new and unique venture in collaboration with the Smithsonian Museum of Natural History's Department of Mineral Sciences, we present preliminary results from a project focusing on the search for superconductivity in mineral specimens provided by Geologists/Curators of the Smithsonian Institution. Including magnetization and transport studies of Wittichenite, Pyrrhotite, Nagyagite, Pyrargyrite and other related compounds, we report preliminary findings of the physical properties of mineral specimens at low temperatures, including several unreported magnetic phases and unconvetional behaviors.

  13. Superconducting magnet system for muon beam cooling

    SciTech Connect

    Andreev, N.; Johnson, R.P.; Kashikhin, V.S.; Kashikhin, V.V.; Novitski, I.; Yonehara, K.; Zlobin, A.; /Fermilab

    2006-08-01

    A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. A novel superconducting magnet system for a muon beam cooling experiment is being designed at Fermilab. The inner volume of the cooling channel is filled with liquid helium where passing muon beam can be decelerated and cooled in a process of ionization energy loss. The magnet parameters are optimized to match the momentum of the beam as it slows down. The results of 3D magnetic analysis for two designs of magnet system, mechanical and quench protection considerations are discussed.

  14. The superconducting magnet for the Maglev transport system

    SciTech Connect

    Nakashima, Hiroshi

    1994-07-01

    Magnetically levitated vehicles (Maglev) using superconducting magnets have been under development in Japan for the past 23 years. The superconducting magnets for the Maglev system are used in a special environment compared to other applications. They have to work stably subject to both mechanical and electromagnetic disturbances. The brief history of the Maglev development in Japan, the planning of new test line, the superconducting magnet`s stability and the on board refrigeration system will be presented.

  15. Superconducting vortex pinning with artificial magnetic nanostructures.

    SciTech Connect

    Velez, M.; Martin, J. I.; Villegas, J. E.; Hoffmann, A.; Gonzalez, E. M.; Vicent, J. L.; Schuller, I. K.; Univ. de Oviedo-CINN; Unite Mixte de Physique CNRS Univ. Paris-Sud; Univ.Complutense de Madrid; Univ. California at San Diego

    2008-11-01

    This review is dedicated to summarizing the recent research on vortex dynamics and pinning effects in superconducting films with artificial magnetic structures. The fabrication of hybrid superconducting/magnetic systems is presented together with the wide variety of properties that arise from the interaction between the superconducting vortex lattice and the artificial magnetic nanostructures. Specifically, we review the role that the most important parameters in the vortex dynamics of films with regular array of dots play. In particular, we discuss the phenomena that appear when the symmetry of a regular dot array is distorted from regularity towards complete disorder including rectangular, asymmetric, and aperiodic arrays. The interesting phenomena that appear include vortex-lattice reconfigurations, anisotropic dynamics, channeling, and guided motion as well as ratchet effects. The different regimes are summarized in a phase diagram indicating the transitions that take place as the characteristic distances of the array are modified respect to the superconducting coherence length. Future directions are sketched out indicating the vast open area of research in this field.

  16. Superconducting Magnets for Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Feenan, Peter

    2000-03-01

    MRI is now a well established diagnostic technique in medicine. The richness of information provided by magnetic resonance gives rise to a variety of techniques which in turn leads to a variety of magnet designs. Magnet designers must consider suitable superconduting materials for the magnet, but need also to consider the overall fomat of the magnet to maximise patient comfort, access for clinicians and convenience of use - in some examples magnets are destined for use within the operating theatre and special considerations are required for this. Magnet types include; (1) low-field general purpose imagers, (2) extremity imaging, (3) open magnets with exellent all-round access often employing iron or permanent magnetic materials, (4) high-field magnets, and (5) very high-field (7 Tesla and more) magnets for spectroscopy and functional imaging research. Examples of these magnet varieties will be shown and some of the design challenges discussed.

  17. Technical issues of a high-Tc superconducting bulk magnet

    NASA Astrophysics Data System (ADS)

    Fujimoto, Hiroyuki

    2000-06-01

    Superconducting magnets made of high-Tc superconductors are promising for industrial applications. It is well known that REBa2Cu3O7-x superconductors prepared by melt processes have a high critical current density, Jc, at 77 K and high magnetic fields. The materials are very promising for high magnetic field applications as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. Light rare-earth (LRE) BaCuO bulks, compared with REBaCuO bulks, exhibit a larger Jc in high magnetic fields and a much improved irreversibility field, Hirr, at 77 K. In this study, we discuss technical issues of a high-Tc superconducting bulk magnet, namely the aspects of the melt processing for bulk superconductors, their characteristic superconducting properties and mechanical properties, and trapped field properties of a superconducting bulk magnet. One of the possible applications is a superconducting bulk magnet for the magnetically levitated (Maglev) train in the future.

  18. Comparing superconducting and permanent magnets for magnetic refrigeration

    NASA Astrophysics Data System (ADS)

    Bjørk, R.; Nielsen, K. K.; Bahl, C. R. H.; Smith, A.; Wulff, A. C.

    2016-05-01

    We compare the cost of a high temperature superconducting (SC) tape-based solenoid with a permanent magnet (PM) Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 /m2 and a price of the permanent magnet of 100 /kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications.

  19. Mesoscopic magnetism and superconductivity: recent perspectives.

    SciTech Connect

    Basaran, Ali C.; Villegas, Javier E.; Jiang, J. S.; Hoffmann, Axel; Schuller, Ivan K.

    2015-11-01

    Mesoscopic Superconductivity and Magnetism at intermediate (“Mesoscopic”) length scales between atomic and bulk, have a long history of interesting new science. The existence of multiple length scales allows for the development of new science when different length scales become comparable to relevant geometric sizes. Different new phenomena appear due to topological interactions, geometric confinement, proximity between dissimilar materials, dimensional crossover, and collective effects induced by the periodicity. In this brief review we are not able to cover comprehensively this vast field. Instead we select a few recent exciting highlights, which illustrate the type of novel science which can be accomplished in superconducting and magnetic structures. Superconductors and magnetic materials can serve as model systems and provide new ideas, which can be extended to other systems such as ferroelectrics and multiferroics. In this paper we also highlight general open questions and new directions in which the field may move.

  20. The superconducting solenoid magnets for MICE

    SciTech Connect

    Green, Michael A.

    2002-12-22

    The Muon Ionization Cooling Experiment (MICE) is a channel of superconducting solenoid magnets. The magnets in MICE are around the RF cavities, absorbers (liquid or solid) and the primary particle detectors [1], [2]. The MICE superconducting solenoid system consists of eighteen coils that are grouped in three types of magnet assemblies. The cooling channel consists of two complete cell of an SFOFO cooling channel. Each cell consists of a focusing coil pair around an absorber and a coupling coil around a RF cavity that re-accelerates the muons to their original momentum. At the ends of the experiment are uniform field solenoids for the particle detectors and a set of matching coils used to match the muon beam to the cooling cells. Three absorbers are used instead of two in order to shield the detectors from dark currents generated by the RF cavities at high operating acceleration gradients.

  1. The advantages and challenges of superconducting magnets in particle therapy

    NASA Astrophysics Data System (ADS)

    Gerbershagen, Alexander; Calzolaio, Ciro; Meer, David; Sanfilippo, Stéphane; Schippers, Marco

    2016-08-01

    This paper provides an overview of the current developments in superconducting magnets for applications in proton and ion therapy. It summarizes the benefits and challenges regarding the utilization of these magnets in accelerating systems (e.g. superconducting cyclotrons) and gantries. The paper also provides examples of currently used superconducting particle therapy systems and proposed designs.

  2. Superconducting magnets and devices for space vehicles and experiments

    NASA Technical Reports Server (NTRS)

    Urban, E. W.

    1971-01-01

    Superconductivity research has been oriented toward those problems that tend to restrict the greater application of superconducting devices in space research and technology. These include magnetic problems of high field magnets, increasing operating temperatures, and development of useful competitive superconducting instruments.

  3. A passive bearing system using superconducting magnets

    NASA Technical Reports Server (NTRS)

    Huang, X.; Eyssa, Y. M.

    1990-01-01

    A passive radial bearing concept is presented using superconducting magnets which can generate a bearing pressure as high as 360 N/sq cm, comparable to a conventional active bearing system. The system consists of a number of solenoidal superconducting coils of alternating current direction. These coils are stacked axially over the bearing length and connected in series. The currents in stator and rotor coils are in the opposite directions, generating repulsive forces. This system, in comparison with an active system, has the advantage of much smaller power dissipation in the coils since the coil currents are mostly dc currents. The cooling for the superconducting coils is therefore simpler, and the coils are more stable. An optimization study seeking the maximum bearing pressure was conducted. Details of the design, pressure calculations, and results are presented.

  4. A current limiter with superconducting coil for magnetic field shielding

    NASA Astrophysics Data System (ADS)

    Kaiho, K.; Yamaguchi, H.; Arai, K.; Umeda, M.; Yamaguchi, M.; Kataoka, T.

    2001-05-01

    The magnetic shield type superconducting fault current limiter have been built and successfully tested in ABB corporate research and so on. The device is essentially a transformer in which the secondary winding is the superconducting tube. However, due to the large AC losses and brittleness of the superconducting bulk tube, they have not yet entered market. A current limiter with superconducting coil for the magnetic field shielding is considered. By using the superconducting coil made by the multi-filamentary high Tc superconductor instead of the superconducting bulk tube, the AC losses can be reduced due to the reduced superconductor thickness and the brittleness of the bulk tube can be avoidable. This paper presents a preliminary consideration of the magnetic shield type superconducting fault current limiter with superconducting coil as secondary winding and their AC losses in comparison to that of superconducting bulk in 50 Hz operation.

  5. Preliminary study of superconducting bulk magnets for Maglev

    NASA Astrophysics Data System (ADS)

    Fujimoto, Hiroyuki; Kamijo, Hiroki

    Recent development shows that melt-processed YBaCuO (Y123) or Rare Earth (RE)123 superconductors have a high Jc at 77 K and high magnetic field, leading to high field application as a superconducting quasi-permanent bulk magnet with the liquid nitrogen refrigeration. One of the promising applications is a superconducting magnet for the magnetically levitated (Maglev) train. We discuss a superconducting bulk magnet for the Maglev train in the aspect of a preliminary design of the bulk magnet and also processing for (L)REBaCuO bulk superconductors and their characteristic superconducting properties.

  6. Permanent magnet design for high-speed superconducting bearings

    DOEpatents

    Hull, John R.; Uherka, Kenneth L.; Abdoud, Robert G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  7. Permanent magnet design for high-speed superconducting bearings

    DOEpatents

    Hull, J.R.; Uherka, K.L.; Abdoud, R.G.

    1996-09-10

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure is disclosed. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing. 9 figs.

  8. Numerical analysis of magnetic field in superconducting magnetic energy storage

    SciTech Connect

    Kanamaru, Y. ); Amemiya, Y. )

    1991-09-01

    This paper reports that the superconducting magnetic energy storage (SMES) is more useful than the other systems of electric energy storage because of larger stored energy and higher efficiency. The other systems are the battery, the flywheel, the pumped-storage power station. Some models of solenoid type SMES are designed in U.S.A. and Japan. But a high magnetic field happens by the large scale SMES in the living environment, and makes the erroneous operations of the computer display, the pacemaker of the heart and the electronic equipments. We study some fit designs of magnetic shielding of the solenoidal type SMES for reduction of the magnetic field in living environment. When some superconducting shielding coils are over the main storage coil, magnetic field reduces remarkably than the case of non shielding coil. The calculated results of the magnetic field are obtained y the finite element method.

  9. Magnetic Field Reentrant Superconductivity in Aluminum Nanowires

    NASA Astrophysics Data System (ADS)

    Bretz-Sullivan, Terence; Goldman, Allen

    Reentrance to the superconducting state through the application of a magnetic field to quasi-one dimensional superconductors driven resistive by current, is counter to the expected properties of superconductors. It was not until recently that a microscopic mechanism explaining the phenomenon was proposed in which superconductivity and phase slip driven dissipation coexist in a non-equilibrium state. Here we present additional results of magnetic field induced reentrance into the superconducting state in quasi-one-dimensional aluminum nanowires with an in-plane magnetic field both transverse to, and along the wire axis. The reentrant behavior is seen in the magnetic field dependence of the I-V characteristic and resistance vs. temperature, and in the wire's magnetoresistance at 450mK. This work was supported by DOE Basic Energy Sciences Grant DE-FG02-02ER46004. Samples were fabricated at the Minnesota Nanofabrication Center. Parts of this work were carried out in the University of Minnesota Characterization Facility, a member of the Materials Research Facilities Network (www.mrfn.org) funded via the NSF MRSEC program.

  10. Superconducting magnets for space flight. [magnetic cosmic ray spectrometers

    NASA Technical Reports Server (NTRS)

    Golden, R. L.

    1975-01-01

    The operating principle and application of superconducting magnetic spectrometers for cosmic ray analysis are described. Magnetic spectrometer experiments are thought to be possible in the areas of charge composition and its possible energy dependence, isotopic separation up to several GeV/n, electrons and positrons energy spectra, galactic secondary antiprotons, searches for primordial antimatter, searches for substructure in energy spectra, and gamma ray astronomy. Operational problems associated with the magnets are discussed, and a possible shuttle payload is also described.

  11. High temperature superconducting magnetic energy storage for future NASA missions

    NASA Technical Reports Server (NTRS)

    Faymon, Karl A.; Rudnick, Stanley J.

    1988-01-01

    Several NASA sponsored studies based on 'conventional' liquid helium temperature level superconductivity technology have concluded that superconducting magnetic energy storage has considerable potential for space applications. The advent of high temperature superconductivity (HTSC) may provide additional benefits over conventional superconductivity technology, making magnetic energy storage even more attractive. The proposed NASA space station is a possible candidate for the application of HTSC energy storage. Alternative energy storage technologies for this and other low Earth orbit missions are compared.

  12. Superconducting magnetic sensors for mine detection and classification

    NASA Astrophysics Data System (ADS)

    Clem, Ted R.; Koch, Roger H.; Keefe, George A.

    1995-06-01

    Sensors incorporating Superconducting Quantum Interference Devices (SQUIDs) provide the greatest sensitivity for magnetic anomaly detection available with current technology. During the 1980's, the Naval Surface Warfare Center Coastal Systems Station (CSS) developed a superconducting magnetic sensor capable of operation outside of the laboratory environment. This sensor demonstrated rugged, reliable performance even onboard undersea towed platforms. With this sensor, the CSS was able to demonstrate buried mine detection for the US Navy. Subsequently the sensor was incorporated into a multisensor suite onboard an underwater towed vehicle to provide a robust mine hunting capability for the Magnetic and Acoustic Detection of Mines (MADOM) project. This sensor technology utilized niobium superconducting componentry cooled by liquid helium to temperatures on the order of 4 degrees Kelvin (K). In the late 1980's a new class of superconductors was discovered with critical temperatures above the boiling point of liquid nitrogen (77K). This advance has opened up new opportunities, especially for mine reconnaissance and hunting from small unmanned underwater vehicles (UUVs). This paper describes the magnetic sensor detection and classification concept developed for MADOM. In addition, opportunities for UUV operations made possible with high Tc technology and the Navy's current efforts in this area will be addressed.

  13. Toroidal constant-tension superconducting magnetic energy storage units

    DOEpatents

    Herring, J. Stephen

    1992-01-01

    A superconducting magnetic energy storage unit is provided in which the magnet is wound in a toroidal fashion such that the magnetic field produced is contained only within the bore of the magnet, and thus producing a very low external field. The superconducting magnet includes a coolant channel disposed through the wire. The bore of the magnet comprises a storage volume in which cryogenic coolant is stored, and this volume supplies the coolant to be delivered to the coolant channel in the magnet.

  14. Magnetic field evolution in superconducting neutron stars

    NASA Astrophysics Data System (ADS)

    Graber, Vanessa; Andersson, Nils; Glampedakis, Kostas; Lander, Samuel K.

    2015-10-01

    The presence of superconducting and superfluid components in the core of mature neutron stars calls for the rethinking of a number of key magnetohydrodynamical notions like resistivity, the induction equation, magnetic energy and flux-freezing. Using a multifluid magnetohydrodynamics formalism, we investigate how the magnetic field evolution is modified when neutron star matter is composed of superfluid neutrons, type-II superconducting protons and relativistic electrons. As an application of this framework, we derive an induction equation where the resistive coupling originates from the mutual friction between the electrons and the vortex/fluxtube arrays of the neutron and proton condensates. The resulting induction equation allows the identification of two time-scales that are significantly different from those of standard magnetohydrodynamics. The astrophysical implications of these results are briefly discussed.

  15. Superconducting magnetic levitation train project in Japan

    SciTech Connect

    Oshima, K.

    1981-09-01

    The superconducting magnetic levitated train of Japanese National Railways at Miyazaki achieved its experimental target speed of 500 km/hr by reaching the world record of 517 km/hr in December 1979. The development project of high speed linear motor propulsion train levitated by superconducting magnet, Maglev, was started in 1970 by constructing a new mass-transportation system in the 1980's. The test track in Miyazaki was constructed in 1977 with an inverted T-shape guideway of about 7 km, and vehicles were tested. Now a part of the guideway was changed to a U shape in 1980 and experiments of a new vehicle of a 2 or 3 car make-up with on-board refrigerators and capacity of carrying 2 persons were undertaken. It is expected that these tests will be finalized with a demonstration track of 40 km in the near future. 3 refs.

  16. Magnetic suspension using high temperature superconducting cores

    NASA Technical Reports Server (NTRS)

    Scurlock, R. G.

    1992-01-01

    The development of YBCO high temperature superconductors, in wire and tape forms, is rapidly approaching the point where the bulk transport current density j vs magnetic field H characteristics with liquid nitrogen cooling will enable its use in model cores. On the other hand, BSCCO high temperature superconductor in wire form has poor j-H characteristics at 77 K today, although with liquid helium or hydrogen cooling, it appears to be superior to NbTi superconductor. Since liquid nitrogen cooling is approx. 100 times cheaper than liquid helium cooling, the use of YBCO is very attractive for use in magnetic suspension. The design is discussed of a model core to accommodate lift and drag loads up to 6000 and 3000 N respectively. A comparison is made between the design performance of a liquid helium cooled NbTi (or BSCCO) superconducting core and a liquid nitrogen cooled YBCO superconducting core.

  17. Magnetic-Field-Tunable Superconducting Rectifier

    NASA Technical Reports Server (NTRS)

    Sadleir, John E.

    2009-01-01

    Superconducting electronic components have been developed that provide current rectification that is tunable by design and with an externally applied magnetic field to the circuit component. The superconducting material used in the device is relatively free of pinning sites with its critical current determined by a geometric energy barrier to vortex entry. The ability of the vortices to move freely inside the device means this innovation does not suffer from magnetic hysteresis effects changing the state of the superconductor. The invention requires a superconductor geometry with opposite edges along the direction of current flow. In order for the critical current asymmetry effect to occur, the device must have different vortex nucleation conditions at opposite edges. Alternative embodiments producing the necessary conditions include edges being held at different temperatures, at different local magnetic fields, with different current-injection geometries, and structural differences between opposite edges causing changes in the size of the geometric energy barrier. An edge fabricated with indentations of the order of the coherence length will significantly lower the geometric energy barrier to vortex entry, meaning vortex passage across the device at lower currents causing resistive dissipation. The existing prototype is a two-terminal device consisting of a thin-film su - perconducting strip operating at a temperature below its superconducting transition temperature (Tc). Opposite ends of the strip are connected to electrical leads made of a higher Tc superconductor. The thin-film lithographic process provides an easy means to alter edge-structures, current-injection geo - metries, and magnetic-field conditions at the edges. The edge-field conditions can be altered by using local field(s) generated from dedicated higher Tc leads or even using the device s own higher Tc superconducting leads.

  18. Design of superconducting magnets for the SSC

    SciTech Connect

    Palmer, R.B. Superconducting Super Collider Lab., Dallas, TX )

    1991-05-01

    In order for a superconducting magnet to operate reliably at a given field the design should have sufficient superconductor to allow operation at currents significantly less than the cable critical current. In addition sufficient copper should be included in the cable to give stability. Such considerations, their basis, and their application to the design of the new 5 cm bore diameter SSC dipoles, are discussed. 3 refs., 5 figs.

  19. Fabrication and assembly of a superconducting undulator for the advanced photon source

    SciTech Connect

    Hasse, Quentin; Fuerst, J. D.; Ivanyushenkov, Y.; Doose, C.; Kasa, M.; Shiroyanagi, Y.; Trakhtenberg, E. M.; Skiadopoulos, D.

    2014-01-29

    A prototype superconducting undulator magnet (SCU0) has been built at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) and has successfully completed both cryogenic performance and magnetic measurement test programs. The SCU0 closed loop, zero-boil-off cryogenic system incorporates high temperature superconducting (HTS) current leads, cryocoolers, a LHe reservoir supplying dual magnetic cores, and an integrated cooled beam chamber. This system presented numerous challenges in the design, fabrication, and assembly of the device. Aspects of this R and D relating to both the cryogenic and overall assembly of the device are presented here. The SCU0 magnet has been installed in the APS storage ring.

  20. Superconducting (radiation hardened) magnets for mirror fusion devices

    SciTech Connect

    Henning, C.D.; Dalder, E.N.C.; Miller, J.R.; Perkins, J.R.

    1983-12-07

    Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10/sup 10/ to 10/sup 11/ rads, while magnet stability must be retained after the copper has been exposed to fluence above 10/sup 19/ neutrons/cm/sup 2/.

  1. Magnetic suspension and balance system advanced study, 1989 design

    NASA Technical Reports Server (NTRS)

    Boom, Roger W.; Eyssa, Y. M.; Abdelsalam, Moustafa K.; Mcintosh, Glen E.

    1991-01-01

    The objectives are to experimentally confirm several advanced design concepts on the Magnetic Suspension and Balance Systems (MSBS). The advanced design concepts were identified as potential improvements by Madison Magnetics, Inc. (MMI) during 1984 and 1985 studies of an MSBS utilizing 14 external superconductive coils and a superconductive solenoid in an airplane test model suspended in a wind tunnel. This study confirmed several advanced design concepts on magnetic suspension and balance systems. The 1989 MSBS redesign is based on the results of these experiments. Savings of up to 30 percent in supporting magnet ampere meters and 50 percent in energy stored over the 1985 design were achieved.

  2. Superconducting Sphere in an External Magnetic Field Revisited

    ERIC Educational Resources Information Center

    Sazonov, Sergey N.

    2013-01-01

    The purpose of this article is to give the intelligible procedure for undergraduate students to grasp proof of the fact that the magnetic field outside the hollow superconducting sphere (superconducting shell) coincides with the field of a point magnetic dipole both when an uniform external magnetic field is applied as when a ferromagnetic sphere…

  3. Torus CLAS12-Superconducting Magnet Quench Analysis

    SciTech Connect

    Kashikhin, V S; Elouadhiri, L; Ghoshal, P K; Kashy, D; Makarov, A; Pastor, O; Quettier, L; Velev, G; Wiseman, M

    2014-06-01

    The JLAB Torus magnet system consists of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration. These coils are wound with SSC-36 Nb-Ti superconductor and have the peak magnetic field of 3.6 T. The first coil manufacturing based on the JLAB design began at FNAL. The large magnet system dimensions (8 m diameter and 14 MJ of stored energy) dictate the need for quench protection. Each coil is placed in an aluminum case mounted inside a cryostat and cooled by 4.6 K supercritical helium gas flowing through a copper tube attached to the coil ID. The large coil dimensions and small cryostat thickness drove the design to challenging technical solutions, suggesting that Lorentz forces due to transport currents and eddy currents during quench and various failure scenarios are analyzed. The paper covers the magnet system quench analysis using the OPERA3d Quench code.

  4. Torus CLAS12-Superconducting Magnet Quench Analysis

    SciTech Connect

    Kashikhin, V. S.; Elouadhiri, L.; Ghoshal, P. K.; Kashy, D.; Makarov, A.; Pastor, O.; Quettier, L.; Velev, G.; Wiseman, M.

    2014-01-01

    The JLAB Torus magnet system consists of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration. These coils are wound with SSC-36 Nb-Ti superconductor and have the peak magnetic field of 3.6 T. The first coil manufacturing based on the JLAB design began at FNAL. The large magnet system dimensions (8 m diameter and 14 MJ of stored energy) dictate the need for quench protection. Each coil is placed in an aluminum case mounted inside a cryostat and cooled by 4.6 K supercritical helium gas flowing through a copper tube attached to the coil ID. The large coil dimensions and small cryostat thickness drove the design to challenging technical solutions, suggesting that Lorentz forces due to transport currents and eddy currents during quench and various failure scenarios are analyzed. The paper covers the magnet system quench analysis using the OPERA3d Quench code.

  5. Design of magnets inside cylindrical superconducting shields

    NASA Technical Reports Server (NTRS)

    Rigby, K. W.

    1988-01-01

    The design of magnets inside closed, cylindrical, superconducting shields is discussed. The Green function is given for the magnetic vector potential for cylindrically symmetric currents inside such a shield. The magnetic field everywhere inside the shield can be obtained from this function, which includes the effects of the induced shield currents exactly. The field is given for a thin solenoid as an example and the convergence of the series solution for this case is discussed. The shield can significantly reduce the strength and improve the homogeneity of a magnet. The improvement in homogeneity is of particular importance in the design of correction coils. These effects, and the maximum field on the shield, are examined for a typical solenoid. The results given are also useful, although not exact, for long shields with one or two open ends.

  6. Permanent superconducting magnets for space applications

    NASA Technical Reports Server (NTRS)

    Weinstein, Roy

    1994-01-01

    Work has been done to develop superconducting trapped field magnets (TFM's) and to apply them to a bumper-tether device for magnetic docking of spacecraft. The quality parameters for TFM's are J(c), the critical current of the superconductor, and d, the diameter of the superconducting tile. During this year we have doubled d, for production models, from 1 cm to 2 cm. This was done by means of seeding, an improved temperature profile in processing, and the addition of 1 percent Pt to the superconductor chemistry. Using these tiles we have set increasing records for the fields' permanent magnets. Magnets fabricated from old 1 cm tiles trapped 1.52 Tesla at 77K, 4.0T at 65K and 7.0T at 55K. The second of these fields broke a 17 year old record set at Stanford. The third field broke our own record. More recently using 2 cm tiles, we have trapped 2.3T at 77K, and 5.3T at 65K. We expect to trap lOT at 55K in this magnet in the near future. We have also achieved increases in J(c) using a method we developed for seeding U-235, and subsequently bombarding with neutrons. This method doubles J(c). We have not yet fabricated magnets from these tiles. During this year we have increased production yields from 15 percent to 95 percent. We have explored the properties of a magnetic bumper-tether for spacecraft. We have measured the bumper forces, and their dependence on time, distance, and the field of the ordinary ferromagnet (used together with a TFM). We have accounted for 85 percent of the collision energy, and its transformation to magnetic energy and heat energy. We have learned to control the relative bumper and tether forces by controlling TFM and ferromagnetic field strengths.

  7. Superconducting flat tape cable magnet

    DOEpatents

    Takayasu, Makoto

    2015-08-11

    A method for winding a coil magnet with the stacked tape cables, and a coil so wound. The winding process is controlled and various shape coils can be wound by twisting about the longitudinal axis of the cable and bending following the easy bend direction during winding, so that sharp local bending can be obtained by adjusting the twist pitch. Stack-tape cable is twisted while being wound, instead of being twisted in a straight configuration and then wound. In certain embodiments, the straight length should be half of the cable twist-pitch or a multiple of it.

  8. Superconductivity and magnetism in rapidly solidified perovskites

    SciTech Connect

    O'Handley, R.C.; Kalonji, G.

    1991-01-01

    The report is divided into six parts, reflecting major thrusts of our work since 1987. The six areas are: molecular orbital theory of high {Tc} superconductivity; rapid solidification processing of oxide superconductors; time dependent magnetic and superconducting properties of these inhomogeneous materials; excess Gd in Gd{sub 1+x}Ba{sub 2-x}Cu{sub 3}O{sub 7-{delta}} perovskites; rapid solidification and directional annealing to achieve high Jc; and Mossbauer studies of T = Fe, Co and Ni site selection in YBa{sub 2}(CuT){sub 3}O{sub 7-{delta}} and GdBa{sub 2}(CuT){sub 3}O{sub 7-{delta}}.

  9. Novel Approach to Linear Accelerator Superconducting Magnet System

    SciTech Connect

    Kashikhin, Vladimir; /Fermilab

    2011-11-28

    Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

  10. THE SUPERCONDUCTION MAGNETS OF THE ILC BEAM DELIVERY SYSTEM.

    SciTech Connect

    PARKER,B.; ANEREELA, M.; ESCALLIE, J.; HE, P.; JAIN, A.; MARONE, A.; NOSOCHKOV, Y.; SERYI, A.

    2007-06-25

    The ILC Reference Design Report was completed early in February 2007. The Magnet Systems Group was formed to translate magnetic field requirements into magnet designs and cost estimates for the Reference Design. As presently configured, the ILC will have more than 13,000 magnetic elements of which more than 2300 will be based on superconducting technology. This paper will describe the major superconducting magnet needs for the ILC as presently determined by the Area Systems Groups, responsible for beam line design, working with the Magnet Systems Group. The superconducting magnet components include Main Linac quadrupoles, Positron Source undulators, Damping Ring wigglers, a complex array of Final Focus superconducting elements in the Beam Delivery System, and large superconducting solenoids in the e{sup +} and e{sup -} Sources, and the Ring to Main Linac lines.

  11. Interplay Of Magnetism And Superconductivity In Cecoin5

    NASA Astrophysics Data System (ADS)

    Movshovich, R.; Tokiwa, Y.; Ronning, F.; Bianchi, A.; Capan, C.; Young, B. L.; Urbano, R. R.; Curro, N. J.; Park, T.; Thompson, J. D.; Bauer, E.; Sarrao, J. L.

    CeCoIn5 is a heavy fermion superconductor which appears to be straddling the boundary between the superconducting and magnetic ground states. At the superconducting critical field H c2 this material displays NFL behavior in transport and thermodynamic properties, pointing at a Quantum Critical Point (QCP) at H c2, and hinting at the presence of magnetic fluctuations, probably due to an AFM order superseded by the superconductivity. In the High-Field-Low-Temperature (HFLT) corner of the superconducting phase of CeCoIn5, within 20% off H c2, an additional phase appears within the superconducting phase, and the normal-to-superconducting transition itself becomes first order. This behavior is consistent with a strong Pauli limited superconductivity, and the low temperature high field phase being an inhomogeneous superconducting FFLO phase. Recent NMR experiments, however, point to a long range magnetic order within HFLT state. Experiments on CeRhIn5 under pressure show magnetic field induced AFM order within the superconducting phase, with some similarities to the phase diagram of CeCoIn5. Could the HFLT phase transition be due to magnetic order? Importantly, the HFLT phase does not extend into the normal state above H c2. We need a picture of a magnetism "attracted" to superconductivity to explain the data on the HFLT phase in CeCoIn5.

  12. SSC (Superconducting Super Collider) magnet technology

    NASA Astrophysics Data System (ADS)

    Taylor, C.

    1987-09-01

    To minimize cost of the SSC facility, small-bore high field dipole magnets have been developed; some of the new technology that has been developed at several U.S. national laboratories and in industry is summarized. Superconducting wire with high J(sub c) and filaments as small as 5 micron diameter is not produced with mechanical properties suitable for reliable cable production. A variety of collar designs of both aluminum and stainless steel have been used in model magnets. A low-heat leak post-type cryostat support system is used and a system for accurate alignment of coil-collar-yoke in the cryostat has been developed. Model magnets of 1 , 1.8 m, 4.5 m, and 17 m lengths have been build during the past two years.

  13. Critical Magnetic Field Determination of Superconducting Materials

    SciTech Connect

    Canabal, A.; Tajima, T.; Dolgashev, V.A.; Tantawi, S.G.; Yamamoto, T.; /Tsukuba, Natl. Res. Lab. Metrol.

    2011-11-04

    Superconducting RF technology is becoming more and more important. With some recent cavity test results showing close to or even higher than the critical magnetic field of 170-180 mT that had been considered a limit, it is very important to develop a way to correctly measure the critical magnetic field (H{sup RF}{sub c}) of superconductors in the RF regime. Using a 11.4 GHz, 50-MW, <1 {mu}s, pulsed power source and a TE013-like mode copper cavity, we have been measuring critical magnetic fields of superconductors for accelerator cavity applications. This device can eliminate both thermal and field emission effects due to a short pulse and no electric field at the sample surface. A model of the system is presented in this paper along with a discussion of preliminary experimental data.

  14. Transformer current sensor for superconducting magnetic coils

    DOEpatents

    Shen, Stewart S.; Wilson, C. Thomas

    1988-01-01

    A transformer current sensor having primary turns carrying a primary current for a superconducting coil and secondary turns only partially arranged within the primary turns. The secondary turns include an active winding disposed within the primary turns and a dummy winding which is not disposed in the primary turns and so does not experience a magnetic field due to a flow of current in the primary turns. The active and dummy windings are wound in opposite directions or connected in series-bucking relationship, and are exposed to the same ambient magnetic field. Voltages which might otherwise develop in the active and dummy windings due to ambient magnetic fields thus cancel out. The resultant voltage is purely indicative of the rate of change of current flowing in the primary turns.

  15. Cooling system for superconducting magnet

    DOEpatents

    Gamble, B.B.; Sidi-Yekhlef, A.

    1998-12-15

    A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir. 3 figs.

  16. Cooling system for superconducting magnet

    DOEpatents

    Gamble, Bruce B.; Sidi-Yekhlef, Ahmed

    1998-01-01

    A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir.

  17. High-Field Superconducting Magnets Supporting PTOLEMY

    NASA Astrophysics Data System (ADS)

    Hopkins, Ann; Luo, Audrey; Osherson, Benjamin; Gentile, Charles; Tully, Chris; Cohen, Adam

    2013-10-01

    The Princeton Tritium Observatory for Light, Early Universe, Massive Neutrino Yield (PTOLEMY) is an experiment planned to collect data on Big Bang relic neutrinos, which are predicted to be amongst the oldest and smallest particles in the universe. Currently, a proof-of-principle prototype is being developed at Princeton Plasma Physics Laboratory to test key technologies associated with the experiment. A prominent technology in the experiment is the Magnetic Adiabatic Collimation with an Electrostatic Filter (MAC-E filter), which guides tritium betas along magnetic field lines generated by superconducting magnets while deflecting those of lower energies. B field mapping is performed to ensure the magnets produce a minimum field at the midpoint of the configuration of the magnets and to verify accuracy of existing models. Preliminary tests indicate the required rapid decrease in B field strength from the bore of the more powerful 3.35 T magnet, with the field dropping to 0.18 T approximately 0.5 feet from the outermost surface of the magnet.

  18. Structural alloys for high field superconducting magnets

    SciTech Connect

    Morris, J.W. Jr.

    1985-08-01

    Research toward structural alloys for use in high field superconducting magnets is international in scope, and has three principal objectives: the selection or development of suitable structural alloys for the magnet support structure, the identification of mechanical phenomena and failure modes that may influence service behavior, and the design of suitable testing procedures to provide engineering design data. This paper reviews recent progress toward the first two of these objectives. The structural alloy needs depend on the magnet design and superconductor type and differ between magnets that use monolithic and those that employ force-cooled or ICCS conductors. In the former case the central requirement is for high strength, high toughness, weldable alloys that are used in thick sections for the magnet case. In the latter case the need is for high strength, high toughness alloys that are used in thin welded sections for the conductor conduit. There is productive current research on both alloy types. The service behavior of these alloys is influenced by mechanical phenomena that are peculiar to the magnet environment, including cryogenic fatigue, magnetic effects, and cryogenic creep. The design of appropriate mechanical tests is complicated by the need for testing at 4/sup 0/K and by rate effects associated with adiabatic heating during the tests. 46 refs.

  19. Development of superconducting magnet systems for HIFExperiments

    SciTech Connect

    Sabbi, Gian Luca; Faltens, A.; Leitzke, A.; Seidl, P.; Lund, S.; Martovets ky, N.; Chiesa, L.; Gung, C.; Minervini, J.; Schultz, J.; Goodzeit, C.; Hwang, P.; Hinson, W.; Meinke, R.

    2004-07-27

    The U.S. Heavy Ion Fusion program is developing superconducting focusing quadrupoles for near-term experiments and future driver accelerators. Following the fabrication and testing of several models, a baseline quadrupole design was selected and further optimized. The first prototype of the optimized design achieved a conductor-limited gradient of 132 T/m in a 70 mm bore, with measured field harmonics within 10 parts in 10{sup 4}. In parallel, a compact focusing doublet was fabricated and tested using two of the first-generation quadrupoles. After assembly in the cryostat, both magnets reached their conductor-limited quench current. Further optimization steps are currently underway to improve the performance of the magnet system and reduce its cost. They include the fabrication and testing of a new prototype quadrupole with reduced field errors as well as improvements of the cryostat design for the focusing doublet. The prototype units will be installed in the HCX beamline at LBNL, to perform accelerator physics experiments and gain operational experience. Successful results in the present phase will make superconducting magnets a viable option for the next generation of integrated beam experiments.

  20. The University of Virginia superconducting magnetic suspension and balance facility

    NASA Technical Reports Server (NTRS)

    Zapata, R. N.

    1973-01-01

    A prototype facility comprising a superconducting magnetic suspension and balance and a supersonic wind tunnel was developed with the objectives of (1) establishing the feasibility of applying the 3-component magnetic balance concept to dynamic stability studies, and (2) investigating design concepts and parameters that are critical for extrapolation to large-scale systems. Many important design and operational aspects as well as safety considerations are dictated by the cryogenic nature of this advanced-technology facility. Results of initial tests demonstrate that super-conductors can be utilized safely and efficiently for wind tunnel magnetic suspensions. At the present stage of development of this facility, controlled one-dimensional support of a spherical model was achieved.

  1. 50 Hz rotating superconducting magnet for screening studies

    SciTech Connect

    Scurlock, R.G.; Stoll, R.; Stovold, R.

    1981-09-01

    A superconducting rotor facility has been constructed to study the magnetic shielding of superconducting ac machines. The superconducting dipolar magnet 128 mm diam, 515 mm long, 40 kg weight, is capable of providing a field of 1.5 T at a radius of 100 mm with 525 amp energizing current. Novel features include helical vapor-cooled current leads, antirecirculation baffles in the vapor space, vapor dump valves and liquid nitrogen cooling.

  2. Ultralow Friction in a Superconducting Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Bornemann, Hans J.; Siegel, Michael; Zaitsev, Oleg; Bareiss, Martin; Laschuetza, Helmut

    1996-01-01

    Passive levitation by superconducting magnetic bearings can be utilized in flywheels for energy storage. Basic design criteria of such a bearing are high levitation force, sufficient vertical and horizontal stability and low friction. A test facility was built for the measurement and evaluation of friction in a superconducting magnetic bearing as a function of operating temperature and pressure in the vacuum vessel. The bearing consists of a commercial disk shaped magnet levitated above single grain, melt-textured YBCO high-temperature superconductor material. The superconductor was conduction cooled by an integrated AEG tactical cryocooler. The temperature could be varied from 50 K to 80 K. The pressure in the vacuum chamber was varied from 1 bar to 10(exp -5) mbar. At the lowest pressure setting, the drag torque shows a linear frequency dependence over the entire range investigated (0 less than f less than 40 Hz). Magnetic friction, the frequency independent contribution, is very low. The frequency dependent drag torque is generated by molecular friction from molecule-surface collisions and by eddy currents. Given the specific geometry of the set-up and gas pressure, the molecular drag torque can be estimated. At a speed of 40 Hz, the coefficient of friction (drag-to-lift ratio) was measured to be mu = 1.6 x 10(exp -7) at 10(exp -5) mbar and T = 60 K. This is equivalent to a drag torque of 7.6 x 10(exp -10) Nm. Magnetic friction causes approx. 1% of the total losses. Molecular friction accounts for about 13% of the frequency dependent drag torque, the remaining 87% being due to eddy currents and losses from rotor unbalance. The specific energy loss is only 0.3% per hour.

  3. Improved cable insulation for superconducting magnets

    SciTech Connect

    Anerella, M.; Ghosh, A.K.; Kelly, E.; Schmalzle, J.; Willen, E.; Fraivillig, J.; Ochsner, J.; Parish, D.J.

    1993-09-01

    Several years ago, Brookhaven joined with DuPont in a cooperative effort to develop improved cable insulation for SSC superconducting dipole magnets. The effort was supported by the SSC Central Design Group and later the SSC Laboratory. It was undertaken because turn-to-turn and midplane shorts were routinely being experienced during the assembly of magnets with coils made of the existing Kapton/Fiberglass (K/FG) system of Kapton film overwrapped with epoxy-impregnated fiberglass tape. Dissection of failed magnets showed that insulation disruption and punch-through was occurring near the inner edges of turns close to the magnet midplane. Coil pressures of greater than 17 kpsi were sufficient to disrupt the insulation at local high spots where wires in neighboring turns crossed one another and where the cable had been strongly compacted in the keystoning operation during cable manufacture. In the joint development program, numerous combinations of polyimide films manufactured by DuPont with varying configurations and properties (including thickness) were subjected to tests at Brookhaven. Early tests were bench trials using wrapped cable samples. The most promising candidates were used in coils and many of these assembled and tested as magnets in both the SSC and RHIC magnet programs currently underway. The Kapton CI (CI) system that has been adopted represents a suitable compromise of numerous competing factors. It exhibits improved performance in the critical parameter of compressive punch-through resistance as well as other advantages over the K/FG system.

  4. Superconducting magnetic energy storage for asynchronous electrical systems

    DOEpatents

    Boenig, H.J.

    1984-05-16

    It is an object of the present invention to provide superconducting magnetic energy storage for a plurality of asynchronous electrical systems. It is a further object of the present invention to provide load leveling and stability improvement in a plurality of independent ac systems using a single superconducting magnetic energy storage coil.

  5. Magnetic Energy Storage System: Superconducting Magnet Energy Storage System with Direct Power Electronics Interface

    SciTech Connect

    2010-10-01

    GRIDS Project: ABB is developing an advanced energy storage system using superconducting magnets that could store significantly more energy than today’s best magnetic storage technologies at a fraction of the cost. This system could provide enough storage capacity to encourage more widespread use of renewable power like wind and solar. Superconducting magnetic energy storage systems have been in development for almost 3 decades; however, past devices were designed to supply power only for short durations—generally less than a few minutes. ABB’s system would deliver the stored energy at very low cost, making it ideal for eventual use in the electricity grid as a costeffective competitor to batteries and other energy storage technologies. The device could potentially cost even less, on a per kilowatt basis, than traditional lead-acid batteries.

  6. Method for obtaining large levitation pressure in superconducting magnetic bearings

    DOEpatents

    Hull, J.R.

    1997-08-05

    A method and apparatus are disclosed for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap. 4 figs.

  7. Method for obtaining large levitation pressure in superconducting magnetic bearings

    DOEpatents

    Hull, John R.

    1997-01-01

    A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

  8. Method for obtaining large levitation pressure in superconducting magnetic bearings

    DOEpatents

    Hull, J.R.

    1996-10-08

    A method and apparatus are disclosed for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap. 4 figs.

  9. Method for obtaining large levitation pressure in superconducting magnetic bearings

    DOEpatents

    Hull, John R.

    1996-01-01

    A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

  10. Superconducting magnets for the RAON electron cyclotron resonance ion source.

    PubMed

    Choi, S; Kim, Y; Hong, I S; Jeon, D

    2014-02-01

    The RAON linear accelerator of Rare Isotope Science Project has been developed since 2011, and the superconducting magnet for ECRIS was designed. The RAON ECR ion source was considered as a 3rd generation source. The fully superconducting magnet has been designed for operating using 28 GHz radio frequency. The RAON ECRIS operates in a minimum B field configuration which means that a magnetic sextupole field for radial confinement is superimposed with a magnetic mirror field for axial confinement. The highest field strength reaches 3.5 T on axis and 2 T at the plasma chamber wall for operating frequency up to 28 GHz. In this paper, the design results are presented of optimized superconducting magnet consisting of four solenoids and sextupole. The prototype magnet for ECRIS was fabricated and tested to verify the feasibility of the design. On the basis of test results, a fully superconducting magnet will be fabricated and tested. PMID:24593485

  11. Estimating the cost of large superconducting thin solenoid magnets

    SciTech Connect

    Green, M.A.; St. Lorant, S.J.

    1993-07-01

    The cost of thin superconducting solenoid magnets can be estimated if one knows the magnet stored energy, the magnetic field volume product or the overall mass of the superconducting coil and its cryostat. This report shows cost data collected since 1979 for large superconducting solenoid magnets used in high energy physics. These magnets are characterized in most cases by the use of indirect two phase helium cooling and a superconductor stabilizer of very pure aluminum. This correlation can be used for making a preliminary cost estimate of proposed one of a kind superconducting magnets. The magnet costs quoted include the power supply and quench protection system but the cost of the helium refrigerator and helium distribution system is not included in the estimated cost.

  12. New Advance in SuperConducting Materials

    SciTech Connect

    2009-03-02

    Superconducting materials will transform the world's electrical infrastructure, saving billions of dollars once the technical details and installation are in place. At Los Alamos National Laborator...  

  13. Analysis of Voltage Signals from Superconducting Accelerator Magnets

    SciTech Connect

    Lizarazo, J.; Caspi, S.; Ferracin, P.; Joseph, J.; Lietzke, A. F.; Sabbi, G. L.; Wang, X.

    2009-10-30

    We present two techniques used in the analysis of voltage tap data collected during recent tests of superconducting magnets developed by the Superconducting Magnet Program at Lawrence Berkeley National Laboratory. The first technique was used on a quadrupole to provide information about quench origins that could not be obtained using the time-of-flight method. The second technique illustrates the use of data from transient flux imbalances occurring during magnet ramping to diagnose changes in the current-temperature margin of a superconducting cable. In both cases, the results of this analysis contributed to make improvements on subsequent magnets.

  14. Novel technologies and configurations of superconducting magnets for MRI

    NASA Astrophysics Data System (ADS)

    Lvovsky, Yuri; Stautner, Ernst Wolfgang; Zhang, Tao

    2013-09-01

    A review of non-traditional approaches and emerging trends in superconducting magnets for MRI is presented. Novel technologies and concepts have arisen in response to new clinical imaging needs, changes in market cost structure, and the realities of newly developing markets. Among key trends are an increasing emphasis on patient comfort and the need for ‘greener’ magnets with reduced helium usage. The paper starts with a brief overview of the well-optimized conventional MR magnet technology that presently firmly occupies the dominant position in the imaging market up to 9.4 T. Non-traditional magnet geometries, with an emphasis on openness, are reviewed. The prospects of MgB2 and high-temperature superconductors for MRI applications are discussed. In many cases the introduction of novel technologies into a cost-conscious commercial market will be stimulated by growing needs for advanced customized procedures, and specialty scanners such as orthopedic or head imagers can lead the way due to the intrinsic advantages in their design. A review of ultrahigh-field MR is presented, including the largest 11.7 T Iseult magnet. Advanced cryogenics approaches with an emphasis on low-volume helium systems, including hermetically sealed self-contained cryostats requiring no user intervention, as well as future non-traditional non-helium cryogenics, are presented.

  15. Toroidal constant-tension superconducting magnetic energy storage units

    DOEpatents

    Herring, J.S.

    1992-11-03

    A superconducting magnetic energy storage unit is provided in which the magnet is wound in a toroidal fashion such that the magnetic field produced is contained only within the bore of the magnet, and thus producing a very low external field. The superconducting magnet includes a coolant channel disposed through the wire. The bore of the magnet comprises a storage volume in which cryogenic coolant is stored, and this volume supplies the coolant to be delivered to the coolant channel in the magnet. 6 figs.

  16. Status of neutron diagnostics on the experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Zhong, G. Q.; Hu, L. Q.; Pu, N.; Zhou, R. J.; Xiao, M.; Cao, H. R.; Zhu, Y. B.; Li, K.; Fan, T. S.; Peng, X. Y.; Du, T. F.; Ge, L. J.; Huang, J.; Xu, G. S.; Wan, B. N.

    2016-11-01

    Neutron diagnostics have become a significant means to study energetic particles in high power auxiliary heating plasmas on the Experimental Advanced Superconducting Tokamak (EAST). Several kinds of neutron diagnostic systems have been implemented for time-resolved measurements of D-D neutron flux, fluctuation, emission profile, and spectrum. All detectors have been calibrated in laboratory, and in situ calibration using 252Cf neutron source in EAST is in preparation. A new technology of digitized pulse signal processing is adopted in a wide dynamic range neutron flux monitor, compact recoil proton spectrometer, and time of flight spectrometer. Improvements will be made continuously to the system to achieve better adaptation to the EAST's harsh γ-ray and electro-magnetic radiation environment.

  17. TOWARDS FAST-PULSED SUPERCONDUCTING SYNCHROTRON MAGNETS.

    SciTech Connect

    MORITZ,G.; MUEHLE,C.; ANERELLA,M.; GHOSH,A.; SAMPSON,W.; WANDERER,P.; WILLEN,E.; AGAPOV,N.; KHODZHIBAGIYAN,H.; KOVALENKO,A.; HASSENZAHL,W.V.; WILSON,M.N.

    2001-06-18

    The concept for the new GSI accelerator facilities is based on a large synchrotron designed for operation at BR=200 Tm and with the short cycle-time of about one second to achieve high average beam intensities. Superconducting magnets may reduce considerably investment and operating costs in comparison with conventional magnets. A R and D program was initiated to develop these magnets for a maximum field of 2-4 Tesla and a ramp rate of 4 T/s. In collaboration with JINR (Dubna), the window-frame type Nuclotron dipole, which has been operated with 4 T/s at a maximum field of 2 Tesla, shall be developed to reduce heat losses and to improve the magnetic field quality. Another collaboration with BNL (Brookhaven) was established to develop the one-layer-coil cos{theta}-type RHIC arc dipole designed for operation at 3.5 Tesla with a rather slow ramp-rate of 0.07 T/s towards the design ramp-rate of 4 T/s. The design concepts for both R and D programs are reported.

  18. JT-60SA superconducting magnet system

    NASA Astrophysics Data System (ADS)

    Koide, Y.; Yoshida, K.; Wanner, M.; Barabaschi, P.; Cucchiaro, A.; Davis, S.; Decool, P.; Di Pietro, E.; Disset, G.; Genini, L.; Hajnal, N.; Heller, R.; Honda, A.; Ikeda, Y.; Kamada, Y.; Kashiwa, Y.; Kizu, K.; Kamiya, K.; Murakami, H.; Michel, F.; Marechal, J. L.; Phillips, G.; Polli, G. M.; Rossi, P.; Shibanuma, K.; Takahata, K.; Tomarchio, V.; Tsuchiya, K.; Usui, K.; Verrecchia, M.; Zani, L.

    2015-08-01

    The most distinctive feature of the superconducting magnet system for JT-60SA is the optimized coil structure in terms of the space utilization as well as the highly accurate coil manufacturing, thus meeting the requirements for the steady-state tokamak research: a conceptually new outer inter-coil structure separated from the casing is introduced to the toroidal field coils to realize their slender shape, allowing large-bore diagnostic ports for detailed plasma measurements. A method to minimize the manufacturing error of the equilibrium-field coils has been established, aiming at the precise plasma shape/position control. A compact butt-joint has been successfully developed for the Central Solenoid, which allows an optimized utilization of the limited space for the Central Solenoid to extend the duration of the plasma pulse.

  19. A thin superconducting solenoid magnet for the WASA detector

    SciTech Connect

    Yamaoka, H.; Yamamoto, A.; Makida, Y.

    1996-07-01

    A thin superconducting solenoid magnet has been developed for the WASA detector. The magnet consists of a pair of coils and it provides a central magnetic field of 1.3T at 900A in a cylindrical volume of 0.65m in diameter and 0.555m in length. The features of this solenoid magnet are the excellent transparency for particles, conducting cooling, thermo siphon method, applying aluminum strip for conduction cooling and corrugated outer wall. Recently, the performance test was successfully carried out. In this report, magnet design and fabrication of the WASA superconducting solenoid magnet will be presented and the test results will be described.

  20. Superconductivity of QCD vacuum in strong magnetic field

    SciTech Connect

    Chernodub, M. N.

    2010-10-15

    We show that in a sufficiently strong magnetic field the QCD vacuum may undergo a transition to a new phase where charged {rho}{sup {+-}}mesons are condensed. In this phase the vacuum behaves as an anisotropic inhomogeneous superconductor which supports superconductivity along the axis of the magnetic field. In the directions transverse to the magnetic field the superconductivity is absent. The magnetic-field-induced anisotropic superconductivity - which is realized in the cold vacuum, i.e. at zero temperature and density - is a consequence of a nonminimal coupling of the {rho} mesons to the electromagnetic field. The onset of the superconductivity of the charged {rho}{sup {+-}}mesons should also induce an inhomogeneous superfluidity of the neutral {rho}{sup 0} mesons. We also argue that due to simple kinematical reasons a strong enough magnetic field makes the lifetime of the {rho} mesons longer by closing the main channels of the strong decays of the {rho} mesons into charged pions.

  1. New Advances in SuperConducting Materials

    ScienceCinema

    None

    2016-07-12

    Superconducting materials will transform the world's electrical infrastructure, saving billions of dollars once the technical details and installation are in place. At Los Alamos National Laboratory, new materials science concepts are bringing this essential technology closer to widespread industrial use.

  2. New Advance in SuperConducting Materials

    ScienceCinema

    None

    2016-07-12

    Superconducting materials will transform the world's electrical infrastructure, saving billions of dollars once the technical details and installation are in place. At Los Alamos National Laborator...  

  3. Thermal expansion of several materials for superconducting magnets. Final report

    SciTech Connect

    Clark, A.F.; Fujii, G.; Ranney, M.A.

    1981-09-01

    The thermal expansion of several materials used in the construction of high field superconducting magnets has been measured from 4 K to room temperature. The materials were a NbTi and two A15 multifilamentary conductors and several nonmetallic composites made from linen/phenolic, fiberglass/epoxy and superconducting wire/epoxy.

  4. Superconducting magnetic energy storage for asynchronous electrical systems

    DOEpatents

    Boenig, Heinrich J.

    1986-01-01

    A superconducting magnetic energy storage coil connected in parallel between converters of two or more ac power systems provides load leveling and stability improvement to any or all of the ac systems. Control is provided to direct the charging and independently the discharging of the superconducting coil to at least a selected one of the ac power systems.

  5. Superconducting magnet and cryostat for a space application

    NASA Technical Reports Server (NTRS)

    Pope, W. L.; Smoot, G. F.; Smith, L. H.; Taylor, C. E.

    1975-01-01

    The paper describes the design concepts, development, and testing of a superconducting coil and cryostat for an orbiting superconducting magnetic spectrometer. Several coils were subject to overall thermal performance and coil charging tests. The coils have low but persistent currents and have proven themselves to be rugged and reliable for mobile balloon flights. Satellite experiments will be conducted on a new, similar design.

  6. Method of constructing a superconducting magnet

    DOEpatents

    Satti, John A.

    1981-01-01

    A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.

  7. Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry

    NASA Astrophysics Data System (ADS)

    Bock, James

    2014-01-01

    We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB

  8. Properties of Ni/Nb magnetic/superconducting multilayers

    SciTech Connect

    Mattson, J.E.; Osgood III, R.M.; Potter, C.D.; Sowers, C.H.; Bader, S.D.

    1997-05-01

    We examine structural, magnetic, and superconducting properties of magnetic/superconducting Ni/Nb multilayers. The Ni(Nb) films are textured {l_brace}111{r_brace}({l_brace}110{r_brace}) and have smooth interfaces. The average moment of the Ni atoms in the structure drops by 80{percent} from that of bulk Ni for 19 {Angstrom} thick Ni layers in proximity to 140 {Angstrom} thick Nb layers, and goes to zero for smaller Ni thicknesses. The Nb layer is not superconducting for thicknesses {lt}100 {Angstrom} in the presence of a 19 {Angstrom} thick ferromagnetic Ni layer. The behavior of the superconducting critical temperature as a function of the superconducting layer thickness was fitted and an interfacial scattering parameter and scattering time for the paramagnetic Ni regime determined.

  9. Low temperature magnetic force microscopy on ferromagnetic and superconducting oxides

    NASA Astrophysics Data System (ADS)

    Sirohi, Anshu; Sheet, Goutam

    2016-05-01

    We report the observation of complex ferromagnetic domain structures on thin films of SrRuO3 and superconducting vortices in high temperature superconductors through low temperature magnetic force microscopy. Here we summarize the experimental details and results of magnetic imaging at low temperatures and high magnetic fields. We discuss these data in the light of existing theoretical concepts.

  10. Superconductivity in an Organic Insulator at Very High Magnetic Fields

    SciTech Connect

    Balicas, L.; Brooks, J. S.; Storr, K.; Uji, S.; Tokumoto, M.; Tanaka, H.; Kobayashi, H.; Kobayashi, A.; Barzykin, V.; Gor'kov, L. P.

    2001-08-06

    We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor {lambda}-(BETS){sub 2}FeCl{sub 4} . Below 4K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41T and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe{sup 3+} ions. We further argue that the Fe{sup 3+} moments are essential to stabilize the resulting singlet, two-dimensional superconducting state.

  11. Advances in superconducting quantum electronic microcircuit fabrication

    NASA Technical Reports Server (NTRS)

    Kirschman, R. K.; Notarys, H. A.; Mercereau, J. E.

    1975-01-01

    Standard microelectronic fabrication techniques have been utilized to produce batch quantities of superconducting quantum electronic devices and circuits. The overall goal is a fabrication technology yielding circuits that are rugged and stable and capable of being fabricated controllably and reproducibly in sizeable quantities. Our progress toward this goal is presented, with primary emphasis on the most recent work, which includes the use of electron-beam lithography and techniques of hybrid microelectronics. Several prototype microcircuits have been successfully fabricated. These microcircuits are formed in a thin-film parent material consisting of layers of superconducting and normal metals, and use proximity-effect structures as the active circuit elements.

  12. Superconducting and hybrid systems for magnetic field shielding

    NASA Astrophysics Data System (ADS)

    Gozzelino, L.; Gerbaldo, R.; Ghigo, G.; Laviano, F.; Truccato, M.; Agostino, A.

    2016-03-01

    In this paper we investigate and compare the shielding properties of superconducting and hybrid superconducting/ferromagnetic systems, consisting of cylindrical cups with an aspect ratio of height/radius close to unity. First, we reproduced, by finite-element calculations, the induction magnetic field values measured along the symmetry axis in a superconducting (MgB2) and in a hybrid configuration (MgB2/Fe) as a function of the applied magnetic field and of the position. The calculations are carried out using the vector potential formalism, taking into account simultaneously the non-linear properties of both the superconducting and the ferromagnetic material. On the basis of the good agreement between the experimental and the computed data we apply the same model to study the influence of the geometric parameters of the ferromagnetic cup as well as of the thickness of the lateral gap between the two cups on the shielding properties of the superconducting cup. The results show that in the considered non-ideal geometry, where the edge effect in the flux penetration cannot be disregarded, the superconducting shield is always the most efficient solution at low magnetic fields. However, a partial recovery of the shielding capability of the hybrid configuration occurs if a mismatch in the open edges of the two cups is considered. In contrast, at high magnetic fields the hybrid configurations are always the most effective. In particular, the highest shielding factor was found for solutions with the ferromagnetic cup protruding over the superconducting one.

  13. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-15

    An X-mode polarized V band (50 GHz–75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz–19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from −1 km/s to −3 km/s.

  14. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-01

    An X-mode polarized V band (50 GHz-75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz-19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from -1 km/s to -3 km/s.

  15. Radial and poloidal correlation reflectometry on Experimental Advanced Superconducting Tokamak.

    PubMed

    Qu, Hao; Zhang, Tao; Han, Xiang; Wen, Fei; Zhang, Shoubiao; Kong, Defeng; Wang, Yumin; Gao, Yu; Huang, Canbin; Cai, Jianqing; Gao, Xiang

    2015-08-01

    An X-mode polarized V band (50 GHz-75 GHz) radial and poloidal correlation reflectometry is designed and installed on Experimental Advanced Superconducting Tokamak (EAST). Two frequency synthesizers (12 GHz-19 GHz) are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together for launching through one single pyramidal antenna. Two poloidally separated antennae are installed to receive the reflected waves from plasma. This reflectometry system can be used for radial and poloidal correlation measurement of the electron density fluctuation. In ohmically heated plasma, the radial correlation length is about 1.5 cm measured by the system. The poloidal correlation analysis provides a means to estimate the fluctuation velocity perpendicular to the main magnetic field. In the present paper, the distance between two poloidal probing points is calculated with ray-tracing code and the propagation time is deduced from cross-phase spectrum. Fluctuation velocity perpendicular to the main magnetic field in the core of ohmically heated plasma is about from -1 km/s to -3 km/s.

  16. Imprinting superconducting vortex footsteps in a magnetic layer

    NASA Astrophysics Data System (ADS)

    Brisbois, Jérémy; Motta, Maycon; Avila, Jonathan I.; Shaw, Gorky; Devillers, Thibaut; Dempsey, Nora M.; Veerapandian, Savita K. P.; Colson, Pierre; Vanderheyden, Benoît; Vanderbemden, Philippe; Ortiz, Wilson A.; Nguyen, Ngoc Duy; Kramer, Roman B. G.; Silhanek, Alejandro V.

    2016-06-01

    Local polarization of a magnetic layer, a well-known method for storing information, has found its place in numerous applications such as the popular magnetic drawing board toy or the widespread credit cards and computer hard drives. Here we experimentally show that a similar principle can be applied for imprinting the trajectory of quantum units of flux (vortices), travelling in a superconducting film (Nb), into a soft magnetic layer of permalloy (Py). In full analogy with the magnetic drawing board, vortices act as tiny magnetic scribers leaving a wake of polarized magnetic media in the Py board. The mutual interaction between superconducting vortices and ferromagnetic domains has been investigated by the magneto-optical imaging technique. For thick Py layers, the stripe magnetic domain pattern guides both the smooth magnetic flux penetration as well as the abrupt vortex avalanches in the Nb film. It is however in thin Py layers without stripe domains where superconducting vortices leave the clearest imprints of locally polarized magnetic moment along their paths. In all cases, we observe that the flux is delayed at the border of the magnetic layer. Our findings open the quest for optimizing magnetic recording of superconducting vortex trajectories.

  17. Imprinting superconducting vortex footsteps in a magnetic layer

    PubMed Central

    Brisbois, Jérémy; Motta, Maycon; Avila, Jonathan I.; Shaw, Gorky; Devillers, Thibaut; Dempsey, Nora M.; Veerapandian, Savita K. P.; Colson, Pierre; Vanderheyden, Benoît; Vanderbemden, Philippe; Ortiz, Wilson A.; Nguyen, Ngoc Duy; Kramer, Roman B. G.; Silhanek, Alejandro V.

    2016-01-01

    Local polarization of a magnetic layer, a well-known method for storing information, has found its place in numerous applications such as the popular magnetic drawing board toy or the widespread credit cards and computer hard drives. Here we experimentally show that a similar principle can be applied for imprinting the trajectory of quantum units of flux (vortices), travelling in a superconducting film (Nb), into a soft magnetic layer of permalloy (Py). In full analogy with the magnetic drawing board, vortices act as tiny magnetic scribers leaving a wake of polarized magnetic media in the Py board. The mutual interaction between superconducting vortices and ferromagnetic domains has been investigated by the magneto-optical imaging technique. For thick Py layers, the stripe magnetic domain pattern guides both the smooth magnetic flux penetration as well as the abrupt vortex avalanches in the Nb film. It is however in thin Py layers without stripe domains where superconducting vortices leave the clearest imprints of locally polarized magnetic moment along their paths. In all cases, we observe that the flux is delayed at the border of the magnetic layer. Our findings open the quest for optimizing magnetic recording of superconducting vortex trajectories. PMID:27263660

  18. Imprinting superconducting vortex footsteps in a magnetic layer.

    PubMed

    Brisbois, Jérémy; Motta, Maycon; Avila, Jonathan I; Shaw, Gorky; Devillers, Thibaut; Dempsey, Nora M; Veerapandian, Savita K P; Colson, Pierre; Vanderheyden, Benoît; Vanderbemden, Philippe; Ortiz, Wilson A; Nguyen, Ngoc Duy; Kramer, Roman B G; Silhanek, Alejandro V

    2016-01-01

    Local polarization of a magnetic layer, a well-known method for storing information, has found its place in numerous applications such as the popular magnetic drawing board toy or the widespread credit cards and computer hard drives. Here we experimentally show that a similar principle can be applied for imprinting the trajectory of quantum units of flux (vortices), travelling in a superconducting film (Nb), into a soft magnetic layer of permalloy (Py). In full analogy with the magnetic drawing board, vortices act as tiny magnetic scribers leaving a wake of polarized magnetic media in the Py board. The mutual interaction between superconducting vortices and ferromagnetic domains has been investigated by the magneto-optical imaging technique. For thick Py layers, the stripe magnetic domain pattern guides both the smooth magnetic flux penetration as well as the abrupt vortex avalanches in the Nb film. It is however in thin Py layers without stripe domains where superconducting vortices leave the clearest imprints of locally polarized magnetic moment along their paths. In all cases, we observe that the flux is delayed at the border of the magnetic layer. Our findings open the quest for optimizing magnetic recording of superconducting vortex trajectories. PMID:27263660

  19. Superconducting magnet for a Ku-band maser.

    NASA Technical Reports Server (NTRS)

    Berwin, R.; Wiebe, E.; Dachel, P.

    1972-01-01

    A superconducting magnet to provide a uniform magnetic field of up to 8000 G in a 1.14-cm gap for the 15.3-GHz (Ku-band) traveling wave maser is described. The magnet operates in a persistent mode in the vacuum environment of a closed-cycle helium refrigerator (4.5 K). The features of a superconducting switch, which has both leads connected to 4.5 K heat stations and thereby does not receive heat generated by the magnet charging leads, are described.

  20. Superconductivity in Strong Magnetic Field (Greater Than Upper Critical Field)

    SciTech Connect

    Tessema, G.X.; Gamble, B.K.; Skove, M.J.; Lacerda, A.H.; Mielke, C.H.

    1998-08-22

    The National High Magnetic Field Laboratory, funded by the National Science Foundation and other US federal Agencies, has in recent years built a wide range of magnetic fields, DC 25 to 35 Tesla, short pulse 50 - 60 Tesla, and quasi-continuous 60 Tesla. Future plans are to push the frontiers to 45 Tesla DC and 70 to 100 Tesla pulse. This user facility, is open for national and international users, and creates an excellent tool for materials research (metals, semiconductors, superconductors, biological systems ..., etc). Here we present results of a systematic study of the upper critical field of a novel superconducting material which is considered a promising candidate for the search for superconductivity beyond H{sub c2} as proposed by several new theories. These theories predict that superconductors with low carrier density can reenter the superconducting phase beyond the conventional upper critical field H{sub c2}. This negates the conventional thinking that superconductivity and magnetic fields are antagonistic.

  1. Development and operating experience of a short-period superconducting undulator at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Ivanyushenkov, Y.; Harkay, K.; Abliz, M.; Boon, L.; Borland, M.; Capatina, D.; Collins, J.; Decker, G.; Dejus, R.; Dooling, J.; Doose, C.; Emery, L.; Fuerst, J.; Gagliano, J.; Hasse, Q.; Jaski, M.; Kasa, M.; Kim, S. H.; Kustom, R.; Lang, J. C.; Liu, J.; Moog, E.; Robinson, D.; Sajaev, V.; Schroeder, K.; Sereno, N.; Shiroyanagi, Y.; Skiadopoulos, D.; Smith, M.; Sun, X.; Trakhtenberg, E.; Vasserman, I.; Vella, A.; Xiao, A.; Xu, J.; Zholents, A.; Gluskin, E.; Lev, V.; Mezentsev, N.; Syrovatin, V.; Tsukanov, V.; Makarov, A.; Pfotenhauer, J.; Potratz, D.

    2015-04-01

    A decade-long effort at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) on development of superconducting undulators culminated in December 2012 with the installation of the first superconducting undulator "SCU0" into Sector 6 of the APS storage ring. The device was commissioned in January 2013 and has been in user operation since. This paper presents the magnetic and cryogenic design of the SCU0 together with the results of stand-alone cold tests. The initial commissioning and characterization of SCU0 as well as its operating experience in the APS storage ring are described.

  2. The effects of magnetization process on levitation characteristics of a superconducting bulk magnet

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Gong, Y. M.; Li, Y. H.; Liang, G.; Yang, X. S.; Cheng, C. H.; Zhao, Y.

    2015-09-01

    In this paper, a bulk YBCO superconductor was magnetized in a chosen magnetic field generated from a superconducting magnet (SM) after field cooling process. The effects of magnetization process with different magnetization intensities on levitation forces and relaxation characteristics were investigated. From the results, it can be confirmed that the superconducting bulk magnet (SBM) magnetized with proper magnetization intensity was beneficial to improve the levitation characteristics of the magnetic levitation system. Nevertheless, when the magnetization intensity exceeded 0.85T, the levitation forces and the relaxation characteristics of the SBM attained saturation.

  3. Whole-head SQUID system in a superconducting magnetic shield.

    PubMed

    Ohta, H; Matsui, T; Uchikawa, Y

    2004-01-01

    We have constructed a mobile whole-head SQUID system in a superconducting magnetic shield - a cylinder of high Tc superconductor BSCCO of 65 cm in diameter and 160 cm in length. We compared the noise spectra of several SQUID sensors of SNS Josephson junctions in the superconducting magnetic shield with those of the same SQUID sensors in a magnetically shielded room of Permalloy. The SQUID sensors in the superconducting magnetic shield are more than 100 times more sensitive than those in a magnetically shielded room of Permalloy below 1 Hz. We tested the whole-head SQUID system in the superconducting magnetic shield observing somatosensory signals evoked by stimulating the median nerve in the right wrist of patients by current pulses. We present data of 64 and 128 traces versus the common time axis for comparison. Most sensory responses of human brains phase out near 250 ms. However monotonic rhythms still remain even at longer latencies than 250 ms. The nodes of these rhythm are very narrow even at these longer latencies just indicating low noise characteristics of the SQUID system at low-frequencies. The current dipoles at the secondary somatosensory area SII are evoked at longer latencies than 250 ms contributing to a higher-level brain function. The SQUID system in a superconducting magnetic shield will also have advantages when it is used as a DC MEG to study very slow activities and function of the brain. PMID:16012595

  4. NASA superconducting magnetic mirror facility. [for thermonuclear research

    NASA Technical Reports Server (NTRS)

    Reinmann, J. J.; Swanson, M. C.; Nichols, C. R.; Bloy, S. J.; Nagy, L. A.; Brady, F. J.

    1973-01-01

    The design details and initial test results of a superconducting magnetic mirror facility that has been constructed at NASA Lewis Research Center for use in thermonuclear research are summarized. The magnet system consists of four solenoidal coils which are individually rated at 5.0 T. Each coll is composed of an inner, middle, and outer winding. The inner winding is wound of stabilized Nb3Sn superconducting ribbon, and the middle and outer windings are wound of stabilized Nb-Ti superconducting wire. When arranged in the mirror geometry, the four coils will produce 8.7 T at the mirrors and a 1.8 mirror ratio. The magnet has a 41-cm diameter clear bore which is open to atmosphere. Distance between the mirrors is 111 cm. Presently there are only three magnets in the facility; the fourth magnet is being rebuilt.

  5. Design study of the KIRAMS-430 superconducting cyclotron magnet

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Wook; Kang, Joonsun; Hong, Bong Hwan; Jung, In Su

    2016-07-01

    Design study of superconducting cyclotron magnet for the carbon therapy was performed at the Korea Institute of Radiological and Medical Science (KIRAMS). The name of this project is The Korea Heavy Ion Medical Accelerator (KHIMA) project and a fixed frequency cyclotron with four spiral sector magnet was one of the candidate for the accelerator type. Basic parameters of the cyclotron magnet and its characteristics were studied. The isochronous magnetic field which can guide the 12C6+ ions up to 430 MeV/u was designed and used for the single particle tracking simulation. The isochronous condition of magnetic field was achieved by optimization of sector gap and width along the radius. Operating range of superconducting coil current was calculated and changing of the magnetic field caused by mechanical deformations of yokes was considered. From the result of magnetic field design, structure of the magnet yoke was planned.

  6. The Superconducting Magnets of the ILC Beam Delivery System

    SciTech Connect

    Parker, B.; Anerella, M.; Escallier, J.; He, P.; Jain, A.; Marone, A.; Nosochkov, Y.; Seryi, Andrei; /SLAC

    2007-09-28

    The ILC Beam Delivery System (BDS) uses a variety of superconducting magnets to maximize luminosity and minimize background. Compact final focus quadrupoles with multifunction correction coils focus incoming beams to few nanometer spot sizes while focusing outgoing disrupted beams into a separate extraction beam line. Anti-solenoids mitigate effects from overlapping focusing and the detector solenoid field. Far from the interaction point (IP) strong octupoles help minimize IP backgrounds. A low-field but very large aperture dipole is integrated with the detector solenoid to reduce backgrounds from beamstrahlung pairs generated at the IP. Physics requirements and magnetic design solutions for the BDS superconducting magnets are reviewed in this paper.

  7. Superconducting accelerator magnets: A review of their design and training

    SciTech Connect

    Palmer, R.B. |

    1992-08-01

    This paper reviews the basic mechanical designs of most of the superconducting magnets developed for high energy hadron accelerators. The training performance of these magnets is compared with an instability factor defined by the square of the current density in the stabilizing copper divided by the surface-to-volume ratio of the strands. A good correlation is observed.

  8. First results from a superconductive detector for moving magnetic monopoles

    NASA Technical Reports Server (NTRS)

    Cabrera, B.

    1982-01-01

    A velocity- and mass-independent search for moving magnetic monopoles is being performed by continuously monitoring the current in a 20-sq cm area superconducting loop. A single candidate event, consistent with one Dirac unit of magnetic charge, has been detected during five runs totaling 151 days. These data set an upper limit of 6.1 x

  9. Magnetic suspension and balance system advanced study, phase 2

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1990-01-01

    The design improvements for the system encompass 14 or 18 external superconductive coils mounted on a 8 x 8 foot wind tunnel, a superconductive model core magnet on a holmium mandrel to fit an F-16 model, model wings of permanent magnet material Nd2Fe14B, and fiber glass epoxy structure. The Magnetic Suspension and Balance System (MSBS) advanced design is confirmed by the successful construction and test of a full size superconductive model core solenoid with holmium mandrel. The solenoid is 75 cm long and 12.6 cm in diameter and produces 6.1 tesla for a hold time of 47 minutes. An integrated coil system design of a new compact configuration without specific coils for roll or pitch shows promise of simplicity; magnet reductions of 30 percent compared to the most recent 1985 design are possible.

  10. Cryocooled superconducting magnets for high magnetic fields at the HFLSM and future collaboration with the TML

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Nishijima, G.; Awaji, S.; Koyama, K.; Takahashi, K.; Kobayashi, N.; Kiyoshi, T.

    2006-11-01

    A hybrid magnet needs a large amount of liquid helium for operation. In order to make an easy-to-operate hybrid magnet system, we constructed a cryocooled 28 T hybrid magnet, consisting of an outer cryocooled 10 T superconducting magnet and an inner traditional water-cooled 19 T resistive magnet. As a performance test, the cryocooled hybrid magnet generated 27.5 T in a 32 mm room temperature experimental bore. As long as Nb3Sn superconducting wires are employed, the expected maximum high field generation in the cryocooled superconducting magnet will be 17 T at 5 K. We adopted the high temperature superconducting insert coil, employing Ag-sheathed Bi2Sr2Ca2Cu3O10superconducting tape. In combination with the low temperature 16.5 T back-up coil with a 174 mm cold bore, the cryocooled high temperature superconducting magnet successfully generated the total central field of 18.1 T in a 52 mm room temperature bore. As a next step, we start the collaboration with the National Institute for Materials Science for the new developmental works of a 30 T high temperature superconducting magnet and a 50 T-class hybrid magnet.

  11. Superconductivity of the magnetized electron gas of a quantum cylinder

    SciTech Connect

    Eminov, P. A. Sezonov, Yu. I.

    2008-10-15

    A microscopic theory of superconductivity is developed for the magnetized electron gas on a cylindrical surface. The Gibbs free energy is calculated for the superconducting system. A gap equation is derived that determines the critical temperature as a function of the quantum-cylinder dimensions and the Aharonov-Bohm parameter. It is shown that the gap not only exhibits Aharonov-Bohm oscillations, but also oscillates with varying curvature of the cylindrical surface.

  12. Single Cell Magnetic Measurements with a Superconducting Quantum Interference Device

    NASA Astrophysics Data System (ADS)

    Palmstrom, Johanna C.; Arps, Jennifer; Dwyer, Bo; Kalisky, Beena; Kirtley, John R.; Moler, Kathryn A.; Qian, Lisa C.; Rosenberg, Aaron J.; Rutt, Brian; Tee, Sui Seng; Theis, Eric; Urbach, Elana; Wang, Yihua

    2014-03-01

    Magnetic nanoparticles play an important role in numerous biomedical applications such as magnetic resonance imaging and targeted drug delivery. There is a need for tools to characterize individual magnetic nanoparticles and the magnetic properties of individual cells. We use a scanning superconducting quantum interference device (SQUID) to observe the magnetic fields from single mammalian cells loaded with superparamagnetic iron oxide nanoparticles. We show that the SQUID is a useful tool for imaging biological magnetism and is capable of resolving cell to cell variations in magnetic dipole moments. We hope to correlate these magnetic images with real space imaging techniques such as optical and scanning electron microscopy. The visualization of single cell magnetism can be used to optimize biological magnetic imaging techniques, such as MRI, by quantifying the strength of magnetic dipole moments of in vitro magnetic labeling. This work is supported by a National Science Foundation Graduate Research Fellowship and a Gabilan Stanford Graduate Fellowship.

  13. Operational experience with superconducting synchrotron magnets

    SciTech Connect

    Martin, P.S.

    1987-03-01

    The operational experience with the Fermilab Tevatron is presented, with emphasis on reliability and failure modes. Comprisons are made between the operating efficiencies for the superconducting machine and for he conventional Main Ring.

  14. The Advanced Superconducting Test Accelerator at Fermilab: Science Program

    SciTech Connect

    Piot, Philippe; Harms, Elvin; Henderson, Stuart; Leibfritz, Jerry; Nagaitsev, Sergei; Shiltsev, Vladimir; Valishev, Alexander

    2014-07-01

    The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.

  15. Superconducting super collider second generation dipole magnet cryostat design

    SciTech Connect

    Niemann, R.C.; Bossert, R.C.; Carson, J.A.; Engler, N.H.; Gonczy, J.D.; Larson, E.T.; Nicol, T.H.; Ohmori, T.

    1989-03-01

    The Superconducting Super Collider, a planned colliding beam particle physics research facility, requires --10,000 superconducting devices for the control of high energy particle beams. The --7,500 collider ring superconducting dipole magnets require cryostats that are functional, cryogenically efficient, mass producible and cost effective. A second generation cryostat design has been developed utilizing the experiences gained during the construction, installation and operation of several full length first generation dipole magnet models. The nature of the cryostat improvements is presented. Considered are the connections between the magnet cold mass and its supports, cryogenic supports, cold mass axial anchor, thermal shields, insulation, vacuum vessel and interconnections. The details of the improvements are enumerated and the abstracted results of available component and system evaluations are presented.

  16. Superconducting super collider second generation dipole magnet cryostat design

    SciTech Connect

    Niemann, R.C.; Bossert, R.C.; Carson, J.A.; Engler, N.H.; Gonczy, J.D.; Larson, E.T.; Nicol, T.H.; Ohmori, T.

    1988-12-01

    The Superconducting Super Collider, a planned colliding beam particle physics research facility, requires /approximately/10,000 superconducting devices for the control of high energy particle beams. The /approximately/7,500 collider ring superconducting dipole magnets require cryostats that are functional, cryogenically efficient, mass producible and cost effective. A second generation cryostat design has been developed utilizing the experiences gained during the construction, installation and operation of several full length first generation dipole magnet models. The nature of the cryostat improvements is presented. Considered are the connections between the magnet cold mass and its supports, cryogenic supports, cold mass axial anchor, thermal shields, insulation, vacuum vessel and interconnections. The details of the improvements are enumerated and the abstracted results of available component and system evaluations are presented. 8 refs., 11 figs.

  17. Single-Flavor Color Superconductivity in a Magnetic Field

    SciTech Connect

    Feng Bo; Hou Defu; Wu Pingping; Ren Haicang

    2010-07-23

    We investigate the single-flavor color superconductivity in a magnetic field. Because of the absence of the electromagnetic Meissner effect, forming a nonspherical CSC phase, polar, A, or planar, does not cost energy of excluding magnetic flux. We found that these nonspherical phases may be reached via a sequence of first order phase transitions under the typical quark density and magnetic field inside a neutron star.

  18. Coexistence of Incommensurate Magnetism and Superconductivity in the Two-Dimensional Hubbard Model.

    PubMed

    Yamase, Hiroyuki; Eberlein, Andreas; Metzner, Walter

    2016-03-01

    We analyze the competition of magnetism and superconductivity in the two-dimensional Hubbard model with a moderate interaction strength, including the possibility of incommensurate spiral magnetic order. Using an unbiased renormalization group approach, we compute magnetic and superconducting order parameters in the ground state. In addition to previously established regions of Néel order coexisting with d-wave superconductivity, the calculations reveal further coexistence regions where superconductivity is accompanied by incommensurate magnetic order.

  19. Thermal expansion of several materials for superconducting magnets

    SciTech Connect

    Clark, A.F.; Fujii, G.; Ranney, M.A.

    1981-09-01

    The thermal expansion of several materials used in the consruction of high field superconducting magnets has been measured from 4 K to room temperature. The materials were a NbTi and two A15 multifilamentary conductors and several nonmetallic composites made from linen/phenolic, fiberglass/epoxy and superconducitng wire/epoxy. The conductor expansions are typical of metals and the composite expansions are highy anisotropic. Both graphic and tabular values are provided by a computer fitting of the experimental data. The importnce of thermal expansion differences in critical current measurement apparatus and superconducting magnet design are discussed. 12 refs.

  20. Axicell MFTF-B superconducting-magnet system

    SciTech Connect

    Wang, S.T.; Bulmer, R.; Hanson, C.; Hinkle, R.; Kozman, T.; Shimer, D.; Tatro, R.; VanSant, J.; Wohlwend, J.

    1982-05-05

    The Axicell MFTF-B magnet system will provide the field environment necessary for tandem mirror plasma physics investigation with thermal barriers. The performance of the device will stimulate DT to achieve energy break-even plasma conditions. Operation will be with deuterium only. There will be 24 superconducting coils consisting of 2 sets of yin-yang pairs, 14 central-cell solenoids, 2 sets of axicell mirror-coil pairs, and 2 transition coils between the axicell mirror coil-pairs and the yin-yang coils. This paper describes the progress in the design and construction of MFTF-B Superconducting-Magnet System.

  1. Hybrid Superconducting Magnetic Bearing (HSMB) for high load devices

    NASA Technical Reports Server (NTRS)

    Mcmichael, C. K.; Ma, K. B.; Lamb, M. A.; Lin, M. W.; Chow, L.; Meng, R. L.; Hor, P. H.; Chu, W. K.

    1992-01-01

    Lifting capacities greater than 41 N/cm(exp 2) (60 psi) at 77 K have been achieved with a new type of levitation (hybrid) using a combination of permanent magnets and high quality melt-mixtured YBa2Cu3O(7-delta) (YBCO). The key concept of the hybrid superconducting magnetic bearing (HSMB) is the use of strong magnetic repulsion and attraction from permanent magnets for high levitation or suspension forces in conjunction with a superconductor's flux pinning characteristics to counteract the inherent instabilities in a system consisting of magnets only. To illustrate this concept, radial and axial forces between magnet/superconductor, magnet/magnet, and magnet/superconductor/magnet, were measured and compared for the thrust bearing configuration

  2. Hybrid Superconducting Magnetic Bearing (HSMB) for high load devices

    NASA Astrophysics Data System (ADS)

    McMichael, C. K.; Ma, K. B.; Lamb, M. A.; Lin, M. W.; Chow, L.; Meng, R. L.; Hor, P. H.; Chu, W. K.

    1992-05-01

    Lifting capacities greater than 41 N/cm(exp 2) (60 psi) at 77 K have been achieved with a new type of levitation (hybrid) using a combination of permanent magnets and high quality melt-mixtured YBa2Cu3O(7-delta) (YBCO). The key concept of the hybrid superconducting magnetic bearing (HSMB) is the use of strong magnetic repulsion and attraction from permanent magnets for high levitation or suspension forces in conjunction with a superconductor's flux pinning characteristics to counteract the inherent instabilities in a system consisting of magnets only. To illustrate this concept, radial and axial forces between magnet/superconductor, magnet/magnet, and magnet/superconductor/magnet, were measured and compared for the thrust bearing configuration

  3. TowardsComputing Ratcheting and Training in Superconducting Magnets

    SciTech Connect

    Ferracin, Paolo; Caspi, Shlomo; Lietzke, A.F.

    2007-06-01

    The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has been developing 3D finite element models to predict the behavior of high field Nb{sub 3}Sn superconducting magnets. The models track the coil response during assembly, cool-down, and excitation, with particular interest on displacements when frictional forces arise. As Lorentz forces were cycled, irreversible displacements were computed and compared with strain gauge measurements. Additional analysis was done on the local frictional energy released during magnet excitation, and the resulting temperature rise. Magnet quenching and training was correlated to the level of energy release during such mechanical displacements under frictional forces. We report in this paper the computational results of the ratcheting process, the impact of friction, and the path-dependent energy release leading to a computed magnet training curve.

  4. Vibration-induced field fluctuations in a superconducting magnet

    NASA Astrophysics Data System (ADS)

    Britton, J. W.; Bohnet, J. G.; Sawyer, B. C.; Uys, H.; Biercuk, M. J.; Bollinger, J. J.

    2016-06-01

    Superconducting magnets enable precise control of nuclear and electron spins, and are used in experiments that explore biological and condensed-matter systems, and fundamental atomic particles. In high-precision applications, a common view is that slow (<1 Hz ) drift of the homogeneous magnetic-field limits control and measurement precision. We report on previously undocumented higher-frequency field noise (10-200 Hz) that limits the coherence time of Be+9 electron-spin qubits in the 4.46 -T field of a superconducting magnet. We measure a spin-echo T2 coherence time of ˜6 ms for the Be+9 electron-spin resonance at 124 GHz , limited by part-per-billion fractional fluctuations in the magnet's homogeneous field. Vibration isolation of the magnet improved T2 to ˜50 ms.

  5. Theoretical and experimental investigations of superconductivity. Amorphous semiconductors, superconductivity and magnetism

    NASA Technical Reports Server (NTRS)

    Cohen, M. H.

    1973-01-01

    The research activities from 1 March 1963 to 28 February 1973 are summarized. Major lectures are listed along with publications on superconductivity, superfluidity, electronic structures and Fermi surfaces of metals, optical spectra of solids, electronic structure of insulators and semiconductors, theory of magnetic metals, physics of surfaces, structures of metals, and molecular physics.

  6. Equilibrium of a magnet floating above a superconducting disk

    NASA Astrophysics Data System (ADS)

    Williams, Richard; Matey, J. R.

    1988-02-01

    A superconducting body will repel a nearby magnet. The repulsion is due to the perfect diamagnetism resulting from the Meissner effect. A small magnet will float above a superconducting disk at an equilibrium position over the disk center, stable against lateral displacements. It is not intuitively obvious why the potential energy of the magnet over a flat disk should have a minimum at the center, rather than a maximum. We have measured the properties of the attractive potential well of a YBa2Cu3O7 disk by two experiments. In the first, we use a low-frequency magnetic field, 0-100 Hz, to excite oscillations of a small, freely levitating bar magnet about its equilibrium position. We find sharp resonances, corresponding to longitudinal, transverse, and torsional modes of oscillation. The frequencies of these resonances define the properties near the bottom of the potential well. In the second experiment, we attach the magnet to a vertical glass fiber of known stiffness. The magnet is suspended horizontally a small known distance, z, above the superconducting disk. By moving the magnet from the center of the disk to the edge and measuring the bending of the support fiber as a function of position we determine the shape of the potential curve for large displacements and the total energy needed to escape from the well.

  7. Noncollinear order and gapless superconductivity in s -wave magnetic superconductors

    NASA Astrophysics Data System (ADS)

    Karmakar, Madhuparna; Majumdar, Pinaki

    2016-05-01

    We study the behavior of magnetic superconductors which involve a local attractive interaction between electrons, and a coupling between local moments and the electrons. We solve this Hubbard-Kondo model through a variational minimization at zero temperature and validate the results via a Monte Carlo based on static auxiliary field decomposition of the Hubbard interaction. Over a magnetic coupling window that widens with increasing attractive interaction, the ground state supports simultaneous magnetic and superconducting order. The pairing amplitude remains s -wave like, without significant spatial modulation, while the magnetic phase evolves from a ferromagnet, through noncollinear "spiral" states, to a Néel state with increasing density and magnetic coupling. We find that at intermediate magnetic coupling, the antiferromagnetic-superconducting state is gapless, except for the regime of Néel order. We map out the phase diagram in terms of density, magnetic coupling, and attractive interaction, establish the electron dispersion and effective "Fermi surface" in the ground state, provide an estimate of the magnetic and superconducting temperature scales via Monte Carlo, and compare our results to available data on the borocarbides.

  8. Magnetic forces in high-Tc superconducting bearings

    NASA Technical Reports Server (NTRS)

    Moon, F. C.

    1991-01-01

    In September 1987, researchers at Cornell levitated a small rotor on superconducting bearings at 10,000 rpm. In April 1989, a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu307. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time.

  9. Route to Topological Superconductivity via Magnetic Field Rotation

    PubMed Central

    Loder, Florian; Kampf, Arno P.; Kopp, Thilo

    2015-01-01

    The verification of topological superconductivity has become a major experimental challenge. Apart from the very few spin-triplet superconductors with p-wave pairing symmetry, another candidate system is a conventional, two-dimensional (2D) s-wave superconductor in a magnetic field with a sufficiently strong Rashba spin-orbit coupling. Typically, the required magnetic field to convert the superconductor into a topologically non-trivial state is however by far larger than the upper critical field Hc2, which excludes its realization. In this article, we argue that this problem can be overcome by rotating the magnetic field into the superconducting plane. We explore the character of the superconducting state upon changing the strength and the orientation of the magnetic field and show that a topological state, established for a sufficiently strong out-of-plane magnetic field, indeed extends to an in-plane field orientation. We present a three-band model applicable to the superconducting interface between LaAlO3 and SrTiO3, which should fulfil the necessary conditions to realize a topological superconductor. PMID:26477669

  10. Possible Frohlich superconductivity in strong magnetic fields.

    SciTech Connect

    Mielke, C. H.; Harrison, N.; Ardavan, A.; Goddard, P.; Singleton, J.; Narduzzo, A.; Montgomery, Lawrence; Balicas, L.; Brooks, J. S.; Tokumoto, M.

    2001-01-01

    A brief review of some of the arguments pointing towards the possibility of organic conductors of the form {alpha}-(BEDT-TTF)&J3g(SCN)4 (where M=K, T1 and Rb) being candidates for Frohlich superconductivity is given.

  11. Mechanical design and analysis of an eight-pole superconducting vector magnet for soft x-ray magnetic dichroism measurements

    SciTech Connect

    Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J.; Arenholz, E.

    2010-01-13

    An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet.

  12. Cryogen free superconducting splittable quadrupole magnet for linear accelerators

    SciTech Connect

    Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab

    2011-09-01

    A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.

  13. Proximity superconductivity in ballistic graphene at high magnetic fields

    NASA Astrophysics Data System (ADS)

    Prance, J. R.; Ben Shalom, M.; Zhu, M. J.; Fal'Ko, V. I.; Mishchenko, A.; Kretinin, A. V.; Novoselov, K. S.; Woods, C. R.; Watanabe, K.; Taniguchi, T.; Geim, A. K.

    We present measurements of the superconducting proximity effect in graphene-based Josephson junctions with a mean free path of several microns, which exceeds the junctions' length. The junctions exhibit low contact resistance and large supercurrents. We observe Fabry-Pérot oscillations in the normal-state resistance and the critical current of the junctions. The proximity effect is mostly suppressed in magnetic fields of <10 mT showing the conventional Fraunhofer interference pattern; however, unexpectedly, a weak proximity effect survives in magnetic fields as high as 1 T. Superconducting states randomly appear and disappear as a function of field and carrier concentration, and each exhibits a supercurrent carrying capacity close to the universal limit of e Δ/h where Δ is the superconducting gap of the contacts. We attribute the high-field supercurrent to mesoscopic Andreev states that persist near graphene edges. Our work reveals new proximity regimes that can be controlled by quantum confinement and cyclotron motion.

  14. Experimental investigation on ejecting low-temperature cooling superconducting magnets

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Zhang, Qiang; Tong, Ming-wei; Hu, Peng; Wu, Shuang-ying; Cai, Qin; Qin, Zeng-hu

    2013-10-01

    With the development of the high-temperature superconducting (HTS) materials and refrigeration technologies, using ejecting refrigeration to cool the superconducting materials becomes the direction of HTS applications. In this paper, an experimental study has been carried out on the basis of the theory of analyzing the ejecting low-temperature cooling superconducting magnet. The relationship between area ratios and refrigeration performance at different system pressures was derived. In addition, the working fluid flow and suction chamber pressure of the ejector with different area ratios at various inlet pressures have been examined to obtain the performance of ejectors under different working conditions. The result shows that the temperature of liquid nitrogen can be reduced to 70 K by controlling the inlet water pressure when the pressurized water at 20 °C is used to eject the saturated liquid nitrogen, which can provide the stable operational conditions for the HTS magnets cooling.

  15. Cryogenic techniques for large superconducting magnets in space

    NASA Technical Reports Server (NTRS)

    Green, M. A.

    1989-01-01

    A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the United States Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 meters in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 meters from the magnet will approach earth's field in low earth orbit. The issue of high Tc superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside of the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: operation with a third shield cooled to 90 K with a sterling cycle cryocooler, and a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points.

  16. Helium cooling systems for large superconducting physics detector magnets

    NASA Astrophysics Data System (ADS)

    Green, M. A.

    The large superconducting detector magnets used for high energy physics experiments are virtually all indirectly cooled. In general, these detector magnets are not cryogenically stabilized. Therefore, there are a number of choices for cooling large indirectly cooled detector magnets. These choices include; 1) forced two-phase helium cooling driven by the helium refrigerator J-T circuit, 2) forced two-phase helium cooling driven by a helium pump, and 3) a peculation gravity feed cooling system which uses liquid helium from a large storage dewar. The choices for the cooling of a large detector magnet are illustrated by applying these concepts to a 4.2 meter diameter 0.5 tesla thin superconducting solenoid for an experiment at the Relativistic Heavy Ion Collider (RHIC).

  17. Survey of high field superconducting material for accelerator magnets

    SciTech Connect

    Scahlan, R.; Greene, A.F.; Suenaga, M.

    1986-05-01

    The high field superconductors which could be used in accelerator dipole magnets are surveyed, ranking these candidates with respect to ease of fabrication and cost as well as superconducting properties. Emphasis is on Nb/sub 3/Sn and NbTi. 27 refs., 2 figs. (LEW)

  18. Superconducting Nb3Ge for high-field magnets

    NASA Technical Reports Server (NTRS)

    Braginski, A. I.; Daniel, M. R.; Roland, C. W.; Woollam, J. A.

    1978-01-01

    Superconducting Nb3Ge tape conductors 5 to 10 m long were fabricated by chemical vapor deposition. Such tapes could be used in high-field magnet applications. Average tape properties set the upper performance limit of a magnet at 17 teslas (4.2 K). Highest critical-current densities obtained in thin and layered films set the upper performance limit at 20 teslas (4.2 K).

  19. Superconducting magnets for 110-150 GHz gyrotrons

    NASA Astrophysics Data System (ADS)

    Baze, J.-M.; Lesmond, C.; Lottin, J.-C.; Capitain, J.-J.; Lafon, D.; Magne, R.; Bonnet, P.; Bourquard, A.; Bresson, D.; Lacaze, A.

    1994-07-01

    Seven superconducting focusing magnets have been constructed for vertical gyrotrons devoted to the plasma heating of the tokomak Tore Supra. The performances in magnetic field strength, profile and homogeneity are spread over a large range so as to suit gyrotrons of microwave frequencies extending from 110 GHz to 150 GHz. The cryostats have a low consumption in cryogenic fluids which insure a one week autonomy.

  20. SERPENTINE COIL TOPOLOGY FOR BNL DIRECT WIND SUPERCONDUCTING MAGNETS.

    SciTech Connect

    PARKER, B.; ESCALLIER, J.

    2005-05-16

    Serpentine winding, a recent innovation developed at BNL for direct winding superconducting magnets, allows winding a coil layer of arbitrary multipolarity in one continuous winding process and greatly simplifies magnet design and production compared to the planar patterns used before. Serpentine windings were used for the BEPC-II Upgrade and JPARC magnets and are proposed to make compact final focus magnets for the EC. Serpentine patterns exhibit a direct connection between 2D body harmonics and harmonics derived from the integral fields. Straightforward 2D optimization yields good integral field quality with uniformly spaced (natural) coil ends. This and other surprising features of Serpentine windings are addressed in this paper.

  1. PREFACE: International Conference on Superconductivity and Magnetism-ICSM2008

    NASA Astrophysics Data System (ADS)

    Gencer, Ali; Grasso, Gianni

    2009-03-01

    The International Conference on Superconductivity and Magnetism (ICSM2008) was held at the congress centre of Ankara University in Side, Antalya, between 25-29 August 2008. The conference was the first conference on the combined fields of superconductivity and magnetism organized in Turkey at international level, and it had broad international participation from 42 countries, with registered delegates numbering over 400. A quarter of the attendees were research students. The conference attracted many of the best known leading scientists and experts in the field of superconductivity and magnetism from all over the world. The scientific program involved the presentation and discussion of 336 papers, classified as 65 invited, 81 oral and 190 posters. Submission of papers for the proceedings was on a volunteer basis and we therefore had nearly half of the presented papers, i.e. 30 submitted invited papers, peer-reviewed by Superconductor Science and Technology, and 85 submitted contributing papers, peer-reviewed by the organizers through processes administered by the Editorial Board and Scientific Committee. Reviews were conducted by expert referees at professional level and with the scientific standards expected of a proceedings journal issue published by IOP Publishing. The invited papers on superconductivity and magnetism with superconductivity were considered and processed for Superconductor Science and Technology by IOP itself. Although there are missing papers from some of the plenary speakers, we believe that this special issue of Superconductor Science and Technology (SUST) and the corresponding issue of Journal of Physics: Conference Series (JPCS) reflect most of the booming research in the fields of superconductivity and magnetism. We are very pleased to have worked with IOP on the conference proceedings, with special thanks to Dr Tom Miller and Dr Graham Douglas. Based on a refereed evaluation of all the papers and posters submitted, about 93 papers were

  2. Rotor assembly including superconducting magnetic coil

    DOEpatents

    Snitchler, Gregory L.; Gamble, Bruce B.; Voccio, John P.

    2003-01-01

    Superconducting coils and methods of manufacture include a superconductor tape wound concentrically about and disposed along an axis of the coil to define an opening having a dimension which gradually decreases, in the direction along the axis, from a first end to a second end of the coil. Each turn of the superconductor tape has a broad surface maintained substantially parallel to the axis of the coil.

  3. Magnetic profiles in ferromagnetic/superconducting superlattices.

    SciTech Connect

    te Velthuis, S. G. E.; Hoffmann, A.; Santamaria, J.; Materials Science Division; Univ. Complutense de Madrid

    2007-02-28

    The interplay between ferromagnetism and superconductivity has been of longstanding fundamental research interest to scientists, as the competition between these generally mutually exclusive types of long-range order gives rise to a rich variety of physical phenomena. A method of studying these exciting effects is by investigating artificially layered systems, i.e. alternating deposition of superconducting and ferromagnetic thin films on a substrate, which enables a straight-forward combination of the two types of long-range order and allows the study of how they compete at the interface over nanometer length scales. While originally studies focused on low temperature superconductors interchanged with metallic ferromagnets, in recent years the scope has broadened to include superlattices of high T{sub c} superconductors and colossal magnetoresistance oxides. Creating films where both the superconducting as well as the ferromagnetic layers are complex oxide materials with similar crystal structures (Figure 1), allows the creation of epitaxial superlattices, with potentially atomically flat and ordered interfaces.

  4. A homogeneous superconducting magnet design using a hybrid optimization algorithm

    NASA Astrophysics Data System (ADS)

    Ni, Zhipeng; Wang, Qiuliang; Liu, Feng; Yan, Luguang

    2013-12-01

    This paper employs a hybrid optimization algorithm with a combination of linear programming (LP) and nonlinear programming (NLP) to design the highly homogeneous superconducting magnets for magnetic resonance imaging (MRI). The whole work is divided into two stages. The first LP stage provides a global optimal current map with several non-zero current clusters, and the mathematical model for the LP was updated by taking into account the maximum axial and radial magnetic field strength limitations. In the second NLP stage, the non-zero current clusters were discretized into practical solenoids. The superconducting conductor consumption was set as the objective function both in the LP and NLP stages to minimize the construction cost. In addition, the peak-peak homogeneity over the volume of imaging (VOI), the scope of 5 Gauss fringe field, and maximum magnetic field strength within superconducting coils were set as constraints. The detailed design process for a dedicated 3.0 T animal MRI scanner was presented. The homogeneous magnet produces a magnetic field quality of 6.0 ppm peak-peak homogeneity over a 16 cm by 18 cm elliptical VOI, and the 5 Gauss fringe field was limited within a 1.5 m by 2.0 m elliptical region.

  5. Development of a superconducting bulk magnet for NMR and MRI.

    PubMed

    Nakamura, Takashi; Tamada, Daiki; Yanagi, Yousuke; Itoh, Yoshitaka; Nemoto, Takahiro; Utumi, Hiroaki; Kose, Katsumi

    2015-10-01

    A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter room-temperature bore of the bulk magnet. A 6.9 ppm peak-to-peak homogeneous region suitable for MRI was achieved in the central cylindrical region (6.2 mm diameter, 9.1 mm length) of the bulk magnet by using a single layer shim coil. A 21 Hz spectral resolution that can be used for high resolution NMR spectroscopy was obtained in the central cylindrical region (1.3 mm diameter, 4 mm length) of the bulk magnet by using a multichannel shim coil. A clear 3D MR image dataset of a chemically fixed mouse fetus with (50 μm)(3) voxel resolution was obtained in 5.5 h. We therefore concluded that the cryogen-free superconducting bulk magnet developed in this study is useful for high-resolution desktop NMR, MRI and mobile NMR device. PMID:26295170

  6. Development of a superconducting bulk magnet for NMR and MRI

    NASA Astrophysics Data System (ADS)

    Nakamura, Takashi; Tamada, Daiki; Yanagi, Yousuke; Itoh, Yoshitaka; Nemoto, Takahiro; Utumi, Hiroaki; Kose, Katsumi

    2015-10-01

    A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter room-temperature bore of the bulk magnet. A 6.9 ppm peak-to-peak homogeneous region suitable for MRI was achieved in the central cylindrical region (6.2 mm diameter, 9.1 mm length) of the bulk magnet by using a single layer shim coil. A 21 Hz spectral resolution that can be used for high resolution NMR spectroscopy was obtained in the central cylindrical region (1.3 mm diameter, 4 mm length) of the bulk magnet by using a multichannel shim coil. A clear 3D MR image dataset of a chemically fixed mouse fetus with (50 μm)3 voxel resolution was obtained in 5.5 h. We therefore concluded that the cryogen-free superconducting bulk magnet developed in this study is useful for high-resolution desktop NMR, MRI and mobile NMR device.

  7. Superconducting Magnet Shielding of Astronauts from Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Fisher, Peter; Hoffman, Jeffrey; Zhou, Feng; Batishchev, Oleg

    2004-11-01

    Protecting astronauts traveling outside the Earth's protective magnetic field from cosmic and solar radiation [1] is one of the critical problems that must be solved in order to realize the nation's new human space exploration vision. Superconducting magnets, such as those under construction for the ATLAS experiment [2] at CERN, have achieved sufficient size to be able to surround a reasonable habitable volume, and their field strength is high enough to deflect a significant portion of the incoming radiation. We have undertaken a research effort aimed at developing an accurate numerical model of a crew compartment surrounded by a large magnetic field, with which we can calculate the effect on incoming charged particles. We will use this model to optimize the magnetic configuration to produce the maximum shielding effect while minimizing the mass of the superconducting magnet system. We are also investigating some of the practical problems that must be solved if large, superconducting magnet systems are to be incorporated into human space systems. We will present preliminary results of our modeling, showing the reduction of radiation exposure as a function of energy and atomic species. [1] Review of Particle Physics, Ed. Particle Data Group, Phys. Lett. B, 1-4 (592) 1-1109, 2004 [2] http://atlasexperiment.org/

  8. Construction of a 25-T cryogen-free superconducting magnet

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Awaji, S.; Oguro, H.; Tsuchiya, Y.; Hanai, S.; Miyazaki, H.; Tosaka, T.; Takahashi, M.; Ioka, S.

    2014-12-01

    The construction of a 25-T cryogen-free superconducting magnet (25T-CSM) has started in 2013 at the High Field Laboratory for Superconducting Materials, Institute for Materials Research, Tohoku University. The 25T-CSM consists of a low-T superconducting (LTS) coil and a high-Tc superconducting (HTS) coil. A high-strength CuNb/Nb3Sn Rutherford cable with the reinforcing stabilizer CuNb composite is adopted for the middle LTS section coil. The characteristic feature of the new technology using a CuNb/Nb3Sn Rutherford cable is a react-and-wind method for the coil-winding process. The LTS coil of 300-mm winding inner diameter is fabricated, and a central magnetic field of 14 T is generated at an operation current of 851 A. The HTS insert coil wound with GdBa2Cu3Oy (Gd123) tape has a 52-mm experimental room temperature bore, and a central magnetic field of 25.5 T will be generated at an operation current of 150 A in a background field of 14 T.

  9. Pool-cooled superconducting magnet design of large helical device

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Miyazawa, H.; Saito, R.; Iida, F.; Ogata, H.; Yamazaki, Y.; Motojima, Osamu; Yamamoto, Junya; Fujiwara, Masami; Takeo, M.

    1990-03-01

    The Large Helical Device is the next generation in helical equipment for nuclear fusion. The large scale superconducting magnets are going to be applied to these coils. The major and minor radius of the helical coil system are 4 and 0.96 m respectively and the magnetic field is 4 T at the plasma center and 8 T at the coil surface. The coil system stores about 2 GJ of total energy. The superconductor of the helical coil is pure aluminum stabilized Nb-Ti compacted strand cable with copper housing. The coils have a stainless-steel helium can that is filled with liquid helium. This pool-cooled superconducting helical coil system satisfies the fully stabilized condition. The superconducting poloidal coils are composed of six (three pairs) circular coils and use forced-cooled superconductors to reduce the eddy current losses by the field changing operation. The helical and poloidal coil system are built in the large bell-jar (vacuum vessel for thermal insulation) with outer diameter of 13 m. Conductor design and stability of superconducting magnets for helical and poloidal coil systems are described.

  10. Interaction of superconductivity and magnetism in borocarbide superconductors

    NASA Astrophysics Data System (ADS)

    Müller, K.-H.; Narozhnyi, V. N.

    2001-08-01

    The interaction of rare-earth magnetism and superconductivity has been a topic of interest for many years. In classical magnetic superconductors (Chevrel phases, ternary rhodium borides, etc) as well as in the high-Tc cuprates the superconducting state usually coexists with antiferromagnetic order on the rare-earth sublattice. In these compounds the magnetic ordering temperature TN is much below the superconducting transition temperature Tc. The discovery of superconducting borocarbides RT2B2C with R = Sc, Y, La, Th, Dy, Ho, Er, Tm or Lu and T = Ni, Ru, Pd or Pt (where not all of these combinations of R and T result in superconductivity) has reanimated the research on the coexistence of superconductivity and magnetic order. Most of these borocarbides crystallize in the tetragonal LuNi2B2C type structure which is an interstitial modification of the ThCr2Si2 type. Contrary to the behaviour of Cu in the cuprates Ni does not carry a magnetic moment in the borocarbides. Various types of antiferromagnetic structures on the rare-earth sublattice have been found to coexist with superconductivity in RNi2B2C for R = Tm, Er, Ho and Dy. Particularly of interest is the case of HoNi2B2C for which three different types of antiferromagnetic structures have been observed: (i) a commensurate one with Ho moments aligned ferromagnetically within layers perpendicular to the tetragonal c axis where consecutive layers are aligned in opposite directions, (ii) an incommensurate spiral along the c axis and (iii) an incommensurate a-axis-modulated structure with a modulation vector τ≈(0.55,0,0). This wave vector emerges in various RNi2B2C compounds with magnetic as well as nonmagnetic R elements and is connected with Fermi surface nesting. Both incommensurate magnetization structures have been shown to be related to the near-reentrant behaviour observed in HoNi2B2C whereas the commensurate structure coexists well with the superconducting state in this compound. The variation of TN and Tc

  11. Imprinted labyrinths and percolation in Nd-Co/Nb magnetic/superconducting hybrids

    NASA Astrophysics Data System (ADS)

    Ruiz-Valdepeñas, L.; Velez, M.; Valdés-Bango, F.; Alvarez-Prado, L. M.; Garcia-Alonso, F. J.; Martin, J. I.; Navarro, E.; Alameda, J. M.; Vicent, J. L.

    2014-06-01

    Magnetization reversal processes have been studied in hybrid magnetic/superconducting Nd-Co/Nb bilayers by the comparison of out-of-plane magnetic hysteresis loops and superconducting phase diagrams as a function of magnetic layer thickness and of disorder in the magnetic layer induced by a nanostructured copolymer template. A good correlation is found between the regimes corresponding to percolation effects in the superconductor and to the transition from extended to confined superconductivity with the characteristic fields for reverse domain nucleation and fast domain expansion in the magnetic layer, indicating that superconductivity nucleates on the disordered network imprinted on the superconducting layer by the labyrinth domain structure of the magnetic layer. As disorder increases in the magnetic layer, percolation effects disappear from the superconducting transitions in agreement with a more homogeneous magnetization reversal process.

  12. Magnetic signature of granular superconductivity in electrodeposited Pb nanowires

    SciTech Connect

    Riminucci, Alberto; Schwarzacher, Walther

    2014-06-14

    Nanocrystalline freestanding Pb nanowires ∼200 nm in diameter were fabricated by electrodeposition into track etched polycarbonate membranes in order to study their superconducting properties. Their superconducting critical temperature, as determined by measuring the Meissner effect, was the same as for bulk Pb, but their critical field was greatly enhanced up to ∼3000 Oe. By assuming the wires consisted of spherical superconducting grains, an estimated grain size r = 60 ± 25 nm was obtained from the magnetization measured as a function of the applied magnetic field at a fixed temperature. An independent estimate for r = 47 ± 12 nm, in good agreement with the previous one, was obtained from the magnetization measured as a function of temperature at a fixed applied magnetic field. Transmission electron microscopy was used to characterize grain size at the wire edges, where a grain size in agreement with the magnetic studies was observed.

  13. The superconducting magnet system for the Tokamak Physics Experiment

    SciTech Connect

    Lang, D.D.; Bulmer, R.J.; Chaplin, M.R.

    1994-06-18

    The superconducting magnet system for the Tokamak Physics experiment (TPX) will be the first all superconducting magnet system for a Tokamak, where the poloidal field coils, in addition to the toroidal field coils are superconducting. The magnet system is designed to operate in a steady state mode, and to initiate the plasma discharge ohmically. The toroidal field system provides a peak field of 4.0 Tesla on the plasma axis at a plasma major radius of 2.25 m. The peak field on the niobium 3-tin, cable-in-conduit (CIC) conductor is 8.4 Tesla for the 16 toroidal field coils. The toroidal field coils must absorb approximately 5 kW due to nuclear heating, eddy currents, and other sources. The poloidal field system provides a total of 18 volt seconds to initiate the plasma and drive a plasma current up to 2 MA. The poloidal field system consists of 14 individual coils which are arranged symmetrically above and below the horizontal mid plane. Four pairs of coils make up the central solenoid, and three paris of poloidal ring coils complete the system. The poloidal field coils all use a cable-in-conduit conductor, using either niobium 3-tin (NB{sub 3}Sn) or niobium titanium (NbTi) superconducting strands depending on the operating conditions for that coil. All of the coils are cooled by flowing supercritical helium, with inlet and outlet connections made on each double pancake. The superconducting magnet system has gone through a conceptual design review, and is in preliminary design started by the LLNL/MIT/PPPL collaboration. A number of changes have been made in the design since the conceptual design review, and are described in this paper.

  14. Vortices in magnetically coupled superconducting layered systems

    SciTech Connect

    Mints, Roman G.; Kogan, Vladimir G.; Clem, John R.

    2000-01-01

    Pancake vortices in stacks of thin superconducting films or layers are considered. It is stressed that in the absence of Josephson coupling topological restrictions upon possible configurations of vortices are removed and various examples of structures forbidden in bulk superconductors are given. In particular, it is shown that vortices may skip surface layers in samples of less than a certain size R{sub c} which might be macroscopic. The Josephson coupling suppresses R{sub c} estimates. (c) 2000 The American Physical Society.

  15. Magnetic forces in high-T(sub c) superconducting bearings

    NASA Technical Reports Server (NTRS)

    Moon, F. C.

    1990-01-01

    In September 1987 research at Cornell levitated a small rotor on superconducting bearing at 10,000 rpm. In April 1989 a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu3O7. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic drag forces of a magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the drag force reaches a constant value, independent of the speed. Dampling of lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time.

  16. On nematicity, magnetism and superconductivity in FeSe

    NASA Astrophysics Data System (ADS)

    Böhmer, Anna

    FeSe is unique among iron-based superconductors, notably regarding the interrelationships of structure, magnetism, and superconductivity. At ambient pressure, FeSe exhibits a tetragonal-to-orthorhombic (nematic) phase transition at Ts = 90 K, similar to other iron-based materials, but unlike them, no long-range magnetic order. One consequence is the unique possibility to study the in-plane resistivity anisotropy, arguably the most investigated 'nematic property', without interfering effects from the Fermi surface reconstruction induced by antiferromagnetic order. Recent findings pose the question whether nematicity in FeSe is driven by magnetic fluctuations, as often assumed in other iron-based systems. In particular, magnetic fluctuations, which are prominent at low temperatures, are not observed above Ts in FeSe by NMR, even though indicated by inelastic neutron scattering. The pressure-temperature phase diagram, recently obtained in new comprehensiveness using vapor-grown single crystals, shows that the structural transition is suppressed at 2 GPa and a new, likely magnetic phase is stabilized above 0.8 GPa, where Tc has a local maximum. Various theoretical scenarios have been proposed to explain this nematic transition far away from the magnetic order. Surprisingly, the degree of the orthorhombic distortion does not decrease below the superconducting transition at Tc = 8 K, suggesting that nematic and superconducting ``channels'' do not compete. Our new results on the superconducting state under pressure, show a non-monotonic pressure dependence of the upper critical field, which is well explained by the Fermi surface evolution. Further, we have successfully detwinned FeSe crystals and measured the in-plane resistivity anisotropy and elastoresistivity coefficients and compared them with model calculations of inelastic scattering from spin fluctuations. This work was supported by the Ames Laboratory, US DOE, under Contract No. DE-AC02-07CH11358.

  17. Progress on the superconducting magnets for the MICE cooling channel

    NASA Astrophysics Data System (ADS)

    Green, M. A.; Virostek, S. P.; Li, D.; Zisman, M. S.; Wang, L.; Pan, H.; Wu, H.; Guo, X. L.; Xu, F. Y.; Liu, X. K.; Zheng, S. X.; Bradshaw, T.; Baynham, D. E.; Cobb, J.; Lau, W.; Lau, P.; Yang, S. Q.

    2010-06-01

    The muon ionization cooling experiment (MICE) consists of a target, a beam line, a pion decay channel, the MICE cooling channel. Superconducting magnets are used in the pion decay channel and the MICE cooling channel. This report describes the MICE cooling channel magnets and the progress in the design and fabrication of these magnets. The MICE cooling channel consists of three types of superconducting solenoids; the spectrometer solenoids, the coupling solenoids and the focusing solenoids. The three types of magnets are being fabricated in the United States, China, and the UK respectively. The spectrometer magnets are used to analyze the muon beam before and after muon cooling. The coupling magnets couple the focusing sections and keep the muon beam contained within the iris of the RF cavities that are used to recover the muon momentum lost during ionization cooling. The focusing magnets focus the muon beam in the center of a liquid hydrogen absorber. The first of the cooling channel magnets will be operational in MICE in the spring of 2010.

  18. Progress on Superconducting Magnets for the MICE Cooling Channel

    SciTech Connect

    Green, Michael A; Virostek, Steve P.; Li, Derun; Zisman, Michael S.; Wang, Li; Pan, Heng; Wu, Hong; Guo, XingLong; Xu, FengYu; Liu, X. K.; Zheng, S. X.; Bradshaw, Thomas; Baynham, Elwyn; Cobb, John; Lau, Wing; Lau, Peter; Yang, Stephanie Q.

    2009-09-09

    The muon ionization cooling experiment (MICE) consists of a target, a beam line, a pion decay channel, the MICE cooling channel. Superconducting magnets are used in the pion decay channel and the MICE cooling channel. This report describes the MICE cooling channel magnets and the progress in the design and fabrication of these magnets. The MICE cooling channel consists of three types of superconducting solenoids; the spectrometer solenoids, the coupling solenoids and the focusing solenoids. The three types of magnets are being fabricated in he United States, China, and the United Kingdom respectively. The spectrometer magnets are used to analyze the muon beam before and after muon cooling. The coupling magnets couple the focusing sections and keep the muon beam contained within the iris of the RF cavities that re used to recover the muon momentum lost during ionization cooling. The focusing magnets focus the muon beam in the center of a liquid hydrogen absorber. The first of the cooling channel magnets will be operational in MICE in the spring of 2010.

  19. Superconducting Magnet Technology for the Upgrade

    SciTech Connect

    Todesco, E.; Ambrosio, G.; Ferracin, P.; Rifflet, J. M.; Sabbi, G. L.; Segreti, M.; Nakamoto, T.; van Weelderen, R.; Xu, Q.

    2015-10-01

    In this section we present the magnet technology for the High Luminosity LHC. After a short review of the project targets and constraints, we discuss the main guidelines used to determine the technology, the field/gradients, the operational margins, and the choice of the current density for each type of magnet. Then we discuss the peculiar aspects of each class of magnet, with special emphasis on the triplet.

  20. Phase structure of cold magnetized color superconducting quark matter

    NASA Astrophysics Data System (ADS)

    Allen, PG; Grunfeld, AG; Scoccola, NN

    2016-04-01

    The influence of intense magnetic fields on the behavior of color superconducting cold quark matter is investigated using an SU(2) f NJL-type model for which a novel regulation scheme is introduced. In such a scheme the contributions which are explicitly dependent on the magnetic field turn out to be finite and, thus, do not require to be regularized. As a result of this, non-physical oscillations that arise from regularizing magnetic field dependent terms are naturally removed, and oscillations that are actually physical can be better appreciated. The phase diagrams in the ẽB – μ plane are presented for different values of the diquark coupling.

  1. Scientific Affairs Division of NATO Advanced Study Institute: abstracts for nonequilibrium superconductivity, phonons and Kapitza boundaries

    SciTech Connect

    1980-05-01

    Abstracts of papers presented at the meeting are given. Topics covered include: Kapitza resistance; superconducting tunneling; energy gap enhancement in superconductors; instabilities in nonequilibrium superconducting states; exchange of charge between superconducting pairs and quasiparticles; motion of magnetic flux (flux flow); and other new phenomena. (GHT)

  2. Recent progress towards developing a high field, high-T(sub c) superconducting magnet for magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Derochemont, L. Pierre; Oakes, Carlton E.; Squillante, Michael R.; Duan, Hong-Min; Hermann, Allen M.; Andrews, Robert J.; Poeppel, Roger B.; Maroni, Victor A.; Carlberg, Ingrid A.; Kelliher, Warren C.

    1992-01-01

    This paper reviews superconducting magnets and high T(sub c) superconducting oxide ceramic materials technology to identify areas of fundamental impasse to the fabrication of components and devices that tap what are believed to be the true potential of these new materials. High T(sub c) ceramics pose problems in fundamentally different areas which need to be solved unlike low T(sub c) materials. The authors map out an experimental plan designed to research process technologies which, if suitably implemented, should allow these deficiencies to be solved. Finally, assessments are made of where and on what regimes magnetic system designers should focus their attention to advance the practical development of systems based on these new materials.

  3. Mechanical alignment of particles for use in fabricating superconducting and permanent magnetic materials

    DOEpatents

    Nellis, William J.; Maple, M. Brian

    1992-01-01

    A method for mechanically aligning oriented superconducting or permanently magnetic materials for further processing into constructs. This pretreatment optimizes the final crystallographic orientation and, thus, properties in these constructs. Such materials as superconducting fibers, needles and platelets are utilized.

  4. Modular transportable superconducting magnetic energy systems

    NASA Technical Reports Server (NTRS)

    Lieurance, Dennis; Kimball, Foster; Rix, Craig

    1995-01-01

    Design and cost studies were performed for the magnet components of mid-size (1-5 MWh), cold supported SMES systems using alternative configurations. The configurations studied included solenoid magnets, which required onsite assembly of the magnet system, and toroid and racetrack configurations which consisted of factory assembled modules. For each configuration, design concepts and cost information were developed for the major features of the magnet system including the conductor, electrical insulation, and structure. These studies showed that for mid-size systems, the costs of solenoid and toroid magnet configurations are comparable and that the specific configuration to be used for a given application should be based upon customer requirements such as limiting stray fields or minimizing risks in development or construction.

  5. Modular transportable superconducting magnetic Energy Systems

    SciTech Connect

    Lieurance, D.; Kimball, F.; Rix, C.

    1994-12-31

    Design and cost studies were performed for the magnet components of mid-size (1-5 MWh), cold supported SMES systems using alternative configurations. The configurations studied included solenoid magnets, which required onsite assembly of the magnet system, and toroid and racetrack configurations which consisted of factory assembled modules. For each configuration, design concepts and cost information were developed for the major features of the magnet system including the conductor, electrical insulation, and structure. These studies showed that for mid-size systems, the costs of solenoid and toroid magnet configurations are comparable and that the specific configuration to be used for a given application should be based upon customer requirements such as limiting stray fields or minimizing risks in development or construction.

  6. Magnetic preferential orientation of metal oxide superconducting materials

    DOEpatents

    Capone, D.W.; Dunlap, B.D.; Veal, B.W.

    1990-07-17

    A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) exhibits superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state. 4 figs.

  7. Magnetic preferential orientation of metal oxide superconducting materials

    DOEpatents

    Capone, Donald W.; Dunlap, Bobby D.; Veal, Boyd W.

    1990-01-01

    A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state.

  8. Magnetic field effects on superconductivity in alkali metal intercalates of MoS2

    NASA Technical Reports Server (NTRS)

    Woollam, J. A.; Flood, D. J.; Wagoner, D. E.; Somoano, R. B.; Rembaum, A.

    1972-01-01

    The effects of a magnetic field on the superconducting transition in MoS2 intercalated with potassium and sodium were studied. It was found that the potassium intercalated MoS2 has better properties in a magnetic field. In zero magnetic field the transition to superconductivity begins near 6.4 K. Diagrams of the basic circuitry for superconducting transition studies, and charts showing critical magnetic field versus critical temperature for the intercalated MoS2 are included.

  9. Application of superconducting coils to the NASA prototype magnetic balance

    NASA Technical Reports Server (NTRS)

    Haldeman, C. W.; Kraemer, R. A.; Phey, S. W.; Alishahi, M. M.; Covert, E. E.

    1981-01-01

    Application of superconducting coils to a general purpose magnetic balance was studied. The most suitable currently available superconducting cable for coils appears to be a bundle of many fine wires which are transposed and are mechanically confined. Sample coils were tested at central fields up to .5 Tesla, slewing rates up to 53 Tesla/ sec and frequencies up to 30 Hz. The ac losses were measured from helium boil-off and were approximately 20% higher than those calculated. Losses were dominated by hysteresis and a model for loss calculation which appears suitable for design purposes is presented along with computer listings. Combinations of two coils were also tested and interaction losses are reported. Two feasible geometries are also presented for prototype magnetic balance using superconductors.

  10. Superconducting magnetic energy storage apparatus structural support system

    DOEpatents

    Withers, Gregory J.; Meier, Stephen W.; Walter, Robert J.; Child, Michael D.; DeGraaf, Douglas W.

    1992-01-01

    A superconducting magnetic energy storage apparatus comprising a cylindrical superconducting coil; a cylindrical coil containment vessel enclosing the coil and adapted to hold a liquid, such as liquefied helium; and a cylindrical vacuum vessel enclosing the coil containment vessel and located in a restraining structure having inner and outer circumferential walls and a floor; the apparatus being provided with horizontal compression members between (1) the coil and the coil containment vessel and (2) between the coil containment vessel and the vacuum vessel, compression bearing members between the vacuum vessel and the restraining structure inner and outer walls, vertical support members (1) between the coil bottom and the coil containment vessel bottom and (2) between the coil containment vessel bottom and the vacuum vessel bottom, and external supports between the vacuum vessel bottom and the restraining structure floor, whereby the loads developed by thermal and magnetic energy changes in the apparatus can be accommodated and the structural integrity of the apparatus be maintained.

  11. Zinc contamination from brass upon heat treating a superconducting magnet

    SciTech Connect

    Stevens, D.W.; Hassenzahl, W.V.

    1994-07-01

    Theoretical calculations predicted that zinc outgassing from brass spacers during a planned heat treatment would likely damage a lab-scale superconducting magnet. This specter was reinforced by a simulated heat treatment, the samples of which were analyzed by gravimetry, metallography, and microprobe chemical analysis. It was found that zinc escaping from the brass could diffuse 80 {mu}m into copper electrical conductors and degrade their conductivity. To avoid this, steel was temporarily substituted for the brass during the heat treatment process.

  12. Halo current diagnostic system of experimental advanced superconducting tokamak

    SciTech Connect

    Chen, D. L.; Shen, B.; Sun, Y.; Qian, J. P. Wang, Y.; Xiao, B. J.; Granetz, R. S.

    2015-10-15

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well.

  13. Halo current diagnostic system of experimental advanced superconducting tokamak.

    PubMed

    Chen, D L; Shen, B; Granetz, R S; Sun, Y; Qian, J P; Wang, Y; Xiao, B J

    2015-10-01

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well.

  14. Tests of prototype SSC (Superconducting Super Collider) magnets

    SciTech Connect

    Strait, J.; Brown, B.C.; Hanft, R.; Koepke, K.; Kuchnir, M.; Lundy, R.; Mantsch, P.; Mazur, P.O.; McInturff, A.; Orr, J.R.

    1987-09-21

    Results are presented from tests of the third full scale development dipole magnet for the Superconducting Super Collider and from a retest of a 4.5 m model magnet of the same design mounted in an SSC cryostat. The 4.5 m magnet shows consistent quench performance between its original tests in boiling liquid helium in a vertical dewar and the current tests in forced flow helium in a horizontal cryostat. Little or no retraining is observed over several thermal cycles. The full length magnet requires 12 quenches to train to its short sample limit of 6800 A and displays a reasonably stable quench plateau following training. This represents a great improvement over the performance of the first two full length magnets. Data are presented on quench behavior as a function of current and temperature and on azimuthal and longitudinal loading of the coil by the support structure. 14 refs., 7 figs.

  15. Maximum field capability of Energy-Saver superconducting magnets

    SciTech Connect

    Turkot, F.; Cooper, W.E.; Hanft, R.; McInturff, A.

    1983-03-01

    At an energy of 1 TeV, the superconducting cable in the Energy Saver dipole magnets will be operating at approx. 96% of its nominal short sample limit; the corresponding number in the quadrupole magnets is 81%. All magnets for the Saver are individually tested for maximum current capability under two modes of operation; some 900 dipoles and 275 quadrupoles have now been measured. The dipole winding is composed of four individually wound coils. In general, the cable in the four coils comes from four different reels of cable. As part of magnet fabrication quality control, a short piece of cable from both ends of each reel has its critical current (rho = 1 x 10/sup -12/'..cap omega..-cm) measured at 5T and 4.3/sup 0/K. We present the statistical results of the maximum field tests on Saver magnets and explore the correlation with cable critical current.

  16. Particle astronomy with a superconducting magnet.

    NASA Technical Reports Server (NTRS)

    Buffington, A.

    1972-01-01

    The magnetic spectrometer measures deflections of charged particles moving in a magnetic field and provides a direct means of determining the rigidity of charged primary cosmic rays up to about 100 GV/c rigidity. The underlying concepts of the method are reviewed, and factors delineating the applicable momentum range and accuracy are described along with calibration techniques. Previous experiments employing this technique are summarized, and prospects for future applications are evaluated with emphasis on separate measurement of electron and positron spectra and on isotopic separation.

  17. Test equipment for a flywheel energy storage system using a magnetic bearing composed of superconducting coils and superconducting bulks

    NASA Astrophysics Data System (ADS)

    Ogata, M.; Matsue, H.; Yamashita, T.; Hasegawa, H.; Nagashima, K.; Maeda, T.; Matsuoka, T.; Mukoyama, S.; Shimizu, H.; Horiuchi, S.

    2016-05-01

    Energy storage systems are necessary for renewable energy sources such as solar power in order to stabilize their output power, which fluctuates widely depending on the weather. Since ‘flywheel energy storage systems’ (FWSSs) do not use chemical reactions, they do not deteriorate due to charge or discharge. This is an advantage of FWSSs in applications for renewable energy plants. A conventional FWSS has capacity limitation because of the mechanical bearings used to support the flywheel. Therefore, we have designed a superconducting magnetic bearing composed of a superconducting coil stator and a superconducting bulk rotor in order to solve this problem, and have experimentally manufactured a large scale FWSS with a capacity of 100 kWh and an output power of 300 kW. The superconducting magnetic bearing can levitate 4 tons and enables the flywheel to rotate smoothly. A performance confirmation test will be started soon. An overview of the superconducting FWSS is presented in this paper.

  18. Nuclear Magnetic Resonance Study of High Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Mounce, Andrew M.

    The high temperature superconductors HgBa2CuO 4+delta (Hg1201) and Bi2SrCa2Cu2O 8+delta (Bi2212) have been treated with 17O for both nuclear magnetic resonance (NMR) sensitivity and various electronic properties. Subsequently, NMR experiments were performed on Hg1201 and Bi2212 to reveal the nature of the pseudogap, in the normal state, and vortex phases, in the superconducting state. NMR has been performed on 17O in an underdoped Hg1201 crystal with a superconducting transition transition temperature of 74 K to look for circulating orbital currents proposed theoretically and inferred from neutron scattering. The measurements reveal narrow spectra which preclude static local fields in the pseudogap phase at the apical site, suggesting that the moments observed with neutrons are fluctuating or the orbital current ordering is not the correct model for the neutron scattering observation. The fine detail of the NMR frequency shifts at the apical oxygen site are consistent with a dipolar field from the Cu+2 site and diamagnetism below the superconducting transition. It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for high temperature superconductors. Here it is shown that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at sufficiently high magnetic field if there is charge trapped on the vortex core for highly anisotropic superconductors. NMR measurements of the magnetic fields generated by vortices in Bi2212 single crystals provide evidence for an electro-statically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of 2x10-3e, depending on doping, in line with theoretical estimates. Competition with magnetism is at the heart of high temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism spatially resolved NMR has been used, finding a strongly non

  19. Non-magnetic and magnetic impurity effects on superconductivity in the ternary iron-silicide Lu2FeSi

    NASA Astrophysics Data System (ADS)

    Watanabe, Tadataka; Okuyama, Hiroaki; Takase, Kouichi; Takano, Yoshiki

    2010-12-01

    We studied effect of non-magnetic and magnetic impurities on superconductivity in LuFeSi by investigating superconducting properties of (LuFeSi (R=Sc,Y, and Dy). The rapid depression of Tc by non-magnetic impurities reveals strong pair breaking by disorder, providing compelling evidence for the sign reversal of the superconducting order parameter in LuFeSi.

  20. REAL-WORLD SORTING OF RHIC SUPERCONDUCTING MAGNETS.

    SciTech Connect

    WEI,J.; GUPTA,R.; HARRISON,M.; JAIN,A.; PEGGS,S.; THOMPSON,P.; TRBOJEVIC,D.; WANDERER,P.

    1999-03-29

    During the seven-year construction of the Relativistic Heavy Ion Collider (RHIC), more than 1700 superconducting dipoles, quadrupoles, sextupoles, and multi-layer correctors have been constructed and installed. These magnets have been sorted at several production stages to optimize their performance and reliability. For arc magnets, priorities have been put first on quench performance and operational risk minimization, second on field transfer function and other first-order quantities, and finally on nonlinear field errors which were painstakingly optimized at design. For Interaction-Region (IR) magnets, sorting is applied to select the best possible combination of magnets for the low-{beta}* interaction points (IP). This paper summarizes the history of this real-world sorting process.

  1. Tunnel-diode resonator and nuclear magnetic resonance studies of low-dimensional magnetic and superconducting systems

    SciTech Connect

    Yeninas, Steven Lee

    2013-01-01

    This thesis emphasizes two frequency-domain techniques which uniquely employ radio frequency (RF) excitations to investigate the static and dynamic properties of novel magnetic and superconducting materials.

  2. Superconducting and magnetic properties of Sn-doped Ru-1222

    NASA Astrophysics Data System (ADS)

    Balchev, N.; Nenkov, K.; Mihova, G.; Kunev, B.; Pirov, J.

    2007-12-01

    Samples with nominal compositions Ru1-xSnxSr2Gd1.4Ce0.6Cu2Oy (0 ⩽ x ⩽ 0.2) were synthesized and their superconducting and magnetic properties were investigated. A non-monotonic behaviour of the lattice parameters and Tc with the increase of the dopant content was observed. It was established that small doping levels (0superconducting, i.e. the Sn-doping more rapidly destroys the superconductivity in Ru-1222 than in the conventional superconductors. The initial increase of Tc was associated with an increase of the hole concentration. The decrease of Tc and suppression of SC at higher doping levels may be explained by an enhanced disorder in the system, due to a possible presence of Sn in both Ru and Cu sites. The latter fact could also explain that the onset of the magnetic transition Tmag weakly depends on the dopant content.

  3. Bulk Magnetization in the Superconducting State of UPt3

    NASA Astrophysics Data System (ADS)

    Gannon, William; Halperin, William; Rastovski, Catherine; Eskildsen, Morten; Dai, Pengcheng; Stunault, Anne

    2013-03-01

    The unconventional superconductor UPt3 has long been thought to have an odd parity orbital, and triplet spin state. An important signature of such a state is the temperature independence of the spin susceptibility across the superconducting transition temperature. Here, we report bulk measurements of the susceptibility of UPt3 for magnetic fields along the crystal a-axis performed with polarized neutron diffraction. Temperature independence at all magnetic fields is observed, suggesting a spin triplet superconducting state for the entirety of the phase diagram, with equal spin pairs in the crystal basal plane. These results will be discussed in the context of existing theories for the superconducting state of this paradigm heavy fermion material [Graf et. al., PRB 62, 14393; Tsutsumi et. al., JPSJ 81, 074717 (2012)]. Support from US Department of Energy, Basic Energy Science, Division of Materials Science and Engineering awards DE-FG02-05ER46248, DE-FG02-10ER46783, and DE-FG02-05ER46202

  4. Transformer current sensor for superconducting magnetic coils

    DOEpatents

    Shen, S.S.; Wilson, C.T.

    1985-04-16

    The present invention is a current transformer for operating currents larger than 2kA (two kiloamps) that is capable of detecting a millivolt level resistive voltage in the presence of a large inductive voltage. Specifically, the present invention includes substantially cylindrical primary turns arranged to carry a primary current and substantially cylindrical secondary turns arranged coaxially with and only partially within the primary turns, the secondary turns including an active winding and a dummy winding, the active and dummy windings being coaxial, longitudinally separated and arranged to mutually cancel voltages excited by commonly experienced magnetic fields, the active winding but not the dummy winding being arranged within the primary turns.

  5. Design optimization of superconducting magnetic energy storage coil

    NASA Astrophysics Data System (ADS)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-05-01

    An optimization formulation has been developed for a superconducting magnetic energy storage (SMES) solenoid-type coil with niobium titanium (Nb-Ti) based Rutherford-type cable that minimizes the cryogenic refrigeration load into the cryostat. Minimization of refrigeration load reduces the operating cost and opens up the possibility to adopt helium re-condensing system using cryo-cooler especially for small-scale SMES system. Dynamic refrigeration load during charging or discharging operational mode of the coil dominates over steady state load. The paper outlines design optimization with practical design constraints like actual critical characteristics of the superconducting cable, maximum allowable hoop stress on winding, etc., with the objective to minimize refrigeration load into the SMES cryostat. Effect of design parameters on refrigeration load is also investigated.

  6. Pareto optimal design of sectored toroidal superconducting magnet for SMES

    NASA Astrophysics Data System (ADS)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-10-01

    A novel multi-objective optimization design approach for sectored toroidal superconducting magnetic energy storage coil has been developed considering the practical engineering constraints. The objectives include the minimization of necessary superconductor length and torus overall size or volume, which determines a significant part of cost towards realization of SMES. The best trade-off between the necessary conductor length for winding and magnet overall size is achieved in the Pareto-optimal solutions, the compact magnet size leads to increase in required superconducting cable length or vice versa The final choice among Pareto optimal configurations can be done in relation to other issues such as AC loss during transient operation, stray magnetic field at outside the coil assembly, and available discharge period, which is not considered in the optimization process. The proposed design approach is adapted for a 4.5 MJ/1 MW SMES system using low temperature niobium-titanium based Rutherford type cable. Furthermore, the validity of the representative Pareto solutions is confirmed by finite-element analysis (FEA) with a reasonably acceptable accuracy.

  7. A Superconducting Magnet Upgrade of the ATF2 Final Focus

    SciTech Connect

    Parker B.; Anerella M.; Escallier J.; He P.; Jain A.; Marone A.; Wanderer P.; Wu K.C.; Hauviller C.; Marin E.; Tomas R.; Zimmermann F.; Bolzon B.; Jeremie A.; Kimura N.; Kubo K.; Kume T.; Kuroda S.; Okugi T.; Tauchi T.; Terunuma N.; Tomaru T.; Tsuchiya K.; Urakawa J.; Yamamoto A.; Bambabe P.; Coe P.; Urner D.; Seryi A.; Spencer C.; White G.

    2010-05-23

    The ATF2 facility at KEK is a proving ground for linear collider technology with a well instrumented extracted beam line and Final Focus (FF). The primary ATF2 goal is to demonstrate the extreme beam demagnification and spot stability needed for a linear collider FF. But the ATF2 FF uses water cooled magnets and the ILC baseline has a superconducting (SC) FF. We plan to upgrade ATF2 and replace some of the warm FF magnets with SC FF magnets. The ATF2 SC magnets, like the ILC FF, will made via direct wind construction. ATF2 coil winding is in progress at BNL and warm magnetic measurements indicate we have achieved good field quality. Studies indicate that having ATF2 FF magnets with larger aperture and better field quality should allow reducing the ATF2 FF beta function for study of focusing regimes relevant to CLIC. The ATF2 magnet cryostat will have laser view ports for directly monitoring cold mass movement. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC QD0 R and D FF prototype under construction at BNL.

  8. A Superconducting Magnet Upgrade of the ATF2 Final Focus

    SciTech Connect

    Parker, Brett; Anerella, Michael; Escallier, John; He, Ping; Jain, Animesh; Marone, Andrew; Wanderer, Peter; Wu, Kuo-Chen; Bambade, Philip; Bolzon, Benoit; Jeremie, Andrea; Coe, Paul; Urner, David Hauviller, Claude; Marin, Eduardo; Tomas, Rogelio; Zimmermann, Frank; Kimura, Nobuhiro; Kubo, Kiyoshi; Kume, Tatsuya Kuroda, Shigeru; /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /KEK, Tsukuba /SLAC /SLAC /SLAC

    2012-07-05

    The ATF2 facility at KEK is a proving ground for linear collider technology with a well instrumented extracted beam line and Final Focus (FF). The primary ATF2 goal is to demonstrate the extreme beam demagnification and spot stability needed for a linear collider FF. But the ATF2 FF uses water cooled magnets and the ILC baseline has a superconducting (SC) FF. We plan to upgrade ATF2 and replace some of the warm FF magnets with SC FF magnets. The ATF2 SC magnets, like the ILC FF, will made via direct wind construction. ATF2 coil winding is in progress at BNL and warm magnetic measurements indicate we have achieved good field quality. Studies indicate that having ATF2 FF magnets with larger aperture and better field quality should allow reducing the ATF2 FF beta function for study of focusing regimes relevant to CLIC. The ATF2 magnet cryostat will have laser view ports for directly monitoring cold mass movement. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC QD0 R&D FF prototype under construction at BNL.

  9. Superconducting magnetic energy storage (SMES) program. Progress report, January 1-December 31, 1980

    SciTech Connect

    Rogers, J.D.

    1981-03-01

    Work is reported on the development of two superconducting magnetic energy storage (SMES) units. One is a 30-MJ unit for use by the Bonneville Power Administration (BPA) to stabilize power oscillations on their Pacific AC Intertie, and the second is a 1- to 10-GWh unit for use as a diurnal load leveling device. Emphasis has been on the stabilizing system. The manufacturing phase of the 30-MJ superconducting coil was initiated and the coil fabrication has advanced rapidly. The two converter power transformers were manufactured, successfully factory tested, and shipped. One transformer reached the Tacoma Substation in good condition; the other was dropped enroute and has been returned to the factory for rebuilding. Insulation of the 30-MJ coil has been examined for high voltage effects apt to be caused by transients such as inductive voltage spikes from the protective dump circuit. The stabilizing system converter and protective energy dump system were completed, factory tested, and delivered.

  10. Characterization of superconducting magnetic bearings (dynamic stiffness and damping coefficient in axial direction)

    NASA Technical Reports Server (NTRS)

    Takahata, Ryoichi; Ueyama, Hirochika; Yotsuya, Tsutom

    1992-01-01

    High T(sub c) superconductor as a stator and permanent magnets for a rotor were assembled into a superconducting magnetic bearing. The dynamic stiffness and the damping coefficient of the superconducting magnetic bearing in axial direction were measured. The dynamic stiffness depended on an axial gap between superconductor and permanent magnet. The superconducting magnetic bearings are advantageous for a passive bearing, because they have a vibration damping effect that a permanent magnet bearing does not have. The tendency of its vibration damping coefficient indicated an increase as the resonant frequency increased.

  11. Superconducting magnets in high radiation environments: Design problems and solutions

    SciTech Connect

    St. Lorant, S.J.; Tillmann, E.

    1989-11-01

    As part of the Stanford Linear Collider Project, three high-field superconducting solenoid magnets are used to rotate the spin direction of a polarized electron beam. The magnets are installed in a high-radiation environment, where they will receive a dose of approximately 10{sup 3} rad per hour, or 10{sup 8} rad over their lifetimes. This level of radiation and the location in which the magnets are installed, some 10 meters below ground in contiguous tunnels, required careful selection of materials for the construction of the solenoids and their ancillary cryogenic equipment, as well as the development of compatible component designs. This paper describes the materials used and the design of the equipment appropriate for the application. Included are summaries of the physical and mechanical properties of the materials and how they behave when irradiated. 16 refs., 7 figs., 1 tab.

  12. A novel rotating experimental platform in a superconducting magnet.

    PubMed

    Chen, Da; Cao, Hui-Ling; Ye, Ya-Jing; Dong, Chen; Liu, Yong-Ming; Shang, Peng; Yin, Da-Chuan

    2016-08-01

    This paper introduces a novel platform designed to be used in a strong static magnetic field (in a superconducting magnet). The platform is a sample holder that rotates in the strong magnetic field. Any samples placed in the platform will rotate due to the rotation of the sample holder. With this platform, a number of experiments such as material processing, culture of biological systems, chemical reactions, or other processes can be carried out. In this report, we present some preliminary experiments (protein crystallization, cell culture, and seed germination) conducted using this platform. The experimental results showed that the platform can affect the processes, indicating that it provides a novel environment that has not been investigated before and that the effects of such an environment on many different physical, chemical, or biological processes can be potentially useful for applications in many fields. PMID:27587133

  13. Local magnetization fluctuations in superconducting glasses resolved by Hall sensors

    NASA Astrophysics Data System (ADS)

    Lefebvre, J.; Hilke, M.; Altounian, Z.; West, K. W.; Pfeiffer, L. N.

    2009-05-01

    We report on magnetization measurements performed on a series of FexNi1-xZr2 superconducting metallic glasses with 0≤x≤0.5 using the Hall effect of a nearby two-dimensional electron gas (2DEG) in a GaAs/Al0.33Ga0.67As heterostructure as a local probe. The great sensitivity of the Hall effect of the 2DEG in such heterostructure is exploited to determine the magnetization of the superconductor due to the Meissner effect and flux trapping. The data are used to determine the lower critical-field Bc1 of the superconductors as a function of temperature. Surprisingly large fluctuations in the magnetization are also observed and attributed to the presence of large flux clusters in the superconductor.

  14. Magnetized neutron stars with superconducting cores: effect of entrainment

    NASA Astrophysics Data System (ADS)

    Palapanidis, K.; Stergioulas, N.; Lander, S. K.

    2015-09-01

    We construct equilibrium configurations of magnetized, two-fluid neutron stars using an iterative numerical method. Working in Newtonian framework we assume that the neutron star has two regions: the core, which is modelled as a two-component fluid consisting of type-II superconducting protons and superfluid neutrons, and the crust, a region composed of normal matter. Taking a new step towards more complete equilibrium models, we include the effect of entrainment, which implies that a magnetic force acts on neutrons, too. We consider purely poloidal field cases and present improvements to an earlier numerical scheme for solving equilibrium equations, by introducing new convergence criteria. We find that entrainment results in qualitative differences in the structure of field lines along the magnetic axis.

  15. Magnetic flux studies in horizontally cooled elliptical superconducting cavities

    SciTech Connect

    Martinello, M. Checchin, M.; Grassellino, A. Crawford, A. C.; Melnychuk, O.; Romanenko, A.; Sergatskov, D. A.

    2015-07-28

    Previous studies on magnetic flux expulsion as a function of cooldown procedures for elliptical superconducting radio frequency (SRF) niobium cavities showed that when the cavity beam axis is placed parallel to the helium cooling flow and sufficiently large thermal gradients are achieved, all magnetic flux could be expelled and very low residual resistance could be achieved. In this paper, we investigate flux trapping for the case of resonators positioned perpendicularly to the helium cooling flow, which is more representative of how SRF cavities are cooled in accelerators and for different directions of the applied magnetic field surrounding the resonator. We show that different field components have a different impact on the surface resistance, and several parameters have to be considered to fully understand the flux dynamics. A newly discovered phenomenon of concentration of flux lines at the cavity top leading to temperature rise at the cavity equator is presented.

  16. A novel rotating experimental platform in a superconducting magnet

    NASA Astrophysics Data System (ADS)

    Chen, Da; Cao, Hui-Ling; Ye, Ya-Jing; Dong, Chen; Liu, Yong-Ming; Shang, Peng; Yin, Da-Chuan

    2016-08-01

    This paper introduces a novel platform designed to be used in a strong static magnetic field (in a superconducting magnet). The platform is a sample holder that rotates in the strong magnetic field. Any samples placed in the platform will rotate due to the rotation of the sample holder. With this platform, a number of experiments such as material processing, culture of biological systems, chemical reactions, or other processes can be carried out. In this report, we present some preliminary experiments (protein crystallization, cell culture, and seed germination) conducted using this platform. The experimental results showed that the platform can affect the processes, indicating that it provides a novel environment that has not been investigated before and that the effects of such an environment on many different physical, chemical, or biological processes can be potentially useful for applications in many fields.

  17. Performance of a 12-coil superconducting 'bumpy torus' magnet facility.

    NASA Technical Reports Server (NTRS)

    Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

    1972-01-01

    The NASA-Lewis 'bumpy torus' facility consists of 12 superconducting coils, each 19 cm ID and capable of 3.0 tesla on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas has been held for a period of more than sixty minutes without a coil normalcy.

  18. Superconducting magnets in high-radiation environment at supercolliders

    SciTech Connect

    Mokhov, N.V.; Chichili, D.R.; Gourlay, S.A.; Van Sciver, S.; Zeller, A.

    2006-07-01

    The principal challenges arising from beam-induced energy deposition in superconducting (SC) magnets at high-energy high-luminosity hadron and lepton colliders are described. Radiation constraints are analyzed that include quench stability, dynamic heat loads on the cryogenic system, radiation damage limiting the component lifetime, and residual dose rates related to hands-on maintenance. These issues are especially challenging for the interaction regions (IR), particularly for the considered upgrade layouts of the Large Hadron Collider. Up to a few kW of beam power can dissipate in a single SC magnet, and a local peak power density can substantially exceed the quench levels. Just formally, the magnet lifetime is limited to a few months under these conditions. Possible solutions and the ways to mitigate these problems are described in this paper along with R&D needed.

  19. Voltage spike detection in high field superconducting accelerator magnets

    SciTech Connect

    Orris, D.F.; Carcagno, R.; Feher, S.; Makulski, A.; Pischalnikov, Y.M.; /Fermilab

    2004-12-01

    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 {approx}15mV in magnitude and lasts for {approx}30 {micro}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 Nb{sub 3}Sn magnets at currents up to {approx}20KA will also be shown.

  20. Magnetic imaging of superconducting tapes to determine current flow

    SciTech Connect

    Brown, G. W.; Hawley, M. E.; Foltyn, S. R.; Mueller, F. M.

    2001-01-01

    We have developed a magnetic imaging system that uses magnetoresistive read heads from computer hard disk drives to map the transport-current-induced magnetic field at the surface of superconducting tapes at liquid nitrogen temperature. Transport current pathways are determined from the 2-dimensional magnetic field maps using established inversion schemes. We examined the current flow in pulsed-laser-deposited YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} a films patterned on single crystal SrTiO{sub 3} substrates and on a textured yttria-stabilized-zirconia layer deposited on an Inconel ribbon by ion beam assisted deposition. The transport current densities in all cases were consistent with the Critical State Model. For the Inconel-based sample, the transport current density maps have allowed us to observe defects and determine the region that limits the current carrying capacity of the structure.

  1. High-Density Superconducting Cables for Advanced ACTPol

    NASA Astrophysics Data System (ADS)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-07-01

    Advanced ACTPol (AdvACT) is an upcoming Atacama Cosmology Telescope (ACT) receiver upgrade, scheduled to deploy in 2016, that will allow measurement of the cosmic microwave background polarization and temperature to the highest precision yet with ACT. The AdvACT increase in sensitivity is partly provided by an increase in the number of transition-edge sensors (TESes) per array by up to a factor of two over the current ACTPol receiver detector arrays. The high-density AdvACT TES arrays require 70 \\upmu m pitch superconducting flexible cables (flex) to connect the detector wafer to the first-stage readout electronics. Here, we present the flex fabrication process and test results. For the flex wiring layer, we use a 400-nm-thick sputtered aluminum film. In the center of the cable, the wiring is supported by a polyimide substrate, which smoothly transitions to a bare (uncoated with polyimide) silicon substrate at the ends of the cable for a robust wedge wire-bonding interface. Tests on the first batch of flex made for the first AdvACT array show that the flex will meet the requirements for AdvACT, with a superconducting critical current above 1 mA at 500 mK, resilience to mechanical and cryogenic stress, and a room temperature yield of 97 %.

  2. Magnetic and levitation characteristics of bulk high-temperature superconducting magnets above a permanent magnet guideway

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Zheng, Botian; He, Dabo; Sun, Ruixue; Deng, Zigang; Xu, Xun; Dou, Shixue

    2016-09-01

    Due to the large levitation force or the large guidance force of bulk high-temperature superconducting magnets (BHTSMs) above a permanent magnet guideway (PMG), it is reasonable to employ pre-magnetized BHTSMs to replace applied-magnetic-field-cooled superconductors in a maglev system. There are two combination modes between the BHTSM and the PMG, distinguished by the different directions of the magnetization. One is the S-S pole mode, and the other is the S-N pole mode combined with a unimodal PMG segment. A multi-point magnetic field measurement platform was employed to acquire the magnetic field signals of the BHTSM surface in real time during the pre-magnetization process and the re-magnetization process. Subsequently, three experimental aspects of levitation, including the vertical movement due to the levitation force, the lateral movement due to the guidance force, and the force relaxation with time, were explored above the PMG segment. Moreover, finite element modeling by COMSOL Multiphysics has been performed to simulate the different induced currents and the potentially different temperature rises with different modes inside the BHTSM. It was found that the S-S pole mode produced higher induced current density and a higher temperature rise inside the BHTSM, which might escalate its lateral instability above the PMG. The S-N pole mode exhibits the opposite characteristics. In general, this work is instructive for understanding and connecting the magnetic flux, the inner current density, the levitation behavior, and the temperature rise of BHTSMs employed in a maglev system.

  3. Testing beam-induced quench levels of LHC superconducting magnets

    NASA Astrophysics Data System (ADS)

    Auchmann, B.; Baer, T.; Bednarek, M.; Bellodi, G.; Bracco, C.; Bruce, R.; Cerutti, F.; Chetvertkova, V.; Dehning, B.; Granieri, P. P.; Hofle, W.; Holzer, E. B.; Lechner, A.; Nebot Del Busto, E.; Priebe, A.; Redaelli, S.; Salvachua, B.; Sapinski, M.; Schmidt, R.; Shetty, N.; Skordis, E.; Solfaroli, M.; Steckert, J.; Valuch, D.; Verweij, A.; Wenninger, J.; Wollmann, D.; Zerlauth, M.

    2015-06-01

    In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam-induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy deposition in the coils is compared to the quench levels predicted by electrothermal models, thus allowing one to validate and improve the models which are used to set beam-dump thresholds on beam-loss monitors for run 2.

  4. Magnetic field dependence of critical currents in superconducting polycrystals

    SciTech Connect

    Kugel, K.I.; Lisovskaya, T.Y. ); Mints, R.G. )

    1992-02-10

    The authors study the dependence of critical current j{sub c} on magnetic field H in superconducting polycrystals which are considered as system of superconducting crystallites (isotropic or anisotropic) with Josephson contacts between them. Isotropy or anisotropy of contacts depends on the orientation of their crystallographic axes relatively to edges of contact planes. In this paper it is shown that for a system of randomly oriented isotropic contacts, the dependence j{sub c}(H) in a relatively wide field range has the asymptotic form j{sub c} {approximately} (InH)/H{sup 2}. This differs drastically from j{sub c}(H) for single contacts. Anisotropy effects due to large differences in London penetration depth {lambda} values corresponding to external magnetic field directed along different axes are analyzed in detail. It is shown that for uniaxal crystals with {lambda}{sub 1} = {lambda}{sub 2} {lt} {lambda}{sub 3}, this anisotropy leads to the relation j{sub c} {approximately} {radical}{lambda}{sub 3}/{lambda}{sub 1} for chaotic orientation of crystallites. The form of j{sub c}(H) curves for two different orientations of the magnetic field relatively to the transport current through the sample is found.

  5. The use of superconductivity in magnetic balance design

    NASA Technical Reports Server (NTRS)

    Moss, F. E.

    1973-01-01

    The magnetic field and field gradient requirements for magnetic suspension in a Mach 3, 6-in. diameter wind tunnel are stated, along with the power requirements for gradient coil pairs wound of copper operating at room temperature and aluminum cooled to 20 K. The power dissipated is large enough that the use of superconductivity in the coil design becomes an attractive alternative. The problems of stability and ac losses are outlined along with the properties of stabilized superconductors. A brief review of a simplified version of the critical state model of C. P. Bean is presented, and the problems involved in calculations of the ac losses in superconducting coils are outlined. A summary of ac loss data taken on pancake coils wound of commercially available Nb3Sn partially stabilized tape is presented and shown as leading to the U.Va. gradient coil design. The actual coil performance is compared with predictions based on the BNL results. Finally, some remarks are presented concerning scaling of the ac losses to larger magnetic suspension systems as well as prospects for improved performance using newer multifilament superconductors.

  6. Magnetic response measurements of mesoscopic superconducting and normal metal rings

    NASA Astrophysics Data System (ADS)

    Bluhm, Hendrik

    The main part of this thesis reports three experiments on the magnetic response of mesoscopic superconducting and normal metal rings using a scanning SQUID microscope. The first experiment explores the magnetic response and fluxoid transitions of superconducting, mesoscopic bilayer aluminum rings in the presence of two coupled order parameters arising from the layered structure. For intermediate couplings, metastable states that have different phase winding numbers around the ring in each of the two order parameters were observed. Larger coupling locks the relative phase, so that the two order parameters are only manifest in the temperature dependence of the response. With increasing proximitization, this signature gradually disappears. The data can be described with a two-order-parameter Ginzburg-Landau theory. The second experiment concentrates on fluxoid transitions in similar, but single-layer rings. Near the critical temperature, the transitions, which are induced by applying a flux to the ring, only admit a single fluxoid at a time. At lower temperatures, several fluxoids enter or leave at once, and the final state approaches the ground state. Currently available theoretical frameworks cannot quantitatively explain the data. Heating and quasiparticle diffusion are likely important for a quantitative understanding of this experiment, which could provide a model system for studying the nonlinear dynamics of superconductors far from equilibrium. The third and most important scanning SQUID study concerns 33 individual mesoscopic gold rings. All measured rings show a paramagnetic linear susceptibility and a poorly understood anomaly around zero field, both of which are likely due to unpaired defect spins. The response of sufficiently small rings also has a component that is periodic in the flux through the ring, with a period close to h/e. Its amplitude varies in sign and magnitude from ring to ring, and its typical value and temperature dependence agree with

  7. Filterscope diagnostic system on the Experimental Advanced Superconducting Tokamak (EAST)

    NASA Astrophysics Data System (ADS)

    Xu, Z.; Wu, Z. W.; Gao, W.; Chen, Y. J.; Wu, C. R.; Zhang, L.; Huang, J.; Chang, J. F.; Yao, X. J.; Gao, W.; Zhang, P. F.; Jin, Z.; Hou, Y. M.; Guo, H. Y.

    2016-11-01

    A filterscope diagnostic system has been mounted to observe the line emission and visible bremsstrahlung emission from plasma on the experimental advanced superconducting tokamak during the 2014 campaign. By this diagnostic system, multiple wavelengths including Dα (656.1 nm), Dγ (433.9 nm), He ii (468.5 nm), Li i (670.8 nm), Li ii (548.3 nm), C iii (465.0 nm), O ii (441.5 nm), Mo i (386.4 nm), W i (400.9 nm), and visible bremsstrahlung radiation (538.0 nm) are monitored with corresponding wavelength filters. All these multi-channel signals are digitized at up to 200 kHz simultaneously. This diagnostic plays a crucial role in studying edge localized modes and H-mode plasmas, due to the high temporal resolution and spatial resolution that have been designed into it.

  8. Design of vibration compensation interferometer for Experimental Advanced Superconducting Tokamak.

    PubMed

    Yang, Y; Li, G S; Liu, H Q; Jie, Y X; Ding, W X; Brower, D L; Zhu, X; Wang, Z X; Zeng, L; Zou, Z Y; Wei, X C; Lan, T

    2014-11-01

    A vibration compensation interferometer (wavelength at 0.532 μm) has been designed and tested for Experimental Advanced Superconducting Tokamak (EAST). It is designed as a sub-system for EAST far-infrared (wavelength at 432.5 μm) poloarimeter/interferometer system. Two Acoustic Optical Modulators have been applied to produce the 1 MHz intermediate frequency. The path length drift of the system is lower than 2 wavelengths within 10 min test, showing the system stability. The system sensitivity has been tested by applying a periodic vibration source on one mirror in the system. The vibration is measured and the result matches the source period. The system is expected to be installed on EAST by the end of 2014.

  9. A cryogenic test stand for large superconducting solenoid magnets

    NASA Astrophysics Data System (ADS)

    Rabehl, R.; Carcagno, R.; Nogiec, J.; Orris, D.; Soyars, W.; Sylvester, C.

    2014-01-01

    A new test stand for testing large superconducting solenoid magnets at the Fermilab Central Helium Liquefier (CHL) has been designed, installed, and operated. This test stand is being used to test a coupling coil for the Muon Ionization Cooling Experiment (MICE), and future uses include solenoids for the Fermilab μ2e experiment. This paper describes the test stand design and operation including controlled cool-down and warm-up. Overviews of the process controls system and the quench management system are also included.

  10. Fermi surface, magnetic, and superconducting properties in actinide compounds

    NASA Astrophysics Data System (ADS)

    Ōnuki, Yoshichika; Settai, Rikio; Haga, Yoshinori; Machida, Yo; Izawa, Koichi; Honda, Fuminori; Aoki, Dai

    2014-08-01

    The de Haas-van Alphen effect, which is a powerful method to explore Fermi surface properties, has been observed in cerium, uranium, and nowadays even in neptunium and plutonium compounds. Here, we present the results of several studies concerning the Fermi surface properties of the heavy fermion superconductors UPt3 and NpPd5Al2, and of the ferromagnetic pressure-induced superconductor UGe2, together with those of some related compounds for which fascinating anisotropic superconductivity, magnetism, and heavy fermion behavior has been observed. xml:lang="fr"

  11. Superconducting Magnetic Energy Storage:. Conventional and Trapped Field

    NASA Astrophysics Data System (ADS)

    Rabinowitz, Mario

    Superconducting magnetic energy storage (SMES) is a most efficient system for energy storage because it stores energy directly in electrical form. The SMES concept is described and analyzed with an examination of its economic viability. The impact of high-temperature supeconductivity on SMES is explored, and a trapped energy storage (TES) innovation that may have beneficial technical and economic ramifications is introduced. In addition to presenting a broad overview, this paper may be of help to those making an evaluation of the potential impact of SMES/TES on the development of new energy sources, and to determine for which energy sources it is most appropriate.

  12. A Cryogenic Test Stand for Large Superconducting Solenoid Magnets

    SciTech Connect

    Rabehl, R.; Carcagno, R.; Nogiec, J.; Orris, D.; Soyars, W.; Sylvester, C.

    2013-01-01

    A new test stand for testing large superconducting solenoid magnets at the Fermilab Central Helium Liquifier (CHL) has been designed, and operated. This test stand has been used to test a coupling coil for the Muon Ionization Cooling Experiment (MICE), and future uses include solenoids for the Fermilab mu2e experiment. This paper describes the test stand design and operation including controlled cool-down and warm-up. Overviews of the process controls system and the quench management system are also included.

  13. A 3 T superconducting magnet for the amy detector

    NASA Astrophysics Data System (ADS)

    Doi, Y.; Haruyama, T.; Hirabayashi, H.; Ishimoto, S.; Maki, A.; Mito, T.; Omori, T.; Terada, S.; Tsuchiya, K.

    1989-01-01

    A 3 T high field superconducting magnet was constructed for the AMY detector at the TRISTAN electron-positron storage ring. Cooldown and excitation tests of the magnet were carried out with the detector in its final configuration. The coil is made with a fully stabilized superconductor wound into an eight layer cylinder with a 2.39 m inner diameter, a 2.58 m outer diameter and 1.54 m in length. An outer jacket of thick stainless steel was shrunk-fit around the coil to provide strength to contain the magnetic forces and to serve as a liquid helium container for the pool boiling cooling system for the coil. A computer controlled refrigeration system with a capacity of 300 W at 4.4. K (100 l/h) was prepared to cool down the 17 t of cold mass of the magnet. It took about five days to cool down from room temperature and achieve a superconducting state, and an additional two days to completely fill the coil with liquid helium and to prepare for the excitation of the magnet. The thermal stresses on the coil support rods were evenly balanced during the cooldown, and the mechanical stresses on the support rods at full excitation (a current of 5000 A) were well below the allowed maximum. In order to verify the safe operation of the magnet system, we carried out fast discharge tests with a time constant of 21 s, which was optimized to protect the magnet from quench. The pressure rise in the helium vessel during the discharge from 5000 A was an easily manageable 1.38 × 10 5 Pa. During the fast discharge of the 5000 A excitation, the coil showed no signs of developing any normal regions. At the maximum rated current of 5000 A, the central magnetic field and the inductance were measured to be 3.0367 and 3.2 H, respectively, corresponding to a stored energy of 40 MJ, in good agreement with magnetic field calculations. During these tests and in the succeeding long term operation, the magnet showed excellent stability and reliability.

  14. CABLE DESIGN FOR FAST RAMPED SUPERCONDUCTING MAGNETS (COS-0 DESIGN).

    SciTech Connect

    GHOSH,A.

    2004-03-22

    The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 300 T-m and 100 T-m. Fast ramp times are needed, which can cause significant problems for the magnets, particularly in the areas of ac loss and magnetic field distortion. The development of the low loss Rutherford cable that can be used is described, together with a novel insulation scheme designed to promote efficient cooling. Measurements of contact resistance in the cable are presented and the results of these measurements are used to predict the ac losses, in the magnets during fast ramp operation. For the high energy ring, a lm model dipole magnet was built, based on the RHIC dipole design. This magnet was tested under boiling liquid helium in a vertical cryostat. The quench current showed very little dependence on ramp rate. The ac losses, measured by an electrical method, were fitted to straight line plots of loss/cycle versus ramp rate, thereby separating the eddy current and hysteresis components. These results were compared with calculated values, using parameters which had previously been measured on short samples of cable. Reasonably good agreement between theory and experiment was found, although the measured hysteresis loss is higher than expected in ramps to the highest field levels.

  15. Flow Cooling of Superconducting Magnets for Spacecraft Applications

    NASA Astrophysics Data System (ADS)

    Dietz, A. J.; Audette, W. E.; Barton, M. D.; Hilderbrand, J. K.; Marshall, W. S.; Rey, C. M.; Winter, D. S.; Petro, A. J.

    2008-03-01

    The development and testing of a flow cooling system for high-temperature superconducting (HTS) magnets is described. The system includes a turbo-Brayton cryocooler, a magnet thermal interface, and a magnet thermal isolation and support system. The target application is the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Turbo-Brayton coolers are well suited to such spacecraft applications, as they are compact, modular, lightweight, and efficient, with long maintenance-free lifetimes. Furthermore, the technology scales well to high-cooling capacities. The feasibility of using turbo-Brayton coolers in this application was proven in a design exercise in which existing cooler designs were scaled to provide cooling for the magnet sets required by 200 kW and 1 MW VASIMR engines. The performance of the concepts for the thermal interface and the thermal isolation and support system were measured in separate laboratory tests with a demonstration system built about a representative HTS magnet. Cooling for these tests was provided by a flow cooling loop comprising a compressor, recuperator and GM cryocooler, with the flow pressure, temperature, and mass flow rate selected to effectively simulate the turbo-Brayton operating condition. During system testing, the magnet was cooled below its design operating temperature of 35 K, and good thermal uniformity (<0.4 K) and low thermal loads (<0.5 W) were demonstrated.

  16. High-[Tc] superconducting magnets based on thick film arrangements

    SciTech Connect

    Kirschner, I.; Zsolt, G.; Karman, T.; Porjesz, T. . Dept. for Low Temperature Physics); Leppaevuori, S.; Uusimaeki, A. . Microelectronics Lab.); Lukacs, P. )

    1993-11-01

    On the basis of the authors' earlier idea on magnetic feeding, high-[Tc] superconducting magnets can be built consisting of Y-Ba-Cu-O or Bi(Pb)-Sr-Ca-Cu-O thick films. Critical current densities of the samples prepared by an oxalate route are between 7,000 and 23,000 A/cm[sup 2] at helium temperatures depending on the details of the preparation. The self-magnetic field of the individual layer rings are 0.5--1.7 mT which can produce field strength of the magnets of 55 178 mT, corresponding to the experimental critical currents. If the specimens of oxide-nitrate reactions can provide critical current densities of 5,000--15,000 A/cm[sup 2] at nitrogen temperatures they lead to the number of ampere-turns of 550--22,500 A/cm and magnetic field intensity of 69 mT--2.82 T. Since the applicable techniques of the film preparation are very flexible concerning the shape and size of the products, magnetic field profiles of different character can be obtained for various purposes.

  17. PREFACE: International Conference on Superconductivity and Magnetism-ICSM2008

    NASA Astrophysics Data System (ADS)

    Gencer, Ali; Grasso, Gianni

    2009-03-01

    The International Conference on Superconductivity and Magnetism (ICSM2008) was held at the congress centre of Ankara University in Side, Antalya, between 25-29 August 2008. The conference was the first conference on the combined fields of superconductivity and magnetism organized in Turkey at international level, and it had broad international participation from 42 countries, with registered delegates numbering over 400. A quarter of the attendees were research students. The conference attracted many of the best known leading scientists and experts in the field of superconductivity and magnetism from all over the world. The scientific program involved the presentation and discussion of 336 papers, classified as 65 invited, 81 oral and 190 posters. Submission of papers for the proceedings was on a volunteer basis and we therefore had nearly half of the presented papers, i.e. 30 submitted invited papers, peer-reviewed by Superconductor Science and Technology, and 85 submitted contributing papers, peer-reviewed by the organizers through processes administered by the Editorial Board and Scientific Committee. Reviews were conducted by expert referees at professional level and with the scientific standards expected of a proceedings journal issue published by IOP Publishing. The invited papers on superconductivity and magnetism with superconductivity were considered and processed for Superconductor Science and Technology by IOP itself. Although there are missing papers from some of the plenary speakers, we believe that this special issue of Superconductor Science and Technology (SUST) and the corresponding issue of Journal of Physics: Conference Series (JPCS) reflect most of the booming research in the fields of superconductivity and magnetism. We are very pleased to have worked with IOP on the conference proceedings, with special thanks to Dr Tom Miller and Dr Graham Douglas. Based on a refereed evaluation of all the papers and posters submitted, about 93 papers were

  18. Recent advances in planetary magnetism

    NASA Technical Reports Server (NTRS)

    Ness, N. F.

    1978-01-01

    During the past decade, significant advances in the in situ measurements of planetary magnetic fields have been made. The U.S.A. and U.S.S.R. have conducted spacecraft investigations of all the planets, from innermost Mercury out to Jupiter. Unexpectedly, Mercury was found to possess a global magnetic field but neither the Moon nor Venus do. The results at Mars are incomplete but if a global field exists, it is clearly quite weak. The main magnetic field of Jupiter has been measured directly for the first time and confirms, as well as augments appreciably, the past 2 decades of ground-based radio astronomical studies which provided indirect evidence of the field. Progress in developing analytically complete models of the dynamo process suggests a possible common origin for Mercury, earth and Jupiter.

  19. Deep superconducting magnetic traps for neutral atoms and molecules

    NASA Astrophysics Data System (ADS)

    Harris, J. G. E.; Michniak, R. A.; Nguyen, S. V.; Campbell, W. C.; Egorov, D.; Maxwell, S. E.; van Buuren, L. D.; Doyle, J. M.

    2004-01-01

    We describe the design, construction and performance of three realizations of a high-field superconducting magnetic trap for neutral atoms and molecules. Each of these traps utilizes a pair of coaxial coils in the anti-Helmholtz geometry and achieves depths greater than 4 T, allowing it to capture magnetic atoms and molecules cooled in a cryogenic buffer gas. Achieving this depth requires that the repulsive force between the coils (which can exceed 30 metric tons) be contained. We also describe additional features of the traps, including the elimination of trapped fluxes from the coils and the integration of the coils into a cryogenic vacuum environment suitable for producing cold atoms and molecules.

  20. High Temperature Superconducting Reciprocating Magnetic Separator Final Report

    SciTech Connect

    James F. Maguire

    2008-06-05

    In 2001, under DOE's Superconductivity Partnership Initiative (SPI), E. I. du Pont de Nemours & Co. (Dupont) was awarded a cost-share contract to build a fully functional full-scale model high temperature superconducting reciprocating magnet unit specifically designed for the koalin clay industry. After competitive bidding, American Superconductor (AMSC) was selected to provide the coil for the magnet. Dupont performed the statement of work until September 2004, when it stopped work, with the concurrence of DOE, due to lack of federal funds. DOE had paid all invoices to that point, and Dupont had provided all cost share. At this same time, Dupont determined that this program did not fit with its corporate strategies and notified DOE that it was not interesting in resuming the program when funding became available. AMSC expressed interest in assuming performance of the Agreement to Dupont and DOE, and in March 2005, this project was transferred to AMSC by DOE amendment to the original contract and Novation Agreement between AMSC and Dupont. Design drawings and some hardware components and subassemblies were transferred to AMSC. However, no funding was obligated by DOE and AMSC never performed work on the project. This report contains a summary of the work performed by Dupont up to the September 04 timeframe.

  1. A helium based pulsating heat pipe for superconducting magnets

    NASA Astrophysics Data System (ADS)

    Fonseca, Luis Diego; Miller, Franklin; Pfotenhauer, John

    2014-01-01

    This study was inspired to investigate an alternative cooling system using a helium-based pulsating heat pipes (PHP), for low temperature superconducting magnets. In addition, the same approach can be used for exploring other low temperature applications. The advantages of PHP for transferring heat and smoothing temperature profiles in various room temperature applications have been explored for the past 20 years. An experimental apparatus has been designed, fabricated and operated and is primarily composed of an evaporator and a condenser; in which both are thermally connected by a closed loop capillary tubing. The main goal is to measure the heat transfer properties of this device using helium as the working fluid. The evaporator end of the PHP is comprised of a copper winding in which heat loads up to 10 watts are generated, while the condenser is isothermal and can reach 4.2 K via a two stage Sumitomo RDK408A2 GM cryocooler. Various experimental design features are highlighted. Additionally, performance results in the form of heat transfer and temperature characteristics are provided as a function of average condenser temperature, PHP fill ratio, and evaporator heat load. Results are summarized in the form of a dimensionless correlation and compared to room temperature systems. Implications for superconducting magnet stability are highlighted.

  2. Design and investigations of the superconducting magnet system for the multipurpose superconducting electron cyclotron resonance ion source

    SciTech Connect

    Tinschert, K.; Lang, R.; Maeder, J.; Rossbach, J.; Spaedtke, P.; Komorowski, P.; Meyer-Reumers, M.; Krischel, D.; Fischer, B.; Ciavola, G.; Gammino, S.; Celona, L.

    2012-02-15

    The production of intense beams of heavy ions with electron cyclotron resonance ion sources (ECRIS) is an important request at many accelerators. According to the ECR condition and considering semi-empirical scaling laws, it is essential to increase the microwave frequency together with the magnetic flux density of the ECRIS magnet system. A useful frequency of 28 GHz, therefore, requires magnetic flux densities above 2.2 T implying the use of superconducting magnets. A cooperation of European institutions initiated a project to build a multipurpose superconducting ECRIS (MS-ECRIS) in order to achieve an increase of the performances in the order of a factor of ten. After a first design of the superconducting magnet system for the MS-ECRIS, the respective cold testing of the built magnet system reveals a lack of mechanical performance due to the strong interaction of the magnetic field of the three solenoids with the sextupole field and the magnetization of the magnetic iron collar. Comprehensive structural analysis, magnetic field calculations, and calculations of the force pattern confirm thereafter these strong interactions, especially of the iron collar with the solenoidal fields. The investigations on the structural analysis as well as suggestions for a possible mechanical design solution are given.

  3. Magnetism and superconductivity of some Tl-Cu oxides

    NASA Technical Reports Server (NTRS)

    Datta, Timir

    1990-01-01

    Many copper oxide based Thallium compounds have now been discovered. In comparison to the Bi-compounds, the Tl-system shows a richer diversity; viz., High Temperature Superconductors (HTSC) can be obtained with either one or two Tl-0 layers (m = 1,2); also, the triple-digit phases are easier to synthesize. The value of d, oxygen stoichiometry, is critical to achieving superconductivity. The Tl system is robust to oxygen loss; Tl may be lost or incorporated by diffusion. A diffusion coefficient equal to 10 ms at 900 C was determined. Both ortho-rhombic and tetragonal structures are evidenced, but HTSC behavior is indifferent to the crystal symmetry. This system has the highest T(sub c) confirmed. T(sub c) generally increases with p, the number of CuO layers, but tends to saturate at p = 3. Zero resistance as high as 125K has been observed. Most of these HTSC's are hole type, but the Ce-doped specimens may be electronic. The magnetic aspects were studied; because in addition to defining the perfectly diamagnetic ground state as in the conventional superconductors, magnetism of the copper oxides show a surprising variety. This is true of both the normal and the superconducting states. Also, due to the large phonon contribution to the specific heat at the high T(sub c) accurate thermal measurement of important parameters such as the sp. heat jump, electronic density of states, D(Ef) and coherence length are uncertain, and thus, are estimated from the magnetic results. Results from the Tl-system CuO, LaBaCuO, 120 and the Bi-CuO compounds are discussed. The emphasis is on the role of magnetism in the TlCuO HTSC, but technological aspects are also pointed out.

  4. Magnetism and superconductivity of some Tl-Cu oxides

    NASA Technical Reports Server (NTRS)

    Datta, Timir

    1991-01-01

    Many copper oxide based Thallium compounds are now known. In comparison to the Bi-compounds, the Tl-system shows a richer diversity; i.e., High Temperature Superconductors (HTSC) can be obtained with either one or two Tl-0 layers (m = 1,2); also, the triple-digit phases are easier to synthesize. The value of d, oxygen stoichiometry, is critical to achieving superconductivity. The Tl system is robust to oxygen loss; Tl may be lost or incorporated by diffusion. A diffusion coefficient equal to 10 ms at 900 C was determined. Both ortho-rhombic and tetragonal structures are found, but HTSC behavior is indifferent to the crystal symmetry. This system has the highest T(sub c) confirmed. T(sub c) generally increases with p, the number of CuO layers, but tends to saturate at p = 3. Zero resistance was observed at temperatures as great as 125 K. Most of these HTSC's are hole type, but the Ce-doped specimens may be electronic. The magnetic aspects were studied; because in addition to defining the perfectly diamagnetic ground state as in conventional superconductors, magnetism of the copper oxides show a surprising variety. This is true of both the normal and the superconducting states. Also, due to the large phonon contribution to the specific heat at the high T(sub c) jump, electronic density of states, D(Ef), and coherence length are uncertain, and thus, are estimated from the magnetic results. Results from the Tl-system CuO, LaBaCuO,120 and the Bi-CuO compounds are discussed. The emphasis is on the role of magnetism in the Tl-CuO HTSC, but technological aspects are also pointed out.

  5. High temperature superconducting axial field magnetic coupler: realization and test

    NASA Astrophysics Data System (ADS)

    Belguerras, L.; Mezani, S.; Lubin, T.; Lévêque, J.; Rezzoug, A.

    2015-09-01

    Contactless torque transmission through a large airgap is required in some industrial applications in which hermetic isolation is necessary. This torque transmission usually uses magnetic couplers, whose dimension strongly depends on the airgap flux density. The use of high temperature superconducting (HTS) coils to create a strong magnetic field may constitute a solution to reduce the size of the coupler. It is also possible to use this coupler to replace a torque tube in transmitting the torque produced by a HTS motor to its load. This paper presents the detailed construction and tests of an axial field HTS magnetic coupler. Pancake coils have been manufactured from BSCCO tape and used in one rotor of the coupler. The second rotor is mainly composed of NdFeB permanent magnets. Several tests have been carried out showing that the constructed coupler is working properly. A 3D finite element (FE) model of the studied coupler has been developed. Airgap magnetic field and torque measurements have been carried out and compared to the FE results. It has been shown that the measured and the computed quantities are in satisfactory agreement.

  6. Performance of a 12-coil superconducting bumpy torus magnet facility

    NASA Technical Reports Server (NTRS)

    Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

    1972-01-01

    The bumpy torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 teslas on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas was held for a period of more than sixty minutes without a coil normalcy. The design field was 3.00 teslas. The steady-state liquid helium boil-off rate was 87 liters per hour of liquid helium without the coils charged. The coil array was stable when subjected to an impulsive loading, even with the magnets fully charged. When the coils were charged to a maximum magnetic field of 3.35 teslas, the system was driven normal without damage.

  7. High-T/sub c/ superconductor and its use in superconducting magnets

    SciTech Connect

    Green, M.A.

    1988-02-01

    Many of the proposed uses for the high-T/sub c/ superconductor involve the creation of a magnetic field using superconducting coils. This report will assess what is known about the high-T/sub c/ superconductors and take a realistic look at their potential use in various kinds of superconducting magnets. Based on what is known about the high-T/sub c/ superconductors, one can make a ''wish list'' of things that will make such materials useful for magnets. Then, the following question is asked. If one had a high-T/sub c/ superconductor with the same properties as modern niobium-titanium superconductor, how would the superconductor work in a magnet environment. Finally, this report will show the potential impact of the ideal high-T/sub c/ superconductor on: 1) accelerator dipole and quadrupole magnets, 2) superconducting magnets for use in space, and 3) superconducting solenoids for magnetic resonance imaging. 78 refs., 11 tabs.

  8. Magnetic suspension and balance system advanced study

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1985-01-01

    An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design.

  9. Magnetic Ordering In Superconducting Nb-doped Bi2Se3

    NASA Astrophysics Data System (ADS)

    Corbae, Paul; Lawson, Benjamin; Li, Gang; Yu, Fan; Asaba, Tomoya; Tinsman, Colin; Qui, Yusheng; Hor, Yew San; Li, Lu

    Coexistence of superconductivity and magnetic order has been suggested by early studies of topological superconductor candidate, niobium doped Bi2Se3. In order to elucidate the interesting physics of this coexistence, we performed highly sensitive torque magnetometry to study the material's magnetization. We observed a bump feature in the magnetization around 8 Tesla in both the superconducting and non-superconducting samples. This is distinct from the paramagnetic torque response of the parent compound, Bi2Se3, suggesting some interesting magnetic order in Nb-doped Bi2Se3.

  10. Magnetic characteristics and measurements of filamentary Nb-Ti wire for the Superconducting Super Collider

    SciTech Connect

    Goldfarb, R.B.; Spomer, R.L.

    1989-12-31

    In synchrotron accelerator applications, such as the Superconducting Super Collider (SSC), superconducting magnets are cycled in magnetic field. Desirable properties of the magnets include field uniformity, field stability with time, small residual field, and fairly small energy losses upon cycling. This paper discusses potential sources of problems in achieving these goals, describes important magnetic characteristics to be considered, and reviews measurement techniques for magnetic evaluation of candidate SSC wires. Instrumentation that might be practical for use in a wire-fabrication environment is described. The authors report on magnetic measurements of prototype SSC wires and cables and speculate on causes for instability in multipole fields of dipole magnets constructed with such cables.

  11. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs

    DOE PAGES

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K.; Ruegg, Christian; Susner, Michael A.; Sefat, Athena S.; Zhigadlo, Nikolai D.; et al

    2015-09-08

    We report that the recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreasesmore » upon increasing the pressure. In the intermediate pressure region (3.5≲ p ≲ 7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc3.2 as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.« less

  12. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs.

    PubMed

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K; Rüegg, Christian; Susner, Michael A; Sefat, Athena S; Zhigadlo, Nikolai D; Morenzoni, Elvezio

    2015-01-01

    The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5 < or ~  p < or ~ 7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc(3.2) as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs. PMID:26346548

  13. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs

    SciTech Connect

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K.; Ruegg, Christian; Susner, Michael A.; Sefat, Athena S.; Zhigadlo, Nikolai D.; Morenzoni, Elvezio

    2015-09-08

    We report that the recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5≲ p ≲ 7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc3.2 as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.

  14. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs

    PubMed Central

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K.; Rüegg, Christian; Susner, Michael A.; Sefat, Athena S.; Zhigadlo, Nikolai D.; Morenzoni, Elvezio

    2015-01-01

    The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p  3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p  7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc  1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5  p  7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs. PMID:26346548

  15. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs.

    PubMed

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K; Rüegg, Christian; Susner, Michael A; Sefat, Athena S; Zhigadlo, Nikolai D; Morenzoni, Elvezio

    2015-09-08

    The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p ≃ 3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p ≃ 7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc ≃ 1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5 < or ~  p < or ~ 7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with Tc(3.2) as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.

  16. Pressure-induced electronic phase separation of magnetism and superconductivity in CrAs

    NASA Astrophysics Data System (ADS)

    Khasanov, Rustem; Guguchia, Zurab; Eremin, Ilya; Luetkens, Hubertus; Amato, Alex; Biswas, Pabitra K.; Rüegg, Christian; Susner, Michael A.; Sefat, Athena S.; Zhigadlo, Nikolai D.; Morenzoni, Elvezio

    2015-09-01

    The recent discovery of pressure (p) induced superconductivity in the binary helimagnet CrAs has raised questions on how superconductivity emerges from the magnetic state and on the mechanism of the superconducting pairing. In the present work the suppression of magnetism and the occurrence of superconductivity in CrAs were studied by means of muon spin rotation. The magnetism remains bulk up to p  3.5 kbar while its volume fraction gradually decreases with increasing pressure until it vanishes at p  7 kbar. At 3.5 kbar superconductivity abruptly appears with its maximum Tc  1.2 K which decreases upon increasing the pressure. In the intermediate pressure region (3.5  p  7 kbar) the superconducting and the magnetic volume fractions are spatially phase separated and compete for phase volume. Our results indicate that the less conductive magnetic phase provides additional carriers (doping) to the superconducting parts of the CrAs sample thus leading to an increase of the transition temperature (Tc) and of the superfluid density (ρs). A scaling of ρs with as well as the phase separation between magnetism and superconductivity point to a conventional mechanism of the Cooper-pairing in CrAs.

  17. Modified magnetism within the coherence volume of superconducting FeSeTe

    SciTech Connect

    Leiner, Jonathan C; Thampy, Vivek; Christianson, Andrew D; Abernathy, D.; Stone, Matthew B; Lumsden, Mark D; Sales, Brian C; Safa-Sefat, Athena; Hu, Jin; Mao, Zhiqiang; Bao, Wei; Broholm, Collin L

    2014-01-01

    Neutron Scattering is used to probe magnetic interactions as superconductivity develops in opti- mally doped Fe_(1+ )Se_xTe_(1 x). Applying the first moment sum-rule to comprehensive neutron scatter- ing data, we extract the change in magnetic exchange energy [J_(R-R ) S_R S_R ] in the superconducting state referenced to the normal state. Oscillatory changes are observed for Fe-Fe displacements | R| < , where = 1.3(1) nm is the superconducting coherence length. Dominated by a large reduction in the second nearest neighbor exchange energy (-1.2(2) meV/Fe), the overall reduction in magnetic interaction energy is Hmag = 0.31(9) meV/Fe. Comparison to the superconducting condensation energy E_sc = 0.013(1) meV/Fe, which we extract from specific heat data, suggests the modified magnetism we probe drives superconductivity in Fe_(1+ )Se_xTe_(1 x)

  18. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    NASA Astrophysics Data System (ADS)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  19. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

    PubMed

    Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

    2010-02-01

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water

  20. Nb{sub 3}Sn superconducting magnets for electron cyclotron resonance ion sources

    SciTech Connect

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2010-02-15

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb{sub 3}Sn superconducting technology for several years. At the moment, Nb{sub 3}Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb{sub 3}Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb{sub 3}Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb{sub 3}Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell

  1. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources

    SciTech Connect

    Ferracin, P.; Caspi, S.; Felice, H.; Leitner, D.; Lyneis, C. M.; Prestemon, S.; Sabbi, G. L.; Todd, D. S.

    2009-05-04

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb{sub 3}Sn superconducting technology for several years. At the moment, Nb{sub 3}Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb{sub 3}Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb{sub 3}Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb{sub 3}Sn- , particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell

  2. Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

    PubMed

    Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

    2010-02-01

    Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water

  3. High temperature superconductivity technology for advanced space power systems

    NASA Technical Reports Server (NTRS)

    Faymon, Karl A.; Myers, Ira T.; Connolly, Denis J.

    1990-01-01

    In 1987, the Lewis Research center of the NASA and the Argonne National Laboratory of the Department of Energy joined in a cooperative program to identify and assess high payoff space and aeronautical applications of high temperature superconductivity (HTSC). The initial emphasis of this effort was limited, and those space power related applications which were considered included microwave power transmission and magnetic energy storage. The results of these initial studies were encouraging and indicated the need of further studies. A continuing collaborative program with Argonne National Laboratory has been formulated and the Lewis Research Center is presently structuring a program to further evaluate HTSC, identify applications and define the requisite technology development programs for space power systems. This paper discusses some preliminary results of the previous evaluations in the area of space power applications of HTSC which were carried out under the joint NASA-DOE program, the future NASA-Lewis proposed program, its thrusts, and its intended outputs and give general insights on the anticipated impact of HTSC for space power applications of the future.

  4. Microtesla magnetic resonance imaging with a superconducting quantum interference device

    SciTech Connect

    McDermott, Robert; Lee, SeungKyun; ten Haken, Bennie; Trabesinger, Andreas H.; Pines, Alexander; Clarke, John

    2004-03-15

    We have constructed a magnetic resonance imaging (MRI) scanner based on a dc Superconducting QUantum Interference Device (SQUID) configured as a second-derivative gradiometer. The magnetic field sensitivity of the detector is independent of frequency; it is therefore possible to obtain high-resolution images by prepolarizing the nuclear spins in a field of 300 mT and detecting the signal at 132 fYT, corresponding to a proton Larmor frequency of 5.6 kHz. The reduction in the measurement field by a factor of 10,000 compared with conventional scanners eliminates inhomogeneous broadening of the nuclear magnetic resonance lines, even in fields with relatively poor homogeneity. The narrow linewidths result in enhanced signal-to-noise ratio and spatial resolution for a fixed strength of the magnetic field gradients used to encode the image. We present two-dimensional images of phantoms and pepper slices, obtained in typical magnetic field gradients of 100 fYT/m, with a spatial resolution of about 1mm. We further demonstrate a slice-selected image of an intact pepper. By varying the time delay between removal of the polarizing field and initiation of the spin echo sequence we acquire T1-weighted contrast images of water phantoms, some of which are doped with a paramagnetic salt; here, T1 is the nuclear spin-lattice relaxation time. The techniques presented here could readily be adapted to existing multichannel SQUID systems used for magnetic source imaging of brain signals. Further potential applications include low-cost systems for tumor screening and imaging peripheral regions of the body.

  5. Various forms of coexistence of superconductivity and magnetism in iron-pnictide superconductors: a NMR study

    NASA Astrophysics Data System (ADS)

    Bobroff, Julien

    2013-03-01

    Our NMR studies of iron pnictides allowed us to discover various forms of coexistence between superconductivity and magnetism. In Co-doped BaFe2As2, superconductivity and incommensurate antiferromagnetism coexist at the atomic level in an homogeneous state. In contrast, Ru isovalent doping leads to a disorderd situation where superconducting clusters appear in an antiferromagnetic background. Finally, in the 245 iron-selenide RbFeSe, antiferromagnetism and superconductivity separate in alternate layers of nanometer thickness. But in all these componds, the superconducting state remains similar in terms of local susceptibility and carrier doping. It looks as if, for superconductivity to appear, frozen Fe magnetic moments need to be small enough or far enough in distance, whatever the cause. Y. Texier et al., PRL 108, 237002 (2012); Y. Laplace et al., PRB Rapid Com 86, 020510(R) (2012); Y. Laplace, PRB Rapid Com 80, 140501 (2009) This work benefited from the support of the ANR PNICTIDES.

  6. Using fiberglass volumes for VPI of superconductive magnetic systems’ insulation

    SciTech Connect

    Andreev, I. S.; Bezrukov, A. A.; Pischugin, A. B.; Bursikov, A. S.; Klimchenko, Y. A.; Marushin, E. L.; Mednikov, A. A.; Rodin, I. Y.; Stepanov, D. B.

    2014-01-29

    The paper describes the method of manufacturing fiberglass molds for vacuum pressure impregnation (VPI) of high-voltage insulation of superconductive magnetic systems (SMS) with epoxidian hot-setting compounds. The basic advantages of using such vacuum volumes are improved quality of insulation impregnation in complex-shaped areas, and considerable cost-saving of preparing VPI of large-sized components due to dispensing with the stage of fabricating a metal impregnating volume. Such fiberglass vacuum molds were used for VPI of high-voltage insulation samples of an ITER reactor’s PF1 poloidal coil. Electric insulation of these samples has successfully undergone a wide range of high-voltage and mechanical tests at room and cryogenic temperatures. Some results of the tests are also given in this paper.

  7. Improved capacitive stress transducers for high-field superconducting magnets

    NASA Astrophysics Data System (ADS)

    Benson, Christopher Pete; Holik, Eddie Frank, III; Jaisle, Andrew; McInturff, A.; McIntyre, P.

    2012-06-01

    High-field (12-18 Tesla) superconducting magnets are required to enable an increase in the energy of future colliders. Such field strength requires the use of Nb3Sn superconductor, which has limited tolerance for compressive and shear strain. A strategy for stress management has been developed at Texas A&M University and is being implemented in TAMU3, a short-model 14 Tesla stress-managed Nb3Sn block dipole. The strategy includes the use of laminar capacitive stress transducers to monitor the stresses within the coil package. We have developed fabrication techniques and fixtures, which improve the reproducibility of the transducer response both at room temperature and during cryogenic operation. This is a report of the status of transducer development.

  8. Cryogenic expansion joint for large superconducting magnet structures

    DOEpatents

    Brown, Robert L.

    1978-01-01

    An expansion joint is provided that accommodates dimensional changes occurring during the cooldown and warm-up of large cryogenic devices such as superconducting magnet coils. Flattened tubes containing a refrigerant such as gaseous nitrogen (N.sub.2) are inserted into expansion spaces in the structure. The gaseous N.sub.2 is circulated under pressure and aids in the cooldown process while providing its primary function of accommodating differential thermal contraction and expansion in the structure. After lower temperatures are reached and the greater part of the contraction has occured, the N.sub.2 liquefies then solidifies to provide a completely rigid structure at the cryogenic operating temperatures of the device.

  9. Low cost composite structures for superconducting magnetic energy storage systems

    SciTech Connect

    Rix, C. ); McColskey, D. ); Acree, R. )

    1994-07-01

    As part of the Superconducting Magnetic Energy Storage/Engineering Test Model (SMES-ETM) programs, design, analysis, fabrication and test programs were conducted to evaluate the low cost manufacturing of Fiberglass Reinforced Plastic (FRP) beams for usage as major components of the structural and electrical insulation systems. These studies utilized pultrusion process technologies and vinylester resins to produce large net sections at costs significantly below that of conventional materials. Demonstration articles incorporating laminate architectures and design details representative of SMES-ETM components were fabricated using the pultrusion process and epoxy, vinylester, and polyester resin systems. The mechanical and thermal properties of these articles were measured over the temperature range from 4 K to 300 K. The results of these tests showed that the pultruded, vinylester components have properties comparable to those of currently used materials, such as G-10, and are capable of meeting the design requirements for the SMES-ETM system.

  10. Low cost composite structures for superconducting magnetic energy storage systems

    NASA Astrophysics Data System (ADS)

    Rix, Craig; McColskey, David; Acree, Robert

    1994-07-01

    As part of the Superconducting Magnetic Energy Storage/Engineering Test Model (SMES-ETM) program, design, analysis, fabrication and test programs were conducted to evaluate the low cost manufacturing of Fiberglass Reinforced Plastic (FRP) beams for usage as major components of the structural and electrical insulation systems. These studies utilized pultrusion process technologies and vinylester resins to produce large net sections at costs significantly below that of conventional materials. Demonstration articles incorporating laminate architectures and design details representative of SMES-ETM components were fabricated using the pultrusion process and epoxy, vinylester, and polyester resin systems. The mechanical and thermal properties of these articles were measured over the temperature range from 4 K to 300 K. The results of these tests showed that the pultruded, vinylester components have properties comparable to those of currently used materials, such as G-10, and are capable of meeting the design requirements for the SMES-ETM system.

  11. Damping subsynchronous resonance using superconducting magnetic energy storage unit

    SciTech Connect

    Wang, L.; Lee, S.M.; Huang, C.L. . Dept. of Electrical Engineering)

    1994-12-01

    A novel damping scheme using superconducting magnetic energy storage (SMES) unit is proposed in this paper to damp subsynchronous resonance (SSR) of the IEEE Second Benchmark Model, system-1 which is a widely employed standard model for computer simulation of SSR. The studied system contains a turbine-generator set connected to an infinite bus through two parallel transmission lines, one of which is series-capacitor compensated. In order to stabilize all SSR modes, simultaneous active and reactive power modulation and a proportional-integral-derivative (PID) damping controller designed by modal control theory are proposed for the SMES unit. Frequency-domain approach based on eigenvalue analysis and time-domain approach based on nonlinear-model simulations are performed to validate the effectiveness of the damping method. It can be concluded from the simulation results that the proposed damping scheme can effectively suppress SSR of the studied system.

  12. The fabrication and characterization of high temperature superconducting magnetic shields

    SciTech Connect

    Purpura, J.W.; Clem, T.R.

    1989-03-01

    Tubes fabricated of polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-x/ are characterized and details of the fabrication procedure are discussed. The microstructure of the tubes determined by scanning electron microscopy and x-ray diffractometry is described. Resistive measurements of T/sub c/ and /Delta/T/sub c/ have been made. The tubes have also been characterized by means of SQUID magnetometry. The temperature dependence of magnetic fields trapped axially in the tubes has been measured and estimates of penetration depth are given. Moreover, measurements of transverse shielding effectiveness of the tubes have been made and are compared with theoretical predictions. Studies on flux penetration into the tubes are described. Findings from the microstructure studies are correlated with the observed superconductivity properties. The results on the high temperature materials are compared to results obtained previously on tubes made from conventional superconductors.

  13. Epoxy resin developments for large superconducting magnets impregnation

    NASA Astrophysics Data System (ADS)

    Rey, J. M.; Gallet, B.; Kircher, F.; Lottin, J. C.

    The future detectors ATLAS and CMS of the Large Hadron Collider at CERN will use two huge superconducting magnets. Both are now under design, and their electrical insulation could be realized using epoxy resin and a wet impregnation technique. Because of their large dimensions, and the indirect cooling of the superconductor, the strengths of the resin and of the resin/conductor interface are of major importance. A new generation of epoxy resins for vacuum/pressure impregnation methods has been tested, and compared with some classical and well-known epoxy resins used in impregnation techniques. In order to understand the mechanical behaviour at 4 K, the complete evolution from liquid state to low temperature service condition is considered. The paper will present some results on the mechanical properties, the density and the chemical shrinkage occurring during the polymerization and the thermal contraction between room temperature and 4 K for these different types of epoxy resins.

  14. Superconducting FCL using a combined inducted magnetic field trigger and shunt coil

    DOEpatents

    Tekletsadik, Kasegn D.

    2007-10-16

    A single trigger/shunt coil is utilized for combined induced magnetic field triggering and shunt impedance. The single coil connected in parallel with the high temperature superconducting element, is designed to generate a circulating current in the parallel circuit during normal operation to aid triggering the high temperature superconducting element to quench in the event of a fault. The circulating current is generated by an induced voltage in the coil, when the system current flows through the high temperature superconducting element.

  15. Superconducting properties of experimental YBCO coils for FFAG accelerator magnets

    NASA Astrophysics Data System (ADS)

    Takayama, S.; Koyanagi, K.; Tosaka, T.; Tasaki, K.; Kurusu, T.; Ishii, Y.; Amemiya, N.; Ogitsu, T.

    2014-05-01

    A project to develop fundamental technologies for accelerator magnets using high-Tc coated conductors is currently in progress. The primary applications of this project are fixed field alternating gradient (FFAG) accelerators for carbon cancer therapy systems and accelerator-driven subcritical reactors. Several types of superconducting coils for FFAG accelerators have been conceptually designed. These coils have complicated shapes, including a negative-bend part or a three-dimensional bent part. One of the aims of the project is to establish winding technologies for complicated coil shapes using coated conductors. To demonstrate winding technologies for YBa2Cu3O7-x (YBCO) coils, small test coils having a negative-bend part or a three-dimensional bent part were designed and fabricated according to the present design of the FFAG magnet. The outside dimensions of the negative-bend test coil were 460 mm long and 190 mm wide, and the radius of curvature of the negative-bend part was 442 mm. The outside dimensions of the three-dimensional test coil were 380 mm long and 280 mm wide, and the radius of curvature of the mandrel of the three-dimensional coil was 700 mm. The test coils were wound using YBCO coated conductors with a length of about 100 m and were then impregnated with epoxy resin. The coils were placed in liquid nitrogen and excited to measure their V-I characteristics. From the V-I characteristics throughout a voltage range down to 10-9 V/cm, the V-I characteristics before and after impregnation were approximately the same, demonstrating that the superconducting properties were not degraded.

  16. Acoustic emission during quench training of superconducting accelerator magnets

    NASA Astrophysics Data System (ADS)

    Marchevsky, M.; Sabbi, G.; Bajas, H.; Gourlay, S.

    2015-07-01

    Acoustic emission (AE) sensing is a viable tool for superconducting magnet diagnostics. Using in-house developed cryogenic amplified piezoelectric sensors, we conducted AE studies during quench training of the US LARP's high-field quadrupole HQ02 and the LBNL's high-field dipole HD3. For both magnets, AE bursts were observed, with spike amplitude and frequency increasing toward the quench current during current up-ramps. In the HQ02, the AE onset upon current ramping is distinct and exhibits a clear memory of the previously-reached quench current (Kaiser effect). On the other hand, in the HD3 magnet the AE amplitude begins to increase well before the previously-reached quench current (felicity effect), suggesting an ongoing progressive mechanical motion in the coils. A clear difference in the AE signature exists between the untrained and trained mechanical states in HD3. Time intervals between the AE signals detected at the opposite ends of HD3 coils were processed using a combination of narrow-band pass filtering; threshold crossing and correlation algorithms, and the spatial distributions of AE sources and the mechanical energy release were calculated. Both distributions appear to be consistent with the quench location distribution. Energy statistics of the AE spikes exhibits a power-law scaling typical for the self-organized critical state.

  17. Superconducting magnetic Wollaston prism for neutron spin encoding

    SciTech Connect

    Li, F. Parnell, S. R.; Wang, T.; Baxter, D. V.; Hamilton, W. A.; Maranville, B. B.; Semerad, R.; Cremer, J. T.; Pynn, R.

    2014-05-15

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ∼30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ∼98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  18. Potential damage to dc superconducting magnets due to high frequency electromagnetic waves

    NASA Technical Reports Server (NTRS)

    Gabriel, G. J.; Burkhart, J. A.

    1977-01-01

    Studies of a d.c. superconducting magnet coil indicate that the large coil behaves as a straight waveguide structure. Voltages between layers within the coil sometimes exceeded those recorded at terminals where protective resistors are located. Protection of magnet coils against these excessive voltages could be accomplished by impedance matching throughout the coil system. The wave phenomenon associated with superconducting magnetic coils may create an instability capable of converting the energy of a quiescent d.c. superconducting coil into dissipative a.c. energy, even in cases when dielectric breakdown does not take place.

  19. Robustness of superconductivity to competing magnetic phases in tetragonal FeS

    NASA Astrophysics Data System (ADS)

    Kirschner, Franziska K. K.; Lang, Franz; Topping, Craig V.; Baker, Peter J.; Pratt, Francis L.; Wright, Sophie E.; Woodruff, Daniel N.; Clarke, Simon J.; Blundell, Stephen J.

    2016-10-01

    We have determined the superconducting and magnetic properties of a hydrothermally synthesized powder sample of tetragonal FeS using muon spin rotation (μ SR ) . The superconducting properties are entirely consistent with those of a recently published study, showing fully gapped behavior and giving a penetration depth of λa b=204 (3 ) nm. However, our zero-field μ SR data are rather different and indicate the presence of a small, nonsuperconducting magnetic phase within the sample. These results highlight that sample-to-sample variations in magnetism can arise in hydrothermally prepared phases, but interestingly the superconducting behavior is remarkably insensitive to these variations.

  20. Electromagnetically superconducting phase of QCD vacuum induced by strong magnetic field

    SciTech Connect

    Chernodub, M. N.

    2011-05-23

    In this talk we discuss our recent suggestion that the QCD vacuum in a sufficiently strong magnetic field (stronger than 10{sup 16} Tesla) may undergo a spontaneous transition to an electromagnetically superconducting state. The possible superconducting state is anisotropic (the vacuum exhibits superconductivity only along the axis of the uniform magnetic field) and inhomogeneous (in the transverse directions the vacuum structure shares similarity with the Abrikosov lattice of an ordinary type-II superconductor). The electromagnetic superconductivity of the QCD vacuum is suggested to occur due to emergence of specific quark-antiquark condensates which carry quantum numbers of electrically charged rho mesons. A Lorentz-covariant generalization of the London transport equations for the magnetic-field-induced superconductivity is given.

  1. Analysis of line integrated electron density using plasma position data on Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Nam, Y. U.; Chung, J.

    2010-10-15

    A 280 GHz single-channel horizontal millimeter-wave interferometer system has been installed for plasma electron density measurements on the Korea Superconducting Tokamak Advanced Research (KSTAR) device. This system has a triangular beam path that does not pass through the plasma axis due to geometrical constraints in the superconducting tokamak. The term line density on KSTAR has a different meaning from the line density of other tokamaks. To estimate the peak density and the mean density from the measured line density, information on the position of the plasma is needed. The information has been calculated from tangentially viewed visible images using the toroidal symmetry of the plasma. Interface definition language routines have been developed for this purpose. The calculated plasma position data correspond well to calculation results from magnetic analysis. With the position data and an estimated plasma profile, the peak density and the mean density have been obtained from the line density. From these results, changes of plasma density themselves can be separated from effects of the plasma movements, so they can give valuable information on the plasma status.

  2. Superconducting Pb stripline resonators in parallel magnetic field and their application for microwave spectroscopy

    NASA Astrophysics Data System (ADS)

    Ebensperger, Nikolaj G.; Thiemann, Markus; Dressel, Martin; Scheffler, Marc

    2016-11-01

    Planar superconducting microwave resonators are key elements in a variety of technical applications and also act as sensitive probes for microwave spectroscopy of various materials of interest in present solid state research. Here superconducting Pb is a suitable material as a basis for microwave stripline resonators. To utilize Pb stripline resonators in a variable magnetic field (e.g. in ESR measurements), the electrodynamics of such resonators in a finite magnetic field has to be fully understood. Therefore we performed microwave transmission measurements (with ample applied power to work in linear response) on superconducting Pb stripline resonators in a variable, parallel magnetic field. We determined surface resistance, penetration depth, as well as real and imaginary parts, {σ }1 and {σ }2, of the complex conductivity of superconducting Pb as a function of a magnetic field. Here we find features reminiscent of those in temperature-dependent measurements, such as a maximum in {σ }1 (coherence peak). At magnetic fields above the critical field of this type-I superconductor we still find a low-loss microwave response, which we assign to remaining superconductivity in the form of filaments within the Pb. Hysteresis effects are found in the quality factor of resonances once the swept magnetic field has exceeded the critical magnetic field. This is due to normal conducting areas that are pinned and can therefore persist in the superconducting phase. Besides zero-field-cooling we show an alternative way to eliminate these even at T\\lt {T}c. Based on our microwave data, we also determine the critical magnetic field and the critical temperature of Pb in a temperature range between 1.6 K and 6.5 K and magnetic fields up to 140 mT, showing good agreement with BCS predictions. We also study a Sn sample in a Pb resonator to demonstrate the applicability of superconducting Pb stripline resonators in the experimental study of other (super-)conducting materials in a

  3. Interplay between superconductivity and magnetism in Fe(1-x)Pd(x)Te.

    PubMed

    Karki, Amar B; Garlea, V Ovidiu; Custelcean, Radu; Stadler, Shane; Plummer, E W; Jin, Rongying

    2013-06-01

    The attractive/repulsive relationship between superconductivity and magnetic ordering has fascinated the condensed matter physics community for a century. In the early days, magnetic impurities doped into a superconductor were found to quickly suppress superconductivity. Later, a variety of systems, such as cuprates, heavy fermions, and Fe pnictides, showed superconductivity in a narrow region near the border to antiferromagnetism (AFM) as a function of pressure or doping. However, the coexistence of superconductivity and ferromagnetic (FM) or AFM ordering is found in a few compounds [RRh4B4 (R = Nd, Sm, Tm, Er), R'Mo6X8 (R' = Tb, Dy, Er, Ho, and X = S, Se), UMGe (M = Ge, Rh, Co), CeCoIn5, EuFe2(As(1-x)P(x))2, etc.], providing evidence for their compatibility. Here, we present a third situation, where superconductivity coexists with FM and near the border of AFM in Fe(1-x)Pd(x)Te. The doping of Pd for Fe gradually suppresses the first-order AFM ordering at temperature T(N/S), and turns into short-range AFM correlation with a characteristic peak in magnetic susceptibility at T'(N). Superconductivity sets in when T'(N) reaches zero. However, there is a gigantic ferromagnetic dome imposed in the superconducting-AFM (short-range) cross-over regime. Such a system is ideal for studying the interplay between superconductivity and two types of magnetic (FM and AFM) interactions.

  4. Interplay between superconductivity and magnetism in Fe1−xPdxTe

    PubMed Central

    Karki, Amar B.; Garlea, V. Ovidiu; Custelcean, Radu; Stadler, Shane; Plummer, E. W.; Jin, Rongying

    2013-01-01

    The attractive/repulsive relationship between superconductivity and magnetic ordering has fascinated the condensed matter physics community for a century. In the early days, magnetic impurities doped into a superconductor were found to quickly suppress superconductivity. Later, a variety of systems, such as cuprates, heavy fermions, and Fe pnictides, showed superconductivity in a narrow region near the border to antiferromagnetism (AFM) as a function of pressure or doping. However, the coexistence of superconductivity and ferromagnetic (FM) or AFM ordering is found in a few compounds [RRh4B4 (R = Nd, Sm, Tm, Er), R′Mo6X8 (R′ = Tb, Dy, Er, Ho, and X = S, Se), UMGe (M = Ge, Rh, Co), CeCoIn5, EuFe2(As1−xPx)2, etc.], providing evidence for their compatibility. Here, we present a third situation, where superconductivity coexists with FM and near the border of AFM in Fe1−xPdxTe. The doping of Pd for Fe gradually suppresses the first-order AFM ordering at temperature TN/S, and turns into short-range AFM correlation with a characteristic peak in magnetic susceptibility at T′N. Superconductivity sets in when T′N reaches zero. However, there is a gigantic ferromagnetic dome imposed in the superconducting-AFM (short-range) cross-over regime. Such a system is ideal for studying the interplay between superconductivity and two types of magnetic (FM and AFM) interactions. PMID:23690601

  5. Interplay between Superconductivity and Magnetism in Fe1-xPdxTe

    SciTech Connect

    Karki, A B; Garlea, Vasile O; Custelcean, Radu; Stadler, S.; Plummer, E. W.; Jin, Rongying

    2013-01-01

    The love/hate relationship between superconductivity and magnetic ordering has fascinated the condensed matter physics community for a century. In the early days, magnetic impurities doped into a superconductor were found to quickly suppress superconductivity. Later, a variety of systems, such as cuprates, heavy fermions and Fe pnictides, show superconductivity in a narrow region near the border to antiferromagnetism (AFM) as a function of pressure or doping. On the other hand, the coexistence of superconductivity and ferromagnetic (FM) or AFM ordering is found in a few compounds (RRh4B4 (R = Nd, Sm, Tm, Er), R'Mo6X8 (R' = Tb, Dy, Er, Ho, and X = S, Se), UMGe (M = Ge, Rh, Co), CeCoIn5, EuFe2(As1-xPx)2 etc.), providing evidence for their compatibility. Here, we present a third situation, where superconductivity coexists with FM and near the border of AFM in Fe1-xPdxTe. The doping of Pd for Fe gradually suppresses the first-order AFM ordering at temperature TN/S, and turns into short-range (SR) AFM correlation with a characteristic peak in magnetic susceptibility at T'N. Superconductivity sets in when T'N reaches zero. However, there is a gigantic ferromagnetic dome imposed in the superconducting-AFM (SR) crossover regime. Such a system is ideal for studying the interplay between superconductivity and two types of magnetic interactions (FM and AFM).

  6. Suite of three protein crystallography beamlines with single superconducting bend magnet as the source

    SciTech Connect

    MacDowell, Alastair A.; Celestre, Richard S.; Howells, Malcolm; McKinney, Wayne; Krupnick, James; Cambie, Daniella; Domning, Edward E; Duarte, Robert M.; Kelez, Nicholas; Plate, David W.; Cork, Carl W.; Earnest, Thomas N.; Dickert, Jeffery; Meigs, George; Ralston, Corie; Holton, James M.; Alber, Thomas; Berger, James M.; Agard, David A.; Padmore, Howard A.

    2004-08-01

    At the Advanced Light Source (ALS), three protein crystallography (PX) beamlines have been built that use as a source one of the three 6 Tesla single pole superconducting bending magnets (superbends) that were recently installed in the ring. The use of such single pole superconducting bend magnets enables the development of a hard x-ray program on a relatively low energy 1.9 GeV ring without taking up insertion device straight sections. The source is of relatively low power, but due to the small electron beam emittance, it has high brightness. X-ray optics are required to preserve the brightness and to match the illumination requirements for protein crystallography. This was achieved by means of a collimating premirror bent to a plane parabola, a double crystal monochromator followed by a toroidal mirror that focuses in the horizontal direction with a 2:1 demagnification. This optical arrangement partially balances aberrations from the collimating and toroidal mirrors such that a tight focused spot size is achieved. The optical properties of the beamline are an excellent match to those required by the small protein crystals that are typically measured. The design and performance of these new beamlines are described.

  7. New Challenges in Superconductivity: Experimental Advances and Emerging Theories

    NASA Astrophysics Data System (ADS)

    Ashkenazi, J.; Eremin, Mikhail V.; Cohn, Joshua L.; Eremin, Ilya; Manske, Dirk; Pavuna, Davor; Zuo, Fuliln

    This volume contains the proceedings of the 2004 University of Miami Workshop onUnconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-TC Superconductivity and related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The volume includes high-quality papers on state of the art works on unconventional superconductivity. A key issue, discussed by many in the workshop, was how homogeneous the cuprates are.

  8. Electromagnetic characteristics of the superconducting magnets for the 28-GHz ECR ion source

    NASA Astrophysics Data System (ADS)

    Lee, Hongseok; Kang, Jong O.; Kang, Hyoungku; Heo, Jeong Il; Choi, Sukjin; Kim, Yong Hwan; Hong, Jonggi

    2015-02-01

    Many laboratories have been involved in the development of electron cyclotron resonance (ECR) ion source for linear accelerators all over the world. The superconducting magnets for the 28-GHz ECR ion source consist of a Hexapole Coil and four Solenoid Coils. The Solenoid Coils produce an axial mirror magnetic field, and the Hexapole Coil produces a radial magnetic field. In this paper, the specifications of the superconducting magnets for the 28-GHz ECR ion source are deduced by using the finite-element method (FEM) to perform simulations. The research presents the result of analyses on the magnetic field and the electromagnetic force of the superconducting magnets for the ECR ion source for different the conditions of the Inner Yokes. The design of the Inner Yokes for a Hexapole Coil is performed to enhance the characteristics of the radial magnetic field and to lower the operating current level.

  9. Performance of conduction cooled splittable superconducting magnet package for linear accelerators

    DOE PAGES

    Kashikhin, Vladimire S.; Andreev, N.; Cheban, S.; DiMarco, J.; Kimura, N.; Makarov, A.; Orlov, Y.; V. Poloubotko; Tartaglia, M.; Yamamoto, A.

    2016-02-19

    New Linear Superconducting Accelerators need a superconducting magnet package installed inside SCRF Cryomodules to focus and steer electron or proton beams. A superconducting magnet package was designed and built as a collaborative effort of FNAL and KEK. The magnet package includes one quadrupole, and two dipole windings. It has a splittable in the vertical plane configuration, and features for conduction cooling. The magnet was successfully tested at room temperature, in a liquid He bath, and in a conduction cooling experiment. The paper describes the design and test results including: magnet cooling, training, and magnetic measurements by rotational coils. Furthermore, themore » effects of superconductor and iron yoke magnetization, hysteresis, and fringe fields are discussed.« less

  10. Two-dimensional Magnetism in Arrays of Superconducting Rings

    NASA Astrophysics Data System (ADS)

    Reich, Daniel H.

    1996-03-01

    An array of superconducting rings in an applied field corresponding to a flux of Φ0 /2 per ring behaves like a 2D Ising antiferromagnet. Each ring has two energetically equivalent states with equal and opposite magnetic moments due to fluxoid quantization, and the dipolar coupling between rings favors antiparallel alignment of the moments. Using SQUID magnetometry and scanning Hall probe microscopy, we have studied the dynamics and magnetic configurations of micron-size aluminum rings on square, triangular, honeycomb, and kagomé lattices. We have found that there are significant antiferromagnetic correlations between rings, and that effects of geometrical frustration can be observed on the triangular and kagomé lattices. Long range correlations on the other lattices are suppressed by the analog of spin freezing that locks the rings in metastable states at low temperatures, and by quenched disorder due to imperfections in the fabrication. This disorder produces a roughly 1% variation in the rings' areas, which translates into an effective random field on the spins. The ring arrays are thus an extremely good realization of the 2D random-field Ising model. (Performed in collaboration with D. Davidović, S. Kumar, J. Siegel, S. B. Field, R. C. Tiberio, R. Hey, and K. Ploog.) (Supported by NSF grants DMR-9222541, and DMR-9357518, and by the David and Lucile Packard Foundation.)

  11. Method and apparatus for making superconductive magnet coils

    DOEpatents

    Borden, A.R.

    1983-11-07

    A curved, shell-type magnet coil, adapted to be used in a superconducting magnet, is wound by providing a mandrel having a tubular cylindrical mid-portion terminating at both ends in tapered end portions formed with longitudinal slots having flexible fingers therebetween. An elongated electrical conductor is wound around an elongated oval-shaped pole island engaged with the outside of the cylindrical mid-portion, to form a multiplicity of oval-shaped turns engaged with a 180-degree segment of the mandrel. The coil turns have longitudinal portions with curved portions therebetween, engaging the tapered end portions of the mandrel. Upon completion of the winding, tapered expansion members are fully inserted into the tapered end portions, to displace the flexible fingers outwardly into a cylindrical form and to displace the curved portions of the turns into a shape conforming to such cylindrical form while also exerting increased tension upon the turns to minimize draping of the turns and to enhance the mechanical integrity of the coil. A half cylinder clamp may then be employed to clamp the coil, whereupon the coil may be solidified by the use of an epoxy adhesive.

  12. Method and apparatus for making superconductive magnet coils

    DOEpatents

    Borden, Albert R.

    1985-01-01

    A curved, shell-type magnet coil, adapted to be used in a superconducting magnet, is wound by providing a mandrel having a tubular cylindrical mid-portion terminating at both ends in tapered end portions formed with longitudinal slots having flexible fingers therebetween. An elongated electrical conductor is wound around an elongated oval-shaped pole island engaged with the outside of the cylindrical mid-portion, to form a multiplicity of oval-shaped turns engaged with a 180-degree segment of the mandrel. The coil turns have longitudinal portions with curved portions therebetween, engaging the tapered end portions of the mandrel. Upon completion of the winding, tapered expansion members are fully inserted into the tapered end portions, to displace the flexible fingers outwardly into a cylindrical form and to displace the curved portions of the turns into a shape conforming to such cylindrical form while also exerting increased tension upon the turns to minimize draping of the turns and to enhance the mechanical integrity of the coil. A half cylinder clamp may then be employed to clamp the coil, whereupon the coil may be solified by the use of an epoxy adhesive.

  13. Superconducting plate in a transverse magnetic field: New state

    SciTech Connect

    Batyev, E. G.

    2012-07-15

    A model is proposed for describing Cooper pairs near the transition (in temperature and magnetic field) point when their spacing is larger than their size. The essence of the model is as follows: the Ginzburg-Landau functional is written in operator form in terms of field operators of the Bose type so that the average value of the density operator gives the concentration of Cooper pairs, and the same Ginzburg-Landau expression is obtained for the Bose condensate. The model is applied to a superconducting plate with a thickness smaller than the size of a pair in a transverse magnetic field near its upper critical value H{sub c2}. A new state is discovered that is energetically more advantageous in a certain interval in the vicinity of the transition point as compared to the Abrikosov vortex state. The wavefunction of the system in this state is of the type of the Laughlin function used in the fractional quantum Hall effect (naturally, as applied to Cooper pairs as Bose particles in our case) and corresponds to a homogeneous incompressible fluid. The energy of this state is proportional to the first power of quantity (1 - H/H{sub c2}) in contrast to the energy of the vortex state containing the square of this quantity. The interval of the existence of the new state is the larger, the dirtier the sample.

  14. Assessment of some of the problems in the USA of superconducting magnets for fusion research

    SciTech Connect

    Cornish, D.N.

    1981-11-05

    This paper discusses some of the general difficulties and problems encountered during the development of the technology of superconductors and superconducting magnets for fusion and expresses some personal concerns.

  15. Study of some superconducting and magnetic materials on high T sub c oxide superconductors

    NASA Technical Reports Server (NTRS)

    Wu, M. K.

    1987-01-01

    On the basis of existing data it appears that the high-temperature superconductivity above 77 K reported here, occurs only in compound systems consisting of a phase other than the K2NiF4 phase. A narrow superconducting transition was obtained with T sub c0 = 98 K and T sub c1 = 94 K in Y-Ba-Cu-O (YBCO). Preliminary results indicate that YBCO is rather different from the layered LaBCO, LaSCO, and LaCCO. While electron-photon interaction cannot be absent from this compound system, nonconventional enhanced superconducting interactions due to interfaces, Resonating Valence Bond (RVB) states, or even a superconducting state beyond the BCS framework, may be required to account for the high T sub c in YBCO. It is believed that study of the possible subtle correlation between magnetism and superconductivity will definitely provide important insight into the superconducting mechanism in YBCO and other oxides.

  16. Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet

    SciTech Connect

    Benjegerdes, R.; Bish, P.; Byford, D.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, R.; Hannaford, R.; Higley, H.; Jackson, A.; Lietzke, A.; Liggins, N.; McInturff, A.D.; O'Neill, J.; Palmerston, E.; Sabbi, G.; Scanlan, R.M.; Swanson, J.

    2001-06-15

    The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb{sub 3}Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and tested results are discussed.

  17. High Tc superconducting magnetic multivibrators for fluxgate magnetic-field sensors

    SciTech Connect

    Mohri, K.; Uchiyama, T.; Ozeki, A. . Faculty of Engineering)

    1989-09-01

    Sensitive and quick-response nonlinear inductance characteristics are found for high Tc superconducting (YBa/sub 2/Cu/sub 3/O/sub 7-chi/) disk cores at 77K in which soft magnetic BH hysteresis loops are observed. Various quick response magnetic devices such as modulators, amplifiers and sensors are built using these cores. The magnetizing frequency can be set to more than 20 MHz, which is difficult for conventional ferromagnetic bulk materials such as Permalloy amorphous alloys and ferrite. New quick-response fluxgate type magnetic-field sensors are made using ac and dc voltage sources. The former is used for second-harmonic type sensors, while the latter is for voltage-output multivibrator type sensors. Stable and quick-response sensor characteristics were obtained for two-core type multivibrators.

  18. Three-dimensional magnetic field analysis of superconducting 180 degrees bending magnets

    SciTech Connect

    Nakata, J.; Nakajima, M.; Hosokawa, T.; Kitayama, T. )

    1990-03-01

    To design the superconducting 180{degrees} bending magnets for compact electron storage rings used in SOR lithography, large-scale 3-dimensional (3-D) magnetic field analyses were performed. Three types of magnets, -- air core, iron yoke, and iron pole -- were minutely computed. Optimizing the coil positions and iron yoke configurations, were found the proper parameters for obtaining wide good field regions along the electron orbit, for all three types. This paper discusses how the iron yoke type was minutely studied an very low liquid helium consumption, wide good field regions that were not changed from low to high field, very low stray fields around the magnet and good tracking controllability could be obtained.

  19. Recent advances in magnetic heat pump technology

    NASA Astrophysics Data System (ADS)

    Uherka, Kenneth L.; Hull, John R.; Scheihing, Paul E.

    Magnetic heat pump (MHP)/refrigeration systems, incorporating state-of-the-art superconducting magnet technology, were assessed for industrial applications ranging from the liquefaction of gases (20 K to 100 K range) to cold storage refrigeration for food preservation (250 K to 320 K range). Initial market penetration of MHP technology is anticipated to occur in the gas liquefaction sector, since the performance advantages of magnetic refrigeration cycles relative to gas compression cycles and other conventional systems are more pronounced in the lower temperature ranges. Design options for rotary MHP devices include alternative regeneration schemes to obtain the temperature spans necessary for industrial applications. The results of preliminary design assessment studies indicate that active magnetic regenerator concepts, in which the magnetic working material also serves as the regenerative medium, offer advantages over alternative MHP designs for industrial applications.

  20. A Single-band Cold Mass Support System for the MICE Superconducting Coupling Magnet

    SciTech Connect

    Wu, Hong; Wang, Li; Liu, X.K.; Liu, C.S.; Li, L.K.; Xu, Feng Yu; Jia, Lin X.; Green, Michael A.

    2008-04-02

    The cooling channel of the Muon Ionization Cooling Experiment (MICE) consists of eighteen superconducting solenoid coils, which are magnetically hooked together and contained in seven modules. The operations of a pair of MICE superconducting coupling magnets are affected directly by the other solenoid coils in the MICE channel. In order to meet the stringent requirement for the magnet center and axis azimuthal angle at 4.2 K, a self-centered tension-band cold mass support system with intermediate thermal interruption was applied for the MICE superconducting coupling magnet. The physical center of the magnet does not change as it is cooled down from 300 K to 4.2 K using this support system. This paper analyzed and calculated force loads on the coupling magnet under various operation modes of the MICE cooling channel. The performance parameters of a single-band cold mass support system were calculated also.

  1. High-field magnets using high-critical-temperature superconducting thin films

    DOEpatents

    Mitlitsky, Fred; Hoard, Ronald W.

    1994-01-01

    High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field.

  2. High-field magnets using high-critical-temperature superconducting thin films

    DOEpatents

    Mitlitsky, F.; Hoard, R.W.

    1994-05-10

    High-field magnets fabricated from high-critical-temperature superconducting ceramic (HTSC) thin films which can generate fields greater than 4 Tesla are disclosed. The high-field magnets are made of stackable disk-shaped substrates coated with HTSC thin films, and involves maximizing the critical current density, superconducting film thickness, number of superconducting layers per substrate, substrate diameter, and number of substrates while minimizing substrate thickness. The HTSC thin films are deposited on one or both sides of the substrates in a spiral configuration with variable line widths to increase the field. 4 figures.

  3. Magnetism, structure and superconductivity in CaFe2As2

    SciTech Connect

    Park, Tuson O; Lee, Han; Ronning, Filip; Bauer, Eric D; Thompson, Joe D

    2008-01-01

    Tbe spin-density-wave (SDW) anti ferromagnet CaFe{sub 2}As{sub 2} becomes superconducting under pressure. By measuring electrical resistivity and magnetic susceptibility under pressure, we show that bulk superconductivity is present in a narrow pressure range where a collapsed tetrgaonal structure is favored. At higher pressures, a new low-temperature structure appears, with the boundary between this new structure and the collapsed tetragonal structure strongly dependent on pressure history. Magnetic fluctuations in the collapsed phase appear to be important for superconductivity.

  4. Analytical design of a superconducting magnetic energy storage for pulsed power peak

    SciTech Connect

    Netter, D.; Leveque, J.; Rezzoug, A.; Caron, J.P.; Sargos, F.M.

    1996-09-01

    A Superconducting Magnetic Energy Storage can be used to produce very high pulsed power peak. A superconducting coil is magnetically coupled with another coil linked to the load. During the storage phase, the current is constant. In order to transfer the energy to the load, the authors cause the quench of the superconducting coil. It is very important to know the efficiency of the transfer and how much energy is discharged in the Helium vessel. In this paper, they propose an analytical method which enables to calculate very quickly the electrical parameters of such a device.

  5. Superconducting RF cavities and magnets for a 4-TeV energy muon collider

    SciTech Connect

    Shu, Q.S. |; Green, M.; Neuffer, D.; Summers, D.; Simrock, S.; Willen, E.

    1997-11-01

    The accelerators must take the muon beams from {approximately} 100 MeV to 2 TeV energies within the muon lifetime for a 4 TeV energy muon collider. These constraints plus the muon decay heating seriously challenge the designs of the superconducting RF (SRF) cavities and magnets in the accelerators and collider ring. The multiple superconducting recirculation linac and the very rap8id-cycling superconducting synchrotron approach are both studied. The authors briefly introduce the technical considerations and preliminary designs of the SRF systems and magnets.

  6. Advances in the development of piezoelectric quartz-crystal oscillators, hydrogen masers, and superconducting frequency standards

    NASA Technical Reports Server (NTRS)

    Suter, Joseph J.

    1988-01-01

    This paper describes recent research advances made in the development of radiation-hardened piezoelectric quartz oscillators, hydrogen masers, and superconducting oscillators, with emphasis placed on the principles involved in the operation of these oscillators and the factors affecting the operation. Particular attention is given to the radiation-susceptibility studies of quartz-crystal resonators, the hydrogen-maser relaxation process and noise sources, and low-phase-noise superconducting oscillators. Diagrams of these devices and performance graphs are included.

  7. Jefferson Lab CLAS12 Superconducting Solenoid magnet Requirements and Design Evolution

    SciTech Connect

    Rajput-Ghoshal, Renuka; Hogan, John P.; Fair, Ruben J.; Ghoshal, Probir K.; Luongo, Cesar; Elouadrhiri, Latifa

    2014-12-01

    As part of the Jefferson Lab 12GeV accelerator upgrade project, one of the experimental halls (Hall B) requires two superconducting magnets. One is a magnet system consisting of six superconducting trapezoidal racetrack-type coils assembled in a toroidal configuration and the second is an actively shielded solenoidal magnet system consisting of 5 coils. In this presentation the physics requirements for the 5 T solenoid magnet, design constraints, conductor decision, and cooling choice will be discussed. The various design iterations to meet the specification will also be discussed in this presentation.

  8. Zeeman effect in superconducting two-leg ladders: irrational magnetization plateaus and exceeding the Pauli limit.

    PubMed

    Roux, G; White, S R; Capponi, S; Poilblanc, D

    2006-08-25

    The effect of a parallel magnetic field on superconducting two-leg ladders is investigated numerically. The magnetization curve displays an irrational plateau at a magnetization equal to the hole density. Remarkably, its stability is fundamentally connected to the existence of a well-known magnetic resonant mode. Once the zero-field spin gap is suppressed by the field, pairs acquire a finite momentum characteristic of a Fulde-Ferrell-Larkin-Ovchinnikov phase. In addition, Sz = 0 triplet superconducting correlations coexist with singlet ones above the irrational plateau. This provides a simple mechanism in which the Pauli limit is exceeded as suggested by recent experiments.

  9. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    SciTech Connect

    Boom, R.W.; Abdelsalam, M.K.; Bakerek, K.; Britcher, C.P.; Esking, J.; Eyssa, Y.M.; Goodyer, M.J.; McIntosh, G.E.; Scurlock, R.G.; Wu, Y.Y.

    1985-03-01

    This paper presents a new design study of a Magnetic Suspension and Balance System (MSBS) for airplane models in a large 8 ft x 8 ft wind tunnel. New developments in the design include: use of a superconducting solenoid as a model core instead of magnetized iron; combination of permanent magnet material in the model wings along with four race-track coils to produce the required roll torque; and mounting of all the magnets in an integral cold structure instead of in separate cryostats. Design of superconducting solenoid model cores and practical experience with a small-scale prototype are discussed.

  10. Research & Development on Superconducting Niobium Materials via Magnetic Measurements

    SciTech Connect

    S. B. Roy, V. C. Sahni, and G. R. Myneni

    2011-03-01

    We present a study of superconducting properties of both large grain (1 mm average grain size) and small grain (50 micron average grain size) Niobium materials containing varying amounts of Tantalum impurities that have been used in the fabrication of high accelerating gradient superconducting radio frequency cavities. We found that a buffered chemical polishing of these Niobium samples causes a distinct reduction in the superconducting parameters like TC, wt- ppm to 1300 wt-ppm. Implications of these results on the performance of niobium superconducting radio frequency cavities are discussed, especially the anomalous high field RF losses that have been reported in the literature.

  11. Medical protein separation system using high gradient magnetic separation by superconducting magnet

    NASA Astrophysics Data System (ADS)

    Kamioka, Y.; Agatsuma, K.; Kajikawa, K.; Ueda, H.; Furuse, M.; Fuchino, S.; Iitsuka, T.; Nakamura, S.

    2014-01-01

    A high gradient magnetic separation system for medical protein using affinity magnetic nano-beads has been developed. Medical protein such as monoclonal antibody or immunoglobulin is an important substance as a medicine for cancer etc. However; the separation system of these medical protein has very low separation rate and the cost of product is extremely high. The developed system shows very high separation efficiency and can achieve low cost by large production rate compared to the system now using in this field. The system consists of a 3T superconducting magnet cooled by a cryo-cooler, a filter made of fine magnetic metal wires of about 30μm diameter and a demagnetization circuit and a liquid circulation pump for solvent containing medical protein. Affinity magnetic nano-beads is covered with the medical protein after agitation of solvent containing the protein and nano-beads, then the solvent flows through the system and the beads are trapped in the filters by high gradient magnetic field. The beads are released and flow out of the system by the AC demagnetization of the filters using LC resonance circuits after discharge of the magnet. The test results shows 97.8% of the magnetic nano-beads in pure water were captured and 94.1% of total beads were collected.

  12. Biological effects of magnetic fields from superconducting magnetic energy storage systems

    SciTech Connect

    Tenforde, T.S.

    1989-12-01

    Physical interaction mechanisms and potential biological effects of static and slowly time-varying magnetic fields are summarized. The results of laboratory and human health studies on this topic are related to the fringe magnetic field levels anticipated to occur in the proximity of superconducting magnetic energy storage (SMES) systems. The observed biological effects of magnetic fields include: (1) magnetic induction of electrical potentials in the circulatory system and other tissues, (2) magneto-orientation of macromolecules and membranes in strong magnetic fields, and (3) Zeeman interactions with electronic spin states in certain classes of charge transfer reactions. In general, only the first of these interactions is relevant to the establishment of occupational exposure guidelines. Physical hazards posed by the interactions of magnetic fields with cardiac pacemakers and other implanted medical devices, e.g., aneurysm clips and prostheses, are important factors that must also be considered in establishing exposure guidelines. Proposed guidelines for limiting magnetic field exposure are discussed. 50 refs., 1 fig.

  13. Evaluation of Superconducting Magnet Shield Configurations for Long Duration Manned Space Missions

    PubMed Central

    Ambroglini, Filippo; Battiston, Roberto; Burger, William J.

    2016-01-01

    A manned mission to Mars would present an important long-term health risk to the crew members due to the prolonged exposure to the ionizing radiation of galactic cosmic-rays. The radiation levels would largely exceed those encountered in the Apollo missions. An increase in the passive shielding provided by the spacecraft implies a significant increase of the mass. The advent of superconducting magnets in the early 1960s was considered an attractive alternative. The technology allows to generate magnetic fields capable to deflect the cosmic-rays in a manner analogous to the reduction of the particle fluxes in the upper atmosphere due to the Earth’s dipole magnetic field. A series of the three studies have been conducted over the last 5 years, funded successively by European Space Agency (ESA), the NASA Innovative Advanced Concepts (NIAC) program, and the Union European’s Seventh Framework Programme (FP7). The shielding configurations studied are based on high-temperature superconductors, which eliminate the need to operate with liquid helium. The mass estimates of the coils and supporting structure of the engineering designs are based on the current and expected near-future performance of the superconducting materials. In each case, the shield performance, in terms of dose reduction, is provided by a 3-dimensional Monte Carlo simulation, which treats in detail the electromagnetic and hadronic interactions of the galactic-cosmic rays, and the secondary particles they produce in the materials of the shield and spacecraft. A summary of the results of the studies, representing one of the most detailed and comprehensive efforts made in the field, is presented. PMID:27376023

  14. Evaluation of Superconducting Magnet Shield Configurations for Long Duration Manned Space Missions.

    PubMed

    Ambroglini, Filippo; Battiston, Roberto; Burger, William J

    2016-01-01

    A manned mission to Mars would present an important long-term health risk to the crew members due to the prolonged exposure to the ionizing radiation of galactic cosmic-rays. The radiation levels would largely exceed those encountered in the Apollo missions. An increase in the passive shielding provided by the spacecraft implies a significant increase of the mass. The advent of superconducting magnets in the early 1960s was considered an attractive alternative. The technology allows to generate magnetic fields capable to deflect the cosmic-rays in a manner analogous to the reduction of the particle fluxes in the upper atmosphere due to the Earth's dipole magnetic field. A series of the three studies have been conducted over the last 5 years, funded successively by European Space Agency (ESA), the NASA Innovative Advanced Concepts (NIAC) program, and the Union European's Seventh Framework Programme (FP7). The shielding configurations studied are based on high-temperature superconductors, which eliminate the need to operate with liquid helium. The mass estimates of the coils and supporting structure of the engineering designs are based on the current and expected near-future performance of the superconducting materials. In each case, the shield performance, in terms of dose reduction, is provided by a 3-dimensional Monte Carlo simulation, which treats in detail the electromagnetic and hadronic interactions of the galactic-cosmic rays, and the secondary particles they produce in the materials of the shield and spacecraft. A summary of the results of the studies, representing one of the most detailed and comprehensive efforts made in the field, is presented.

  15. Evaluation of Superconducting Magnet Shield Configurations for Long Duration Manned Space Missions.

    PubMed

    Ambroglini, Filippo; Battiston, Roberto; Burger, William J

    2016-01-01

    A manned mission to Mars would present an important long-term health risk to the crew members due to the prolonged exposure to the ionizing radiation of galactic cosmic-rays. The radiation levels would largely exceed those encountered in the Apollo missions. An increase in the passive shielding provided by the spacecraft implies a significant increase of the mass. The advent of superconducting magnets in the early 1960s was considered an attractive alternative. The technology allows to generate magnetic fields capable to deflect the cosmic-rays in a manner analogous to the reduction of the particle fluxes in the upper atmosphere due to the Earth's dipole magnetic field. A series of the three studies have been conducted over the last 5 years, funded successively by European Space Agency (ESA), the NASA Innovative Advanced Concepts (NIAC) program, and the Union European's Seventh Framework Programme (FP7). The shielding configurations studied are based on high-temperature superconductors, which eliminate the need to operate with liquid helium. The mass estimates of the coils and supporting structure of the engineering designs are based on the current and expected near-future performance of the superconducting materials. In each case, the shield performance, in terms of dose reduction, is provided by a 3-dimensional Monte Carlo simulation, which treats in detail the electromagnetic and hadronic interactions of the galactic-cosmic rays, and the secondary particles they produce in the materials of the shield and spacecraft. A summary of the results of the studies, representing one of the most detailed and comprehensive efforts made in the field, is presented. PMID:27376023

  16. Manufacturing, characterization and stability of magnesium diboride superconducting magnets

    NASA Astrophysics Data System (ADS)

    Alessandrini, Matteo

    Some of the interesting features of MgB2 such as low cost, compatibility with existing processing methods and intermediate critical temperatures induced the scientific community to invest in its development with large efforts. In order to promote the use of this compound for military and aerospace activities requiring lightweight devices, we tested titanium as a sheath material. We fabricated Ti-sheathed MgB2 through the powder-in-tube (PIT) process. These wires showed similar results to those sheathed with steel. At 4 K and self field, the critical current density Jc is well above 7x105 A/cm2. Analyses of the interface reaction layer between titanium and MgB2 were carried out using XRD, SEM-EDS and EMPA equipment. In addition to wire development, investigation of the so-called quench events is needed. Quench detection and protection systems depend on how fast the normal zone propagates through the coil, after a disturbance occurs. During this doctorate program two codes were developed. The first is designed to compute the magnetic field of a multilayer solenoid, find the maximum field the superconductor is exposed to and define the critical quench current. Results are used to minimize the wire length required to reach the desired magnetic field. The second code simulates quench events by solving the heat transfer equation for a monodimensional case under adiabatic conditions. Among others, two solenoids were built and tested in order to investigate quench events under different conditions. The first was made with 500 m of commercial MgB2 tape and generates up to 1 T at 16 K. The second was wound with 40 m of the same tape. This thesis was supported by the State of Texas through the Texas Center for Superconductivity and by Ad Astra Rocket company (Houston, TX).

  17. Superconducting magnet and on-board refrigeration system on Japanese MAGLEV vehicle

    SciTech Connect

    Tsuchishima, H.; Herai, T. )

    1991-03-01

    This paper reports on a superconducting magnet and on-board refrigeration system on Japanese MAGLEV vehicles. Running tests on the Miyazaki test track are repeatedly carried out at speeds over 300 km/h using the MAGLEV vehicle, MLU002. The development of the MAGLEV system for the new test line has already started, and a new superconducting magnet for it has been manufactured. An on-board refrigerator is installed in the superconducting magnet to keep the liquid helium temperature without the loss of liquid helium. The helium gas produced when energizing or de-energizing the magnet is stored in on-board gas helium tanks temporarily. The on-board refrigerator is connected directly to the liquid helium tank of the magnet.

  18. Tests of a 3 meter curved superconducting beam transport dipole magnet

    SciTech Connect

    Allinger, J E; Carroll, A S; Danby, G T; DeVito, B; Jackson, J W; Leonhardt, W J; Prodell, A G; Weisenbloom, J

    1981-01-01

    Initial tests of one of the curved 3 m long superconducting dipole magnets intended to generate 6.0 T and produce a 20.4/sup 0/ bend in the primary proton beam to a new D-target station at the Brookhaven National Laboratory AGS have been completed. Although this magnet, whose window frame design generally follows that of the successful 8/sup 0/ and Model T superconducting dipoles, demonstrates many of the desirable characteristics of these earlier magnets such as excellent quench propagation and good ramping properties, it has only reached a disappointingly low magnetic field of 3.5 to 4.0 T. Because of the great interest in superconducting magnet technology, this report will describe the diagnostic tests performed and plans for future modifications.

  19. Development of superconducting magnet for high-field MR systems in China

    NASA Astrophysics Data System (ADS)

    Wang, Zanming; van Oort, Johannes M.; Zou, Mark X.

    2012-11-01

    In this paper we describe the development of superconducting magnets for high-field Magnetic Resonance Imaging (MRI) by various businesses and institutions in China. As the Chinese MR market rapidly expands, many foreign and domestic companies and research institutions are joining the race to meet the burgeoning demand by developing key MRI components for various magnetic field configurations. After providing a brief introduction to research on MRI superconducting magnets that dates back to the 1980s, the first large-bore 1.5 T superconducting magnet with 50-cm DSV for whole-body MRI - successfully developed and manufactured by AllTech Medical Systems in Chengdu, China-is presented and its specifications are described.

  20. First results on disruption mitigation by massive gas injection in Korea Superconducting Tokamak Advanced Research

    SciTech Connect

    Yu Yaowei; Kim, Young-Ok; Kim, Hak-Kun; Kim, Hong-Tack; Kim, Woong-Chae; Kim, Kwang-Pyo; Son, Soo-Hyun; Bang, Eun-Nam; Hong, Suk-Ho; Yoon, Si-Woo; Zhuang Huidong; Chen Zhongyong

    2012-12-15

    Massive gas injection (MGI) system was developed on Korea Superconducting Tokamak Advanced Research (KSTAR) in 2011 campaign for disruption studies. The MGI valve has a volume of 80 ml and maximum injection pressure of 50 bar, the diameter of valve orifice to vacuum vessel is 18.4 mm, the distance between MGI valve and plasma edge is {approx}3.4 m. The MGI power supply employs a large capacitor of 1 mF with the maximum voltage of 3 kV, the valve can be opened in less than 0.1 ms, and the amount of MGI can be controlled by the imposed voltage. During KSTAR 2011 campaign, MGI disruptions are carried out by triggering MGI during the flat top of circular and limiter discharges with plasma current 400 kA and magnetic field 2-3.5 T, deuterium injection pressure 39.7 bar, and imposed voltage 1.1-1.4 kV. The results show that MGI could mitigate the heat load and prevent runaway electrons with proper MGI amount, and MGI penetration is deeper under higher amount of MGI or lower magnetic field. However, plasma start-up is difficult after some of D{sub 2} MGI disruptions due to the high deuterium retention and consequently strong outgassing of deuterium in next shot, special effort should be made to get successful plasma start-up after deuterium MGI under the graphite first wall.

  1. First results on disruption mitigation by massive gas injection in Korea Superconducting Tokamak Advanced Research

    NASA Astrophysics Data System (ADS)

    Yu, Yaowei; Kim, Young-Ok; Kim, Hak-Kun; Kim, Hong-Tack; Kim, Woong-Chae; Kim, Kwang-Pyo; Son, Soo-Hyun; Bang, Eun-Nam; Zhuang, Huidong; Chen, Zhongyong; Hong, Suk-Ho; Yoon, Si-Woo

    2012-12-01

    Massive gas injection (MGI) system was developed on Korea Superconducting Tokamak Advanced Research (KSTAR) in 2011 campaign for disruption studies. The MGI valve has a volume of 80 ml and maximum injection pressure of 50 bar, the diameter of valve orifice to vacuum vessel is 18.4 mm, the distance between MGI valve and plasma edge is ˜3.4 m. The MGI power supply employs a large capacitor of 1 mF with the maximum voltage of 3 kV, the valve can be opened in less than 0.1 ms, and the amount of MGI can be controlled by the imposed voltage. During KSTAR 2011 campaign, MGI disruptions are carried out by triggering MGI during the flat top of circular and limiter discharges with plasma current 400 kA and magnetic field 2-3.5 T, deuterium injection pressure 39.7 bar, and imposed voltage 1.1-1.4 kV. The results show that MGI could mitigate the heat load and prevent runaway electrons with proper MGI amount, and MGI penetration is deeper under higher amount of MGI or lower magnetic field. However, plasma start-up is difficult after some of D2 MGI disruptions due to the high deuterium retention and consequently strong outgassing of deuterium in next shot, special effort should be made to get successful plasma start-up after deuterium MGI under the graphite first wall.

  2. First results on disruption mitigation by massive gas injection in Korea Superconducting Tokamak Advanced Research.

    PubMed

    Yu, Yaowei; Kim, Young-Ok; Kim, Hak-Kun; Kim, Hong-Tack; Kim, Woong-Chae; Kim, Kwang-Pyo; Son, Soo-Hyun; Bang, Eun-Nam; Zhuang, Huidong; Chen, Zhongyong; Hong, Suk-Ho; Yoon, Si-Woo

    2012-12-01

    Massive gas injection (MGI) system was developed on Korea Superconducting Tokamak Advanced Research (KSTAR) in 2011 campaign for disruption studies. The MGI valve has a volume of 80 ml and maximum injection pressure of 50 bar, the diameter of valve orifice to vacuum vessel is 18.4 mm, the distance between MGI valve and plasma edge is ~3.4 m. The MGI power supply employs a large capacitor of 1 mF with the maximum voltage of 3 kV, the valve can be opened in less than 0.1 ms, and the amount of MGI can be controlled by the imposed voltage. During KSTAR 2011 campaign, MGI disruptions are carried out by triggering MGI during the flat top of circular and limiter discharges with plasma current 400 kA and magnetic field 2-3.5 T, deuterium injection pressure 39.7 bar, and imposed voltage 1.1-1.4 kV. The results show that MGI could mitigate the heat load and prevent runaway electrons with proper MGI amount, and MGI penetration is deeper under higher amount of MGI or lower magnetic field. However, plasma start-up is difficult after some of D(2) MGI disruptions due to the high deuterium retention and consequently strong outgassing of deuterium in next shot, special effort should be made to get successful plasma start-up after deuterium MGI under the graphite first wall.

  3. Development of Magnetic Refrigerator

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyasu; Nakagome, Hideki; Kuriyama, Tohru

    A series of R & D of magnetic refrigerators has been done in order to realize an advanced type cryocooler for superconducting magnets of maglev trains and MRI medical system. As a result of efforts on both the magnetic refrigerator and superconducting magnets, a parasitic type magnetic refrigeration system was proposed.

  4. Quench protection tests of a cryocooler cooled 6 T NbTi superconducting magnet by an active power method

    NASA Astrophysics Data System (ADS)

    Nanato, Nozomu; Inoue, Takahiro; Murase, Satoru; Nishijima, Gen; Tamakawa, Katsunori; Amaya, Munenori; Uemura, Yoshifumi

    2012-07-01

    When a quench occurs in a superconducting magnet, excessive joule heating may damage the magnet. We have presented the quench protection system based on an active power method. Our previous quench protection tests have been carried out for small superconducting magnets whose self inductances are less than several hundred mH to verify principles of our proposed system. In this paper, we present experimental results of quench protection tests of a cryocooler cooled 6 T NbTi superconducting magnet (self inductance 15.5 H), which is a commercial size magnet made by Tamakawa Co., Ltd. We confirmed that our proposed system could inhibit the maximum temperature of the superconducting magnet (initial temperature 4.3 K) after the quench to less than about 44 K at operation magnetic field 5.5 T. Experimental results suggest that our proposed system is useful for practical used superconducting magnets.

  5. Design of a horizonal liquid helium cryostat for refrigerating a flying superconducting magnet in a wind tunnel

    NASA Technical Reports Server (NTRS)

    Wu, Y. Y.

    1982-01-01

    The design of a horizontal liquid helium cryostat for refrigerating a flying superconducting magnet in a wind tunnel is presented. The basic principles of magnetic suspension theory are described and theoretical calculations of the superconducting magnet are provided. The experimental results of the boil-off of liquid nitrogen and liquid helium in the cryostat are reported.

  6. Spiral magnetic order and pressure-induced superconductivity in transition metal compounds

    PubMed Central

    Wang, Yishu; Feng, Yejun; Cheng, J.-G.; Wu, W.; Luo, J. L.; Rosenbaum, T. F.

    2016-01-01

    Magnetic and superconducting ground states can compete, cooperate and coexist. MnP provides a compelling and potentially generalizable example of a material where superconductivity and magnetism may be intertwined. Using a synchrotron-based non-resonant X-ray magnetic diffraction technique, we reveal a spiral spin order in MnP and trace its pressure evolution towards superconducting order via measurements in a diamond anvil cell. Judging from the magnetostriction, ordered moments vanish at the quantum phase transition as pressure increases the electron kinetic energy. Spins remain local in the disordered phase, and the promotion of superconductivity is likely to emerge from an enhanced coupling to residual spiral spin fluctuations and their concomitant suppression of phonon-mediated superconductivity. As the pitch of the spiral order varies across the 3d transition metal compounds in the MnP family, the magnetic ground state switches between antiferromagnet and ferromagnet, providing an additional tuning parameter in probing spin-fluctuation-induced superconductivity. PMID:27708255

  7. Spiral magnetic order and pressure-induced superconductivity in transition metal compounds

    NASA Astrophysics Data System (ADS)

    Wang, Yishu; Feng, Yejun; Cheng, J.-G.; Wu, W.; Luo, J. L.; Rosenbaum, T. F.

    2016-10-01

    Magnetic and superconducting ground states can compete, cooperate and coexist. MnP provides a compelling and potentially generalizable example of a material where superconductivity and magnetism may be intertwined. Using a synchrotron-based non-resonant X-ray magnetic diffraction technique, we reveal a spiral spin order in MnP and trace its pressure evolution towards superconducting order via measurements in a diamond anvil cell. Judging from the magnetostriction, ordered moments vanish at the quantum phase transition as pressure increases the electron kinetic energy. Spins remain local in the disordered phase, and the promotion of superconductivity is likely to emerge from an enhanced coupling to residual spiral spin fluctuations and their concomitant suppression of phonon-mediated superconductivity. As the pitch of the spiral order varies across the 3d transition metal compounds in the MnP family, the magnetic ground state switches between antiferromagnet and ferromagnet, providing an additional tuning parameter in probing spin-fluctuation-induced superconductivity.

  8. Beam heating studies on an early model is a superconducting cosine theta magnet

    SciTech Connect

    Bozoki, G; Bunce, G; Danby, G; Foelsche, H; Jackson, J; Prodell, A; Soukas, A; Stevens, A; Stoehr, R; Weisenbloom, J

    1980-01-01

    Superconducting magnets for accelerators can be accidentally quenched by heat resulting from beam losses in the magnet. The threshold for such quenches is determined by the time structure of the beam loss and by details of the magnet application, construction and cooling. A 4.25 m long superconducting cosine theta dipole magnet, MARK VI, constructed during the research and development phase of the ISABELLE Project at BNL was installed in the 28.5 GeV/c primary proton beam line from the AGS. By energizing the magnet, the proton beam could be deflected into the magnet. The beam intensity required to quench the magnet was observed for different beam sizes and at several values of magnet current up to 2400 A or approximately 70% of the highest magnet operating current. The maximum current was limited by the gas-cooled power lead flow available using pool-boiling helium rather than single phase forced-flow helium at 5 atm for which the magnet system was designed. Details of the experimental setup including the magnet and cryogenic system, the beam-monitoring equipment and instrumentation are described. The measurements are discussed and compared with beam heating measurements made on another superconducting magnet and interpreted using the Cascade Simulation Program, CASIM.

  9. Classification of magnetic inhomogeneities and 0 -π transitions in superconducting-magnetic hybrid structures

    NASA Astrophysics Data System (ADS)

    Baker, Thomas E.; Richie-Halford, Adam; Bill, Andreas

    2016-09-01

    We present a comparative study of pair correlations and currents through superconducting-magnetic hybrid systems with a particular emphasis on the tunable Bloch domain wall of an exchange spring. This study of the Gor'kov functions contrasts magnetic systems with domain walls that change at discrete points in the magnetic region with those that change continuously throughout. We present results for misaligned homogeneous magnetic multilayers, including spin valves, for discrete domain walls, as well as exchange springs and helical domain walls—such as Holmium—for the continuous case. Introducing a rotating basis to disentangle the role of singlet and triplet correlations, we demonstrate that substantial amounts of (so-called short-range) singlet correlations are generated throughout the magnetic system in a continuous domain wall via the cascade effect. We propose a classification of 0 -π transitions of the Josephson current into three types, according to the predominant pair correlations symmetries involved in the current. Properties of exchange springs for an experimental study of the proposed effects are discussed. The interplay between components of the Gor'kov function that are parallel and perpendicular to the local magnetization lead to a novel prediction about their role in a proximity system with a progressively twisting helix that is experimentally measurable.

  10. Superconducting magnet performance for 28 GHz electron cyclotron resonance ion source developed at the Korea Basic Science Institute.

    PubMed

    Park, Jin Yong; Choi, Seyong; Lee, Byoung-Seob; Yoon, Jang-Hee; Ok, Jung-Woo; Kim, Byoung Chul; Shin, Chang Seouk; Ahn, Jung Keun; Won, Mi-Sook

    2014-02-01

    A superconducting magnet for use in an electron cyclotron resonance ion source was developed at the Korea Basic Science Institute. The superconducting magnet is comprised of three solenoids and a hexapole magnet. According to the design value, the solenoid magnets can generate a mirror field, resulting in axial magnetic fields of 3.6 T at the injection area and 2.2 T at the extraction region. A radial field strength of 2.1 T can also be achieved by hexapole magnet on the plasma chamber wall. NbTi superconducting wire was used in the winding process following appropriate techniques for magnet structure. The final assembly of the each magnet involved it being vertically inserted into the cryostat to cool down the temperature using liquid helium. The performance of each solenoid and hexapole magnet was separately verified experimentally. The construction of the superconducting coil, the entire magnet assembly for performance testing and experimental results are reported herein.

  11. Superconducting magnet performance for 28 GHz electron cyclotron resonance ion source developed at the Korea Basic Science Institute

    SciTech Connect

    Park, Jin Yong; Choi, Seyong; Lee, Byoung-Seob; Yoon, Jang-Hee; Ok, Jung-Woo; Shin, Chang Seouk; Won, Mi-Sook; Kim, Byoung Chul; Ahn, Jung Keun

    2014-02-15

    A superconducting magnet for use in an electron cyclotron resonance ion source was developed at the Korea Basic Science Institute. The superconducting magnet is comprised of three solenoids and a hexapole magnet. According to the design value, the solenoid magnets can generate a mirror field, resulting in axial magnetic fields of 3.6 T at the injection area and 2.2 T at the extraction region. A radial field strength of 2.1 T can also be achieved by hexapole magnet on the plasma chamber wall. NbTi superconducting wire was used in the winding process following appropriate techniques for magnet structure. The final assembly of the each magnet involved it being vertically inserted into the cryostat to cool down the temperature using liquid helium. The performance of each solenoid and hexapole magnet was separately verified experimentally. The construction of the superconducting coil, the entire magnet assembly for performance testing and experimental results are reported herein.

  12. Superconductivity and magnetism in intermetallic Bi3Ni1-xFex superconductor

    NASA Astrophysics Data System (ADS)

    Gonsalves, Silvio Henrique; Opata, Yuri Aparecido; Pinheiro, Lincoln Brum Leite Gusmão; Da Silva Leal, Adriane Consuelo; Monteiro, João Frederico Haas Leandro; Siqueira, Ezequiel Costa; de Andrade, André Vitor Chaves; Jurelo, Alcione Roberto

    2016-09-01

    In this work, we investigated the apparent coexistence of superconductivity and magnetism in polycrystalline Bi3Ni1-xFex samples for low concentrations of iron (0 ≤ x ≤ 0.10). The compound was synthesized by the solid-state reaction method and characterized by X-ray diffraction and magnetic measurements. From X-ray, it was observed that the main phase corresponds to an orthorhombic structure with space group Pnma and shows no dependence on the Fe concentration. From magnetic measurements, it was observed that the critical temperature was not affected by iron doping and that ferromagnetism and superconductivity coexist apparently in an interesting interplay.

  13. The cryogenics of the LHC interaction region final focus superconducting magnets

    SciTech Connect

    Byrns, R.; et al., FNAL

    1998-08-01

    The LHC interaction region final focus magnets will include four superconducting quadrupoles cooled with pressurized, static superfluid helium at 1.9 K. The heat absorbed in pressurized He II, which may be more than 10 Watts per meter due to dynamic heating from the particle beam halo, will be transported to saturated He II at 1.8 K and removed by the 16 mbar vapor. This paper discusses the conceptual design for the cryogenics of the interaction region final focus superconducting magnets and the integration of this magnet system into the overall LHC cryogenic system.

  14. Superconductivity:

    NASA Astrophysics Data System (ADS)

    Sacchetti, N.

    In this paper a short historical account of the discovery of superconductivity and of its gradual development is given. The physical interpretation of its various aspects took about forty years (from 1911 to 1957) to reach a successful description of this phenomenon in terms of a microscopic theory At the very end it seemed that more or less everything could be reasonably interpreted even if modifications and refinements of the original theory were necessary. In 1986 the situation changed abruptly when a cautious but revolutionary paper appeared showing that superconductivity was found in certain ceramic oxides at temperatures above those up to then known. A rush of frantic experimental activity started world-wide and in less than one year it was shown that superconductivity is a much more widespread phenomenon than deemed before and can be found at temperatures well above the liquid air boiling point. The complexity and the number of the substances (mainly ceramic oxides) involved call for a sort of modern alchemy if compounds with the best superconducting properties are to be manufactured. We don't use the word alchemy in a deprecatory sense but just to emphasise that till now nobody can say why these compounds are what they are: superconductors.

  15. Pressure induced superconductivity on the border of magnetic order in MnP.

    PubMed

    Cheng, J-G; Matsubayashi, K; Wu, W; Sun, J P; Lin, F K; Luo, J L; Uwatoko, Y

    2015-03-20

    We report the discovery of superconductivity on the border of long-range magnetic order in the itinerant-electron helimagnet MnP via the application of high pressure. Superconductivity with T(sc)≈1  K emerges and exists merely near the critical pressure P(c)≈8  GPa, where the long-range magnetic order just vanishes. The present finding makes MnP the first Mn-based superconductor. The close proximity of superconductivity to a magnetic instability suggests an unconventional pairing mechanism. Moreover, the detailed analysis of the normal-state transport properties evidenced non-Fermi-liquid behavior and the dramatic enhancement of the quasiparticle effective mass near P(c) associated with the magnetic quantum fluctuations.

  16. Correlated Trends of Coexisting Magnetism and Superconductivity in Optimally Electron-Doped Oxypnictides

    NASA Astrophysics Data System (ADS)

    Sanna, S.; Carretta, P.; Bonfà, P.; Prando, G.; Allodi, G.; de Renzi, R.; Shiroka, T.; Lamura, G.; Martinelli, A.; Putti, M.

    2011-11-01

    We report on the recovery of the short-range static magnetic order and on the concomitant degradation of the superconducting state in optimally F-doped SmFe1-xRuxAsO0.85F0.15 for 0.1≤x≲0.5. The two reduced order parameters coexist within nanometer-size domains in the FeAs layers and eventually disappear around a common critical threshold xc˜0.6. Superconductivity and magnetism are shown to be closely related to two distinct well-defined local electronic environments of the FeAs layers. The two transition temperatures, controlled by the isoelectronic and diamagnetic Ru substitution, scale with the volume fraction of the corresponding environments. This fact indicates that superconductivity is assisted by magnetic fluctuations, which are frozen whenever a short-range static order appears, and totally vanish above the magnetic dilution threshold xc.

  17. Correlated trends of coexisting magnetism and superconductivity in optimally electron-doped oxypnictides.

    PubMed

    Sanna, S; Carretta, P; Bonfà, P; Prando, G; Allodi, G; De Renzi, R; Shiroka, T; Lamura, G; Martinelli, A; Putti, M

    2011-11-25

    We report on the recovery of the short-range static magnetic order and on the concomitant degradation of the superconducting state in optimally F-doped SmFe(1-x)Ru(x)AsO(0.85)F(0.15) for 0.1≤x≲0.5. The two reduced order parameters coexist within nanometer-size domains in the FeAs layers and eventually disappear around a common critical threshold x(c)~0.6. Superconductivity and magnetism are shown to be closely related to two distinct well-defined local electronic environments of the FeAs layers. The two transition temperatures, controlled by the isoelectronic and diamagnetic Ru substitution, scale with the volume fraction of the corresponding environments. This fact indicates that superconductivity is assisted by magnetic fluctuations, which are frozen whenever a short-range static order appears, and totally vanish above the magnetic dilution threshold x(c).

  18. A novel design of iron dominated superconducting multipole magnets with circular coils

    SciTech Connect

    Kashikhin, Vladimir; /Fermilab

    2009-10-01

    Linear accelerators based on superconducting magnet technology use a large number of relatively weak superconducting quadrupoles. In this case an iron dominated quadrupole is the most cost effective solution. The field quality in this magnet is defined by iron poles; the magnet air gap is minimal as are coil ampere-turns. Nevertheless, it has long racetrack type coils, which must be rigid and fixed by a mechanical structure to provide the needed mechanical stability. The novel concept of using circular superconducting coils in such a quadrupole type is described, with a discussion of quadrupole parameters, and results of 3D magnetic designs. Variants of short and long sectional quadrupoles and multipoles are presented.

  19. Superconductivity of magnetic Sm-substituted LaCo{sub 2}B{sub 2}

    SciTech Connect

    Wang, Y.; Ren, W. J. Duan, T. F.; Li, D.; Li, J.; Zhang, Z. D.

    2015-05-07

    In this work, superconductivity with a maximum superconducting transition onset temperature T{sub C} of 3.6 K is reported in La{sub 1-x}Sm{sub x}Co{sub 2}B{sub 2} in the concentration range 0.12 ≤ x ≤ 0.20. Substitution of magnetic Sm ions with 4f electrons for La is beneficial for superconductivity in the system. The low upper critical field of La{sub 0.8}Sm{sub 0.2}Co{sub 2}B{sub 2} suggests that the dominant magnetic-field suppressing superconducting mechanism is the orbit pair-breaking effect. A special specific-heat anomaly is observed around T{sub C}.

  20. Neutron scattering study on the magnetic and superconducting phases of MnP

    NASA Astrophysics Data System (ADS)

    Yano, Shinichiro; Lancon, Diane; Ronnow, Henrik; Hansen, Thomas; Gardner, Jason

    We have performed series of neutron scattering experiments on MnP. MnP has been investigated for decades because of its rich magnetic phase diagram. The magnetic structure of MnP is ferromagnetic (FM) below TC = 291 K. It transforms into a helimagnetic structure at TS = 47 K with a propagation vector q = 0 . 117a* . Superconductivity was found in MnP under pressures of 8 GPa with a TSC around 1 K by J.-G. Cheng. Since Mn-based superconductors are rare, and the superconducting phase occurs in the vicinity of FM, new magnetic and helimagnetic phases, there is a need to understand how the magnetism evolves as one approach the superconducting state. MnP is believed to be a double helix magnetic structure at TS = 47 K. We observed new 2 δ and 3 δ satellite peaks whose intensity are 200 ~ 1000 times smaller than these of 1 δ satellite peaks on the cold triple axis spectrometer SIKA under zero magnetic fields. We also found the periods of helimagnetic structure changes as a function of temperature. If time permits, we will discuss recent experiments under pressure. However, we have complete picture of magnetic structure of this system with and without applied pressure, revealing the interplay between the magnetic and superconducting phases.

  1. FAST TRACK COMMUNICATION: Magnetic excitations of Fe1 + ySexTe1 - x in magnetic and superconductive phases

    NASA Astrophysics Data System (ADS)

    Babkevich, P.; Bendele, M.; Boothroyd, A. T.; Conder, K.; Gvasaliya, S. N.; Khasanov, R.; Pomjakushina, E.; Roessli, B.

    2010-04-01

    We have used inelastic neutron scattering and muon-spin rotation to compare the low energy magnetic excitations in single crystals of superconducting Fe1.01Se0.50Te0.50 and non-superconducting Fe1.10Se0.25Te0.75. We confirm the existence of a spin resonance in the superconducting phase of Fe1.01Se0.50Te0.50, at an energy of 7 meV and a wavevector of (1/2, 1/2, 0). The non-superconducting sample exhibits two incommensurate magnetic excitations at (1/2, 1/2, 0) ± (0.18, - 0.18, 0) which rise steeply in energy, but no resonance is observed at low energies. A strongly dispersive low energy magnetic excitation is also observed in Fe1.10Se0.25Te0.75 close to the commensurate antiferromagnetic ordering wavevector (1/2 - δ, 0, 1/2), where δ≈0.03. The magnetic correlations in both samples are found to be quasi-two-dimensional in character and persist well above the magnetic (Fe1.10Se0.25Te0.75) and superconducting (Fe1.01Se0.50Te0.50) transition temperatures.

  2. Quench Detection/Protection of a Cryocooled NbTi Superconducting Magnet by using an Active Power Method

    NASA Astrophysics Data System (ADS)

    Nanato, Nozomu; Murase, Satoru; Nishijima, Gen; Tamakawa, Katsunori; Amaya, Munenori

    When a quench occurs in a superconducting magnet, excessive joule heating may damage the magnet. The authors have presented a quench detection/protection system based on an activ e power method, which can detect the quench quickly and precisely by measuring an active power dissipated within the magnet after the quench. In this paper, the authors show usefulness of a softwa re quench detection/protection system for a cr yocooled NbTi superconducting magnet which is a commercial size magnet made by Tamakawa Co., Ltd.. Experimental results show that the proposed system is useful for the practical used superconducting magnet.

  3. Superconductive material and magnetic field for damping and levitation support and damping of cryogenic instruments

    NASA Technical Reports Server (NTRS)

    Dolgin, Benjamin P. (Inventor)

    1994-01-01

    A superconductive load bearing support without a mechanical contact and vibration damping for cryogenic instruments in space is presented. The levitation support and vibration damping is accomplished by the use of superconducting magnets and the 'Meissner' effect. The assembly allows for transfer of vibration energy away from the cryogenic instrument which then can be damped by the use of either an electronic circuit or conventional vibration damping mean.

  4. Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors.

    PubMed

    Li, Jun; Ji, Min; Schwarz, Tobias; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Yuan, Jie; Pereira, Paulo J; Huang, Ya; Zhang, Gufei; Feng, Hai-Luke; Yuan, Ya-Hua; Hatano, Takeshi; Kleiner, Reinhold; Koelle, Dieter; Chibotaru, Liviu F; Yamaura, Kazunari; Wang, Hua-Bing; Wu, Pei-Heng; Takayama-Muromachi, Eiji; Vanacken, Johan; Moshchalkov, Victor V

    2015-07-03

    The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm(2) cross-section. The impurities suppress superconductivity in a three-dimensional 'Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ∼1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.

  5. Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors

    NASA Astrophysics Data System (ADS)

    Li, Jun; Ji, Min; Schwarz, Tobias; Ke, Xiaoxing; van Tendeloo, Gustaaf; Yuan, Jie; Pereira, Paulo J.; Huang, Ya; Zhang, Gufei; Feng, Hai-Luke; Yuan, Ya-Hua; Hatano, Takeshi; Kleiner, Reinhold; Koelle, Dieter; Chibotaru, Liviu F.; Yamaura, Kazunari; Wang, Hua-Bing; Wu, Pei-Heng; Takayama-Muromachi, Eiji; Vanacken, Johan; Moshchalkov, Victor V.

    2015-07-01

    The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm2 cross-section. The impurities suppress superconductivity in a three-dimensional `Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ~1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities.

  6. Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors

    PubMed Central

    Li, Jun; Ji, Min; Schwarz, Tobias; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Yuan, Jie; Pereira, Paulo J.; Huang, Ya; Zhang, Gufei; Feng, Hai-Luke; Yuan, Ya-Hua; Hatano, Takeshi; Kleiner, Reinhold; Koelle, Dieter; Chibotaru, Liviu F.; Yamaura, Kazunari; Wang, Hua-Bing; Wu, Pei-Heng; Takayama-Muromachi, Eiji; Vanacken, Johan; Moshchalkov, Victor V.

    2015-01-01

    The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm2 cross-section. The impurities suppress superconductivity in a three-dimensional ‘Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ∼1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities. PMID:26139568

  7. Local destruction of superconductivity by non-magnetic impurities in mesoscopic iron-based superconductors.

    PubMed

    Li, Jun; Ji, Min; Schwarz, Tobias; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Yuan, Jie; Pereira, Paulo J; Huang, Ya; Zhang, Gufei; Feng, Hai-Luke; Yuan, Ya-Hua; Hatano, Takeshi; Kleiner, Reinhold; Koelle, Dieter; Chibotaru, Liviu F; Yamaura, Kazunari; Wang, Hua-Bing; Wu, Pei-Heng; Takayama-Muromachi, Eiji; Vanacken, Johan; Moshchalkov, Victor V

    2015-01-01

    The determination of the pairing symmetry is one of the most crucial issues for the iron-based superconductors, for which various scenarios are discussed controversially. Non-magnetic impurity substitution is one of the most promising approaches to address the issue, because the pair-breaking mechanism from the non-magnetic impurities should be different for various models. Previous substitution experiments demonstrated that the non-magnetic zinc can suppress the superconductivity of various iron-based superconductors. Here we demonstrate the local destruction of superconductivity by non-magnetic zinc impurities in Ba0.5K0.5Fe2As2 by exploring phase-slip phenomena in a mesoscopic structure with 119 × 102 nm(2) cross-section. The impurities suppress superconductivity in a three-dimensional 'Swiss cheese'-like pattern with in-plane and out-of-plane characteristic lengths slightly below ∼1.34 nm. This causes the superconducting order parameter to vary along abundant narrow channels with effective cross-section of a few square nanometres. The local destruction of superconductivity can be related to Cooper pair breaking by non-magnetic impurities. PMID:26139568

  8. A universal relationship between magnetic resonance and superconducting gap in unconventional superconductors

    NASA Astrophysics Data System (ADS)

    Yu, G.; Li, Y.; Motoyama, E. M.; Greven, M.

    2009-12-01

    Superconductivity involves the formation of electron pairs (Cooper pairs) and their condensation into a macroscopic quantum state. In conventional superconductors, such as Nb3Ge and elemental Hg, weakly interacting electrons pair through the electron-phonon interaction. In contrast, unconventional superconductivity occurs in correlated-electron materials in which electronic interactions are significant and the pairing mechanism may not be phononic. In the cuprates, the superconductivity arises on doping charge carriers into the copper-oxygen layers of antiferromagnetic Mott insulators. Other examples of unconventional superconductors are the heavy-fermion compounds, which are metals with coupled conduction and localized f-shell electrons, and the recently discovered iron-arsenide superconductors. These unconventional superconductors show a magnetic resonance, a prominent collective spin-1 excitation mode in the superconducting state. Here we demonstrate the existence of a universal linear relation, Er~2Δ, between the magnetic resonance energy (Er) and the superconducting pairing gap (Δ), which spans two orders of magnitude in energy. This relationship is valid for the three different classes of unconventional superconductors, which range from being close to the Mott-insulating limit to being on the border of itinerant magnetism. As the common excitonic picture of the resonance has not led to such universality, our observation suggests a much deeper connection between antiferromagnetic fluctuations and unconventional superconductivity.

  9. Applications in the Advanced Transportation System and Impact on Superconductivity Industry of Htsm

    NASA Astrophysics Data System (ADS)

    Zhang, Y. P.; Zhao, Y.

    As the information technology grows up and its application penetrates into every area of this world, how to faster and more efficiently transport people and goods is becoming the new social demand, which indicates a new revolution on advanced transportation technology being brewed. High-temperature Superconductivity Maglev (HTSM) is one with the best development potential among most transportation technologies. It could be used in many advanced transportation fields, overcoming the key contradiction and shortcoming of the current transportation patterns such as train, automobile and airplane. On the other hand, HTSM will promote theoretical study and technology exploitation on superconductivity. HTSM's applications in a large scale will bring up profound effect on the forming and development of the superconductivity industry.

  10. Alternating-gradient canted cosine theta superconducting magnets for future compact proton gantries

    NASA Astrophysics Data System (ADS)

    Wan, Weishi; Brouwer, Lucas; Caspi, Shlomo; Prestemon, Soren; Gerbershagen, Alexander; Schippers, Jacobus Maarten; Robin, David

    2015-10-01

    We present a design of superconducting magnets, optimized for application in a gantry for proton therapy. We have introduced a new magnet design concept, called an alternating-gradient canted cosine theta (AG-CCT) concept, which is compatible with an achromatic layout. This layout allows a large momentum acceptance. The 15 cm radius of the bore aperture enables the application of pencil beam scanning in front of the SC-magnet. The optical and dynamic performance of a gantry based on these magnets has been analyzed using the fields derived (via Biot-Savart law) from the actual windings of the AG-CCT combined with the full equations of motion. The results show that with appropriate higher order correction, a large 3D volume can be rapidly scanned with little beam shape distortion. A very big advantage is that all this can be done while keeping the AG-CCT fields fixed. This reduces the need for fast field ramping of the superconducting magnets between the successive beam energies used for the scanning in depth and it is important for medical application since this reduces the technical risk (e.g., a quench) associated with fast field changes in superconducting magnets. For proton gantries the corresponding superconducting magnet system holds promise of dramatic reduction in weight. For heavier ion gantries there may furthermore be a significant reduction in size.

  11. New levitation scheme with AC superconducting magnet for EDS MAGLEV system

    SciTech Connect

    Kim, D.H.; Lee, J.K.; Hahn, S.Y.; Cha, G.

    1996-09-01

    This paper proposes a new magnetic levitation scheme which is able to generate levitation force for all speeds including a standstill. Auxiliary wheels which are needed in EDS MAGLEV vehicle can be eliminated. This scheme uses AC superconducting magnets to generate levitation force. In this paper, magnetic fields, forces and power dissipations generated by AC magnets moving above a conducting slab are calculated analytically. Results of calculation show characteristics of EDS system with AC magnet, such as levitation force and loss, are superior to those of EDS system with DC magnets for all speeds.

  12. Levitation and lateral forces between a point magnetic dipole and a superconducting sphere

    NASA Astrophysics Data System (ADS)

    H, M. Al-Khateeb; M, K. Alqadi; F, Y. Alzoubi; B, Albiss; M, K. Hasan (Qaseer; N, Y. Ayoub

    2016-05-01

    The dipole–dipole interaction model is employed to investigate the angular dependence of the levitation and lateral forces acting on a small magnet in an anti-symmetric magnet/superconducting sphere system. Breaking the symmetry of the system enables us to study the lateral force which is important in the stability of the magnet above a superconducting sphere in the Meissner state. Under the assumption that the lateral displacement of the magnet is small compared to the physical dimensions of our proposed system, analytical expressions are obtained for the levitation and lateral forces as a function of the geometrical parameters of the superconductor as well as the height, the lateral displacement, and the orientation of the magnetic moment of the magnet. The dependence of the levitation force on the height of the levitating magnet is similar to that in the symmetric magnet/superconducting sphere system within the range of proposed lateral displacements. It is found that the levitation force is linearly dependent on the lateral displacement whereas the lateral force is independent of this displacement. A sinusoidal variation of both forces as a function of the polar and azimuthal angles specifying the orientation of the magnetic moment is observed. The relationship between the stability and the orientation of the magnetic moment is discussed for different orientations.

  13. Improving the design and analysis of superconducting magnets for particle accelerators

    SciTech Connect

    Gupta, R C

    1996-11-01

    High energy particle accelerators are now the primary means of discovering the basic building blocks of matter and understanding the forces between them. In order to minimize the cost of building these machines, superconducting magnets are used in essentially all present day high energy proton and heavy ion colliders. The cost of superconducting magnets is typically in the range of 20--30% of the total cost of building such machines. The circulating particle beam goes through these magnets a large number of times (over hundreds of millions). The luminosity performance and life time of the beam in these machines depends significantly on the field quality in these magnets. Therefore, even a small error in the magnetic field shape may create a large cumulative effect in the beam trajectory to throw the particles of the magnet aperture. The superconducting accelerator magnets must, therefore, be designed and constructed so that these errors are small. In this thesis the research and development work will be described 3which has resulted in significant improvements in the field quality of the superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). The design and the field quality improvements in the prototype of the main collider dipole magnet for the Superconducting Super Collider (SSC) will also be presented. RHIC will accelerate and collide two counter rotating beams of heavy ions up to 100 GeV/u and protons up to 250 GeV. It is expected that RHIC will create a hot, dense quark-gluon plasma and the conditions which, according to the Big Bang theory, existed in the early universe.

  14. Development of frequency modulation reflectometer for Korea Superconducting Tokamak Advanced Research tokamak

    NASA Astrophysics Data System (ADS)

    Seo, Seong-Heon; Park, Jinhyung; Wi, H. M.; Lee, W. R.; Kim, H. S.; Lee, T. G.; Kim, Y. S.; Kang, Jin-Seob; Bog, M. G.; Yokota, Y.; Mase, A.

    2013-08-01

    Frequency modulation reflectometer has been developed to measure the plasma density profile of the Korea Superconducting Tokamak Advanced Research tokamak. Three reflectometers are operating in extraordinary polarization mode in the frequency range of Q band (33.6-54 GHz), V band (48-72 GHz), and W band (72-108 GHz) to measure the density up to 7 × 1019 m-3 when the toroidal magnetic field is 2 T on axis. The antenna is installed inside of the vacuum vessel. A new vacuum window is developed by using 50 μm thick mica film and 0.1 mm thick gold gasket. The filter bank of low pass filter, notch filter, and Faraday isolator is used to reject the electron cyclotron heating high power at attenuation of 60 dB. The full frequency band is swept in 20 μs. The mixer output is directly digitized with sampling rate of 100 MSamples/s. The phase is obtained by using wavelet transform. The whole hardware and software system is described in detail and the measured density profile is presented as a result.

  15. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak.

    PubMed

    Ren, J; Zuo, G Z; Hu, J S; Sun, Z; Yang, Q X; Li, J G; Zakharov, L E; Xie, H; Chen, Z X

    2015-02-01

    A program involving the extensive and systematic use of lithium (Li) as a "first," or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak-both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST. PMID:25725839

  16. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Ren, J.; Zuo, G. Z.; Hu, J. S.; Sun, Z.; Yang, Q. X.; Li, J. G.; Xie, H.; Chen, Z. X.; Zakharov, L. E.

    2015-02-15

    A program involving the extensive and systematic use of lithium (Li) as a “first,” or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak—both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST.

  17. A flowing liquid lithium limiter for the Experimental Advanced Superconducting Tokamak.

    PubMed

    Ren, J; Zuo, G Z; Hu, J S; Sun, Z; Yang, Q X; Li, J G; Zakharov, L E; Xie, H; Chen, Z X

    2015-02-01

    A program involving the extensive and systematic use of lithium (Li) as a "first," or plasma-facing, surface in Tokamak fusion research devices located at Institute of Plasma Physics, Chinese Academy of Sciences, was started in 2009. Many remarkable results have been obtained by the application of Li coatings in Experimental Advanced Superconducting Tokamak (EAST) and liquid Li limiters in the HT-7 Tokamak-both located at the institute. In furtherance of the lithium program, a flowing liquid lithium (FLiLi) limiter system has been designed and manufactured for EAST. The design of the FLiLi limiter is based on the concept of a thin flowing film which was previously tested in HT-7. Exploiting the capabilities of the existing material and plasma evaluation system on EAST, the limiter will be pre-wetted with Li and mechanically translated to the edge of EAST during plasma discharges. The limiter will employ a novel electro-magnetic pump which is designed to drive liquid Li flow from a collector at the bottom of limiter into a distributor at its top, and thus supply a continuously flowing liquid Li film to the wetted plasma-facing surface. This paper focuses on the major design elements of the FLiLi limiter. In addition, a simulation of incoming heat flux has shown that the distribution of heat flux on the limiter surface is acceptable for a future test of power extraction on EAST.

  18. Development of frequency modulation reflectometer for Korea Superconducting Tokamak Advanced Research tokamak

    SciTech Connect

    Seo, Seong-Heon; Wi, H. M.; Lee, W. R.; Kim, H. S.; Lee, T. G.; Kim, Y. S.; Park, Jinhyung; Kang, Jin-Seob; Bog, M. G.; Yokota, Y.; Mase, A.

    2013-08-15

    Frequency modulation reflectometer has been developed to measure the plasma density profile of the Korea Superconducting Tokamak Advanced Research tokamak. Three reflectometers are operating in extraordinary polarization mode in the frequency range of Q band (33.6–54 GHz), V band (48–72 GHz), and W band (72–108 GHz) to measure the density up to 7 × 10{sup 19} m{sup −3} when the toroidal magnetic field is 2 T on axis. The antenna is installed inside of the vacuum vessel. A new vacuum window is developed by using 50 μm thick mica film and 0.1 mm thick gold gasket. The filter bank of low pass filter, notch filter, and Faraday isolator is used to reject the electron cyclotron heating high power at attenuation of 60 dB. The full frequency band is swept in 20 μs. The mixer output is directly digitized with sampling rate of 100 MSamples/s. The phase is obtained by using wavelet transform. The whole hardware and software system is described in detail and the measured density profile is presented as a result.

  19. Magnetism and superconductivity driven by identical 4f states in a heavy-fermion metal

    SciTech Connect

    Thompson, Joe E; Nair, S; Stockert, O; Witte, U; Nicklas, M; Schedler, R; Bianchi, A; Fisk, Z; Wirth, S; Steglich, K

    2009-01-01

    The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. Particularly enigmatic is the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. Therefore, a single 4f state could be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.

  20. Feasibility of Using Conductively Cooled Magnets in Cryomidules of Superconducting Linacs

    SciTech Connect

    Terechkine, I.; Cheban, Cheban,S.; Nicol. T., Nicol. T.; Poloubotko, V.; Sergatskov, D.

    2013-09-01

    As part of a search for optimal ways to configure cryomodules of the low-beta section of a high-current, high-power superconducting linac, an option of using conductively cooled superconducting focusing lenses was evaluated. Superconducting magnet was installed inside existing test cryostat, which was modified by adding current feed-throughs and two conductively cooled current leads. Each lead was equipped with heat sinks at the temperatures of liquid nitrogen and liquid helium. The magnet was mounted inside the cryostat on an individual heat sink plate, and thermometers were installed on the leads, heat sinks, and on the magnet. In this report we provide some details of the test setup and analyse results of the temperature measurements.

  1. Magnetic field measurements of the harmonic generation FEL superconducting undulator at BNL-NSLS

    SciTech Connect

    Solomon, L.; Graves, W.S.; Lehrman, I.

    1994-12-31

    A three stage superconducting undulator (modulator, dispersive section, and radiator) is under construction at Brookhaven National Laboratory. Sections of the radiator, consisting of 25cm long steel yokes, each with 18mm period, 0.54 Tesla field, and 8.6mm gap are under test. The magnetic measurements and operational characteristics of the magnet are discussed. Measurement results and analysis are presented, with emphasis on the integrated field quality. The magnet winding and the effects of the various trims are discussed.

  2. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    NASA Astrophysics Data System (ADS)

    Schoenhuber, P.; Moon, F. C.

    1995-04-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation

  3. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    NASA Technical Reports Server (NTRS)

    Schoenhuber, P.; Moon, F. C.

    1995-01-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation

  4. Effect of superconducting solenoid model cores on spanwise iron magnet roll control

    NASA Technical Reports Server (NTRS)

    Britcher, C. P.

    1985-01-01

    Compared with conventional ferromagnetic fuselage cores, superconducting solenoid cores appear to offer significant reductions in the projected cost of a large wind tunnel magnetic suspension and balance system. The provision of sufficient magnetic roll torque capability has been a long-standing problem with all magnetic suspension and balance systems; and the spanwise iron magnet scheme appears to be the most powerful system available. This scheme utilizes iron cores which are installed in the wings of the model. It was anticipated that the magnetization of these cores, and hence the roll torque generated, would be affected by the powerful external magnetic field of the superconducting solenoid. A preliminary study has been made of the effect of the superconducting solenoid fuselage model core concept on the spanwise iron magnet roll torque generation schemes. Computed data for one representative configuration indicate that reductions in available roll torque occur over a range of applied magnetic field levels. These results indicate that a 30-percent increase in roll electromagnet capacity over that previously determined will be required for a representative 8-foot wind tunnel magnetic suspension and balance system design.

  5. How the Performance of a Superconducting Magnet is affected by theConnection between a small cooler and the Magnet

    SciTech Connect

    Green, Michael A.

    2005-09-08

    As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low temperature coolers to superconducting magnets have been studied. The first method uses a cold strap to connect the cold heads directly to the loads. This method is commonly used for cryogen-free magnets. The second method uses a thermal siphon and liquid cryogens to make the connection between the load being cooled and the cold head. The two methods of transferring heat from the magnet to the cooler low temperature cold head are compared for the two temperature ranges given above.

  6. Precooling of a superconducting magnet using a cryocooler and thermal switches.

    PubMed

    Yamamoto, J; Yanai, M

    1979-11-01

    A simple precooling system for a superconducting magnet is developed using a Cryomech GB02 cryocooler and gas filled thermal switches. A superconducting magnet (NbTi wire, 7 T of maximum field, 5.6 kg of weight) is precooled to 16 K in about 70 h without any manual control. Heat transfer rate of each thermal switch (H2 or N2 gas filled at 1.3 MPa at room temperature) is about 3x10(-1) W/K during the ON state, and 5x10(-3) W/K during the OFF state.

  7. Concepts of flywheels for energy storage using autostable high-T(sub c) superconducting magnetic bearings

    NASA Technical Reports Server (NTRS)

    Bornemann, Hans J.; Zabka, R.; Boegler, P.; Urban, C.; Rietschel, H.

    1994-01-01

    A flywheel for energy storage using autostable high-T(sub c) superconducting magnetic bearings has been built. The rotating disk has a total weight of 2.8 kg. The maximum speed is 9240 rpm. A process that allows accelerated, reliable and reproducible production of melt-textured superconducting material used for the bearings has been developed. In order to define optimum configurations for radial and axial bearings, interaction forces in three dimensions and vertical and horizontal stiffness have been measured between superconductors and permanent magnets in different geometries and various shapes. Static as well as dynamic measurements have been performed. Results are being reported and compared to theoretical models.

  8. The spheromak as a prototype for ultra-high-field superconducting magnets

    SciTech Connect

    Furth, H.P.; Jardin, S.C.

    1987-08-01

    In view of current progress in the development of superconductor materials, the ultimate high-field limit of superconducting magnets is likely to be set by mechanical stress problems. Maximum field strength should be attainable by means of approximately force-free magnet windings having favorable ''MHD'' stability properties (so that small winding errors will not grow). Since a low-beta finite-flux-hole spheromak configuration qualifies as a suitable prototype, the theoretical and experimental spheromak research effort of the past decade has served to create a substantial technical basis for the design of ultra-high-field superconducting coils. 11 refs.

  9. Resource Letter Scy-3: Superconductivity

    NASA Astrophysics Data System (ADS)

    Butch, N. P.; de Andrade, M. C.; Maple, M. B.

    2008-02-01

    This Resource Letter provides a guide to the literature on superconductivity. Since the last Resource Letter on superconductivity, Scy-2, was published in 1970, there have been dramatic advances in our basic understanding of superconductivity, discovery of new superconducting materials, and improved technological exploitation of superconductors. We review basic phenomenology, followed by concise descriptions of several main classes of superconductors recognized today. Journal articles and books are cited for the following topics: Conventional superconductors, paramagnetic impurities in superconductors, magnetically ordered superconductors, heavy fermion superconductors, high Tc superconductors, organic superconductors, applications of superconductivity, and laboratory demonstrations of superconductivity. Owing to the large volume of available literature on superconductivity, the journal articles and books we discuss constitute good starting points for further exploration of particular topics.

  10. Feasibility of turbidity removal by high-gradient superconducting magnetic separation.

    PubMed

    Zeng, Hua; Li, Yiran; Xu, Fengyu; Jiang, Hao; Zhang, Weimin

    2015-01-01

    Several studies have focused on pollutant removal by magnetic seeding and high-gradient superconducting magnetic separation (HGSMS). However, few works reported the application of HGSMS for treating non-magnetic pollutants by an industrial large-scale system. The feasibility of turbidity removal by a 600 mm bore superconducting magnetic separation system was evaluated in this study. The processing parameters were evaluated by using a 102 mm bore superconducting magnetic separation system that was equipped with the same magnetic separation chamber that was used in the 600 mm bore system. The double-canister system was used to process water pollutants. Analytical grade magnetite was used as a magnetic seed and the turbidity of the simulated raw water was approximately 110 NTU, and the effects of polyaluminum chloride (PAC) and magnetic seeds on turbidity removal were evaluated. The use of more PAC and magnetic seeds had few advantages for the HGSMS at doses greater than 8 and 50 mg/l, respectively. A magnetic intensity of 5.0 T was beneficial for HGSMS, and increasing the flow rate through the steel wool matrix decreased the turbidity removal efficiency. In the breakthrough experiments, 90% of the turbidity was removed when 100 column volumes were not reached. The processing capacity of the 600 mm bore industry-scale superconducting magnetic separator for turbidity treatment was approximately 78.0 m(3)/h or 65.5 × 10(4) m(3)/a. The processing cost per ton of water for the 600 mm bore system was 0.1 $/t. Thus, the HGSMS separator could be used in the following special circumstances: (1) when adequate space is not available for traditional water treatment equipment, especially the sedimentation tank, and (2) when decentralized sewage treatment HGSMS systems are easier to transport and install.

  11. Numerical analysis of the superconducting magnet outer vessel of a Maglev train by a structural and electromagnetic coupling method

    NASA Astrophysics Data System (ADS)

    Matsue, H.; Demachi, K.; Miya, K.

    2001-09-01

    The harmonic magnetic field generated by the ground coils can cause vibration of the superconducting magnet, which must be reduced as it generates heat in the liquid helium temperature range. Therefore, it is important for the design of lighter magnets to exactly estimate the electromagnetic force on the superconducting magnet. Some causes of the vibration were analyzed by the structural and electromagnetic coupling FEM-BEM method.

  12. Performance of current measurement system in poloidal field power supply for Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Liu, D. M.; Li, J.; Wan, B. N.; Lu, Z.; Wang, L. S.; Jiang, L.; Lu, C. H.; Huang, J.

    2016-11-01

    As one of the core subsystems of the Experimental Advanced Superconducting Tokamak (EAST), the poloidal field power system supplies energy to EAST's superconducting coils. To measure the converter current in the poloidal field power system, a current measurement system has been designed. The proposed measurement system is composed of a Rogowski coil and a newly designed integrator. The results of the resistor-inductor-capacitor discharge test and the converter equal current test show that the current measurement system provides good reliability and stability, and the maximum error of the proposed system is less than 1%.

  13. Superconducting Magnets for the 12 GeV Upgrade at Jefferson Lab

    SciTech Connect

    Fair, Ruben J.; Young, Glenn R.

    2015-06-01

    Jefferson Laboratory is embarked on an energy upgrade to its flagship continuous electron beam accelerator in order to expand the scope of its research capabilities and probe further into the structure of nuclear particles. The 12 GeV upgrade includes the design, manufacture, integration, installation and commissioning of eight different superconducting magnets in three separate experimental halls. The effort involves other national laboratories, universities and industry spanning three countries. This paper will summarize the key characteristics of these magnets, ranging in size from 0.2 to 23 MJ in stored energy, and featuring many different types and configurations. The paper will also give an overview of the specific technical challenges for each magnet, and a status report on magnet manufacture and expected delivery dates. The 12GeV upgrade at J-Lab represents the largest superconducting magnet fabrication and installation program currently ongoing in the United States and this paper will present the breadth of collaborations supporting it.

  14. Topological superconductivity and anti-Shiba states in disordered chains of magnetic adatoms

    NASA Astrophysics Data System (ADS)

    Westström, Alex; Pöyhönen, Kim; Ojanen, Teemu

    2016-09-01

    Regular arrays of magnetic atoms on a superconductor provide a promising platform for topological superconductivity. In this work, we study the effects of disorder in these systems, focusing on vacancies realized by missing magnetic atoms. We develop approaches that allow treatment of ferromagnetic dense chains as well as long-range hopping ferromagnetic and helical Shiba chains at arbitrary subgap energies. Vacancies in magnetic chains play an analogous role to magnetic impurities in a clean s -wave superconductor. A single vacancy in a topological chain gives rise to a low-lying "anti-Shiba" state below the band edge of a regular magnetic chain. Proliferation of the anti-Shiba band formed by a finite density of hybridized vacancy states leads to deterioration of the topological phase, which exhibits unusual fragility in a particular parameter region in dilute chains. We also consider local fluctuation in the Shiba coupling and discuss how vacancy states could contribute to experimental verification of topological superconductivity.

  15. Evaluation of the magnetic properties of cosmetic contact lenses with a superconducting quantum interference device.

    PubMed

    Kuroda, Kagayaki; Shirakawa, Naoki; Yoshida, Yoshiyuki; Tawara, Kazuya; Kobayashi, Akihiro; Nakai, Toshiharu

    2014-01-01

    We evaluated the magnetization of 21 cosmetic contact lens samples that included various coloring materials with a superconducting quantum interference device with regard to magnetic resonance (MR) safety. We found 7 samples were ferromagnetic; two had both ferromagnetic and diamagnetic properties; and the rest were diamagnetic. The saturated magnetization of the most ferromagnetic sample was 15.0 µJ/T, which yielded a magnetically induced displacement force of 90.0 µN when the spatial gradient of the static magnetic field was 6.0 T/m. The force was less than one-third of the gravitational force.

  16. Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

    SciTech Connect

    Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A. F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.

    2000-02-06

    A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.

  17. Design of magnetic traps for neutral atoms with vortices in type-II superconducting microstructures

    SciTech Connect

    Zhang, B.; Dumke, R.; Fermani, R.; Mueller, T.; Lim, M. J.

    2010-06-15

    We design magnetic traps for atoms based on the average magnetic field of vortices induced in a type-II superconducting thin film. This magnetic field is the critical ingredient of the demonstrated vortex-based atom traps, which operate without transport current. We use Bean's critical-state method to model the vortex field through mesoscopic supercurrents induced in the thin strip. The resulting inhomogeneous magnetic fields are studied in detail and compared to those generated by multiple normally conducting wires with transport currents. Various vortex patterns can be obtained by programing different loading-field and transport-current sequences. These variable magnetic fields are employed to make versatile trapping potentials.

  18. First Operational Results with the SST-1 Superconducting Magnet & its Cryogenics

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Tanna, V.; Sharma, A.; Khan, Z.; Prasad, U.; Doshi, K.; Khristi, Y.; Parghi, B.; Banoudha, M.; Mahesuria, G.; Patel, R.; Panchal, P.; Panchal, R.; Tank, J.; Sonara, D.; Sharma, D.; Vora, M.; Varadarajulu, A.

    The Steady State Superconducting Tokamak (SST-1) at the Institute for Plasma Research was commissioned in 2013 with the successful experimental validations of its magnets and cryogenic systems. Subsequently, the first plasma in SST-1 has been obtained on June 20, 2013. Since then, the cryo-magnetic systems of SST-1 have been operating reliably, in successive plasma campaigns. Unlike other contemporary cable-in-conduit-conductor (CICC) based superconducting Tokamak magnets, SST-1 CICC in Toroidal Field (TF) winding packs are cooled with two phase helium from a dedicated 1.3 kW helium refrigerator liquefier plant. The TF magnets in SST-1 together with other magnets have been supporting creditable plasma operational scenarios since then, with the TF magnets being charged up to a maximum of 2.0 T on the plasma major radius so far. The vapour cooled current leads of SST-1 are also uniquely operated with cooled helium vapour all along, instead of liquid helium being stored in the lower superconducting sections. The operational experiences with SST-1 TF magnets, PF magnets, and the supporting 5 K and 80 K cryogenic systems contributing towards successful operations of SST-1 plasma experiments are elaborated in this paper.

  19. Magnetic levitation using high temperature superconducting pancake coils as composite bulk cylinders

    NASA Astrophysics Data System (ADS)

    Patel, A.; Hopkins, S. C.; Baskys, A.; Kalitka, V.; Molodyk, A.; Glowacki, B. A.

    2015-11-01

    Stacks of superconducting tape can be used as composite bulk superconductors for both trapped field magnets and for magnetic levitation. Little previous work has been done on quantifying the levitation force behavior between stacks of tape and permanent magnets. This paper reports the axial levitation force properties of superconducting tape wound into pancake coils to act as a composite bulk cylinder, showing that similar stable forces to those expected from a uniform bulk cylinder are possible. Force creep was also measured and simulated for the system. The geometry tested is a possible candidate for a rotary superconducting bearing. Detailed finite element modeling in COMSOL Multiphysics was also performed including a full critical state model for induced currents, with temperature and field dependent properties and 3D levitation force models. This work represents one of the most complete levitation force modeling frameworks yet reported using the H-formulation and helps explain why the coil-like stacks of tape are able to sustain levitation forces. The flexibility of geometry and consistency of superconducting properties offered by stacks of tapes, make them attractive for superconducting levitation applications.

  20. Enhancement of magnetic flux distribution in a DC superconducting electric motor

    NASA Astrophysics Data System (ADS)

    Hamid, N. A.; Ewe, L. S.; Chin, K. M.

    2013-06-01

    Most motor designs require an air gap between the rotor and stator to enable the armature to rotate freely. The interaction of magnetic flux from rotor and stator within the air gap will provide the thrust for rotational motion. Thus, the understanding of magnetic flux in the vicinity of the air gap is very important to mathematically calculate the magnetic flux generated in the area. In this work, a finite element analysis was employed to study the behavior of the magnetic flux in view of designing a synchronous DC superconducting electric motor. The analysis provides an ideal magnetic flux distribution within the components of the motor. From the flux plot analysis, it indicates that flux losses are mainly in the forms of leakage and fringe effect. The analysis also shows that the flux density is high at the area around the air gap and the rotor. The high flux density will provide a high force area that enables the rotor to rotate. In contrast, the other parts of the motor body do not show high flux density indicating low distribution of flux. Consequently, a bench top model of a DC superconducting motor was developed where by motor with a 2-pole type winding was chosen. Each field coil was designed with a racetrack-shaped double pancake wound using DI-BSCCO Bi-2223 superconducting tapes. The performance and energy efficiency of the superconducting motor was superior when compared to the conventional motor with similar capacity.

  1. Superconducting layer thickness dependence of magnetic relaxation property in CVD processed YGdBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Kiuchi, M.; Otabe, E. S.; Matsushita, T.; Shikimachi, K.; Watanabe, T.; Kashima, N.; Nagaya, S.

    2011-11-01

    One of the most important properties of coated conductors for Superconducting Magnetic Energy Storage (SMES) is the relaxation property of persistent superconducting current. This property can be quantitatively characterized by the apparent pinning potential U0∗. In this paper, the dependence of U0∗ on the thickness of superconducting layer d is investigated in the range of 0.33-1.43 μm at the temperature range of 20-30 K and in magnetic fields up to 6.5 T for Y 0.7Gd 0.3Ba 2Cu 3O 7- δ coated conductors. It was found that the value of critical current density did not appreciably depend on d at 20 K. This indicates that no structural deterioration of superconducting layer occurs during the process of increasing thickness. U0∗ increases and then tends to decrease with an increasing magnetic field. The magnetic field at which U0∗ starts to decrease increases with increasing thickness. This property was analyzed using the flux creep-flow model. Application of scaling law is examined for the dependence of U0∗ on magnetic field and temperature. It was found that the dependence could be expressed using scaling parameters B,U0 peak∗ in the temperature range 20-30 K.

  2. A Cryogenic Magnetostrictive Actuator Using a Persistent High Temperature Superconducting Magnet. Part 1; Concept and Design

    NASA Technical Reports Server (NTRS)

    Horner, Garnett; Bromberg, Leslie; Teter, J. P.

    2000-01-01

    Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSCCO 2212 with a magnetostrictive element will be discussed.

  3. Cryogenic helium gas circulation system for advanced characterization of superconducting cables and other devices

    NASA Astrophysics Data System (ADS)

    Pamidi, Sastry; Kim, Chul Han; Kim, Jae-Ho; Crook, Danny; Dale, Steinar

    2012-04-01

    A versatile cryogenic test bed, based on circulating cryogenic helium gas, has been designed, fabricated, and installed at the Florida State University Center for Advanced Power Systems (FSU-CAPS). The test bed is being used to understand the benefits of integrating the cryogenic systems of multiple superconducting power devices. The helium circulation system operates with four sets of cryocooler and heat exchanger combinations. The maximum operating pressure of the system is 2.1 MPa. The efficacy of helium circulation systems in cooling superconducting power devices is evaluated using a 30-m-long simulated superconducting cable in a flexible cryostat. Experiments were conducted at various mass flow rates and a variety of heat load profiles. A 1-D thermal model was developed to understand the effect of the gas flow parameters on the thermal gradients along the cable. Experimental results are in close agreement with the results from the thermal model.

  4. Magnetic Exchange Between Superconducting and Ferromagnetic Oxide Layers

    NASA Astrophysics Data System (ADS)

    Giblin, Sean; Taylor, Jon; Duffy, Jon; Dugdale, Stephen; Nakamura, T.; Santamaria, Jacobo

    2012-02-01

    The origins of high temperature superconductivity and the rich phase diagrams in complex oxides are still a matter of contention that have stimulated many novel experimental studies and observations. Recently the improvement of layer by layer growth techniques of thin films has enabled investigations of both bulk and surface properties. For most common superconductors the order parameter is thought to be antagonistic to that of the exchange mechanism in ferromagnets. Accurately grown thin fllms have enabled these competing interactions to be probed experimentally. In particular, the growth of epitaxial oxide layers, with well-characterized atomically flat interfaces, consisting of superconducting layers of YBa2Cu3O7 (YBCO) and lattice-matched ferromagnetic La2/3Ca1/3MnO3 (LCMO) has flourished. Using XMCD we demonstrate that the known superexchange between Mn and Cu across the YBCO/LCMO is modified when an apparent critical thickness of the superconducting layer is reduced. All samples show an apparent exchange below the superconducting transition but above it is dependent on the YBCO thickness. Possible origins of this behaviour will be discussed.

  5. Study on magnetic separation for decontamination of cesium contaminated soil by using superconducting magnet

    NASA Astrophysics Data System (ADS)

    Igarashi, Susumu; Nomura, Naoki; Mishima, Fumihito; Akiyama, Yoko

    2014-09-01

    The accident of Fukushima Daiichi nuclear power plant caused the diffusion of radioactive cesium over the wide area. We examined the possibility of applying magnetic separation method using the superconducting magnet, which can process a large amount of the soil in high speed, to the soil decontamination and volume reduction of the radioactive cesium contaminated soil. Clay minerals are classified as 2:1 and 1:1 types by the difference of their layer structures, and these types of minerals are respectively paramagnetic and diamagnetic including some exception. It is known that most of the radioactive cesium is strongly adsorbed on the clay, especially on 2:1 type clay minerals. It is expected that the method which can separate only 2:1 type clay minerals selectively from the mixture clay minerals can enormously contribute to the volume reduction of the contaminated soil. In this study, the components in the clay before and after separation were evaluated to estimate the magnetic separation efficiency by using X-ray diffraction. From the results, the decontamination efficiency and the volume reduction ratio were estimated in order to examine the appropriate separation conditions for the practical decontamination of the soil.

  6. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system

    SciTech Connect

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2014-09-15

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.

  7. Optical Probe of the Superconducting Normal Mixed State in a Magnetic Penetration Thermometer

    NASA Technical Reports Server (NTRS)

    Stevenson, T. R.; Balvin, M. A.; Bandler, S. R.; Denis, K. L.; Lee, S. -J.; Nagler, P. C.; Smith, S. J.

    2016-01-01

    Using ultraviolet photon pulses, we have probed the internal behavior of a molybdenum-gold Magnetic Penetration Thermometer (MPT) that we designed for x-ray microcalorimetry. In this low-temperature detector, the diamagnetic response of a superconducting MoAu bilayer is used to sense temperature changes in response to absorbed photons. We have previously described an approximate model that explains the high responsivity of the detector to temperature changes as a consequence of a Meissner transition of the molybdenum-gold film in the magnetic field applied by the superconducting circuit used to bias the detector. We compare measurements of MPT heat capacity and thermal conductance, derived from UV photon pulse data, to our model predictions for the thermodynamic properties of the sensor and for the electron cooling obtained by quasiparticle recombination. Our data on electron cooling power is also relevant to the operation of other superconducting detectors, such as Microwave Kinetic Inductance Detectors.

  8. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system.

    PubMed

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2014-09-01

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems. PMID:25273745

  9. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system.

    PubMed

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2014-09-01

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.

  10. A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2014-09-01

    Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.

  11. Heat load tests of superconducting magnets vibrated electromagnetically for the Maglev train

    NASA Astrophysics Data System (ADS)

    Ohmori, J.; Nakao, H.; Yamashita, T.; Sanada, Y.; Shudou, M.; Kawai, M.; Fujita, M.; Terai, M.; Miura, A.

    Superconducting magnets on Maglev trains vibrate due to harmonic ripples of electromagnetic flux generated by ground coils. Heat load caused by vibration in the magnet amounted to several tens of watts in the electromagnetic vibration test. This was mainly because a.c. loss was induced in the helium vessel housing the superconducting coil, due to relative vibration between the aluminium thermal shield and the coil. The heat load caused by vibration should be strictly restricted to less than 4W due to limited cryogenic refrigeration capacity. The heat load was tested using electromagnetic flux ripples for a superconducting magnet model of one coil which corresponds to 1/4 of an actual magnet. The flux ripples simulated the 6th harmonic of the actual ground levitation coil. Some ideas to reduce the heat load were tried for the magnet model, such as applying high resistance thermal radiation shielding, increasing rigidity of the vacuum vessel, and using high purity copper plating on the helium vessel. These ideas proved effective, and the maximum heat load due to vibration was held to less than 4 W per magnet for the one coil magnet model.

  12. Superconducting toroidal combined-function magnet for a compact ion beam cancer therapy gantry

    NASA Astrophysics Data System (ADS)

    Robin, D. S.; Arbelaez, D.; Caspi, S.; Sun, C.; Sessler, A.; Wan, W.; Yoon, M.

    2011-12-01

    A superconducting, combined-function, 5 T, 90°, toroidal magnet with a large bore is described in this paper. This magnet is designed to be the last and most difficult part of a compact superconducting magnet-based carbon gantry optics for ion beam cancer therapy. The relatively small size of this toroidal magnet allows for a gantry the size of which is smaller or at least comparable to that of a proton gantry. The gantry design places the toroidal magnet between the scanning magnets and the patient, that is the scanning magnets are placed midway through the gantry. By optimizing the coil winding configuration of this magnet, near point-to-parallel optics is achieved between the scanning magnets and the patient; while at the same time there is only a small distortion of the beam-shape when scanning. We show that the origin of the beam-shape distortion is the strong sextupole components, whose effects are greatly pronounced when the beam is widely steered in the magnet. A method to correct such an undesirable effect is suggested and demonstrated by a numerical particle tracking through the calculated three-dimensional magnetic field.

  13. Annealing effects on superconductivity and magnetism in Fe1+yTe1-xSx single crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Z. T.; Yang, Z. R.; Li, L.; Pi, L.; Tan, S.; Zhang, Y. H.

    2012-04-01

    The annealing effects on superconductivity and magnetism in Fe1 + yTe1-xSx single crystals have been investigated. It is found that the superconductivity is improved not only by annealing in air but also by annealing in vacuum or argon. In addition, even for a low S content sample with long-range magnetic order, the superconductivity is also obviously improved by air annealing. These are inconsistent with the previous results of other groups. In the air annealing case, energy dispersive x-ray spectrometer analyses and heat capacity results show that oxygen is incorporated into the system and the long-range magnetic order is partially suppressed. In contrast, for vacuum or argon annealing, no change of composition is detected and no other ions are incorporated, and the enhancement of superconductivity clearly indicates that the modulation of the microstructure plays an important role in the annealing effect on superconductivity and magnetism.

  14. Second generation superconducting super collider dipole magnet cryostat design

    SciTech Connect

    Niemann, R.C.; Bossert, R.C.; Carson, J.A.; Engler, N.H.; Gonczy, J.D.; Larson, E.T.; Nicol, T.H.; Ohmori, T.

    1988-12-01

    The SSC Magnet Development Program is developing accelerator dipole magnets in successive iterations. The initial iteration is complete with six full length model magnets and a thermal model having been built and tested. This initial experience along with the evolving SSC Magnet System Requirements have resulted in the second generation magnet cryostat design. It is this configuration that will be employed for the near term ongoing magnetic, thermal, string and accelerated life testing and will be the design considered for Phase I; i.e., Technology Orientation, of the SSC Magnet Industrialization Program. 5 refs., 7 figs., 1 tab.

  15. Foundations of Advanced Magnetic Resonance Imaging

    PubMed Central

    Bammer, Roland; Skare, Stefan; Newbould, Rexford; Liu, Chunlei; Thijs, Vincent; Ropele, Stefan; Clayton, David B.; Krueger, Gunnar; Moseley, Michael E.; Glover, Gary H.

    2005-01-01

    Summary: During the past decade, major breakthroughs in magnetic resonance imaging (MRI) quality were made by means of quantum leaps in scanner hardware and pulse sequences. Some advanced MRI techniques have truly revolutionized the detection of disease states and MRI can now—within a few minutes—acquire important quantitative information noninvasively from an individual in any plane or volume at comparatively high resolution. This article provides an overview of the most common advanced MRI methods including diffusion MRI, perfusion MRI, functional MRI, and the strengths and weaknesses of MRI at high magnetic field strengths. PMID:15897944

  16. Foundations of advanced magnetic resonance imaging.

    PubMed

    Bammer, Roland; Skare, Stefan; Newbould, Rexford; Liu, Chunlei; Thijs, Vincent; Ropele, Stefan; Clayton, David B; Krueger, Gunnar; Moseley, Michael E; Glover, Gary H

    2005-04-01

    During the past decade, major breakthroughs in magnetic resonance imaging (MRI) quality were made by means of quantum leaps in scanner hardware and pulse sequences. Some advanced MRI techniques have truly revolutionized the detection of disease states and MRI can now-within a few minutes-acquire important quantitative information noninvasively from an individual in any plane or volume at comparatively high resolution. This article provides an overview of the most common advanced MRI methods including diffusion MRI, perfusion MRI, functional MRI, and the strengths and weaknesses of MRI at high magnetic field strengths.

  17. ASTROMAG: A superconducting particle astrophysics magnet facility for the space station

    SciTech Connect

    Green, M.A.; Smoot, G.F.; Golden, R.L.; Israel, M.H.; Kephart, R.; Niemann, R.; Mewalt, R.A.; Ormes, J.F.; Spillantini, P.; Widenbeck, M.E.

    1986-09-01

    This paper describes a superconducting magnet system which is the heart of a particle astrophysics facility to be mounted on a portion of the proposed NASA space station. This facility will complete the studies done by the electromagnetic observatories now under development and construction by NASA. The paper outlines the selection process of the type of magnet to be used to analyze the energy and momentum of charged particles from deep space. The ASTROMAG superconducting magnet must meet all the criteria for a shuttle launch and landing, and it must meet safety standards for use in or near a manned environment such as the space station. The magnet facility must have a particle gathering aperture of at least 1 square meter steradian and the facility should be capable of resolving heavy nuclei with a total energy of 10 Tev or more. 4 refs., 3 figs.

  18. A 12-coil superconducting 'bumpy torus' magnet facility for plasma research.

    NASA Technical Reports Server (NTRS)

    Roth, J. R.; Holmes, A. D.; Keller, T. A.; Krawczonek, W. M.

    1972-01-01

    A retrospective summary is presented of the performance of the two-coil superconducting pilot rig which preceded the NASA Lewis bumpy torus. The NASA Lewis bumpy torus facility consists of 12 superconducting coils, each with a 19 cm i.d. and capable of producing magnetic field strengths of 3.0 teslas on their axes. The magnets are equally spaced around a major circumference 1.52 m in diameter, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.59 m in diameter. The design value of maximum magnetic field on the magnetic axis (3.0 T) has been reached and exceeded.

  19. A New Facility for Testing Superconducting Solenoid Magnets with Large Fringe Fields at Fermilab

    SciTech Connect

    Orris, D.; Carcagno, R.; Nogiec, J.; Rabehl, R.; Sylvester, C.; Tartaglia, M.

    2013-09-01

    Testing superconducting solenoid with no iron flux return can be problematic for a magnet test facility due to the large magnetic fringe fields generated. These large external fields can interfere with the operation of equipment while precautions must be taken for personnel supporting the test. The magnetic forces between the solenoid under test and the external infrastructure must also be taken under consideration. A new test facility has been designed and built at Fermilab specifically for testing superconducting magnets with large external fringe fields. This paper discusses the test stand design, capabilities, and details of the instrumentation and controls with data from the first solenoid tested in this facility: the Muon Ionization Cooling Experiment (MICE) coupling coil.

  20. Superconductivity and Magnetism in Organic Materials Studied with μSR

    NASA Astrophysics Data System (ADS)

    Pratt, Francis

    2016-09-01

    A review is given of the current status and recent progress in the use of μSR for the study of superconductivity and magnetism in organic materials. For organic superconductors, important factors are discussed that influence the observed μSR line widths and their field and temperature dependences in the superconducting state. The accumulated μSR results give direct information about the scaling relationship between superfluid stiffness and transition temperature that provides a strong constraint for theories of organic superconductors. For organic magnetism, μSR offers a sensitive probe for detecting various weak magnetic phenomena ranging from spin-density-wave transitions through spin dynamics and 3D ordering of Heisenberg chain systems to field induced magnetism of quantum spin liquids. Finally, experiments are described that focus on two current issues in organic spintronics: direct measurement of the spin coherence length and the identification of the relative importance of different mechanisms of spin decoherence.

  1. ASTROMAG: A superconducting particle astrophysics magnet facility for the space station

    NASA Technical Reports Server (NTRS)

    Green, M. A.; Smoot, G. F.; Golden, R. L.; Israel, M. H.; Kephart, R.; Niemann, R.; Mewalt, R. A.; Ormes, J. F.; Spillantini, P.; Widenbeck, M. E.

    1986-01-01

    This paper describes a superconducting magnet system which is the heart of a particle astrophysics facility to be mounted on a portion of the proposed NASA space station. This facility will complete the studies done by the electromagnetic observatories now under development and construction by NASA. The paper outlines the selection process of the type of magnet to be used to analyze the energy and momentum of charged particles from deep space. The ASTROMAG superconducting magnet must meet all the criteria for a shuttle launch and landing, and it must meet safety standards for use in or near a manned environment such as the space station. The magnet facility must have a particle gathering aperture of at least 1 square meter steradian and the facility should be capable of resolving heavy nuclei with a total energy of 10 Tev or more.

  2. Preliminary design of a superconducting coil array for NASA prototype magnetic balance. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Alishahi, M. M.

    1980-01-01

    Using a computer program a partly optimized configuration for a supeconducting version of side and lift coil system of NASA-MIT prototype is presented. Cable size for the mentioned coils and also for superconducting drag and magnetizing coils regarding the overall computed field was determined.

  3. One-phase dual converter for two quadrant power control of superconducting magnets

    SciTech Connect

    Ehsani, M.; Kustom, R.I.; Boom, R.W.

    1985-01-01

    This paper presents the results of theoretical and experimental development of a new dc-ac-dc converter for superconducting magnet power supplies. The basic operating principles of the circuit are described followed by a theoretical treatment of the dynamics and control of the system. The successful results of the first experimental operation and control of such a circuit are presented and discussed.

  4. Finite Element Model of Training in the superconducting quadrupole magnet SQ02

    SciTech Connect

    Caspi, Shlomo; Ferracin, Paolo

    2007-11-01

    This paper describes the use of 3D finite element models to study training in superconducting magnets. The simulations are used to examine coil displacements when the electromagnetic forces are cycled, and compute the frictional energy released during conductor motion with the resulting temperature rise. A computed training curve is then presented and discussed. The results from the numerical computations are compared with test results of the Nb{sub 3}Sn racetrack quadrupole magnet SQ02.

  5. Structural performance of the first SSC (Superconducting Super Collider) Design B dipole magnet

    SciTech Connect

    Nicol, T.H.

    1989-09-01

    The first Design B Superconducting Super Collider (SSC) dipole magnet has been successfully tested. This magnet was heavily instrumented with temperature and strain gage sensors in order to evaluate its adherence to design constraints and design calculations. The instrumentation and associated data acquisition system allowed monitoring of the magnet during cooldown, warmup, and quench testing. This paper will focus on the results obtained from structural measurements on the suspension system during normal and rapid cooldowns and during quench studies at full magnet current. 4 refs., 9 figs.

  6. Magnetic shielding in a low temperature torsion pendulum experiment. [superconducting cylinders for attenuation earth field

    NASA Technical Reports Server (NTRS)

    Phillips, P. R.

    1979-01-01

    A new type of ether drift experiment searches for anomalous torques on a permanent magnet. A torsion pendulum is used at liquid helium temperature, so that superconducting cylinders can be used to shield magnetic fields. Lead shields attenuate the earth's field, while Nb-Sn shields fastened to the pendulum contain the fields of the magnet. The paper describes the technique by which the earth's field can be reduced below 0.0001 G while simultaneously the moment of the magnet can be reduced by a factor 7 x 10 to the 4th.

  7. The role of superconductivity in magnetic bearings for high-load applications

    NASA Technical Reports Server (NTRS)

    Downer, James; Eisenhaure, David

    1993-01-01

    Slewing of large payloads will require control torque and angular momentum storage capacities that are large in comparison to the capabilities of available control moment gyros (CMG's). SatCon Technology Corporation is currently designing a CMG which may be employed as a slew actuator for large spacecraft or other payloads. The slew actuator employs a type of magnetic bearing which may be used in high load applications. The magnetic bearing is also used to fully gimbal the suspended rotor of the slew actuator. The use of magnetic bearings in angular momentum exchange actuators has the primary advantage that physical contact between the rotor and stator is eliminated. This leads to greatly extended life, increased reliability, and reduced vibrations. Several actuators operating on magnetic bearings have been demonstrated in previous research efforts. These were sized for use in small satellites. For conventional magnetic bearings, which employ magnetic cores, high torsional loading may require that the magnetic structure be excessively massive. An alternative magnetic bearing design which employs a superconducting coil and eliminates conventional magnetic structures is discussed. The baseline approach is to replace the field coil of a conventional magnetic bearing with the superconducting coil.

  8. SUPERCONDUCTING COMBINED FUNCTION MAGNET SYSTEM FOR J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    OGITSU, T.; AJIMA, Y.; ANERELLA, M.; ESCALLIER, J.; GANETIS, G.; GUPTA, R.; HAGEDOM, D.; HARRISON, M.; HIGASHI, N.; IWAMOTO, Y.; ICHIKAWA, A.; JAIN, A.; KIMURA, N.; KOBAYASHI, T.; MAKIDA, Y.; MURATORE, J.; NAKAMOTO, T.; OHHATA, H.; TAKASAKI, N.; TANAKA, K.; TERASHIMA, A.; YAMOMOTO, A.; OBANA, T.; PARKER, B.; WANDERER, P.

    2004-10-03

    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.

  9. Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype

    SciTech Connect

    Spencer, Cherrill M.; Adolphsen, Chris; Berndt, Martin; Jensen, David R.; Rogers, Ron; Sheppard, John C.; Lorant, Steve St; Weber, Thomas B.; Weisend, John, II; Brueck, Heinrich; Toral, Fernando; /Madrid, CIEMAT

    2011-02-07

    The main linacs of the proposed International Linear Collider (ILC) consist of superconducting cavities operated at 2K. The accelerating cavities are contained in a contiguous series of cryogenic modules that also house the main linac quadrupoles, thus the quadrupoles also need to be superconducting. In an early ILC design, these magnets are about 0.6 m long, have cos (2{theta}) coils, and operate at constant field gradients up to 60 T/m. In order to preserve the small beam emittances in the ILC linacs, the e+ and e- beams need to traverse the quadrupoles near their magnetic centers. A quadrupole shunting technique is used to measure the quadrupole alignment with the beams; this process requires the magnetic centers move by no more than about 5 micrometers when their strength is changed. To determine if such tight stability is achievable in a superconducting quadrupole, we at SLAC measured the magnetic center motions in a prototype ILC quadrupole built at CIEMAT in Spain. A rotating coil technique was used with a better than 0.1 micrometer precision in the relative field center position, and less than a 2 micrometer systematic error over 30 minutes. This paper describes the warm-bore cryomodule that houses the quadrupole in its Helium vessel, the magnetic center measurement system, the measured center data and strength and harmonics magnetic data.

  10. Interplay of structure, magnetism and superconductivity in the 112 Fe based superconducting family

    NASA Astrophysics Data System (ADS)

    Ni, Ni

    Both cuprates and Fe-based superconductors, the two known high Tc superconducting families, show rich emergent phenomena near the superconductivity (SC). To understand the mechanism of unconventional SC, it is crucial to unravel the nature of these emergent orders. The 112 Fe pnictide superconductor (FPS), Ca1-xRExFeAs2 (CaRE112), shows SC up to 42 K, the highest bulk Tc among all nonoxide FPS [2]. Being an exceptional FPS where the global C4 rotational symmetry is broken even at room temperature, it is important to extract the similarities and differences between 112 and other FPS so that critical ingredients in inducing SC in FPS can be filtered. In this talk, I will review current progress in the study of 112. The comparison between Co doped CaLa112 and Co doped 10-3-8 will be made and the importance of interlayer coupling will be discussed. The work on 112 is supported by NSF while the work on 10-3-8 is supported by DOE.

  11. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak

    SciTech Connect

    Han, X.; Liu, X.; Liu, Y. Li, E. Z.; Hu, L. Q.; Gao, X.; Domier, C. W.; Luhmann, N. C.

    2014-07-15

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104–168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ∼500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.

  12. ELMy H-mode linear simulation with 3-field model on experimental advanced superconducting tokamak using BOUT++

    SciTech Connect

    Liu, Z. X.; Gao, X.; Liu, S. C.; Ding, S. Y.; Li, J. G.; Xia, T. Y.; Xu, X. Q.; Hughes, J. W.

    2012-10-15

    H-mode plasmas with ELM (edge localized mode) have been realized on experimental advanced superconducting tokamak (EAST) with 2.45 GHz low hybrid wave at P{sub LHW}{approx}1 MW in 2010. Data from EAST experiments including magnetic geometry, measured pressure profiles, and calculated current profiles are used to investigate the physics of ELM utilizing the BOUT++ code. Results from linear simulations show that the ELMs in EAST are dominated by resistive ballooning modes. When the Lundquist number (dimensionless ratio of the resistive diffusion time to the Alfven time) is equal to or less than 10{sup 7}, the resistive ballooning modes are found to become unstable in the ELMy H-mode plasma. For a fixed pedestal pressure profile, increasing plasma current generates more activities of low-n ELMs.

  13. Superconducting Multi-Cell Deflecting Cavity for Short-Pulse X-Ray Generation at the Advanced Photon Source

    SciTech Connect

    G.J. Waldschmidt, L.H. Morrison, R. Nassiri, R.A. Rimmer, K. Tian, H. Wang

    2009-05-01

    A superconducting multi-cell cavity for the production of short x-ray pulses at the Advanced Photon Source (APS) has been explored as an alternative to a single-cell cavity design in order to improve the packing factor and potentially reduce the number of high-power RF systems and low-level RF controls required. The cavity will operate at 2815 MHz in the APS storage ring and will require heavy damping of parasitic modes to maintain stable beam operation. Novel on-cell dampers, attached directly to the cavity body, have been utilized by taking advantage of the magnetic field null on the equatorial plane in order to enhance damping. Design issues and simulation results will be discussed.

  14. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak

    SciTech Connect

    Liu, X.; Zhao, H. L.; Liu, Y. Li, E. Z.; Han, X.; Ti, A.; Hu, L. Q.; Zhang, X. D.; Domier, C. W.; Luhmann, N. C.

    2014-09-15

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems.

  15. An advanced arrangement of the combined propulsion, levitation and guidance system of superconducting Maglev

    SciTech Connect

    Fujie, Junji

    1999-09-01

    The PLG (combined Propulsion, Levitation and Guidance) method was proposed for a more favorable Maglev ground coil system, combining the functions of propulsion, levitation, and guidance of the vehicle into one coil. Research and development is currently being conducted on this method. In this paper, the characteristics of a newly-structured system for the PLG method is examined. The discussed characteristics include propulsion, levitation-guidance, vehicle dynamics in the cases of problems with the superconducting magnets, and the magnetic field on board the vehicle.

  16. Advances in applied superconductivity: A preliminary evaluation of goals and impacts

    NASA Astrophysics Data System (ADS)

    Wolsky, A. M.; Daniels, E. J.; Giese, R. F.; Harkness, J. B. L.; Johnson, L. R.; Rote, D. M.; Zwick, S. A.

    1988-01-01

    This document is meant to aid the U.S. Department of Energy, Assistant Secretary for Conservation and Renewable Energy by discussing the likely impacts of recent results from research on superconducting materials. The discussions in this document concern terrestrial applications that would substantially affect the production and use of electricity. The sections of the report each address a particular topic. The topics are: (1) electric generators, (2) transformers, (3) power transmission, (4) magnetic energy storage, (5) electric motors, (6) separation industry, and (7) maglev (magnetic-levitation) trains.

  17. Conceptual design of a superconducting magnet ECR ion source for the Korean rare isotope accelerator

    NASA Astrophysics Data System (ADS)

    Oh, Byung-Hoon; In, Sang-Ryul; Lee, Kwang-Won; Lee, Cheol Ho; Jeong, Seung-Ho; Chang, Dae-Sik; Seo, Chang Seog

    2013-11-01

    Based on proven technology, an upgraded 28-GHz superconducting electron cyclotron resonance ion source is suggested to produce a wide range of different ion beams from protons for isotope separator on-line to uranium for in-flight fragmentation. The suggested ion source has the following characteristics: (1) The shapes of the minimum B z layer can be controlled using five superconducting solenoid coils. (2) Two solenoid lenses, the first one side a cryostat and the second one outside it, control the beam envelope at the entrance of the analyzing magnet.

  18. Methods for field computations for the development of SSC superconducting magnets

    SciTech Connect

    Jayakumar, R.; Orrell, D.; Snitchler, G.; Haddock, C.; Turner, J.; Kallas, N.; Spigo, G. )

    1992-03-01

    This paper reports that the Superconducting Super Collider Program will require a large number of superconducting dipole and quadrupole magnets with a variety of designs. Analysis methods are being developed to facilitate rapid and accurate calculation of fields and optimization of design. 2-D and 3-D field computations are fully developed for analysis of coils in the straight section and ends. These are being linked to structural codes and CAD software for design optimization and studies. Other codes have been developed for coil errors, and for persistent and eddy current effects. The attempt is underway to integrate all the codes into a design software package.

  19. Low-temperature neutron irradiation tests of superconducting magnet materials using reactor neutrons at KUR

    NASA Astrophysics Data System (ADS)

    Yoshida, M.; Nakamoto, T.; Ogitsu, T.; Xu, Q.; Itahashi, T.; Kuno, Y.; Kuriyama, Y.; Mori, Y.; Qin, B.; Sato, A.; Sato, K.; Yoshiie, T.

    2012-06-01

    Radiation resistant superconducting magnets are required for high intensity particle accelerators and associated secondary particle beamlines, such as the LHC upgrade and the COMET experiment at J-PARC. Expected neutron fluence on the superconducting coils reaches 1021 n/m2 or higher, therefore the magnet should be designed taking into account the irradiation effects. Irradiation tests for superconducting magnet materials have been carried out using reactor neutrons at Kyoto Univ. Research Reactor Institute. As a first step of the experiment, aluminum alloy stabilizer for superconducting cable was exposed to the reactor neutrons at low temperature and the resistance has been measured in situ during neutron exposure. After the irradiation at 12 K-15 K, the sample resistance increase was proportional to the integrated neutron fluence, and reached almost double for a fast-neutron fluence of 2.3×1020 n/m2 (>0.1 MeV). It is also confirmed that the induced resistance is fully recovered by thermal cycling to room temperature. Details of the irradiation test and the prospects are described.

  20. Structural safety assessment under the low temperature of KSTAR superconducting magnet-supporting post

    NASA Astrophysics Data System (ADS)

    Her, N. I.; Sa, J. W.; Cho, S.; Do, C. J.; Choi, C. H.; Kim, B. C.; Im, K. H.; Kyum, M.; Kim, W. C.; Kim, G. H.; Yoo, B. J.; Oh, Y. K.; Kim, D. L.; Kwon, M.; Lee, G. S.; Kstar Team

    2001-01-01

    A magnet-supporting post installed between the lower TF coil cooled by 4.5 K supercritical helium and the cryostat base is one of the most important components of the superconducting magnet-supporting structure for KSTAR Tokamak. This structure should be flexible to absorb thermal shrink of the magnet and should also be rigid to support the magnet weight and the plasma disruption load. The post was designed with stainless steel (SS) 316 LN and carbon fiber reinforced plastic (CFRP) that has low thermal conductivity and high structural strength at low temperature. In order to verify the fabricability and the structural safety, a whole scale prototype of the KSTAR magnet-supporting post was manufactured and tested. Both static and compressive cyclic load tests under the maximum plasma vertical disruption load and the magnet dead weight were performed. The test results showed that the magnet-supporting post of KSTAR Tokamak was fabricable and structurally rigid.

  1. Fabrication and Test Results of a Prototype, Nb3Sn Superconducting Racetrack Dipole Magnet

    SciTech Connect

    Gourlay, S. A.; Chow, K.; Dietderich, D.R.; Gupta, R.; Hannaford, R.; Harnden, W.; Lietzke, A.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.

    1998-09-01

    A prototype, Nb{sub 3}Sn superconducting magnet, utilizing a racetrack coil design has been built and tested. This magnet represents the first step in a recently implemented program to develop a high field, accelerator quality magnet. This magnet was constructed with coils wound from conductor developed for the ITER project, limiting the magnet to a field of 6-7 Tesla. Subsequent magnets in the program will utilize improved conductor, culminating in a magnet design capable of producing fields approaching 15 Tesla. The simple geometry is more suitable for the use of brittle superconductors necessary to eventually reach high field levels. In addition, fewer and simpler parts are used in fabricating these coils compared with the more conventional cosine theta cross section coils. The general fabrication steps, mechanical design and quench performance are discussed.

  2. Strong correlations between vacancy and magnetic ordering in superconducting K0.8Fe2 -ySe2

    NASA Astrophysics Data System (ADS)

    Yang, J.; Duan, C.; Huang, Q.; Brown, C.; Neuefeind, J.; Louca, Despina

    2016-07-01

    The coexistence of magnetic and nonmagnetic phases in the superconducting potassium iron selenide, KxFe2 -ySe2 , has been intensely debated. With superconductivity proposed to appear in a stoichiometric, nonmagnetic phase with I4/mmm crystal symmetry, the proposed nonsuperconducting phase is magnetic and has a lower symmetry, I4/m. The latter consists of Fe vacancies that go through a disordered-to-ordered transition in which the partially filled Fe sites create a supercell upon ordering. We show, using neutron scattering on the optimally doped composition, K0.8Fe2 -ySe2 , that the absence of magnetism does not signal the presence of superconductivity. Moreover, the degree of vacancy order is coupled to the strength of the magnetic order. Superconductivity coincides with the presence of the magnetic order parameter, albeit the latter is significantly weaker than previously reported, contradicting the current understanding of this ˜30 K superconductor.

  3. MAGNETIC MEASUREMENT SYSTEM FOR THE NSLS SUPERCONDUCTING UNDULATOR VERTICAL TEST FACILITY.

    SciTech Connect

    HARDER, D.; CHOUHAN, S.; LEHECKA, M.; RAKOWSKY, G.; SKARITKA, J.; TANABE, T.

    2005-05-16

    One of the challenges of small-gap superconducting undulators is measurement of magnetic fields within the cold bore to characterize the device performance and to determine magnetic field errors for correction or shimming, as is done for room-temperature undulators. Both detailed field maps and integrated field measurements are required. This paper describes a 6-element, cryogenic Hall probe field mapper for the NSLS superconducting undulator Vertical Test Facility (VTF) [1]. The probe is designed to work in an aperture only 3 mm high. A pulsed-wire insert is also being developed, for visualization of the trajectory, for locating steering errors and for determining integrated multi-pole errors. The pulsed-wire insert will be interchangeable with the Hall probe mapper. The VTF and the magnetic measurement systems can accommodate undulators up to 0.4 m in length.

  4. Development of superconducting magnets for RAON 28 GHz ECR ion source.

    PubMed

    Heo, Jeongil; Choi, Sukjin; Kim, Yonghwan; Hong, In-Seok

    2016-02-01

    RAON, a 28 GHz electron cyclotron resonance ion source (ECR IS), was designed and tested as a Rare Isotope Science Project. It is expected that RAON would provide not only rare-isotope beams but also stable heavy ions ranging from protons to uranium. In order to obtain the steady heavy-ion beam required for ECR IS, we must use a 28 GHz microwave source as well as a high magnetic field. A superconducting magnet using a NbTi wire was designed and manufactured for producing the ECR IS and a test was conducted. In this paper, the design and fabrication of the superconducting magnet for the ECR IS are presented. Experimental results show that the quench current increases whenever quenching occurs, but it has not yet reached the designed current. The experiment is expected to reveal the ideal conditions required to reach the designed current. PMID:26931952

  5. Design, Fabrication, and Test of a Superconducting Dipole Magnet Based on Tilted Solenoids

    SciTech Connect

    Caspi, S.; Dietderich, D. R.; Ferracin, P.; Finney, N. R.; Fuery, M. J.; Gourlay, S. A.; Hafalia, A. R.

    2007-06-01

    It can be shown that, by superposing two solenoid-like thin windings that are oppositely skewed (tilted) with respect to the bore axis, the combined current density on the surface is 'cos-theta' like and the resulting magnetic field in the bore is a pure dipole. As a proof of principle, such a magnet was designed, built and tested as part of a summer undergraduate intern project. The measured field in the 25mm bore, 4 single strand layers using NbTi superconductor, exceeded 1 T. The simplicity of this high field quality design, void of typical wedges end-spacers and coil assembly, is especially suitable for insert-coils using High Temperature Superconducting wire as well as for low cost superconducting accelerator magnets for High Energy Physics. Details of the design, construction and test are reported.

  6. Test of a NbTi Superconducting Quadrupole Magnet Based on Alternating Helical Windings

    SciTech Connect

    Caspi, S.; Trillaud, F.; Godeke, A.; Dietderich, D.; Ferracin, P.; Sabbi, G.; Giloux, C.; Perez, J. G.; Karppinen, M.

    2009-08-16

    It has been shown that by superposing two solenoid-like thin windings, that are oppositely skewed (tilted) with respect to the bore axis, the combined current density on the surface is cos({theta})-like and the resulting magnetic field in the bore is a pure dipole field. Following a previous test of such a superconducting dipole magnet, a quadrupole magnet was designed and built using similar principles. This paper describes the design, construction and test of a 75 mm bore 600 mm long superconducting quadrupole made with NbTi wire. The simplicity of the design, void of typical wedges, end-spacers and coil assembly, is especially suitable for future high field insert coils using Nb{sub 3}Sn as well as HTS wires. The 3 mm thick coil reached 46 T/m but did not achieve its current plateau.

  7. Superconducting electromagnets for large wind tunnel magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.; Scurlock, R. G.; Wu, Y. Y.; Goodyer, M. J.; Balcerek, K.; Eskins, J.; Britcher, C. P.

    1984-01-01

    A superconducting electromagnetic suspension and balance system for an 8 x 8-ft, Mach 0.9 wind tunnel is presented. The system uses a superconducting solenoid as a model core 70 cm long and with a 11.5 cm OD, and a combination of permanent magnet material in the model wings to produce the required roll torque. The design, which uses an integral cold structure rather than separate cryostats for mounting all control magnets, has 14 external magnets, including 4 racetrack-shaped roll coils. Helium capacity of the system is 3.0 to 3.5 l with idling boiloff rate predicted at 0.147 to 0.2 l/h. The improvements yielded a 50-percent reduction in the system size, weight, and cost.

  8. Invited Article: Development of high-field superconducting Ioffe magnetic traps

    NASA Astrophysics Data System (ADS)

    Yang, L.; Brome, C. R.; Butterworth, J. S.; Dzhosyuk, S. N.; Mattoni, C. E. H.; McKinsey, D. N.; Michniak, R. A.; Doyle, J. M.; Golub, R.; Korobkina, E.; O'Shaughnessy, C. M.; Palmquist, G. R.; Seo, P.-N.; Huffman, P. R.; Coakley, K. J.; Mumm, H. P.; Thompson, A. K.; Yang, G. L.; Lamoreaux, S. K.

    2008-03-01

    We describe the design, construction, and performance of three generations of superconducting Ioffe magnetic traps. The first two are low current traps, built from four racetrack shaped quadrupole coils and two solenoid assemblies. Coils are wet wound with multifilament NbTi superconducting wires embedded in epoxy matrices. The magnet bore diameters are 51 and 105mm with identical trap depths of 1.0T at their operating currents and at 4.2K. A third trap uses a high current accelerator-type quadrupole magnet and two low current solenoids. This trap has a bore diameter of 140mm and tested trap depth of 2.8T. Both low current traps show signs of excessive training. The high current hybrid trap, on the other hand, exhibits good training behavior and is amenable to quench protection.

  9. Soldered joints—an essential component of demountable high temperature superconducting fusion magnets

    NASA Astrophysics Data System (ADS)

    Tsui, Yeekin; Surrey, Elizabeth; Hampshire, Damian

    2016-07-01

    Demountable superconducting magnet coils would offer significant benefits to commercial nuclear fusion power plants. Whether large pressed joints or large soldered joints provide the solution for demountable fusion magnets, a critical component or building block for both will be the many, smaller-scale joints that enable the supercurrent to leave the superconducting layer, cross the superconducting tape and pass into the solder that lies between the tape and the conductor that eventually provides one of the demountable surfaces. This paper considers the electrical and thermal properties of this essential component part of demountable high temperature superconducting (HTS) joints by considering the fabrication and properties of jointed HTSs consisting of a thin layer of solder (In52Sn48 or Pb38Sn62) sandwiched between two rare-earth-Ba2Cu3O7 (REBCO) second generation HTS coated conductors (CCs). The HTS joints are analysed using numerical modelling, critical current and resistivity measurements on the joints from 300 to 4.2 K in applied magnetic fields up to 12 T, as well as scanning electron microscopy studies. Our results show that the copper/silver layers significantly reduce the heating in the joints to less than a few hundred mK. When the REBCO alone is superconducting, the joint resistivity (R J) predominantly has two sources, the solder layer and an interfacial resistivity at the REBCO/silver interface (∼25 nΩ cm2) in the as-supplied CCs which together have a very weak magnetoresistance in fields up to 12 T. We achieved excellent reproducibility in the R J of the In52Sn48 soldered joints of better than 10% at temperatures below T c of the REBCO layer which can be compared to variations of more than two orders of magnitude in the literature. We also show that demountable joints in fusion energy magnets are viable and need only add a few percent to the total cryogenic cost for a fusion tokamak.

  10. Magnetic field dependence of Interface Superconductivity in LSCO/LCO bilayers

    NASA Astrophysics Data System (ADS)

    Riggs, Scott; Balakirev, Fedor; Migliori, Albert; Boebinger, Greg; Logvenov, Gena; Bollinger, Anthony; Gozar, Adrian; Bozovic, Ivan

    2008-03-01

    Interface superconductivity (IS) with a high Tc has been discovered recently in bi-layer films consisting of a thin layer of La1.55Sr0.45CuO4 (overdoped and metallic but not superconducting) covered with a thin layer of La2CuO4 (undoped, insulating, and antiferromagnetic) grown by molecular beam epitaxy (MBE)^1. Here we report on a study of magneto-transport properties in such IS systems. By measuring the magnetic-field dependence of in-plane longitudinal and Hall resistivities we find the temperature dependence of the upper critical field (Hc2). Other findings and inferences on the nature of IS and Tc enhancement will be discussed as well. ^1A. Gozar, G. Logvenov, A. T. Bollinger and I. Bozovic, ``Interface superconductivity between a metal and a Mott insulator'', submitted for publication.

  11. 30-MJ superconducting magnetic energy storage for electric-transmission stabilization

    SciTech Connect

    Turner, R.D.; Rogers, J.D.

    1981-01-01

    The Bonneville Power Administration operates the electric power transmission system that connects the Pacific Northwest and southern California. The HVAC interties develop 0.35 Hz oscillations when the lines are heavily loaded. A 30 MJ (8.4 kWh) Superconducting Magnetic Energy Storage (SMES) unit with a 10 MW converter can provide system damping for the oscillation. The unit is scheduled for installation in 1982 and operation in 1982-83. Status of the project is described. The conductor has been fully tested electrically and mechanically and the 5 kA superconducting cable has been produced. The 30 MJ superconducting coil is essentially complete. All major components of the electrical and cryogenic systems except the nonconducting dewar have been completed. The refrigerator and converter are undergoing tests. The system is to be located at the BPA Tacoma Substation and operated by microwave link from Portland, OR.

  12. Superconducting and Insulating Phases of Disordered FeSe Thin Films in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Schneider, R.; Zaitsev, A. G.; Fuchs, D.; von Löhneysen, H.

    2015-01-01

    The temperature-dependent electronic transport on the superconducting and insulating sides of the superconductor-insulator transition in disordered quasi-two-dimensional textured FeSe thin films is reported. The transition is driven by a perpendicular magnetic field applied to a film with its thickness close to the critical thickness of the thickness-, i.e., disorder-induced transition. The resistance in the superconducting phase might be dominated by thermally assisted flux flow, and in the phase diagram a metallic phase might intervene between the superconducting and insulating state at very low temperatures. In the insulating phase, weak insulating behavior is observed that can be described by weak localization theory of bosons, thus supporting the bosonic description of the superconductor-insulator transition in FeSe thin films.

  13. Superconducting and normal state magnetic properties of RNi{sub 2}B{sub 2}C single crystals

    SciTech Connect

    Johnston, D.C.; Borsa, F.; Cho, B.K. |

    1995-10-01

    The authors` studies of the magnetic properties of RNi{sub 2}B{sub 2}C single crystals (R = Y, Gd-Tm, Lu) are reviewed. Of particular interest are the ordered magnetic structures when R is a magnetic rare earth atom, the interaction between magnetism and superconductivity, the influence of crystalline electric fields of the magnetic rare earth ions on these behaviors, and the magnetic character of the Ni sublattice.

  14. IMPROVING THE DESIGN AND ANALYSIS OF SUPERCONDUCTING MAGNETS FOR PARTICLE ACCELERATORS

    SciTech Connect

    GUPTA,R.C.

    1996-11-01

    The field quality in superconducting magnets has been improved to a level that it does not appear to be a limiting factor on the performance of RHIC. The many methods developed, improved and adopted during the course of this work have contributed significantly to that performance. One can not only design and construct magnets with better field quality than in one made before but can also improve on that quality after construction. The relative field error ({Delta}B/B) can now be made as low as a few parts in 10{sup {minus}5} at 2/3 of the coil radius. This is about an order of magnitude better than what is generally expected for superconducting magnets. This extra high field quality is crucial to the luminosity performance of RHIC. The research work described here covers a number of areas which all must be addressed to build the production magnets with a high field quality. The work has been limited to the magnetic design of the cross section which in most cases essentially determines the field quality performance of the whole magnet since these magnets are generally long. Though the conclusions to be presented in this chapter have been discussed at the end of each chapter, a summary of them might be useful to present a complete picture. The lessons learned from these experiences may be useful in the design of new magnets. The possibilities of future improvements will also be presented.

  15. Magnetism and superconductivity in heavy-electron metals

    SciTech Connect

    Ott, H.R.

    1994-12-31

    All the data and features of properties of heavy-electron systems mentioned in this presentation represent only a fraction of recent results obtained in this field. Nevertheless they should demonstrate that interesting physics may be explored in studies of these materials. Most results that are obtained are important with regard to the understanding of metals in general. These substances are suited for studies of all aspects of many-body effects among conduction electrons in metals and are an important link to quantum fluids or solids like {sup 3}He. The quite well established occurrence of unconventional superconductivity is among the most prominent features of heavy-electron physics and, also here, provides a merging of interest with another hot topic of condensed-matter physics, the phenomenon of superconductivity in oxides at relatively high temperatures and in organic substances. As a final comment the author recalls the importance of the materials-science aspects in these problems. The demonstrated strong influence of small amounts of impurities or imperfections on the physical properties of these substances certainly deserves further attention in future experimental and theoretical work.

  16. Developing a high-temperature superconducting bulk magnet for the maglev train of the future

    NASA Astrophysics Data System (ADS)

    Fujimoto, Hiroyuki

    1998-10-01

    The major applications of high-temperature superconductors have mostly been confined to products in the form of wires and thin films. However, recent developments show that rare-earth REBa2Cu3O7-x and light rare-earth LREBa2Cu3O7-3 superconductors prepared by melt processes have a high critical-current density at 77 K and high magnetic fields. These superconductors will promote the application of bulk high-temperature superconductors in high magnetic fields; the superconducting bulk magnet for the Maglev train is one possible application.

  17. Heat load characteristics and new design using one-coil model superconducting magnets

    NASA Astrophysics Data System (ADS)

    Jizo, Yoshihiro; Akagi, Hidenari; Yamaguchi, Takashi; Terai, Motoaki; Shinobu, Masatoshi

    Superconducting magnets (SCM) for Maglev trains are vibrated by the electromagnetic force arising from the magnetic field of higher harmonics, which is due to the arrangement of the ground coils. The heat load within the liquid helium temperature region increases by the vibration of the magnets. This paper reports a heat load generation estimation mechanism due to the above-mentioned vibration, as well as effective measures of reducing heat load generation. In addition, we show how a one-coil type SCM can reduce the heat load generation in electromagnetic disturbance tests.

  18. Radiation-induced electrical breakdown of helium in fusion reactor superconducting magnet systems

    SciTech Connect

    Perkins, L.J.

    1983-12-02

    A comprehensive theoretical study has been performed on the reduction of the electrical breakdown potential of liquid and gaseous helium under neutron and gamma radiation. Extension of the conventional Townsend breakdown theory indicates that radiation fields at the superconducting magnets of a typical fusion reactor are potentially capable of significantly reducing currently established (i.e., unirradiated) helium breakdown voltages. Emphasis is given to the implications of these results including future deployment choices of magnet cryogenic methods (e.g., pool-boiling versus forced-flow), the possible impact on magnet shielding requirements and the analogous situation for radiation-induced electrical breakdown in fusion RF transmission systems.

  19. Field polarity dependent nucleation of superconductivity in quasi-one-dimensional magnetic templates.

    SciTech Connect

    Ataklti, G. W.; Silhanek, A. V.; Van de Vondel, J.; Gillijns, W.; Belkin, A.; Karapetrov, G.; Moshchalkov, V. V.; Materials Science Division; Katholieke Univ. Leuven; Illinois Inst. of Tech.

    2010-01-01

    We investigate the nucleation of superconductivity in an Al/Al{sub 2}O{sub 3}/Py trilayer system by electrical transport measurements. Magnetic force microscopy images taken at room temperature show that the 0.7 {micro}m thick Py-film form stripes of magnetic domains with alternating out-of-plane stray field. After applying a strong out of plane magnetic field H the superconductor/normal phase boundary becomes asymmetric with respect to H = 0. This lack of field polarity symmetry results from the unbalanced size distribution of domains with opposite polarity.

  20. Core/coil assembly for use in superconducting magnets and method for assembling the same

    DOEpatents

    Kassner, David A.

    1979-01-01

    A core/coil assembly for use in a superconducting magnet of the focusing or bending type used in syncronous particle accelerators comprising a coil assembly contained within an axial bore of the stacked, washer type, carbon steel laminations which comprise the magnet core assembly, and forming an interference fit with said laminations at the operating temperature of said magnet. Also a method for making such core/coil assemblies comprising the steps of cooling the coil assembly to cryogenic temperatures and drawing it rapidly upwards into the bore of said stacked laminations.