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Sample records for final focus superconducting

  1. Superconducting final focus quadrupoles for a B Factory

    SciTech Connect

    Ash, W.

    1992-08-01

    The superconducting final focus triplet now operating at the SLAC Linear Collider (SLC) demonstrate most of the features required for a B Factory in terms of detector interaction and high machine tolerances. These features are discussed, together with reasonable expectations for scaling to a B Factory. The effort and schedule for this project are discussed.

  2. Superconducting final focus for the SLAC Linear Collider

    SciTech Connect

    Ash, W.W.; Barrera, F.; Burgess, W.; Cook, K.; Cutler, H.; Ferrie, J.; Petersen, H.; Sawyer, D.; Rinta, R.

    1992-05-01

    Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector`s solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.

  3. Superconducting final focus for the SLAC Linear Collider

    SciTech Connect

    Ash, W.W.; Barrera, F.; Burgess, W.; Cook, K.; Cutler, H.; Ferrie, J.; Petersen, H.; Sawyer, D.; Rinta, R.

    1992-05-01

    Triplets composed of superconducting quadrupoles have been built and installed as the final focusing element for the high-energy positron and electron beams of the SLAC Linear Collider. Special features include independent alignment to 100-micron tolerance inside a common cryostat; non-magnetic materials to allow operation inside the detector's solenoid field; a continuous-flow helium-only system using 50-meter-long flexible transfer lines; and complete operation of the system before installation. The mechanical design and cryogenic operation experience are presented.

  4. 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.

  5. 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.

  6. Final focus test beam

    SciTech Connect

    Not Available

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration.

  7. Focus on superconducting properties of iron chalcogenides

    NASA Astrophysics Data System (ADS)

    Takano, Yoshihiko

    2012-10-01

    Since the discovery of iron-based superconductors, much attention has been given to the exploration of new superconducting compounds. Numerous superconducting iron compounds have been found and categorized into five groups: LnFeAsO (Ln = lanthanide), BaFe2As2, KFeAs, FeSe and FeAs with perovskite blocking layers. Among them, FeSe has the simplest crystal structure. Since the crystal structure is composed of only superconducting Fe layers, the FeSe family must be the best material to investigate the mechanism of iron-based superconductivity. FeSe shows very strong pressure effects. The superconducting transition temperature (Tc) of FeSe is approximately 8 K at ambient pressure. However Tc dramatically increases up to 37 K under applied pressure of 4-6 GPa. This is the third highest Tc value among binary superconductors, surpassed only by CsC60 under pressure (Tc = 38 K) and MgB2 (Tc = 39 K). On the other hand, despite FeTe having a crystal structure analogous to that of FeSe, FeTe shows antiferromagnetic properties without superconductivity. Doping of small ions, either Se or S, however, can induce superconductivity in FeTe1-xSex or FeTe1-xSx . The superconductivity is very weak for small x values, and annealing under certain conditions is required to obtain strong superconductivity, for instance annealing in oxygen or alcoholic beverages such as red wine. The following selection of papers describe many important experimental and theoretical studies on iron chalcogenide superconductors including preparation of single crystals, bulk samples and thin films; NMR measurements; photoemission spectroscopy; high-pressure studies; annealing effects and research on new BiS2-based superconductors. I hope this focus issue will help researchers understand the frontiers of iron chalcogenide superconductors and assist in the discovery of new phenomena related to iron-based superconductivity.

  8. Designing focusing solenoids for superconducting RF accelerators

    SciTech Connect

    Davis, G.; Kashikhin, V.V.; Page, T.; Terechkine, I.; Tompkins, J.; Wokas, T.; /Fermilab

    2006-08-01

    The design of a focusing solenoid for use in a superconducting RF linac requires resolving a range of problems with conflicting requirements. Providing the required focusing strength contradicts the goal of minimizing the stray field on the surfaces of adjacent superconducting RF cavities. The requirement of a compact solenoid, able to fit into a gap between cavities, contradicts the need of mechanical support necessary to restrain electromagnetic forces that can result in coil motion and subsequent quenching. In this report we will attempt to address these and other issues arising during the development of focusing solenoids. Some relevant test data will also be presented.

  9. FOREWORD: Focus on Superconductivity in Semiconductors Focus on Superconductivity in Semiconductors

    NASA Astrophysics Data System (ADS)

    Takano, Yoshihiko

    2008-12-01

    Since the discovery of superconductivity in diamond, much attention has been given to the issue of superconductivity in semiconductors. Because diamond has a large band gap of 5.5 eV, it is called a wide-gap semiconductor. Upon heavy boron doping over 3×1020 cm-3, diamond becomes metallic and demonstrates superconductivity at temperatures below 11.4 K. This discovery implies that a semiconductor can become a superconductor upon carrier doping. Recently, superconductivity was also discovered in boron-doped silicon and SiC semiconductors. The number of superconducting semiconductors has increased. In 2008 an Fe-based superconductor was discovered in a research project on carrier doping in a LaCuSeO wide-gap semiconductor. This discovery enhanced research activities in the field of superconductivity, where many scientists place particular importance on superconductivity in semiconductors. This focus issue features a variety of topics on superconductivity in semiconductors selected from the 2nd International Workshop on Superconductivity in Diamond and Related Materials (IWSDRM2008), which was held at the National Institute for Materials Science (NIMS), Tsukuba, Japan in July 2008. The 1st workshop was held in 2005 and was published as a special issue in Science and Technology of Advanced Materials (STAM) in 2006 (Takano 2006 Sci. Technol. Adv. Mater. 7 S1). The selection of papers describe many important experimental and theoretical studies on superconductivity in semiconductors. Topics on boron-doped diamond include isotope effects (Ekimov et al) and the detailed structure of boron sites, and the relation between superconductivity and disorder induced by boron doping. Regarding other semiconductors, the superconducting properties of silicon and SiC (Kriener et al, Muranaka et al and Yanase et al) are discussed, and In2O3 (Makise et al) is presented as a new superconducting semiconductor. Iron-based superconductors are presented as a new series of high

  10. Focus on Hybrid Magnetic/Superconducting Systems

    SciTech Connect

    Cooley, L.; Li, Q.; Moshchalkov, V.

    2011-02-01

    Like antagonistic cousins from a common heritage, the competition between superconductivity and magnetism for correlated electron states, and coexistence in some rare cases, produces a rich variety of physical behavior, useful materials, and technologically important properties. Many pages of Superconductor Science and Technology are devoted to cuprates, pnictides, and other compounds where the mechanism of superconductivity itself is intertwined with magnetism. This focus issue explores another area, in which superconductivity and magnetism are combined as a hybrid system to create new properties not possible with either system alone, or to improve upon the properties of either system in dramatic ways. In recent years, great progress has been made in this exciting, relatively new field, followed by many workshops and special sessions in major international conferences. A concise and up-to-date focus issue of Superconductor Science and Technology is timely to summarize the latest developments. We, the Guest Editors, would like to thank those colleagues who contributed their most recent and interesting findings to this focus issue: Silhanek and co-workers reported both theoretical and experimental investigations of the dynamics of vortex chains for different arrangements of magnetic moments. Their approach of time-dependent Ginzburg-Landau formalism now replaces the previously proposed empirical models to explain the most relevant properties of the dynamics of these S/F hybrid systems. Hikino and co-workers presented a new route to observe the spin-wave excitation by the Josephson effect, through a theoretical investigation of the resistively shunted junction model, extended by considering the gauge invariance including magnetization. When the magnetization is driven by the microwave adjusted to the ferromagnetic resonance frequency, the dc supercurrent is induced in the junction, and the current-voltage curve shows step structures as a function of applied voltage

  11. Simulations of neutralized final focus

    SciTech Connect

    Welch, D.R.; Rose, D.V.; Genoni, T.C.; Yu, S.S.; Barnard, J.J.

    2005-01-18

    In order to drive an inertial fusion target or study high energy density physics with heavy ion beams, the beam radius must be focused to < 3 mm and the pulse length must be compressed to < 10 ns. The conventional scheme for temporal pulse compression makes use of an increasing ion velocity to compress the beam as it drifts and beam space charge to stagnate the compression before final focus. Beam compression in a neutralizing plasma does not require stagnation of the compression, enabling a more robust method. The final pulse shape at the target can be programmed by an applied velocity tilt. In this paper, neutralized drift compression is investigated. The sensitivity of the compression and focusing to beam momentum spread, plasma, and magnetic field conditions is studied with realistic driver examples. Using the 3D particle-in-cell code, we examine issues associated with self-field generation, stability, and vacuum-neutralized transport transition and focusing.

  12. Final focus system for TLC

    SciTech Connect

    Oide, K.

    1988-11-01

    A limit of the chromaticity correction for the final focus system of a TeV Linear Collider (TLC) is investigated. As the result, it becomes possible to increase the aperture of the final doublet with a small increase of the horizontal US function. The new optics design uses a final doublet of 0.5 mm half-aperture and 1.4 T pole-tip field. The length of the system is reduced from 400 m to 200 m by several optics changes. Tolerances for various machine errors with this optics are also studied. 5 refs., 7 figs., 2 tabs.

  13. Focus on hybrid magnetic/superconducting systems Focus on hybrid magnetic/superconducting systems

    NASA Astrophysics Data System (ADS)

    Cooley, Lance; Moshchalkov, Victor; Li, Qiang

    2011-02-01

    Like antagonistic cousins from a common heritage, the competition between superconductivity and magnetism for correlated electron states, and coexistence in some rare cases, produces a rich variety of physical behavior, useful materials, and technologically important properties. Many pages of Superconductor Science and Technology are devoted to cuprates, pnictides, and other compounds where the mechanism of superconductivity itself is intertwined with magnetism. This focus issue explores another area, in which superconductivity and magnetism are combined as a hybrid system to create new properties not possible with either system alone, or to improve upon the properties of either system in dramatic ways. In recent years, great progress has been made in this exciting, relatively new field, followed by many workshops and special sessions in major international conferences. A concise and up-to-date focus issue of Superconductor Science and Technology is timely to summarize the latest developments. We, the Guest Editors, would like to thank those colleagues who contributed their most recent and interesting findings to this focus issue: Silhanek and co-workers reported both theoretical and experimental investigations of the dynamics of vortex chains for different arrangements of magnetic moments. Their approach of time-dependent Ginzburg-Landau formalism now replaces the previously proposed empirical models to explain the most relevant properties of the dynamics of these S/F hybrid systems. Hikino and co-workers presented a new route to observe the spin-wave excitation by the Josephson effect, through a theoretical investigation of the resistively shunted junction model, extended by considering the gauge invariance including magnetization. When the magnetization is driven by the microwave adjusted to the ferromagnetic resonance frequency, the dc supercurrent is induced in the junction, and the current-voltage curve shows step structures as a function of applied voltage

  14. A Superconducting Solenoid for Heavy Ion Beam Focusing

    NASA Astrophysics Data System (ADS)

    Kim, J. W.; Kubo, Toshiyuki; Kawaguchi, Takeo; Imai, Yoshio; Minato, Tsuneaki; Seo, Kazutaka

    1997-05-01

    A superconducting solenoid has been constructed to use as a final focusing element at the entrance of the projectile fragment separator RIPS (T. Kubo et al, Nucl. Instr. & Meth. B70 (1992) 309) at RIKEN. The design field on axis is 6 tesla, the average current density being 9,600 A/cm^2. The overall coil length is 1.1 meter, and the coil is divided into three sections of equal length to ease winding and possibly to distribute the stored energy. A major feature of the magnet is that cooling is conductive without LHe involved, using a cryocooler directly attached onto the coil. The solenoid is currently being tested, and the test results will be presented. After magnet testing, the solenoid will be installed in the beamline. The results of beam experiment will also be presented, along with calculation results with TRANSPORT.

  15. A continuous plasma final focus

    SciTech Connect

    Whittum, D.H.

    1990-02-01

    Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, {sigma}{sub min} {approximately} {epsilon}{sub n}(I{sub A}/{gamma}I){sup 1/2}, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Three numerical examples are considered. 38 refs., 2 figs., 1 tab.

  16. A continuous plasma final focus

    SciTech Connect

    Whittum, D.H.

    1989-11-01

    Scaling laws are set down for a plasma cell used for transport, focusing and current neutralization of fine, intense, relativistic electron beams. It is found that there exists a minimum beam spot size, {sigma}{sub min} {approximately} {var epsilon}{sub n}(I{sub A}/{gamma}I){sup 1/2}, in such a focusing system. Propagation issues, including channel formation, synchrotron radiation, beam ionization and instabilities, are discussed. Numerical examples are given for a proof-of-principle experiment at KEK, an application for luminosity enhancement at the SLC, and a hypothetical TeV electron-positron collider. For a TeV collider, it is found that the effect of ion-motion on focusing, and the effect of Buneman instability on current neutralization must be considered. 3 figs., 1 tab.

  17. Superconducting-wire fabrication. Final report

    SciTech Connect

    Glad, W.E.; Chase, G.G.

    1990-05-01

    Experiments were done leading to the fabrication of high-temperature superconducting composite wire. Bulk superconductor was characterized by using optical microscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The chemical compatibility of superconducting materials with a number of metal sheathing candidates was tested, with silver offering the best compatibility. Wire was fabricated by drawing 0.250-inch-diameter silver tubing packed with superconducting powder. Single core wires were drawn to 0.037-inch diameter. The best critical current performance (660 A/cm2) for leaded bismuth 2-2-2-3 material was achieved by flattening single-core wire before heat treatment.

  18. Final focus system for high intensity beams

    SciTech Connect

    Henestroza, E.; Bieniosek, F.M.; Eylon, S.; Roy, P.K.; Yu, S.S.

    2003-05-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. The NTX final focus system produces a converging beam at the entrance to the neutralized drift section where it focuses to a small spot. The final focus lattice consists of four pulsed quadrupole magnets. The main issues are the control of emittance growth due to high order fields from magnetic multipoles and image fields. We will present experimental results from NTX on beam envelope and phase space distributions, and compare these results with particle simulations using the particle-in-cell code WARP.

  19. Development of Superconducting Focusing Quadrupoles for Heavy Ion Drivers

    SciTech Connect

    Martovetsky, N; Manahan, R; Lietzke, A F

    2001-09-10

    Heavy Ion Fusion (HIF) is exploring a promising path to a practical inertial-confinement fusion reactor. The associated heavy ion driver will require a large number of focusing quadrupole magnets. A concept for a superconducting quadrupole array, using many simple racetrack coils, was developed at LLNL. Two, single-bore quadrupole prototypes of the same design, with distinctly different conductor, were designed, built, and tested. Both prototypes reached their short sample currents with little or no training. Magnet design, and test results, are presented and discussed.

  20. PREFACE: Focus on superconductivity in Fe-based systems Focus on superconductivity in Fe-based systems

    NASA Astrophysics Data System (ADS)

    Prozorov, Ruslan; Chubukov, Andrey; Meingast, Christoph; Putti, Marina

    2012-08-01

    competes with long-range magnetic order, and magnetic fluctuations are considered by some to be of the utmost importance for the pairing mechanism. Others argue that orbital fluctuations, possibly in combination with phonons, are crucial for the pairing. Fe-based superconductors show extremely large upper critical fields and relatively low electronic anisotropy, which are crucial aspects for power applications. The expectations are high, though it remains unclear what maximal current densities can be supported by a properly designed bulk material with optimal pinning centers. This focus issue of Superconductor Science and Technology is a snapshot of some of the recent progress in materials preparation, experiments and theory. It includes articles on the search for new Fe-based superconductors and on the search for superconductivity at extreme conditions. Particular attention is devoted to: the effects of chemical substitutions; the development of thin films; the introduction of artificial defects to increase critical current density; and a general analysis of vortex physics. The articles on fundamental aspects of superconductivity include: the discussion of various experimental problems; an in-depth analysis of the nodal and nodeless pairing states; the discussion of the pairing mechanism; and the effects of pair-breaking due to disorder. Also discussed are nematic correlations and the coexistence of magnetism and superconductivity. The papers collected in this issue present a detailed review of the accomplishments of the last four years of research into Fe-based superconductors, up to and including last-minute developments. We hope that this combination will make this special section of Superconductor Science and Technology both interesting and useful to a broad spectrum of physicists and materials scientists.

  1. Results from the final focus test beam

    SciTech Connect

    Burke, D.L.; Final Focus Test Beam Collaboration

    1994-07-01

    first experimental results from the Final Focus Test Beam (FFTB) are given in this report. The FFTB has been constructed as a prototype for the final focus system of a future TeV-scale electron-positron linear collider. The vertical dimension of the 47 GeV electron beam form the SLAC linac has been reduced at the focal point of the FFTB by a demagnification of 320 to a beam height of approximately 70 nanometers.

  2. The final focus test beam project

    SciTech Connect

    Burke, D.

    1991-05-01

    An overview is given of the Final Focus Test Beam (FFTB) that is being constructed as a prototype final focus system for a future electron-positron linear collider. This beam line will use as input the 50 GeV electron beam from the SLC linac, and is designed to reduce the transverse dimensions of the beam spot at the focal point to 1 {mu}m. 5 refs., 2 figs., 1 tab.

  3. Optimization of the NLC final focus system

    SciTech Connect

    Zimmermann, F.; Helm, R.; Irwin, J.

    1995-06-01

    An optimization scheme for final focus systems is discussed and applied to the NLC design. The optical functions at the defocusing sextupoles, the sextupole strength, and the length of the system must obey eight conditions that are imposed by the spot size increase due to higher-order aberrations, the effects of synchrotron radiation in the bending magnets, power supply ripple, magnet vibration tolerances, and the estimated orbit stability at the sextupoles. These eight conditions determine the minimum optimum length of the system. The NLC final focus design was shortened to this optimum.

  4. Study of a final focus system for high intensity beams

    SciTech Connect

    Henestroza, Enrique; Eylon, Shmuel; Roy, Prabir K.; Yu, Simon S.; Bieniosek, Frank M.; Shuman, Derek B.; Waldron, William L.

    2004-06-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. The final focus scenario in an HIF driver consists of several large aperture quadrupole magnets followed by a drift section in which the beam space charge is neutralized by a plasma. This beam is required to hit a millimeter-sized target spot at the end of the drift section. The objective of the NTX experiments and associated theory and simulations is to study the various physical mechanisms that determine the final spot size (radius r{sub s}) at a given distance (f) from the end of the last quadrupole. In a fusion driver, f is the standoff distance required to keep the chamber wall and superconducting magnets properly protected. The NTX final quadrupole focusing system produces a converging beam at the entrance to the neutralized drift section where it focuses to a small spot. The final spot is determined by the conditions of the beam entering the quadrupole section, the beam dynamics in the magnetic lattice, and the plasma neutralization dynamics in the drift section. The main issues are the control of emittance growth due to high order fields from magnetic multipoles and image fields. In this paper, we will describe the theoretical and experimental aspects of the beam dynamics in the quadrupole lattice, and how these physical effects influence the final beam size. In particular, we present theoretical and experimental results on the dependence of final spot size on geometric aberrations and perveance.

  5. Diode and Final Focus Simulations for DARHT

    NASA Astrophysics Data System (ADS)

    Hughes, Thomas P.; Welch, Dale R.; Carlson, Randolph L.

    1997-05-01

    We have used the numerical simulation codes uc(ivory,) uc(iprop) and uc(pbguns) to simulate beam dynamics in the diode and final focus of the 4 kA, 20 MV DARHT linear accelerator. A low emittance 4 MV, 4 kA source for a 4-pulse injector was designed using uc(ivory) and uc(pbguns.) Due to the long pulse length (four 70 ns pulses over 1 μsec), we have kept the field stress to < 200 kV/cm over the cathode electrode, and to ≈ 50 kV/cm on the radial insulator stacks. The normalized edge emittance produced by the diode optics is only ≈ 130 mm-mrad. In the final-focus region, we have used uc(iprop) to model the effect of ion emission from the target. The intense electric field of the beam at the 1 mm diameter focal spot produces substantial ion velocities, and, if the space-charge-limited current density can be supplied, significant focal spot degradation may occur due to ion space-charge. Calculations for the ITS test stand, which has a larger focal spot, show that the effect should be observable for H^+ and C^+ ion species. The effect may be lessened if there is insufficient ion density on the target to supply the space-charge-limited current density, or if the ion charge-to-mass ratio is sufficiently large.

  6. Midwest Superconductivity Consortium - Final Progress Report October 2001

    SciTech Connect

    Bement, Arden L.

    2001-10-23

    The basic mission of the Consortium was to advance the science and understanding of high-T{sub c} superconductivity and to promote the development of new materials and improved processing technology. Focused group efforts were the key element of the research program. One program area is the understanding of the layered structures involved in candidate materials and the factors that control their formation, stability and relationship superconductor properties. The other program area had a focus upon factors that limit or control the transport properties such as weak links, flux lattice behavior, and interfaces. Interactions among Consortium d with industrial armiates were an integral part of the program.

  7. Linear collider IR and final focus introduction

    SciTech Connect

    Irwin, J.; Burke, D.

    1991-09-01

    The Linear Collider subgroup of the Accelerator Physics working group concerned itself with all aspects of the Next Linear Collider (NLC) design from the end of the accelerating structure to and through the interaction region. Within this region are: (1) a collimation section, (2) muon protection (of the detector from the collimator), (3) final focus system, (4) interaction point physics, and (5) detector masking from synchrotron radiation and beam-beam pair production. These areas of study are indicated schematically in Fig. 1. The parameters for the Next Linear Collider are still in motion, but attention has settled on a handful of parameter sets. Energies under consideration vary from 0.5 to 1.5 TeV in the center of mass, and luminosities vary from 10{sup 33} to 10{sup 34} cm{sup {minus}2}s{sup {minus}1}. To be concrete we chose as a guide for our studies the parameter sets labeled F and G, Table 1 from Palmer. These cover large and small crossing angle cases and 0.4 m to 1.8 m of free length at the interaction point.

  8. Expanded studies of linear collider final focus systems at the Final Focus Test Beam

    SciTech Connect

    Tenenbaum, P.G.

    1995-12-01

    In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, the FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research.

  9. Superconducting analog-to-digital converters. Final report

    SciTech Connect

    Schoen, J.M.

    1991-09-01

    The contents include: superconducting analog-to-digital converter work at MITRE; development of a rapidly tunable microwave source; design and evaluation of a Josephson array oscillator; obtaining high-accuracy measurements from low-accuracy measurements; superconducting microwave transmission lines; high performance, superconducting analog-to-digital converter; edge sharpening with Josephson Junction; design evaluation of a subranging superconducting analog-to-digital converter; feasibility study of a superconducting sigma-delta analog-to-digital converter, and VHDL simulation study of superconducting sigma delta modulators.

  10. ASC 84: applied superconductivity conference. Final program and abstracts

    SciTech Connect

    Not Available

    1984-01-01

    Abstracts are given of presentations covering: superconducting device fabrication; applications of rf superconductivity; conductor stability and losses; detectors and signal processing; fusion magnets; A15 and Nb-Ti conductors; stability, losses, and various conductors; SQUID applications; new applications of superconductivity; advanced conductor materials; high energy physics applications of superconductivity; electronic materials and characterization; general superconducting electronics; ac machinery and new applications; digital devices; fusion and other large scale applications; in-situ and powder process conductors; ac applications; synthesis, properties, and characterization of conductors; superconducting microelectronics. (LEW)

  11. Focused feasibility study final field sampling plan

    SciTech Connect

    Not Available

    1993-10-01

    At the direction of APG-DSHE, the project has been separated into three work phases to allow for data evaluation and risk determination before a full focused feasibility study is conducted. Phase I of the project consists of an aerial photography investigation, surface/marine geophysical surveys, a flowmeter logging program, sampling surface and subsurface soils, an ecological risk assessment of the Beach Point Test Site, and analysis of chemical groundwater data generated through the separate Canal Creek Groundwater Monitoring Program. Tasks described for Phase II of the FFS will be performed upon evaluation of data needs identified subsequent to completion of the Phase I tasks. Phase II investigations include installation fo additional groundwater monitoring wells, sampling of the new and previously existing monitoring wells, a flowmeter logging program, downhole geophysical logging of new monitoring wells (and one previously existing well), and possible soil gas surveys.

  12. The DARHT-II-DC Final Focus Solenoid

    SciTech Connect

    Paul, A.C.

    2000-03-06

    The baseline DARHT2 external beam uses a pulsed solenoid final focus lens. The design of this lens was presented at TOS2 and has been considered as the final focus lens in all of the Livermore beamlines for DARHT2. In this note, we consider a new alternative DC final focus solenoid. A crude comparison between the parameters of these two designs is given in table 1. The small spot size required by the radiography and the small drift distance available between the last magnetic focusing element and the final focus solenoid imposed by the close proximity between the DARHT 2 building and the DARHT 1 axis, implies a short focal length solenoid. This in turn requires that the final focus solenoid mount inside the re-entrant cavity of the containment vessel in order to accommodate the 0.9 meter conjugate: figure 1. The ID of this cavity is 13.88 inches (35.25 cm).

  13. 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.

  14. Normal zone propagation in superconducting focusing solenoids and related quench protection issues

    SciTech Connect

    Terechkine, I.; /Fermilab

    2007-06-01

    Superconducting solenoids are increasingly used as focusing lenses in transport channels of proton linear RF accelerators. If these accelerators employ superconducting RF cavities, each focusing lens is usually comprised of three coils connected in series: a main coil, which provides the needed focusing strength, and two bucking coils, that help to reduce magnetic field outside the lens. When a normal zone develops in any of the coils in a focusing lens, it propagates with a direction and a rate which depends on the coil and the specific part of the coil in which the quench first occurred. As a result of this propagation process (quenching), the temperature and/or voltage of parts of the lens can exceed safe limits, thus compromising lens reliability. On the other hand, the negative impact of quench events can be significantly mitigated if an external resistor is used to absorb a part of the energy stored in the magnetic field. This paper presents the main results of a solenoid quench protection study based on computational modeling of normal zone propagation in solenoid lenses being built for a superconducting linear RF accelerator under development at Fermilab.

  15. Superconductivity

    SciTech Connect

    Langone, J.

    1989-01-01

    This book explains the theoretical background of superconductivity. Includes discussion of electricity, material fabrication, maglev trains, the superconducting supercollider, and Japanese-US competition. The authors reports the latest discoveries.

  16. Current Lead System of the SuperKEKB Final Focus SC Magnet Cryostats

    NASA Astrophysics Data System (ADS)

    Zong, Z. G.; Ohuchi, N.; Tsuchiya, K.; Arimoto, Y.; Higashi, N.; Yamaoka, H.; Kondou, Y.; Kawai, M.

    To energize the SuperKEKB final focus superconducting (SC) magnets, 110 current leads in total will be equipped in the two service cryostats. For the SC quadrupoles and solenoids, 22 leads are the conventional vapor cooled type and the others for the SC correction coils employ an HTS section at the cold ends. The qualification program on the leads is being carried out at KEK as the cryogenic acceptance test prior to installation. This paper presents the thermal and electrical results of the cryogenic tests.

  17. A final focus system for the Next Linear Collider

    SciTech Connect

    Zimmermann, F.; Brown, K.; Emma, P.; Helm, R.; Irwin, J.; Tenenbaum, P.; Wilson, P.

    1995-06-01

    The final focus of the Next Linear Collider (NLC) demagnifies electron and positron beams of 250--750 GeV energy down to a transverse size of about 2.5 {times} 350 nm{sup 2} at the interaction point (IP). The basic layout, momentum bandwidth, vibration tolerances, wakefield effects, and the tunability of the proposed final focus design are discussed. Also a perspective is given on the crab cavity and on effects of the solenoid field in the interaction region.

  18. Heavy-ion fusion final focus magnet shielding designs

    SciTech Connect

    Latkowski, J F; Meier, W R

    2000-10-11

    At the Thirteenth International Symposium on Heavy Ion Inertial Fusion (HIF Symposium), we presented magnet shielding calculations for 72-, 128, 200, and 288-beam versions of the HYLIFE-II power plant design. In all cases, we found the radiation-limited lifetimes of the last set of final focusing magnets to be unacceptably short. Since that time, we have completed follow-on calculations to improve the lifetime of the 72-beam case. Using a self-consistent final focusing model, we vary parameters such as the shielding thicknesses and compositions, focusing length, angle-of-attack to the target, and the geometric representation of the flibe pocket, chamber, and blanket. By combining many of these shielding features, we are able to demonstrate a magnet shielding design that would enable the last set of final focusing magnets to survive for the lifetime of the power plant.

  19. Next-Generation Linear Collider Final Focus System Stability Tolerances

    SciTech Connect

    Roy, G.; Irwin, J.; /SLAC

    2007-04-25

    The design of final focus systems for the next generation of linear colliders has evolved largely from the experience gained with the design and operation of the Stanford Linear Collider (SLC) and with the design of the Final Focus Test Beam (FFTB). We will compare the tolerances for two typical designs for a next-generation linear collider final focus system. The chromaticity generated by strong focusing systems, like the final quadrupole doublet before the interaction point of a linear collider, can be canceled by the introduction of sextupoles in a dispersive region. These sextupoles must be inserted in pairs separated by a -I transformation (Chromatic Correction Section) in order to cancel the strong geometric aberrations generated by sextupoles. Designs proposed for both the JLC or NLC final focus systems have two separate chromatic correction sections, one for each transverse plane separated by a ''{beta}-exchanger'' to manipulate the {beta}-function between the two CCS. The introduction of sextupoles and bending magnets gives rise to higher order aberrations (long sextupole and chrome-geometries) and radiation induced aberrations (chromaticity unbalance and ''Oide effect'') and one must optimize the lattice accordingly.

  20. A RECIPE FOR LINEAR COLLIDER FINAL FOCUS SYSTEM DESIGN

    SciTech Connect

    Seryi, Andrei

    2003-05-27

    The design of Final Focus systems for linear colliders is challenging because of the large demagnifications needed to produce nanometer-sized beams at the interaction point. Simple first- and second-order matrix matching have proven insufficient for this task, and minimization of third- and higher-order aberrations is essential. An appropriate strategy is required for the latter to be successful. A recipe for Final Focus design, and a set of computational tools used to implement this approach, are described herein. An example of the use of this procedure is given.

  1. Beam-based alignment of the final focus test beam

    SciTech Connect

    Tenenbaum, P.; Burke, D.; Helm, R.; Irwin, J.; Raimondi, P.; Oide, K.; Floettmann, K.

    1995-12-01

    Beam-based alignment of quadrupole and sextupole magnets is crucial for the overall performance of linear collider final focus systems, especially for elimination of backgrounds and higher-order aberrations. At the Final Focus Test Beam (FFTB), alignment tolerances required for achieving the desired spot size are 100 microns in the horizontal and 30 microns in the vertical. Using a combination of independent magnet power supplies, hi-h-resolution stripline beam position monitors and precision magnet movers, the FFTB can be aligned to these tolerances in about 8 hours. Description of the algorithm, presentation of alignment results, and possible improvements to the system are discussed.

  2. Review of tolerances at the Final Focus Test Beam

    SciTech Connect

    Bulos, F.; Burke, D.; Helm, R.; Irwin, J.; Roy, G.; Yamamoto, N.

    1991-05-01

    We review the tolerances associated with the Final Focus Test Beam (FFTB). We have computed the acceptability window of the input beam for orbit jitter, emittance beta functions mismatch, incoming dispersion and coupling; tolerances on magnet alignment, strength and multipole content; and the initial tuneability capture of the line. 2 refs., 1 fig.

  3. Superconductivity

    NASA Astrophysics Data System (ADS)

    Yeo, Yung K.

    Many potential high-temperature superconductivity (HTS) military applications have been demonstrated by low-temperature superconductivity systems; they encompass high efficiency electric drives for naval vessels, airborne electric generators, energy storage systems for directed-energy weapons, electromechanical launchers, magnetic and electromagnetic shields, and cavity resonators for microwave and mm-wave generation. Further HST applications in militarily relevant fields include EM sensors, IR focal plane arrays, SQUIDs, magnetic gradiometers, high-power sonar sources, and superconducting antennas and inertial navigation systems. The development of SQUID sensors will furnish novel magnetic anomaly detection methods for ASW.

  4. Superconducting gravity gradiometers for underground target recognition. Final report

    SciTech Connect

    Adriaans, M.J.

    1998-01-01

    One of the most formidable intelligence challenges existing in the non-proliferation community is the detection of buried targets. The physical parameter that all buried targets share, whether the target is buried armaments, a tunnel or a bunker, is mass. In the case of buried armaments, there is an excess mass (higher density) compared to the surrounding area; for a tunnel or bunker, the mass is missing. In either case, this difference in mass generates a distinct gravitational signature. The Superconducting Gravity Gradiometer project at Sandia worked toward developing an airborne device for the detection of these underground structures.

  5. Superconducting Focusing Lenses for the SSR1 Cryomodule of PXIE Test Stand at Fermilab

    SciTech Connect

    DiMarco, J.; Tartaglia, M.; Terechkine, I.

    2016-01-01

    Five solenoid-based focusing lenses designed for use inside the SSR1 cryomodule of the PXIE test stand at Fermilab have been fabricated and tested. In addition to a focusing solenoid, each lens is equipped with a set of windings that generate magnetic field in the transverse plane and can be used in the steering dipole mode or as a skew quadrupole corrector. The lenses will be installed between superconducting cavities in the cryomodule, so getting sufficiently low fringe magnetic field was one of the main design requirements. Beam dynamics simulations indicated a need for high accuracy positioning of the lenses in the cryomodule, which triggered a study towards understanding uncertainties of the magnetic axis position relative to the geometric features of the lens. This report summarizes the efforts towards certification of the lenses, including results of performance tests, fringe field data, and uncertainty of the magnetic axis position.

  6. 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.

  7. Theoretical investigation of superconductivity in doped fullerenes. Final report

    SciTech Connect

    Jishi, R.A.

    1995-03-01

    The aim of the research the authors are conducting is to understand the phenomenon of superconductivity in the fullerene system. Towards achieving this goal they have conducted a series of studies and have published several papers quite recently. They have developed a force-constant model for the C60 molecule which accounts for all measured frequencies in C60. The model employs four bond-stretching and four angle-bending force constants that were doped to reproduce the correct values of the frequencies of the Raman-active vibrational modes. The model was successfully applied to higher fullerenes, such as C70 and the effect of doping by alkali metal atoms on the phonon modes in C60 and in C70 was considered. The study of the phonon spectrum in doped C60 and doped C70 is an important step in view of the fact that while doped C60 is superconducting, doped C70 is not. The studies the authors have carried out, combined with studies on the electronic states in doped C70, could elucidate the difference in the electrical properties between these two materials.

  8. A Scaled Final Focus Experiment for Heavy Ion Fusion

    SciTech Connect

    MacLaren, Stephan, Alexander

    2000-09-19

    A one-tenth dimensionally scaled version of a final focus sub-system design for a heavy ion fusion driver is built and tested. By properly scaling the physics parameters that relate particle energy and mass, beam current, beam emittance, and focusing field, the transverse dynamics of a driver scale final focus are replicated in a small laboratory beam. The experiment uses a 95 {micro}A beam of 160 keV Cs{sup +} ions to study the dynamics as the beam is brought to a ballistic focus in a lattice of six quadrupole magnets. Diagnostic stations along the experiment track the evolution of the transverse phase space of the beam. The measured focal spot size is consistent with calculations and the report of the design on which the experiment is based. By uniformly varying the strengths of the focusing fields in the lattice, the chromatic effect of a small energy deviation on the spot size can be reproduced. This is done for {+-}1% and {+-}2% shifts and the changes in the focus are measured. Additionally, a 400 {micro}A beam is propagated through the experiment and partially neutralized after the last magnet using electrons released from a hot tungsten filament. The increase in beam current allows for the observation of significant effects on both the size and shape of the focal spot when the electrons are added.

  9. Materials, Strands, and Cables for Superconducting Accelerator Magnets. Final Report

    SciTech Connect

    Sumption, Mike D.; Collings, Edward W.

    2014-09-19

    This report focuses on Materials, Strands and Cables for High Energy Physics Particle accelerators. In the materials area, work has included studies of basic reactions, diffusion, transformations, and phase assemblage of Nb3Sn. These materials science aspects have been married to results, in the form of flux pinning, Bc2, Birr, and transport Jc, with an emphasis on obtaining the needed Jc for HEP needs. Attention has also been paid to the “intermediate-temperature superconductor”, magnesium diboride emphasis being placed on (i) irreversibility field enhancement, (ii) critical current density and flux pinning, and (iii) connectivity. We also report on studies of Bi-2212. The second area of the program has been in the area of “Strands” in which, aside from the materials aspect of the conductor, its physical properties and their influence on performance have been studied. Much of this work has been in the area of magnetization estimation and flux jump calculation and control. One of the areas of this work was strand instabilities in high-performance Nb3Sn conductors due to combined fields and currents. Additionally, we investigated quench and thermal propagation in YBCO coated conductors at low temperatures and high fields. The last section, “Cables”, focussed on interstrand contact resistance, ICR, it origins, control, and implications. Following on from earlier work in NbTi, the present work in Nb3Sn has aimed to make ICR intermediate between the two extremes of too little contact (no current sharing) and too much (large and unacceptable magnetization and associated beam de-focussing). Interstrand contact and current sharing measurements are being made on YBCO based Roebel cables using transport current methods. Finally, quench was investigated for YBCO cables and the magnets wound from them, presently with a focus on 50 T solenoids for muon collider applications.

  10. The optics of the Final Focus Test Beam

    SciTech Connect

    Irwin, J.; Brown, K.; Bulos, F.; Burke, D.; Helm, R.; Roy, G.; Ruth, R.; Yamamoto, N. ); Oide, K. )

    1991-05-01

    The Final Focus Test Beam (FFTB), currently under construction at the end of the SLAC Linac, is being built by an international collaboration as a test bed for ideas and methods required in the design and construction of final focus systems for next generation e{sup +}e{sup {minus}} linear colliders. The FFTB lattice is based on the previously developed principle of using sextupole pairs in a dispersive region to compensate chromaticity. The linear lattice was optimized for length, and implementation of diagnostic procedures. The transformations between sextupole pairs (CCX and CCY) are exactly {minus}I, the matrix for the intermediate transformer (BX) is exactly diagonal, and the dispersion function has zero slope at the sextupoles and is thus zero at the minimum of the {beta}{sub x} function in the intermediate transformer. The introduction of sextupoles in final focus systems leads to the presence of additional optical aberrations, and synchrotron radiation in the dipoles also enlarges the final spot size. The important fourth-order optical aberrations which determine the main features of the design have been identified. Additional lower order aberrations arise in the implementation of these designs, since the real system is not the ideal design. We concentrate on these aberrations and describe strategies for their diagnosis and correction.

  11. Plasma lens experiments at the Final Focus Test Beam

    SciTech Connect

    Barletta, B. |; Chattopadhyay, S.; Chen, P.

    1993-04-01

    We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam ionization of a working gas. At an increased bunch population of 2.5 {times} 10{sup 10}, tunneling ionization of a gas target by an electron beam -- an effect which has never been observed before -- should be significant. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.

  12. Performance of the 1994/95 SLC final focus system

    SciTech Connect

    Zimmermann, F.; Barklow, T.; Ecklund, S.

    1995-06-01

    A major upgrade to the SLC final focus was installed in 1994 to eliminate the dominant third-order aberration of the system, and thereby to reduce the vertical beam size at the IP by a factor of two. At low current, the optimal beam size of about 400 nm is now routinely established, and its sensitivity to orbit variations, to changes of emittance and energy spread, and to other beam parameters has been studied. For intensities above 3 {times} 10{sup 10} particles per bunch, tuning is more difficult due to increased fluctuations of energy, orbit, and emittances. Nonetheless, the expected beam size of about 600 nm has been observed. New procedures and diagnostics allow easier tuning and optimization of the final focus, and also a first measurement of the emittance increase in the arcs.

  13. Discussion on Recipe for Design of a Compact Final Focus

    SciTech Connect

    Seryi, Andrei

    2003-02-13

    On the first day of the Nanobeam Workshop [1], several participants commented that they were having difficulties designing a Raimondi-Seryi final focus system with local chromaticity correction [2], and requested a recipe for tuning such a lattice to cancel higher-order aberrations. In response, such a recipe was written and distributed to those interested on the following day. The text of this recipe is reproduced in Sections 1 and 2 with only minor style and language corrections.

  14. Optimization of Superconducting Focusing Quadrupoles for the HighCurrent Experiment

    SciTech Connect

    Sabbi, GianLuca; Gourlay, Steve; Gung, Chen-yu; Hafalia, Ray; Lietzke, Alan; Martovetski, Nicolai; Mattafirri, Sara; Meinke, Rainer; Minervini, Joseph; Schultz, Joel; Seidl, Peter

    2005-09-16

    The Heavy Ion Fusion (HIF) program is progressing through a series of physics and technology demonstrations leading to an inertial fusion power plant. The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is exploring the physics of intense beams with high line-charge density. Superconducting focusing quadrupoles have been developed for the HCX magnetic transport studies. A baseline design was selected following several pre-series models. Optimization of the baseline design led to the development of a first prototype that achieved a conductor-limited gradient of 132 T/m in a 70 mm bore, without training, with measured field errors at the 0.1% level. Based on these results, the magnet geometry and fabrication procedures were adjusted to improve the field quality. These modifications were implemented in a second prototype. In this paper, the optimized design is presented and comparisons between the design harmonics and magnetic measurements performed on the new prototype are discussed.

  15. Drift compression and final focus options for heavy ionfusion

    SciTech Connect

    Qin, Hong; Davidson, Ronald C.; Barnard, John J.; Lee, Edward P.

    2005-01-18

    A drift compression and final focus lattice for heavy ion beams should focus the entire beam pulse onto the same focal spot on the target. The authors show that this requirement implies that the drift compression design needs to satisfy a self-similar symmetry condition. For un-neutralized beams, the Lie symmetry group analysis is applied to the warm-fluid model to systematically derive the self-similar drift compression solutions. For neutralized beams, the 1D Vlasov equation is solved explicitly and families of self-similar drift compression solutions are constructed. To compensate for the deviation from the self-similar symmetry condition due to the transverse emittance, four time-dependent magnets are introduced in the upstream of the drift compression such that the entire beam pulse can be focused onto the same focal spot.

  16. Drift Compression and Final Focus Options for Heavy Ion Fusion

    SciTech Connect

    Hong Qin; Ronald C. Davidson; John J. Barnard; Edward P. Lee

    2005-02-14

    A drift compression and final focus lattice for heavy ion beams should focus the entire beam pulse onto the same focal spot on the target. We show that this requirement implies that the drift compression design needs to satisfy a self-similar symmetry condition. For un-neutralized beams, the Lie symmetry group analysis is applied to the warm-fluid model to systematically derive the self-similar drift compression solutions. For neutralized beams, the 1-D Vlasov equation is solved explicitly, and families of self-similar drift compression solutions are constructed. To compensate for the deviation from the self-similar symmetry condition due to the transverse emittance, four time-dependent magnets are introduced in the upstream of the drift compression such that the entire beam pulse can be focused onto the same focal spot.

  17. 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.

  18. Measuring micron size beams in the SLC final focus

    SciTech Connect

    McCormick, D.; Ross, M.; DeBarger, S.

    1994-10-01

    A pair of high resolution wire scanners have been built and installed in the SLC final focus. The final focus optics uses a set of de-magnifying telescopes, and an ideal location for a beam size monitor is at one of the magnified image points of the interaction point. The image point chosen for these scanners is in the middle of a large bend magnet. The design beam spots here are about 2 microns in the vertical and 20 microns in the horizontal plane. The scanners presented a number of design challenges. In this paper we discuss the mechanical design of the scanner, and fabrication techniques of its ceramic wire support card which holds many 4 and 7 um carbon wires. Accurate motion of the wire during a scan is critical. In this paper we describe tests of stepper motors, gear combinations, and radiation hardened encoders needed to produce the required motion with a step resolution of 80 nanometers. Also presented here are the results of scattered radiation detector placement studies carried out to optimize the signal from the 4 micron wires. Finally, we present measurements from the scanner.

  19. Final focus test beam alignment: A draft proposal

    SciTech Connect

    Fischer, G.E.; Ruland, R.E.

    1989-03-01

    The Final Focus Test Beam is a transport line designed to transmit 50 GeV electron beams of SLC emittance (3 {times} 10{sup {minus}10} radian-meters) straight through the central arm of the Beam Switchyard (BSY C line) with a final focus point out in the Research Yard but relatively near the end of the switchyard tunnel. The hardware, methods and procedures outlined in this proposal are dedicated to measuring the placement of mechanical objects with respect to certain defined geometric axes. We wish to emphasize that the very difficult problems of locating the effective magnetic axes of focusing elements, the effective electrical center of beam position monitors and even the effective axis of the incident beam relative to mechanical reference surfaces is outside the scope of this work. Further, this proposal is restricted to the act of measurement and does not consider the vital task of on-line mechanical repositioning of elements that will, in likelihood, be called upon during operation of the system. 16 refs., 16 figs., 4 tabs.

  20. The Final Focus Test Beam laser referene system

    SciTech Connect

    Bressler, V.E.; Ruland, R.E.

    1993-05-01

    The original design for the SLAC linac included an alignment reference system with 270 diffraction gratings situated along the 3000 meter linac. These gratings have provided SLAC with a global reference line repeatable to within 200 micro meters. For the Final Focus Test Beam, this laser system has been extended and 13 new diffraction gratings have been installed. Improvements targets and the availability of new instruments allows us to evaluate the performance of the laser reference system at the 510 micro meter level. An explanation of the system and the results of our evaluation are presented.

  1. Diode and final-focus simulations for DARHT

    SciTech Connect

    Hughes, T.P.; Welch, D.R.; Carlson, R.L.

    1997-10-01

    Beam dynamics calculations for the injector and final-focus region of a 4 kA, 20 MeV linear induction accelerator are presented. The injector is a low-emittance 4 MeV thermionic or photocathode diode designed to produce four 70 ns pulses over 2 {micro}sec. Due to the long total pule length, the authors have kept the field stress to < 200 kV/cm over the cathode electrode, and to {approx} 50 kV/cm on the radial insulator stacks. The normalized edge emittance produced by the diode is only {approx} 0.019 cm-rad. In the final-focus region, the authors have modeled the effect of ion emission from the target. The intense electric field of the beam at the 1-mm-diameter focal spot produces substantial ion velocities, and, if the space-charge-limited current density can be supplied, significant focal spot degradation may occur due to ion space-charge. Calculations for the existing Integrated Test Stand, which has a larger focal spot, show that the effect should be observable for H{sup +} and C{sup +} ion species. The effect is lessened if there is insufficient ion density on the target to supply the space-charge-limited current density, or if the ion charge-to-mass ratio is sufficiently small.

  2. Fabrication of superconducting nanowires from ultrathin MgB{sub 2} films via focused ion beam milling

    SciTech Connect

    Zhang, Chen; Wang, Da; Liu, Zheng-Hao; Zhang, Yan; Ma, Ping; Feng, Qing-Rong; Wang, Yue Gan, Zi-Zhao

    2015-02-15

    High quality superconducting nanowires were fabricated from ultrathin MgB{sub 2} films by a focused ion beam milling technique. The precursor MgB{sub 2} films in 10 nm thick were grown on MgO substrates by using a hybrid physical-chemical vapor deposition method. The nanowires, in widths of about 300-600 nm and lengths of 1 or 10 μm, showed high superconducting critical temperatures (T{sub c}’s) above 34 K and narrow superconducting transition widths (ΔT{sub c}’s) of 1-3 K. The superconducting critical current density J{sub c} of the nanowires was above 5 × 10{sup 7} A/cm{sup 2} at 20 K. The high T{sub c}, narrow ΔT{sub c}, and high J{sub c} of the nanowires offered the possibility of making MgB{sub 2}-based nano-devices such as hot-electron bolometers and superconducting nanowire single-photon detectors with high operating temperatures at 15-20 K.

  3. A final-focus magnet for PEP-II

    SciTech Connect

    Taylor, C.E.; Caspi, S.; Saho, N.

    1994-10-17

    A compact quadrupole magnet has been designed for the final-focus of the 3GeV {times} 9GeV PEP II B-factory collider being built at SLAC. The magnet system must fit within the particle detector, has no iron, and consists of four nested separately controlled magnets: a two-layer 11.95 T/m quadrupole; a horizontal dipole; a vertical dipole; and a 1.5T solenoid. The 1.1 m long magnet must produce a highly uniform quadrupole field in the 120 mm ID beam pipe. The cryostat is 140 mm ID. (warm), 314 mm OD, and approximately 1.5 m long. The very compact cryogenic suspension system using Ti alloy plates is designed to withstand large forces due to interaction between the field of the detector solenoid and the four nested magnets. Cryogenic services and magnet leads are provided through a single flexible transfer line approximately 4m long.

  4. First Generation Final Focusing Solenoid For NDCX-I

    SciTech Connect

    Seidl, P. A.; Waldron, W.

    2011-11-09

    This report describes the prototype final focus solenoid (FFS-1G), or 1st generation FFS. In order to limit eddy currents, the solenoid winding consists of Litz wire wound on a non-conductive G-10 tube. For the same reason, the winding pack was inserted into an electrically insulating, but thermally conducting Polypropylene (Cool- Poly© D1202) housing and potted with highly viscous epoxy (to be able to wick the single strands of the Litz wire). The magnet is forced-air cooled through cooling channels. The magnet was designed for water cooling, but he cooling jacket cracked, and therefore cooling (beyond natural conduction and radiation) was exclusively by forced air. Though the design operating point was 8 Tesla, for the majority of running on NDCX-1 it operated up to about 5 Tesla. This was due mostly from limitations of voltage holding at the leads, where discharges at higher pulsed current damaged the leads. Generation 1 was replaced by the 2nd generation solenoid (FFS-2G) about a year later, which has operated reliably up to 8 Tesla, with a better lead design and utilizes water cooling. At this point, FFS-1G was used for plasma source R&D by LBNL and PPPL. The maximum field for those experiments was reduced to 3 Tesla due to continued difficulty with the leads and because higher field was not essential for those experiments. The pulser for the final focusing solenoid is a SCR-switched capacitor bank which produces a half-sine current waveform. The pulse width is ~800us and a charge voltage of 3kV drives ~20kA through the magnet producing ~8T field.

  5. An RF bunch length monitor for the SLC final focus

    SciTech Connect

    Zimmermann, F.; Yocky, G.; Whittum, D.

    1997-05-01

    In preparation for the 1997 SLC run, a novel RF bunch-length monitor has been installed in the SLC South Final Focus. The monitor consists of a ceramic gap in the beam pipe, a 160-ft long X-band waveguide (WR90), and a set of dividers, tapers and microwave detectors. Electromagnetic fields radiated through the ceramic gap excite modes in the nearby open-ended X-band waveguide, which transmits the beam-induced signal to a radiation-free shack outside of the beamline vault. There, a combination of power dividers, tapers, waveguides, and crystal detectors is used to measure the signal power in 4 separate frequency channels between 7 and 110 GHz. For typical rms bunch lengths of 0.5-2 mm in the SLC, the bunch frequency spectrum can extend up to 100 GHz. In this paper, the authors present the overall monitor layout, describe MAFIA calculations of the signal coupled into the waveguide based on a detailed model of the complex beam-pipe geometry, estimate the final power level at the RF conversion points, and report the measured transmission properties of the installed waveguide system.

  6. Electron beam final focus system for Thomson scattering at ELBE

    NASA Astrophysics Data System (ADS)

    Krämer, J. M.; Budde, M.; Bødker, F.; Irman, A.; Jochmann, A.; Kristensen, J. P.; Lehnert, U.; Michel, P.; Schramm, U.

    2016-09-01

    The design of an electron beam final focus system (FFS) aiming for high-flux laser-Thomson backscattering X-ray sources at ELBE is presented. A telescope system consisting of four permanent magnet based quadrupoles was found to have significantly less chromatic aberrations than a quadrupole doublet or triplet as commonly used. Focusing properties like the position of the focal plane and the spot size are retained for electron beam energies between 20 and 30 MeV by adjusting the position of the quadrupoles individually on a motorized stage. The desired ultra-short electron bunches require an increased relative energy spread up to a few percent and, thus, second order chromatic effects must be taken into account. We also present the design and test results of the permanent magnet quadrupoles. Adjustable shunts allow for correction of the field strength and compensation of deviations in the permanent magnet material. For a beam emittance of 13 mm mrad, we predict focal spot sizes of about 40 μm (rms) and divergences of about 10 mrad using the FFS.

  7. Growth and study of superconducting C60 compounds. Final report, October 1992-September 1995

    SciTech Connect

    Liu, J.Z.; Shelton, R.N.; Klavins, P.; Irons, S.H.; Chang, I.C.

    1995-12-01

    A home made semi-automatic feeding plasma arc reactor was used for the mass production fullerenes. Large, high quality single crystals of C60 up to 3mm in length have been grown by both the open-end and sealed vapor transport techniques. Millimeter-sized superconducting single crystals of K3C60 were successfully produced by a sophisticated vacuum doping method. Magnetic and superconducting properties were obtained. Information on the field and temperature dependences of the critical current density J(sub c) and the H(c1) have been reported. New compounds of Yb(x) C60 with x=1-6 were synthesized using a liquid ammonia route at low T and in an inert atmosphere. It turns out that these compounds are amorphous and have a spin glass behavior at a temperature T<15K. Finally, new superconductors with T(sub c) of 134K were found in the system of Tl(1-x)HgBa2Ca2Cu3O(8+y).

  8. FINAL REPORT: NATIONAL CHILDREN'S STUDY FOCUS GROUPS - FOLLOW-UP

    EPA Science Inventory

    The purpose of this work assignment was to add to our knowledge of the issues that will affect

    recruitment and retention of pregnant women into the National Children's Study by conducting 14 focus

    groups comprised of pregnant women, couples, and parents of young chi...

  9. Customer-focused planning: Demonstration project summaries. Final report

    SciTech Connect

    George, S.S.

    1992-12-01

    To succeed in the increasingly competitive and dynamic markets in which they operate, electric utilities are focusing ever greater attention on understanding and meeting customer needs. EPRI`s Customer Focused Planning (CFP) project was established to develop concepts and tools that will help utilities enhance their commitment to customer service. The project team conducted a series of interviews and meetings with participating utilities to collaboratively implement crucial steps in the CFP process. Although there is no unique set of tools or single management approach for improving product and service delivery, customer-focused companies have at least five ideals in common. They (1) define goals and objectives in concrete terms, (2) extend the planning boundaries of the organization to include all members of the energy services infrastructure, (3) painstakingly link functional activities directly to customer needs, (4) incorporate the customer`s voice in new product/ service design, and (5) align performance measures with customer needs. In addition, customer-focused companies use a variety of methods to improve customer satisfaction and company performance. These methods include conducting market research, developing market processes such as demand-side management contracting or bidding to reveal customer preferences, and involving customers more directly in the planning process. This report summarizes two brief demonstration projects conducted as part of EPRI`s CFP project, one at Commonwealth Edison Company (CECo) and one at PSI Energy. The CECo project emphasized developing customer-focused performance measures for telephone inquiries. The PSI Energy project involved a one-day workshop underscoring two important CFP elements-understanding customer wants and explicitly linking those wants to utility activities.

  10. Superconducting squid amplifiers for IR detectors and other applications: Phase 2. Final report. [IR (Infrared)

    SciTech Connect

    Osterman, D.

    1993-05-01

    The subject of this report is a completed Phase II SBIR project to develop a superconducting analog multiplexer circuit. The intended application of the multiplexer is as a component of processing circuitry for a superconducting infrared focal plane array (IR FPA). Development of the IR FPA is in progress under a separate contract. Among the accomplishments that are described below is the fabrication and testing of a functioning, superconducting, 20-input multiplexer, appropriate for use with an IR FPA. The motivation for developing a superconducting multiplexer circuit derives primarily from the significant potential advantages of an all-superconducting IR FPA system, i.e. a system in which the detectors, as well as the associated processing circuitry, are superconducting. Section III of this report reviews the subject of superconducting IR FPAs. Chief among the advantages of such systems is the potential for larger arrays with greater numbers of detectors than is now possible.

  11. Superconductivity and metallic behavior in Pb{sub x}C{sub y}O{sub δ} structures prepared by focused electron beam induced deposition

    SciTech Connect

    Winhold, M. Weirich, P. M.; Schwalb, C. H.; Huth, M.

    2014-10-20

    Focused electron beam induced deposition as a direct-write approach possesses great potential to meet the demands for superconducting nanostructure fabrication especially regarding its 3D patterning capabilities combined with the high resolution in the nanometer regime. So far, however, it was not possible to fabricate superconducting structures with this technique. In this work, we present a lead-based superconductor prepared by focused electron beam induced deposition by dissociation of the precursor tetraethyllead. The as-grown structures exhibit metallic behavior and a minimum resistivity in the normal state of ρ = 16 μΩcm at T = 9 K followed by a superconducting transition at T{sub c} = 7.2 K.

  12. Analyses, algorithms, and computations for models of high-temperature superconductivity. Final report

    SciTech Connect

    Du, Q.

    1997-06-01

    Under the sponsorship of the Department of Energy, the authors have achieved significant progress in the modeling, analysis, and computation of superconducting phenomena. The work so far has focused on mezoscale models as typified by the celebrated Ginzburg-Landau equations; these models are intermediate between the microscopic models (that can be used to understand the basic structure of superconductors and of the atomic and sub-atomic behavior of these materials) and the macroscale, or homogenized, models (that can be of use for the design of devices). The models they have considered include a time dependent Ginzburg-Landau model, a variable thickness thin film model, models for high values of the Ginzburg-landau parameter, models that account for normal inclusions and fluctuations and Josephson effects, and the anisotropic ginzburg-Landau and Lawrence-Doniach models for layered superconductors, including those with high critical temperatures. In each case, they have developed or refined the models, derived rigorous mathematical results that enhance the state of understanding of the models and their solutions, and developed, analyzed, and implemented finite element algorithms for the approximate solution of the model equations.

  13. Analyses, algorithms, and computations for models of high-temperature superconductivity. Final technical report

    SciTech Connect

    Gunzburger, M.D.; Peterson, J.S.

    1998-04-01

    Under the sponsorship of the Department of Energy, the authors have achieved significant progress in the modeling, analysis, and computation of superconducting phenomena. Their work has focused on mezoscale models as typified by the celebrated ginzburg-Landau equations; these models are intermediate between the microscopic models (that can be used to understand the basic structure of superconductors and of the atomic and sub-atomic behavior of these materials) and the macroscale, or homogenized, models (that can be of use for the design of devices). The models the authors have considered include a time dependent Ginzburg-Landau model, a variable thickness thin film model, models for high values of the Ginzburg-Landau parameter, models that account for normal inclusions and fluctuations and Josephson effects, and the anisotropic Ginzburg-Landau and Lawrence-Doniach models for layered superconductors, including those with high critical temperatures. In each case, they have developed or refined the models, derived rigorous mathematical results that enhance the state of understanding of the models and their solutions, and developed, analyzed, and implemented finite element algorithms for the approximate solution of the model equations.

  14. Final Focusing System for the Second Axis of the Dual-Axis Radiographic Hydrodynamic Test Facility

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jiuan; McCarrick, James F.; Paul, Arthur C.; Westenskow, Glen A.

    2002-12-01

    The DARHT-II final focusing system consists of a solenoid and a foil, which is used to confine backstreaming ions. The separation between the converter target and the foil needs to be small to minimize the ion focusing effects. The beam spot size on the foil has to be large enough to ensure survivability of the foil while it is being struck by four high current pulses over 2 microsecond period. We have investigated several final focusing lens and focusing schemes. The simulation results of the beam spot size on the target are presented.

  15. Focusing Electron Beams at SLAC.

    ERIC Educational Resources Information Center

    Taylor, Richard L.

    1993-01-01

    Describes the development of a set of magnets that focus high-energy electron and positron beams causing them to collide, annihilate each other, and generate new particles. Explains how dipoles bend the beam, how quadrupoles focus the beam, how the focal length is calculated, and the superconducting final focus. (MDH)

  16. Optimization of the Processing Parameters of High Temperature Superconducting Glass-Ceramics: Center Director's Discretionary Fund Final Report

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Kaukler, W. F.

    1993-01-01

    A number of promising glass forming compositions of high Tc superconducting Ba-Sr-Ca-Cu-O (BSCCO) materials were evaluated for their glass-ceramic crystallization ability. The BSCCO ceramics belonging to the class of superconductors in the Ba-Sr-Ca-Cu-O system were the focus of this study. By first forming the superconducting material as a glass, subsequent devitrification into the crystalline (glass-ceramic) superconductor can be performed by thermal processing of the glass preform body. Glass formability and phase formation were determined by a variety of methods in another related study. This study focused on the nucleation and crystallization of the materials. Thermal analysis during rapid cooling aids in the evaluation of nucleation and crystallization behavior. Melt viscosity is used to predict glass formation ability.

  17. 'Focus on Marshall' Features Final External Tank Rollout - Duration: 8 minutes, 15 seconds.

    NASA Video Gallery

    Gumbo, Mardi Gras parades and external tanks. All three share a common bond - they are all New Orleans staples. But for one, it's the final send-off, highlighted on the August episode of "Focus on ...

  18. Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet

    SciTech Connect

    Frisch, Josef; Chang, Allison; Decker, Valentin; Doyle, Eric; Eriksson, Leif; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Partridge, Richard; Seryi, Andrei; /SLAC

    2006-09-28

    The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system.

  19. An ion-optical design study of a carbon-ion rotating gantry with a superconducting final bending magnet

    NASA Astrophysics Data System (ADS)

    Bokor, J.; Pavlovič, M.

    2016-03-01

    Ion-optical designs of an isocentric ion gantry with a compact curved superconducting final bending magnet are presented. The gantry is designed for transporting carbon-therapy beams with nominal kinetic energy of 400 MeV/u, which corresponds to the penetration range of C6+ beam in water of about 28 cm. In contrast to other existing designs, we present a "hybrid" beam transport system containing a single superconducting element - the last bending magnet. All other elements are based on conventional warm technology. Ion-optical properties of such a hybrid system are investigated in case of transporting non-symmetric (i.e. different emittance patterns in the horizontal and vertical plane) beams. Different conditions for transporting the non-symmetric beams are analyzed aiming at finding the optimal, i.e. the most compact, gantry version. The final gantry layout is presented including a 2D parallel scanning. The ion-optical and scanning properties of the final gantry design are described, discussed and illustrated by computer simulations performed by WinAGILE.

  20. Thin film synthesis of superconducting chemical compounds. Final report 1 January 1981-30 December 1983

    SciTech Connect

    Sienko, M.J.; Hoffmann, R.; Newman, J.A.; Burlitch, J.M.

    1984-05-31

    The objective of this research was to define the chemical factors that affect onset of superconductivity in ternary compounds: to determine how small changes in stoichiometry and microstructure influence critical temperature, how the number and placing of magnetic ions act to quench superconductivity, and how the crystal structure can be modified to enhance superconductivity. The approach was to synthesize, from ultrapure starting elements, ternary borides, silicides, sulfides and selenides of the second and third row transition elements, to characterize the new compounds for x-ray structure, electric and magnetic behavior, and then compare them with doped materials. Four kinds of compounds were investigated: rare earth diosmium disilicides, rare earth osmium-iridium borides, layered structure transition metal dichalcogenides, and Chevrel type molybdenum ternaries. Both the rare earth osmium-iridium borides and rare earth diosmium disilicides were synthesized by arc melting. The crystal structures were refined and magnetic susceptibility studies revealed conventional Hund's rule behavior in the disilicides while the (Pr, Nd) (Os, Ir) 4B4 compounds are characterized by Van Vleck paramagnetism of closely spaced multiplets. Only LaOs/sub 2/Si/sub 2/ and LuOs/sub 2/Si/sub 2/ compounds are superconducting with Tc's in the 2-4K range. In the layered compounds, lithium intercalated ZrS/sub 2/, ZrSe/sub 2/, NbS/sub 2/, and NbSe/sub 2/ were studied.

  1. Nano Josephson superconducting tunnel junctions in YBa2Cu3O7-δ directly patterned with a focused helium ion beam

    NASA Astrophysics Data System (ADS)

    Cybart, Shane A.; Cho, E. Y.; Wong, T. J.; Wehlin, Björn H.; Ma, Meng K.; Huynh, Chuong; Dynes, R. C.

    2015-07-01

    Since the discovery of the high-transition-temperature superconductors (HTSs), researchers have explored many methods to fabricate superconducting tunnel junctions from these materials for basic science purposes and applications. HTS circuits operating at liquid-nitrogen temperatures (˜77 K) would significantly reduce power requirements in comparison with those fabricated from conventional superconductors. The difficulty is that the superconducting coherence length is very short and anisotropic in these materials, typically ˜2 nm in the a-b plane and ˜0.2 nm along the c axis. The electrical properties of Josephson junctions are therefore sensitive to chemical variations and structural defects on atomic length scales1. To make multiple uniform HTS junctions, control at the atomic level is required. In this Letter we demonstrate all-HTS Josephson superconducting tunnel junctions created by using a 500-pm-diameter focused beam of helium ions to directly write tunnel barriers into YBa2Cu3O7-δ (YBCO) thin films. We demonstrate the ability to control the barrier properties continuously from conducting to insulating by varying the irradiation dose. This technique could provide a reliable and reproducible pathway for scaling up quantum-mechanical circuits operating at liquid-nitrogen temperatures, as well as an avenue to conduct novel planar superconducting tunnelling studies for basic science.

  2. Nano Josephson superconducting tunnel junctions in YBa2Cu3O(7-δ) directly patterned with a focused helium ion beam.

    PubMed

    Cybart, Shane A; Cho, E Y; Wong, T J; Wehlin, Björn H; Ma, Meng K; Huynh, Chuong; Dynes, R C

    2015-07-01

    Since the discovery of the high-transition-temperature superconductors (HTSs), researchers have explored many methods to fabricate superconducting tunnel junctions from these materials for basic science purposes and applications. HTS circuits operating at liquid-nitrogen temperatures (∼77 K) would significantly reduce power requirements in comparison with those fabricated from conventional superconductors. The difficulty is that the superconducting coherence length is very short and anisotropic in these materials, typically ∼2 nm in the a-b plane and ∼0.2 nm along the c axis. The electrical properties of Josephson junctions are therefore sensitive to chemical variations and structural defects on atomic length scales. To make multiple uniform HTS junctions, control at the atomic level is required. In this Letter we demonstrate all-HTS Josephson superconducting tunnel junctions created by using a 500-pm-diameter focused beam of helium ions to directly write tunnel barriers into YBa2Cu3O(7-δ) (YBCO) thin films. We demonstrate the ability to control the barrier properties continuously from conducting to insulating by varying the irradiation dose. This technique could provide a reliable and reproducible pathway for scaling up quantum-mechanical circuits operating at liquid-nitrogen temperatures, as well as an avenue to conduct novel planar superconducting tunnelling studies for basic science. PMID:25915196

  3. Optical tuning in the arcs and final focus sections of the Stanford Linear Collider

    SciTech Connect

    Bambade, P.S.

    1989-03-01

    In this thesis, we present the experimental tuning procedures developed for the Arcs and for the Final Focus Section of the Stanford Linear Collider (SLC). Such tuning is necessary to maximize the luminosity, by minimizing the beam size at the interaction point, and to reduce backgrounds in the experiment. In the final Focus Section, the correction strategy must result from the principles of the optical design, which is based on cancellations between second order aberrations, and on the ability to measure micron-size beams typical of the SLC. In the Arcs, the corrections were designed after the initial commissioning, to make the system more error-tolerant, through a modification in the optical design, and to enable adjustments of the beam phase-space a the injection to the Final Focus System, through a harmonic perturbation technique inspired from circular accelerators. Although the overall optimization of the SLC is not entirely finished, an almost optimal set-up has been achieved for the optics of the Arcs and of the Final Focus Section. Beams with transverse sizes close to the nominal ones, of a few microns, have been obtained at the interaction point. We present and discuss our results and the optical limits to the present performance. 24 refs., 25 figs., 2 tabs.

  4. Final focus shielding designs for modern heavy-ion fusion power plant designs

    NASA Astrophysics Data System (ADS)

    Latkowski, J. F.; Meier, W. R.

    2001-05-01

    Recent work in heavy-ion fusion accelerators and final focusing systems shows a trend towards less current per beam, and thus, a greater number of beams. Final focusing magnets are susceptible to nuclear heating, radiation damage, and neutron activation. The trend towards more beams, however, means that there can be less shielding for each magnet. Excessive levels of nuclear heating may lead to magnet quench or to an intolerable recirculating power for magnet cooling. High levels of radiation damage may result in short magnet lifetimes and low reliability. Finally, neutron activation of the magnet components may lead to difficulties in maintenance, recycling, and waste disposal. The present work expands upon previous, three-dimensional magnet shielding calculations for a modified version of the HYLIFE-II IFE power plant design. We present key magnet results as a function of the number of beams.

  5. Final Focus Shielding Designs for Modern Heavy-Ion Fusion Power Plant Designs

    SciTech Connect

    Latkowski, J F; Meier, W R

    2000-07-05

    Recent work in heavy-ion fusion accelerators and final focusing systems shows a trend towards less current per beam, and thus, a greater number of beams. Final focusing magnets are susceptible to nuclear heating, radiation damage, and neutron activation. The trend towards more beams, however, means that there can be less shielding for each magnet, Excessive levels of nuclear heating may lead to magnet quench or an intolerable recirculating power for magnet cooling. High levels of radiation damage may result in short magnet lifetimes and low reliability. Finally, neutron activation of the magnet components may lead to difficulties in maintenance, recycling, and waste disposal. The present work expands upon previous, three-dimensional magnet shielding calculations for a modified version of the HYLIFE-I1 IFE power plant design. We present key magnet results as a function of the number of beams.

  6. Finite element analysis of time-independent superconductivity. Ph.D. Thesis Final Report

    NASA Technical Reports Server (NTRS)

    Schuler, James J.

    1993-01-01

    The development of electromagnetic (EM) finite elements based upon a generalized four-potential variational principle is presented. The use of the four-potential variational principle allows for downstream coupling of EM fields with the thermal, mechanical, and quantum effects exhibited by superconducting materials. The use of variational methods to model an EM system allows for a greater range of applications than just the superconducting problem. The four-potential variational principle can be used to solve a broader range of EM problems than any of the currently available formulations. It also reduces the number of independent variables from six to four while easily dealing with conductor/insulator interfaces. This methodology was applied to a range of EM field problems. Results from all these problems predict EM quantities exceptionally well and are consistent with the expected physical behavior.

  7. Superconductivity and magnetism in rapidly solidified perovskites. Final report, September 1, 1988--August 31, 1991

    SciTech Connect

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

    1991-12-31

    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}}.

  8. Superconducting quantum interference devices made with normal metal and insulator barrier Josephson junctions in Y-Ba-Cu-O directly written with a focused helium beam

    NASA Astrophysics Data System (ADS)

    Cho, Ethan; Ma, Meng; Huynh, Chuong; Pratt, Kevin; Paulson, Doug; Glyantsev, Victor; Dynes, Robert; Cybart, Shane

    We will present electrical transport data for Y-Ba-Cu-O superconducting quantum interference devices (SQUIDs) with focused helium ion damage Josephson junctions. The junctions were directly written with a 30 keV focused helium ion beam, which locally creates disorder in Y-Ba-Cu-O that induces a superconducting-insulator transition. SQUIDs with Josephson junctions written with a dose of 4 ×1016 He+/cm2 have metallic barriers and show a current-voltage characteristic (I-V) well-described by the resistively shunted junction model. The spectral density of the flux noise is 10 μΦ0 / √ Hz at 10 Hz and the white noise at higher frequencies is 2 μΦ0 / √ Hz. SQUIDs with junctions written with higher ion doses (~ 9 ×1016 He+/cm2) have insulating Josephson barriers with a critical current of 22 μA and a resistance of 12 Ω at 4 K. The I-V for all of these devices is not hysteretic due to the small capacitance and the resistance. At higher voltage the junction I-V curve shows tunnel-junction behavior and a superconducting energy gap edge at 20 mV. We will discuss how these results are a promising step forward for sensitive magnetic sensors made from high temperature superconductors at various temperatures.

  9. 30 MJ superconducting magnetic energy storage stabilizing coil. Final report for construction

    SciTech Connect

    1983-03-01

    This report covers Phase II, Fabrication and Delivery of the 30 MJ Superconducting Magnetic Energy Storage Stabilizing Coil. A history of the manufacturing and assembly phase of the magnet is presented. Major problems and solutions are summarized, and illustrations of the major operations are provided. The Quality Assurance program is described with a listing of all nonconformance reports. Design documentation is provided, including a Design Document Index, monthly progress reports, and a list of papers given on the project. Appendices to the report contain copies of released and revised design calculations, test reports, assembly procedure, and nonconformance reports and engineering dispositions.

  10. Final Report - The Decline and Fall of the Superconducting Super Collider

    SciTech Connect

    RIORDAN, MICHAEL

    2011-11-29

    In October 1993 the US Congress terminated the Superconducting Super Collider — at the time the largest pure-science project ever attempted, with a total cost estimated to exceed $10 billion. It was a stunning loss for the US highenergy physics community, which until that moment had perched for decades at the pinnacle of American science. Ever since 1993, this once-dominant scientific community has been in gradual decline. With the 2010 startup of research on the CERN Large Hadron Collider and the 2011 shutdown of the Fermilab Tevatron, world leadership in elementary-particle physics has crossed the Atlantic and returned to Europe.

  11. Necessity for a DOD capability in superconducting electronics. Final report, Oct 88-Nov 90

    SciTech Connect

    Cohen, L.; Edelsack, E.A.

    1990-11-01

    The technologies of superconductor electronics and hybrid superconductor-semiconductor electronics offer a unique potential for more compact systems that would afford higher performance and lower power consumption than does the present semiconductor electronics. This paper discusses current efforts in superconductor electronics and warns of probable future Department of Defense (DOD) dependence on foreign capabilities in this critical technology. The paper describes selected systems on DOD needs lists and recommends the establishment of programs and processing capabilities that will assure the realization of the many essential benefits offered by superconducting electronics.

  12. 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.

  13. SUPERCONDUCTING MAGNET NEEDS FOR THE ILC.

    SciTech Connect

    PARKER,B.; TOMPKINS, J.C.; KASHIKHIN, VI.; PALMER, M.A.; CLARKE, J.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 lLC 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.

  14. Beam dispersion measurements with wire scanners in the SLC final focus systems

    SciTech Connect

    Emma, P.; McCormick, D.; Ross, M.C.

    1993-05-01

    A method is described to make a direct measurement of the horizontal and vertical momentum dispersion of the electron and positron beams as they pass through the chromatic correction sections (CCS) of the SLC final focus systems. The method is advantageous since it cleanly separates betatron components of the beam size from dispersive components, can be measured during standard colliding beams machine conditions in a minute or two, and directly measures the energy-position correlation within the beam.

  15. Nuclear heating, radiation damage, and waste management options for the HYLIFE-II final focus magnets

    SciTech Connect

    Latkowski, J F; Moir, R W; House, P A

    1999-08-09

    Heavy-ion fusion (HIF) designs for inertial fusion energy (XFE) power plants typically require final focusing magnets just outside the reaction chamber and blanket. Due to penetrations within the chamber and blanket, the magnets are exposed to a radiation environment. Although the magnet bores would be sized to avoid line-of-sight irradiation, the magnets still would be susceptible to nuclear heating and radiation damage from neutrons and y-rays. Additionally, the magnets must be included in waste management considerations due to neutron activation. Modified versions of the HYLIFE-II IFE power plant featuring two-sided illumination by arrays of 32 or 96 beams from each side are presented. A simple, point-of-departure quadrupole magnet design is assumed, and a three-dimensional neutronics model is created for the Flibe pocket, first wall, blanket, shield, and final two focusing magnets. This work details state-of-the-art neutronics calculations and shows that the final focus system needs to be included in the economic and environmental considerations for the driver-chamber interface of any HIF IFE power plant design.

  16. R & D on Very-High-Current Superconducting Proton Linac, Final Report

    SciTech Connect

    Ben-Zvi, Ilan

    2013-03-31

    The aim of this R&D project was to develop a superconducting cavity for a very-­ high-current proton accelerator. The particular application motivating the proposal was a LHC upgrade called the Superconducting Proton Linac, or SPL. Under the grant awarded to Stony Brook University the cavity was designed, a prototype copper cavity, followed by the niobium cavity, were built. A new set of HOM dampers was developed. The cavity has outstanding RF performance parameters – low surface fields, low power loss and all HOMs are fully damped. In fact, it is a “universal cavity” in the sense that it is suited for the acceleration of high-­current protons and well as high current electrons. Its damping of HOM modes is so good that it can see service in a multi-pass linac or an Energy Recovery Linac in addition to the easier service in a single-pass linac. Extensive measurements were made on the cavities and couplers, with the exception of the cold test of the niobium cavity. At the time of this report the cavity has been chemically processed and is ready for vertical testing which will be carried out shortly.

  17. Evaluation of superconducting wiggler designs and free-electron laser support: Final report

    SciTech Connect

    1990-10-12

    This report consists of copies of previous progress reports, and copies of viewgraphs presented in a talk at Los Alamos. The report describes activities carried out as part of a project to evaluate the design and performance of a superconducting wiggler magnet design. It includes work on evaluating the appropriate materials for the magnet coils and poles, and stress evaluations for the design. It includes work on beam optics through the magnet, and design considerations to optimize extraction: work on the cryocooling system; weight minimization efforts; and design work on the vacuum liner for the magnet. A major concern in all of this design work is heat loads which will be dissipated in different parts of the system during operation, as well as transient events.

  18. Analysis of higher order optical aberrations in the SLC final focus using Lie Algebra techniques

    SciTech Connect

    Walker, N.J.; Irwin, J.; Woodley, M.

    1993-04-01

    The SLC final focus system is designed to have an overall demagnification of 30:1, with a {beta} at the interaction point ({beta}*) of 5 mm, and an energy band pass of {approximately}0.4%. Strong sextupole pairs are used to cancel the large chromaticity which accrues primarily from the final triplet. Third-order aberrations limit the performance of the system, the dominating terms being U{sub 1266} and U{sub 3466} terms (in the notation of K. Brown). Using Lie Algebra techniques, it is possible to analytically calculate the soave of these terms in addition to understanding their origin. Analytical calculations (using Lie Algebra packages developed in the Mathematica language) are presented of the bandwidth and minimum spot size as a function of divergence at the interaction point (IP). Comparisons of the analytical results from the Lie Algebra maps and results from particle tracking (TURTLE) are also presented.

  19. Beam-based optical tuning of the final focus test beam

    SciTech Connect

    Tenenbaum, P.; Burke, D.; Hartman, S.; Helm, R.; Irwin, J.; Iverson, R.; Raimondi, P.; Spence, W.; Bharadwaj, V.; Halling, M.

    1995-05-01

    In order to reduce the SLAC 46.6 GeV beam to submicron sizes, the Final Focus Test Beam (FFTB) must meet tight tolerances on many aberrations. These aberrations include: mismatch and coupling of the incoming beam; dispersion; chromaticity; lattice errors in the chromatic correction sections; lattice coupling; and residual sextupole content in the quadrupoles. In order to address these aberrations, the authors have developed a procedure which combines trajectory analysis, use of intermediate wire scanners, and a pair of novel beam size monitors at the IP. This procedure allows the FFTB IP spot to be reduced to sizes under 100 nanometers.

  20. Interactive beam tuning simulator for the SLC (Stanford Linear Collider) final focus

    SciTech Connect

    Ford, W.T.; Kozanecki, W.; Lohse, T.; Servranckx, R.V.

    1989-03-01

    An interface to the DIMAD beam optics computer program enables the operator to perform in simulation the sequence of magnet adjustments that would be used online for tuning the Stanford Linear Collider Final Focus System. The program accepts any input beam matrix from a disk file and presents a menu of magnet adjustments and scan and display options. The results of a ray trace calculation are presented as profiles or envelope plots on the graphics screen. We give results from studies of the optimization of the beam under various input conditions. 11 refs., 4 figs.

  1. Study of neutron focusing at the Texas Cold Neutron Source. Final report

    SciTech Connect

    Wehring, B.W.; Uenlue, K.

    1996-12-19

    The goals of this three-year study were: (1) design a neutron focusing system for use with the Texas Cold Neutron Source (TCNS) to produce an intense beam of cold neutrons appropriate for prompt gamma activation analysis (PGAA); (2) orchestrate the construction of the focusing system, integrate it into the TCNS neutron guide complex, and measure its performance; and (3) design, setup, and test a cold-neutron PGAA system which utilizes the guided focused cold neutron beam. During the first year of the DOE grant, a new procedure was developed and used to design a focusing converging guide consisting of truncated rectangular cone sections. Detailed calculations were performed using a 3-D Monte Carlo code which the authors wrote to trace neutrons through the curved guide of the TCNS into the proposed converging guide. Using realistic reflectivities for Ni-Ti supermirrors, the authors obtained gains of 3 to 5 for 4 different converging guide geometries. During the second year of the DOE grant, the subject of this final report, Ovonic Synthetic Materials Company was contracted to build a converging neutron guide focusing system to the specifications. Considerable time and effort were spent working with Ovonics on selecting the materials for the converging neutron guide system. The major portion of the research on the design of a cold-neutron PGAA system was also completed during the second year. At the beginning of the third year of the grant, a converging neutron guide focusing system had been ordered, and a cold-neutron PGAA system had been designed. Since DOE did not fund the third year, there was no money to purchase the required equipment for the cold-neutron PGAA system and no money to perform tests of either the converging neutron guide or the cold-neutron PGAA system. The research already accomplished would have little value without testing the systems which had been designed. Thus the project was continued at a pace that could be sustained with internal funding.

  2. Superconducting Meissner-effect bearings for cryogenic turbomachines. Phase 1. Final report, September 1988-March 1989

    SciTech Connect

    Iannello, V.; Marshall, J.S.; Stacy, W.D.

    1989-05-01

    State-of-the-art miniature expansion turbines and centrifugal compressors used in spaceborne sensor cryocoolers employ self-acting gas bearings to achieve high reliability and long operating life. Because these bearings must run at room temperature to achieve adequate stiffness and stability, they result in an avoidable source of heat leak to the process gas, thereby lowering overall cycle efficiency and increasing the system launch weight. This report shows that the gas bearings can be replaced by Meissner-effect bearings fabricated from high-temperature superconducting materials. Analyses are presented to predict Meissner bearing performance, and a preliminary design of a miniature expansion incorporating Meissner-bearings is conceptualized. Because these bearings operate at a cryogenic temperatures, a substantial reduction in heat leak to the process gas can be achieved. For a typical cryocooler providing 1 watt of cooling at 10 K, a 40% reduction in input-cycle power can be achieved by replacing the self-acting gas bearings by Meissner bearings in the cold expansion turbine.

  3. Final Commissioning of the Superconducting Heavy Ion Linear Accelerator at IUAC, Delhi

    NASA Astrophysics Data System (ADS)

    Datta, Tripti Sekhar; Choudhury, Anup; Chacko, Jacob; Kar, Soumen; Antony, Joby; Babu, Suresh; Kumar, Manoj; Mathuria, D. S.; Sahu, Santosh; Kanjilal, Dinakar

    The superconducting linac as a booster of the 15UD Pelletron accelerator was partly commissioned with one linac module housing eight quarter wave bulk niobium cavities along with the superbuncher and rebuncher cryomodules. Subsequently two more linac cryomodules were added to have in total 24 cavities for acceleration. In addition, a new Linde helium refrigerator of capacity 750 W @ 4.2 K was installed in parallel to the earlier CCI refrigerator. The new refrigerator was integrated with the earlier cryogenics network system through a specially designed liquid helium distribution line without any valve box. The cooling philosophy with this new system is modified to have a faster cool down rate in the critical zone (150 - 70 K) to avoid Q disease. The helium gas pressure fluctuation in the cavities is reduced significantly to have stable RF locking. The full linac is being operated and beams with higher energy are being delivered to the users. The present paper will highlight the performance of the new cryogenic system with respect to cool down rate, and helium pressure fluctuation.

  4. Development of a superconducting six-axis accelerometer. Final report, 1 April 1985-31 March 1988

    SciTech Connect

    Paik, H.J.; Parke, J.W.; Canavan, E.R.

    1989-07-01

    This report describes research on the superconducting six-axis accelerometer performed at the University of Maryland from April, 1985, to March,1988, under Air Force Contract F19628-85-K-0042. This report consists of four chapters. After an introduction and summary is given in Chapter 1, Chapter 2 discusses the theory of a superconducting six-axis accelerometer. The construction and test of the conducting six-axis accelerometer are given in Chapters 3 and 4, respectively. The superconducting six-axis accelerometer described in this report was invented to monitor the platform motions of a superconducting gravity gradiometer which is under development at the University of Maryland for space application. The signals from the accelerometer will be used to control the position and the attitude of the gradiometer platform. The superconducting six-axis accelerometer represents by itself a complete inertial navigation system. Integrated with the superconducting gravity gradiometer, it becomes a gradiometer-aided inertial navigation system.

  5. Superconducting magnets

    SciTech Connect

    Willen, E.; Dahl, P.; Herrera, J.

    1985-01-01

    This report provides a self-consistent description of a magnetic field in the aperture of a superconducting magnet and details how this field can be calculated in a magnet with cos theta current distribution in the coils. A description of an apparatus that can be used to measure the field uniformity in the aperture has been given. Finally, a detailed description of the magnet being developed for use in the Superconducting Super Collider is given. When this machine is built, it will be by far the largest application of superconductivity to date and promises to make possible the experimental discoveries needed to understand the basic laws of nature governing the world in which we live.

  6. High gradient superconducting quadrupoles

    SciTech Connect

    Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.

    1987-07-01

    Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed.

  7. Superstructures and superconductivity

    SciTech Connect

    Fisk, Z.; Aeppli, G.

    1993-04-02

    Heavy fermion materials - so named because their conduction electrons behave as though they had extra mass - are like the cuprates in that they exhibit unusual superconducting properties. By the time the cuprates had been discovered, a good understanding of these materials was in hand. Unlike theories of high-[Tc] superconductivity, however, ideas about heavy fermions have not been the subject of great controversy. Thus, most of the effort in this backwater of condensed matter physics has focused on certain details of the behavior of one particularly well-studied compounds, UPt[sub 3]. The cause for sustained interest was that the process of developing ever more elaborate explanations for ever more elaborate experiments did not seem to converage. A recent paper by Midgley et al. reporting modulations in the crystal lattice of UPt[sub 3] suggests that theory and experiment might finally converge in a way that, while it does not threaten the broad understanding of heavy fermion systems, involves a degree of freedom ignored until now even in the face of past experience with elemental metallic uranium. Their transmission electron micrograph evidence for the existence of an incommensurate lattice modulation in UPt[sub 3] implicates this modulation as a probable source of the double superconducting transitions. Remarkably, the superconducting and magnetic coherence lengths, and the now discovered modulation period, are all of the same magnitude. For some time people have felt that stacking faults might be relevant to the properties of UPt[sub 3], but these new results are distinct from this. What Midgley et al. suggest is that the complicated superconducting phase diagram of UPt[sub 3] derives from the internal strain field caused by the modulation, and that this strain field lifts the degeneracy associated with unconventional pairing.

  8. Halo Reduction By Means of Non Linear Optical Elements in the NLC Final Focus System

    SciTech Connect

    Seryi, Andrei

    2001-07-23

    In the Beam Delivery Systems (BDS) for linear colliders that have been designed or built, collimators (or scrapers) are used to suppress backgrounds due to the beam halo. Off-energy and off-axis particles are stopped on the collimator jaws, physically limiting the acceptance of the system. This concept does not scale well to higher beam energy, higher intensity or lower emittance. The increased beam density requires longer and more demanding collimator regions. In contrast, this paper studies the possibility of inserting non-linear optical elements into the Final Focus in order to effectively increase the acceptance of the system. This technique could make the traditional collimation scheme obsolete so that only protection collimators would be needed.

  9. International workshop on final focus and interaction regions of next generation linear colliders: Proceedings

    SciTech Connect

    Not Available

    1992-11-01

    The first day of the workshop was devoted to four plenary ``issues`` talks, one for each working group: Beam-Beam Interaction, Detector, Hardware, and Optical Design. The last day was devoted to plenary talks summarizing the activities of the working groups. Each of the three remaining days there,was a short morning plenary devoted to a brief summary of the preceding day and an announcement of planned working group discussions for that day. The transparencies for the ``issues`` and ``summary`` talks are included in this volume, along with some remarks from the working group chairpersons. Very briefly, the beam-beam group continued to address the quantitative study of QED induced backgrounds, and attempted to better understand the nature and prevalence of QCD millijets. The detector group attempted to identify the impact on masking and detector design of the beam-beam backgrounds, the synchrotron radiation induced backgrounds from beam halos and muon backgrounds produced primarily in collimators. Nanosecond timing elements needed in conjunction with multi-bunch operation were discussed. The hardware group addressed the problem of magnet design and support, especially the final doublet magnets suspended within the detector environment, and instrumentation issues, such as high resolution beam position monitors. The optics group discussed new final focus system ideas, collimator design, and improvement of beamline tolerances. If you were not here to participate, we hope that this volume will help you in your orientation to these problems.

  10. International workshop on final focus and interaction regions of next generation linear colliders: Proceedings

    SciTech Connect

    Not Available

    1992-01-01

    The first day of the workshop was devoted to four plenary issues'' talks, one for each working group: Beam-Beam Interaction, Detector, Hardware, and Optical Design. The last day was devoted to plenary talks summarizing the activities of the working groups. Each of the three remaining days there,was a short morning plenary devoted to a brief summary of the preceding day and an announcement of planned working group discussions for that day. The transparencies for the issues'' and summary'' talks are included in this volume, along with some remarks from the working group chairpersons. Very briefly, the beam-beam group continued to address the quantitative study of QED induced backgrounds, and attempted to better understand the nature and prevalence of QCD millijets. The detector group attempted to identify the impact on masking and detector design of the beam-beam backgrounds, the synchrotron radiation induced backgrounds from beam halos and muon backgrounds produced primarily in collimators. Nanosecond timing elements needed in conjunction with multi-bunch operation were discussed. The hardware group addressed the problem of magnet design and support, especially the final doublet magnets suspended within the detector environment, and instrumentation issues, such as high resolution beam position monitors. The optics group discussed new final focus system ideas, collimator design, and improvement of beamline tolerances. If you were not here to participate, we hope that this volume will help you in your orientation to these problems.

  11. Drift compression and final focus systems for heavy ion inertial fusion

    SciTech Connect

    de Hoon, M.J.L.

    2001-05-01

    Longitudinal compression of space-charge dominated beams can be achieved by imposing a head-to-tail velocity tilt on the beam. This tilt has to be carefully tailored, such that it is removed by the longitudinal space-charge repulsion by the time the beam reaches the end of the drift compression section. The transverse focusing lattice should be designed such that all parts of the beam stay approximately matched, while the beam smoothly expands transversely to the larger beam radius needed in the final focus system following drift compression. In this thesis, several drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression. The occurrence of mismatches due to a rapidly increasing current was analyzed. In addition, the sensitivity of drift compression to errors in the initial velocity tilt and current profile was studied. These calculations were done using a new computer code that accurately calculates the longitudinal electric field in the space-charge dominated regime.

  12. YBa2Cu3O7-δ superconducting quantum interference devices with metallic to insulating barriers written with a focused helium ion beam

    NASA Astrophysics Data System (ADS)

    Cho, E. Y.; Ma, M. K.; Huynh, Chuong; Pratt, K.; Paulson, D. N.; Glyantsev, V. N.; Dynes, R. C.; Cybart, Shane A.

    2015-06-01

    In this work, we demonstrate the ability to fabricate superconducting quantum interference devices (SQUIDs) by directly writing Josephson junctions into the plane of YBa2Cu3O7-δ thin films with a focused helium ion beam. This technique allows for the control of the Josephson barrier transport properties through the single parameter, ion dose. SQUIDs written with a dose of 4 × 1016 ions/cm2 had metallic barrier junctions that exhibited nearly ideal electrical transport characteristics at 50 K and a flux noise of 20 μΦ0/√{Hz } at 10 Hz. At higher irradiation doses, the SQUIDs had insulating barrier Josephson junctions with a quasi particle energy gap edge at 20 meV.

  13. Review of project definition studies of possible on-site uses of superconducting super collider assets and facilities. Final report

    SciTech Connect

    1994-12-01

    This document reports on the results of a peer review and evaluation of studies made of potential uses of assets from the terminated Superconducting Super Collider (SSC) project. These project definition studies focused on nine areas of use of major assets and facilities at the SSC site near Waxahachie, Texas. The studies were undertaken as part of the effort to maximize the value of the investment made in the SSC and were supported by two sets of grants, one to the Texas National Research Laboratory Commission (TNRLC) and the second to various universities and other institutions for studies of ideas raised by a public call for expressions of interest. The Settlement Agreement, recently signed by the Department of Energy (DOE) and TNRLC, provides for a division of SSC property. As part of the goal of maximizing the value of the SSC investment, the findings contained in this report are thus addressed to officials in both the Department and TNRLC. In addition, this review had several other goals: to provide constructive feedback to those doing the studies; to judge the benefits and feasibility (including funding prospects) of the projects studied; and to help worthy projects become reality by matching projects with possible funding sources.

  14. Final Report: MATERIALS, STRANDS, AND CABLES FOR SUPERCONDUCTING ACCELERATOR MAGNETS [Grant Number DE-SC0010312

    SciTech Connect

    Sumption, Mike; Collings, E.

    2014-10-29

    Our program consisted of the two components: Strand Research and Cable Research, with a focus on Nb3Sn, Bi2212, and YBCO for accelerator magnet applications. We demonstrated a method to refine the grains in Nb3Sn by a factor of two, reaching 45 nm grain sizes, and layer Jcs of 6 kA/mm2 at 12 T. W also measured conductor magnetization for field quality. This has been done both with Nb3Sn conductor, as well as Bi:2212 strand. Work in support of quench studies of YBCO coils was also performed. Cable loss studies in Nb3Sn focused on connecting and comparing persistent magnetization and coupling magnetization for considering their relative impact on HEP machines. In the area of HTS cables, we have investigated both the quench in multistrand YBCO CORC cables, as well as the magnetization of these cables for use in high field magnets. In addition, we examined the magnetic and thermal properties of large (50 T) solenoids.

  15. Beam-based alignment and tuning procedures for e sup + e sup minus collider final focus systems

    SciTech Connect

    Bulos, F.; Burke, D.; Helm, R.; Irwin, J.; Odian, A.; Roy, G.; Ruth, R.; Yamamoto, N.

    1991-05-01

    For future linear colliders, with very small emittances and beam sizes and demanding tolerances on final focus system alignment and magnet errors, it becomes increasingly important to use the beam as a diagnostic tool. We report here procedures we have identified and will be implemented in the Final Focus Test Beam at SLAC incorporating (1) quadrupole strength changes, (2) central orbit modifications, (3) spot size measurements, and (4) beam stability monitoring. 3 refs., 4 figs., 3 tabs.

  16. PREFACE: Superconducting materials Superconducting materials

    NASA Astrophysics Data System (ADS)

    Charfi Kaddour, Samia; Singleton, John; Haddad, Sonia

    2011-11-01

    and by invited authors selected by the editor. We are grateful to IUPAP, ICTP and the European Office of Aerospace Research and Development, Air Force Office of Scientific Research, United States Air Force Laboratory. We would like to acknowledge the authors for their careful work, and finally we thank Dr L Smith the publisher of Journal of Physics: Condensed Matter for her patience and help. Superconducting materials contents Raman spectrum in the pseudogap phase of the underdoped cuprates: effect of phase coherence and the signature of the KT-type superconducting transitionTao Li and Haijun Liao Pressure effects on Dirac fermions in α-(BEDT-TTF)2I3Takahiro Himura, Takao Morinari and Takami Tohyama Effect of Zn doping in hole-type 1111 phase (Pr, Sr)FeAsOXiao Lin, Chenyi Shen, Chen Lv, Jianjian Miao, Hao Tan, Guanghan Cao and Zhu-An Xu Superconductivity and ferromagnetism in EuFe2(As1 - xPx)2*Guanghan Cao, Shenggao Xu, Zhi Ren, Shuai Jiang, Chunmu Feng and Zhu'an Xu OInhomogeneous superconductivity in organic conductors: the role of disorder and magnetic fieldS Haddad, S Charfi-Kaddour and J-P Pouget

  17. Radiation safety considerations for the parasitic Final Focus Test Beam at SLAC

    SciTech Connect

    Rokni, S.H.; Iverson, R.H.; Keller, L.P.

    1996-11-01

    A low intensity electron beam parasitic to the operation of the Stanford Linear Collider (SLC) has been transported through the Final Focus Test Beam (FFTB) facility making secondary test beams available for users. Photons generated in collimation of the SLC electron and positron beams in the linac pass through a splitter magnet that deflects the primary beams away from the linac axis into the SLC beam lines. These photons are converted to electrons and positrons in a secondary production target located down beam on the linac axis. The secondary electrons are then transported through the FFTB beam line onto experimental detectors. The average power of the parasitic beam is very low, thus, it presents no hazards. However, various accident scenarios involving failure of the splitter magnet and the active protection devices could send much more powerful SLC beams (up to 90 kilo-watts) into this zero-degree secondary beam line. For the accident cases, the average power in the transmitted beam was calculated using the Monte Carlo programs EGS4 and TURTLE. Results from analysis of the radiation protection systems that assure safety during the parasitic operation are presented.

  18. 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.

  19. 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.

  20. Development of cryotribological theories & application to cryogenic devices. Final report

    SciTech Connect

    Iwasa, Yukikazu

    2001-03-12

    This is the final report of a research program on low-temperature friction and wear, primarily focused on development of cryotribological theories and application to cryogenic devices, particularly superconducting magnets.

  1. Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size

    SciTech Connect

    White, Glen; Seryi, Andrei; Woodley, Mark; Bai, Sha; Bambade, Philip; Renier, Yves; Bolzon, Benoit; Kamiya, Yoshio; Komamiya, Sachio; Oroku, Masahiro; Yamaguchi, Yohei; Yamanaka, Takashi; Kubo, Kiyoshi; Kuroda, Shigeru; Okugi, Toshiyuki; Tauchi, Toshiaki; Marin, Eduardo; /CERN

    2012-07-06

    The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing low-emittance electron beams (< 12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere. The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the tuning procedures and describe operational experiences and performances.

  2. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1997-03-11

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly has a superconducting metal-ceramic design. The srf window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  3. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, H.L.; Elliott, T.S.

    1998-05-19

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The SRF window assembly has a superconducting metal-ceramic design. The SRF window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the SRF window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

  4. Present Status And First Results of the Final Focus Beam Line at the KEK Accelerator Test Facility

    SciTech Connect

    Bambade, P.; Alabau Pons, M.; Amann, J.; Angal-Kalinin, D.; Apsimon, R.; Araki, S.; Aryshev, A.; Bai, S.; Bellomo, P.; Bett, D.; Blair, G.; Bolzon, B.; Boogert, S.; Boorman, G.; Burrows, P.N.; Christian, G.; Coe, P.; Constance, B.; Delahaye, Jean-Pierre; Deacon, L.; Elsen, E.; /DESY /Valencia U., IFIC /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Savoie U. /Fermilab /Ecole Polytechnique /KEK, Tsukuba /Kyungpook Natl. U. /KEK, Tsukuba /Pohang Accelerator Lab. /Kyoto U., Inst. Chem. Res. /Savoie U. /Daresbury /Tokyo U. /Royal Holloway, U. of London /Kyungpook Natl. U. /Pohang Accelerator Lab. /Tokyo U. /KEK, Tsukuba /SLAC /University Coll. London /KEK, Tsukuba /SLAC /Royal Holloway, U. of London /KEK, Tsukuba /Tokyo U. /SLAC /Tohoku U. /KEK, Tsukuba /Tokyo U. /Pohang Accelerator Lab. /Brookhaven /SLAC /Oxford U., JAI /SLAC /Orsay /KEK, Tsukuba /Oxford U., JAI /Orsay /Fermilab /Tohoku U. /Manchester U. /CERN /SLAC /Tokyo U. /KEK, Tsukuba /Oxford U., JAI /Hiroshima U. /KEK, Tsukuba /CERN /KEK, Tsukuba /Oxford U., JAI /Ecole Polytechnique /SLAC /Oxford U., JAI /Fermilab /SLAC /Liverpool U. /SLAC /Tokyo U. /SLAC /Tokyo U. /KEK, Tsukuba /SLAC /CERN

    2011-11-11

    ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.

  5. Present status and first results of the final focus beam line at the KEK Accelerator Test Facility

    NASA Astrophysics Data System (ADS)

    Bambade, P.; Alabau Pons, M.; Amann, J.; Angal-Kalinin, D.; Apsimon, R.; Araki, S.; Aryshev, A.; Bai, S.; Bellomo, P.; Bett, D.; Blair, G.; Bolzon, B.; Boogert, S.; Boorman, G.; Burrows, P. N.; Christian, G.; Coe, P.; Constance, B.; Delahaye, J.-P.; Deacon, L.; Elsen, E.; Faus-Golfe, A.; Fukuda, M.; Gao, J.; Geffroy, N.; Gianfelice-Wendt, E.; Guler, H.; Hayano, H.; Heo, A.-Y.; Honda, Y.; Huang, J. Y.; Hwang, W. H.; Iwashita, Y.; Jeremie, A.; Jones, J.; Kamiya, Y.; Karataev, P.; Kim, E.-S.; Kim, H.-S.; Kim, S. H.; Komamiya, S.; Kubo, K.; Kume, T.; Kuroda, S.; Lam, B.; Lyapin, A.; Masuzawa, M.; McCormick, D.; Molloy, S.; Naito, T.; Nakamura, T.; Nelson, J.; Okamoto, D.; Okugi, T.; Oroku, M.; Park, Y. J.; Parker, B.; Paterson, E.; Perry, C.; Pivi, M.; Raubenheimer, T.; Renier, Y.; Resta-Lopez, J.; Rimbault, C.; Ross, M.; Sanuki, T.; Scarfe, A.; Schulte, D.; Seryi, A.; Spencer, C.; Suehara, T.; Sugahara, R.; Swinson, C.; Takahashi, T.; Tauchi, T.; Terunuma, N.; Tomas, R.; Urakawa, J.; Urner, D.; Verderi, M.; Wang, M.-H.; Warden, M.; Wendt, M.; White, G.; Wittmer, W.; Wolski, A.; Woodley, M.; Yamaguchi, Y.; Yamanaka, T.; Yan, Y.; Yoda, H.; Yokoya, K.; Zhou, F.; Zimmermann, F.

    2010-04-01

    ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.

  6. Superconductivity in the system Mo{sub x}C{sub y}Ga{sub z}O{sub δ} prepared by focused ion beam induced deposition

    SciTech Connect

    Weirich, P. M. Schwalb, C. H.; Winhold, M.; Huth, M.

    2014-05-07

    We have prepared the new amorphous superconductor Mo{sub x}C{sub y}Ga{sub z}O{sub δ} with a maximum critical temperature T{sub c} of 3.8 K by the direct-write nano-patterning technique of focused (gallium) ion beam induced deposition (FIBID) using Mo(CO){sub 6} as precursor gas. From a detailed analysis of the temperature-dependent resistivity and the upper critical field, we found clear evidence for proximity of the samples to a disorder-induced metal-insulator transition. We observed a strong dependence of T{sub c} on the deposition parameters and identified clear correlations between T{sub c}, the localization tendency visible in the resistance data and the sample composition. By an in-situ feedback-controlled optimization process in the FIB-induced growth, we were able to identify the beam parameters which lead to samples with the largest T{sub c}-value and sharpest transition into the superconducting state.

  7. Technical analyses and related planning assistance in support of DOE's superconducting magnetic energy storage program. Final report

    SciTech Connect

    Hoenig, M.; Graneau, P.

    1983-03-15

    Various problems are assessed that will be encountered in the design of large superconducting magnetic energy storage (SMES) systems. Then a scoping study on design requirements for a 10,000 MWh SMES system is reported. Basic system requirements are defined, followed by a comparison of two basic coil concepts. (LEW)

  8. 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.

  9. Drift Compression and Final Focus for Intense Heavy Ion Beams with Non-periodic, Time-dependent Lattice

    SciTech Connect

    Hong Qin; Ronald C. Davidson; John J. Barnard; Edward P. Lee

    2005-02-14

    In the currently envisioned configurations for heavy ion fusion, it is necessary to longitudinally compress the beam bunches by a large factor after the acceleration phase. Because the space-charge force increases as the beam is compressed, the beam size in the transverse direction will increase in a periodic quadrupole lattice. If an active control of the beam size is desired, a larger focusing force is needed to confine the beam in the transverse direction, and a non-periodic quadrupole lattice along the beam path is necessary. In this paper, we describe the design of such a focusing lattice using the transverse envelope equations. A drift compression and final focus lattice should focus the entire beam pulse onto the same focal spot on the target. This is difficult with a fixed lattice, because different slices of the beam may have different perveance and emittance. Four time-dependent magnets are introduced in the upstream of drift compression to focus the entire pulse onto the sam e focal spot. Drift compression and final focusing schemes are developed for a typical heavy ion fusion driver and for the Integrated Beam Experiment (IBX) being designed by the Heavy Ion Fusion Virtual National Laboratory.

  10. Analysis of ASSIST Navigability, Usability, and Content Using Student Focus Groups, Spring 2000. Final Report.

    ERIC Educational Resources Information Center

    Taggart, Donna; Valenzuela, Yvonne; Sragovicz, Lisa

    This report details a focus group's efforts to ascertain if the Articulation System Stimulating Interinstitutional Student Transfer (ASSIST) implemented on the World Wide Web was easy for students to navigate and use. Another purpose of the analysis was to discover if the information contained within ASSIST was easily understood by community…

  11. Study of neutron focusing at the Texas Cold Neutron Source. Final report

    SciTech Connect

    Wehring, B.W.; Uenlue, K.

    1995-03-06

    Funds were received for the first year of a three year DOE Nuclear Engineering Research Grant, ``Study of Neutron Focusing at the Texas Cold Neutron Source`` (FGO2-92ER75711). The purpose of this three year study was to develop a neutron focusing system to be used with the Texas Cold Neutron Source (TCNS) to produce an intense beam of neutrons. A prompt gamma activation analysis (PGAA) facility was also to be designed, setup, and tested under the three year project. During the first year of the DOE grant, a new procedure was developed and used to design a focusing converging guide consisting of truncated rectangular cone sections. Detailed calculations were performed using a 3-D Monte Carlo code which we wrote to trace neutrons through the curved guide of the TCNS into the proposed converging guide. Using realistic reflectivities for Ni-Ti supermirrors, we obtained gains of 3 to 5 for the neutron flux averaged over an area of 1 {times} 1 cm.

  12. Superconducting Nanotube Dots

    NASA Astrophysics Data System (ADS)

    Schönenberger, Christian

    2007-03-01

    In this talk, I will focus on charge transport in carbon nanotube devices with superconducting source and drain contacts in the finite-bias non-equilibrium transport regime. As contact material, bi-layers of Au and Al were used and transport has been studied at temperatures in the 0.1 K range. Because carbon nanotubes are quantum dots (qdots), we in fact explore the physics of qdots with superconducting contacts, something which only recently became possible thanks to carbon nanotubes and most recently to semiconducting nanowires. In my talk, I will first summarize our pioneering work on multiwalled carbon nanotubes in which we could demonstrate proximity induced effects both in the weak and the strong coupling regime. In the latter an intriguing interplay between superconductivity and Kondo physics appears. Then, I will discuss the physics of multiple Andreev reflection in a situation when only one resonant state is present and compare this with experimental results. Finally, I will compare our early results with our recent measurements on single-wall carbon nanotubes. This work has been supported by the Swiss Institute on Nanoscience, the Swiss National Science Foundation, EU projects DIENOW and HYSWITCH. I gratefully acknowledge contribution of the following persons to this work (in alphabetic order): B. Babic, W. Belzig, C. Bruder, M. R. Buitelaar, J.-C. Cuevas, A. Eichler, L. Forro, J. Gobrecht, M. Gr"aber, M. Iqbal, T. Kontos, A. Levy Yeyati, A. Martin-Rodero, T. Nussbaumer, S. Oberholzer, C. Strunk, H. Scharf, J. Trbovic, E. Vecino, M. Weiss

  13. Development of a compact HTS lead unit for the SC correction coils of the SuperKEKB final focusing magnet system

    NASA Astrophysics Data System (ADS)

    Zong, Zhanguo; Ohuchi, Norihito; Tsuchiya, Kiyosumi; Arimoto, Yasushi

    2016-09-01

    Forty-three superconducting (SC) correction coils with maximum currents of about 60 A are installed in the SuperKEKB final focusing magnet system. Current leads to energize the SC correction coils should have an affordable heat load and fit the spatial constraints in the service cryostat where the current leads are installed. To address the requirements, design optimization of individual lead was performed with vapor cooled current lead made of a brass material, and a compact unit was designed to accommodate eight current leads together in order to be installed with one port in the service cryostat. The 2nd generation high temperature SC (HTS) tape was adopted and soldered at the cold end of the brass current lead to form a hybrid HTS lead structure. A prototype of the compact lead unit with HTS tape was constructed and tested with liquid helium (LHe) environment. This paper presents a cryogenic measurement system to simulate the real operation conditions in the service cryostat, and analysis of the experimental results. The measured results showed excellent agreement with the theoretical analysis and numerical simulation. In total, 11 sets of the compact HTS lead units were constructed for the 43 SC correction coils at KEK. One set from the mass production was tested in cryogenic conditions, and exhibited the same performance as the prototype. The compact HTS lead unit can feed currents to four SC correction coils simultaneously with the simple requirement of controlling and monitoring helium vapor flow, and has a heat load of about 0.762 L/h in terms of LHe consumption.

  14. Budgeting and control of the mechanical noise in the International Linear Collider final focus system

    NASA Astrophysics Data System (ADS)

    Tshilumba, D.; Oriunno, M.; Markiewicz, T.; Collette, C.

    2014-06-01

    In this paper, we present a simplified vibration model of the silicon detector (SiD), where the final doublet (QD0) is captured inside the detector and the penultimate magnet (QF1) is inside the machine tunnel. Ground motion spectra measured at the detector hall at SLAC have been used together with a spectrum of the technical noise on the detector. The model predicts that the maximum level of rms (root mean square) vibration seen by QD0 is well below the capture range of the interaction point (IP) feedback system available in the ILC. With the addition of an active stabilization system on QD0, it is also possible to get closer to the stability requirements of the compact linear collider (CLIC). These results can have important implications for CLIC.

  15. Superconductive organic polymers: Conceptual design, synthesis, and characterization. Final technical report, 30 September 1992-30 September 1996

    SciTech Connect

    Elsenbaumer, R.L.; Marynick, D.S.; Pomerantz, M.; Sharma, S.C.

    1997-05-27

    Here are significant findings of the project for period September 92-96. Theoretical studies indicate that extended chains consisting of isomeric TTF structures have electronic properties and stabilities comparable to TTF extended structures and are therefore of considerable interest as possible polymeric organic superconductive compositions. Synthetic strategies were developed to prepare polymeric TTF and isomeric TTF structures. Dramatically simplified synthetic procedures were developed to prepare TTF and ET-TTF donors in high yield and large quantities from inexpensive starting materials. Developed new techniques to purify, characterize and grow large single crystals of TTF and ET-TTF. Synthesized new organic conductive polymers with good electrical conductivities and processibility. Developed new processing and doping techniques for polyalkylthiophenes to provide consistently high conductivity materials.

  16. Study of high {Tc} superconducting thin films grown by MOCVD. Final report, July 1, 1986--April 30, 1990

    SciTech Connect

    Erbil, A.

    1990-12-31

    Work is described briefly, which was carried out on development of techniques to grow metal-semiconductor superlattices (artificially layered materials) and on the copper oxide based susperconductors (naturally layered materials). The current growth technique utilized is metalorganic chemical vapor deposition (MOCVD). CdTe, PbTe, La, LaTe, and Bi{sub 2}Te{sub 3} were deposited, mostly on GaAs. Several YBa{sub 2}Cu{sub 3}O{sub 7} compounds were obtained with possible superconductivity at temperatures up to 550 K (1 part in 10{sup 4}). YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub y} thin films were deposited by MOCVD on common substrates such as glass.

  17. Superconductive wire

    DOEpatents

    Korzekwa, David A.; Bingert, John F.; Peterson, Dean E.; Sheinberg, Haskell

    1995-01-01

    A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for time sufficient for the superconductive material or superconductive precursor to exhibit superconductivity.

  18. Superconductive wire

    DOEpatents

    Korzekwa, D.A.; Bingert, J.F.; Peterson, D.E.; Sheinberg, H.

    1995-07-18

    A superconductive article is made by inserting a rigid mandrel into an internal cavity of a first metallic tube, said tube having an interior surface and an exterior surface, said interior surface defining the interior cavity, forming a layer of a superconductive material or superconductive precursor upon the exterior surface of said first metallic tube, machining the layer of superconductive material or superconductive precursor to a predetermined diameter to form an intermediate article configured for insertion into a second metallic tube having an interior diameter corresponding to the predetermined diameter, inserting the machined intermediate article into a second metallic tube having an internal diameter corresponding to the predetermined diameter of the intermediate article to form a composite intermediate article, reducing or ironing the composite intermediate article to a predetermined cross-sectional diameter, and sintering the reduced or ironed composite intermediate article at temperatures and for time sufficient for the superconductive material or superconductive precursor to exhibit superconductivity. 2 figs.

  19. Superconducting transistor

    DOEpatents

    Gray, Kenneth E.

    1979-01-01

    A superconducting transistor is formed by disposing three thin films of superconducting material in a planar parallel arrangement and insulating the films from each other by layers of insulating oxides to form two tunnel junctions. One junction is biased above twice the superconducting energy gap and the other is biased at less than twice the superconducting energy gap. Injection of quasiparticles into the center film by one junction provides a current gain in the second junction.

  20. Production of Seamless Superconducting Radio Frequency Cavities from Ultra-fine Grained Niobium, Phase II Final Report

    SciTech Connect

    Roy Crooks, Ph.D., P.E.

    2009-10-31

    The positron and electron linacs of the International Linear Collider (ILC) will require over 14,000, nine-cell, one meter length, superconducting radio frequency (SRF) cavities [ILC Reference Design Report, 2007]. Manufacturing on this scale will benefit from more efficient fabrication methods. The current methods of fabricating SRF cavities involve deep drawing of the halves of each of the elliptical cells and joining them by high-vacuum, electron beam welding, with at least 19 circumferential welds per cavity. The welding is costly and has undesirable effects on the cavity surfaces, including grain-scale surface roughening at the weld seams. Hydroforming of seamless tubes avoids welding, but hydroforming of coarse-grained seamless tubes results in strain-induced surface roughening. Surface roughness limits accelerating fields, because asperities prematurely exceed the critical magnetic field and become normal conducting. This project explored the technical and economic feasibility of an improved processing method for seamless tubes for hydroforming. Severe deformation of bulk material was first used to produce a fine structure, followed by extrusion and flow-forming methods of tube making. Extrusion of the randomly oriented, fine-grained bulk material proceeded under largely steady-state conditions, and resulted in a uniform structure, which was found to be finer and more crystallographically random than standard (high purity) RRR niobium sheet metal. A 165 mm diameter billet of RRR grade niobium was processed into five, 150 mm I.D. tubes, each over 1.8 m in length, to meet the dimensions used by the DESY ILC hydroforming machine. Mechanical properties met specifications. Costs of prototype tube production were approximately twice the price of RRR niobium sheet, and are expected to be comparable with economies of scale. Hydroforming and superconducting testing will be pursued in subsequent collaborations with DESY and Fermilab. SRF Cavities are used to construct

  1. Assessment of biological effects associated with magnetic fields from a superconducting magnetic energy storage plant: Final report. [Contains glossary

    SciTech Connect

    Tenforde, T.S.

    1986-04-01

    This report provides a detailed evaluation of the potential biological effects of fringe magnetic fields associated with a superconducting magnetic energy storage (SMES) plant. The aspects of magnetic fields that are discussed include mechanisms of interaction of static and slowly time-varying magnetic fields with living systems; biological effects of magnetic fields on human and subhuman species, including the results of both laboratory studies and human epidemiological surveys; physical hazards posed by the interactions of magnetic fields with metallic implants, e.g., aneurysm clips and prostheses, and with medical electronic devices such as cardiac pacemakers; extant guidelines for occupational exposure to magnetic fields are summarized; recommendations for defining acceptable levels of exposure to SMES magnetic fields by occupational personnel and the population-at-large; and recommendations concerning several areas of research that would further our understanding of magnetic field interactions with living systems, and would provide additional elements of information required for the development of future exposure standards. 328 refs., 12 figs., 5 tabs.

  2. Final Scientific/Technical Report: Electronics for Large Superconducting Tunnel Junction Detector Arrays for Synchrotron Soft X-ray Research

    SciTech Connect

    Warburton, William K

    2009-03-06

    Superconducting tunnel junction (STJ) detectors offer a an approach to detecting soft x-rays with energy resolutions 4-5 times better and at rates 10 faster than traditions semiconductor detectors. To make such detectors feasible, however, then need to be deployed in large arrays of order 1000 detectors, which in turn implies that their processing electronics must be compact, fully computer controlled, and low cost per channel while still delivering ultra-low noise performance so as to not degrade the STJ's performance. We report on our progress in designing a compact, low cost preamplifier intended for this application. In particular, we were able to produce a prototype preamplifier of 2 sq-cm area and a parts cost of less than $30 that matched the energy resolution of the best conventional system to date and demonstrated its ability to acquire an STJ I-V curve under computer control, the critical step for determining and setting the detectors' operating points under software control.

  3. Novel cryogen-free actively shielded superconducting magnets for maglev vehicles. Final report, August 1991-June 1992

    SciTech Connect

    Vermilyea, M.E.

    1992-06-01

    The report presents the results of a research effort into the design of a shielded superconducting magnet system for a maglev vehicle. The magnet design is based on a novel cryogen-free technology which allows operation without the use of any cryogenic fluids. This is accomplished by the use of a two-stage Gifford-McMahon (G-M) cryogenic refrigerator to provide cooling of the coil and a single cryostat thermal radiation shield by conduction. The design operating temperature of the magnet is 7.5 K, and that of the shield is 43 K. The magnet is wound with a tape form of niobium tin superconductor which allows operation at a module current density of 8100 A/sq cm at a flux density of 3.4 T at the 7.5 K temperature with a margin of 4.5 K to critical temperature. The magnet design is coupled with a linear synchronous motor and null-flux sidewall levitation system to provide a workable maglev system design. Costs for several components of the design, including coils and cryostat, shielding, and power conditioning apparatus are estimated.

  4. Beam-Based Alignment, Tuning and Beam Dynamics Studies for the ATF2 Extraction Line and Final Focus System

    SciTech Connect

    White, Glen R.; Molloy, S.; Woodley, M.; /SLAC

    2008-07-25

    Using a new extraction line currently under construction, the ATF2 experiment plans to test the novel compact final focus optics design with local chromaticity correction intended for use in future linear colliders. With a 1.3 GeV design beam of 30nm normalized vertical emittance extracted from the ATF damping ring, the primary goal is to achieve a vertical spot-size at the IP waist of 37nm. We discuss our planned strategy for tuning the ATF2 beam to meet the primary goal. Simulation studies have been performed to asses the effectiveness of the strategy, including 'static' (installation) errors and dynamical effects (ground-motion, mechanical vibration, ring extraction jitter etc.). We have simulated all steps in the tuning procedure, from initial orbit establishment to final IP spot-size tuning. Through a Monte Carlo study of 100's of simulation seeds we find we can achieve a spot-size within {approx}10% of the design optics value in at least 75% of cases. We also ran a simulation to study the long-term performance with the use of beam-based feedbacks.

  5. Superconductive radiofrequency window assembly

    DOEpatents

    Phillips, Harry Lawrence; Elliott, Thomas S.

    1998-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  6. Superconducting radiofrequency window assembly

    DOEpatents

    Phillips, Harry L.; Elliott, Thomas S.

    1997-01-01

    The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

  7. Superconducting Cable

    DOEpatents

    Hughey, Raburn L.; Sinha, Uday K.; Reece, David S.; Muller, Albert C.

    2005-03-08

    In order to provide a flexible oxide superconducting cable which is reduced in AC loss, tape-shaped superconducting wires covered with a stabilizing metal are wound on a flexible former. The superconducting wires are preferably laid on the former at a bending strain of not more than 0.2%. In laying on the former, a number of tape-shaped superconducting wires are laid on a core member in a side-by-side manner, to form a first layer. A prescribed number of tape-shaped superconducting wires are laid on top of the first layer in a side-by-side manner, to form a second layer. The former may be made of a metal, plastic, reinforced plastic, polymer, or a composite and provides flexibility to the superconducting wires and the cable formed therewith.

  8. Superconducting Cable

    DOEpatents

    Hughey, Raburn L.; Sinha, Uday K.; Reece, David S.; Muller, Albert C.

    2005-07-22

    In order to provide a flexible oxide superconducting cable which is reduced in AC loss, tape-shaped superconducting wires covered with a stabilizing metal are wound on a flexible former. The superconducting wires are preferably laid on the former at a bending strain of not more than 0.2%. In laying on the former, a number of tape-shaped superconducting wires are laid on a core member in a side-by-side manner, to form a first layer. A prescribed number of tape-shaped superconducting wires are laid on top of the first layer in a side-by-side manner, to form a second layer. The former may be made of a metal, plastic, reinforced plastic, polymer, or a composite and provides flexibility to the superconducting wires and the cable formed therewith.

  9. Compact injector with alternating phase focusing-interdigital H-mode linac and superconducting electron cyclotron resonance ion source for heavy ion cancer therapy

    NASA Astrophysics Data System (ADS)

    Hayashizaki, Noriyosu; Hattori, Toshiyuki; Matsui, Shinjiro; Tomizawa, Hiromitsu; Yoshida, Toru; Isokawa, Katsushi; Kitagawa, Atsushi; Muramatsu, Masayuki; Yamada, Satoru; Okamura, Masahiro

    2000-02-01

    We have researched a compact medical accelerator with low investment and running cost for the popularization of heavy ion cancer therapy. As the first step, the compact injector system has been investigated for a Heavy Ion Medical Accelerator in Chiba at National Institute of Radiological Sciences. The proposed new injector system consists of a 6 MeV/u interdigital H-mode (IH) linac of 3.1 m long and a 18 GHz superconducting electron cyclotron resonance (ECR) (SC-ECR) ion source. The IH linac with high power efficiency is appropriate to a medical and industrial injector system. Its beam trajectory was simulated and a prototype has been constructed. The SC-ECR ion source has been designed to realize lightweight and low power consumption and the mirror field distribution was estimated.

  10. SSC [Superconducting Super Collider] Project: Technical Training for the Future of Texas. Navarro College/Dallas Community College District. Final Report for Year One.

    ERIC Educational Resources Information Center

    Orsak, Charles; McGlohen, Patti J.

    The Superconducting Super Collider Laboratory (SSCL) is a national lab for research on the fundamental forces and constituents of the universe. A major part of the research will involve an oval ring 54 miles in circumference through which superconducting magnets will steer two beams of protons in opposite directions. In response to the…

  11. Superconducting Structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2005-09-13

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  12. Superconducting structure

    DOEpatents

    Kwon, Chuhee; Jia, Quanxi; Foltyn, Stephen R.

    2003-04-01

    A superconductive structure including a dielectric oxide substrate, a thin buffer layer of a superconducting material thereon; and, a layer of a rare earth-barium-copper oxide superconducting film thereon the thin layer of yttrium-barium-copper oxide, the rare earth selected from the group consisting of samarium, gadolinium, ytterbium, erbium, neodymium, dysprosium, holmium, lutetium, a combination of more than one element from the rare earth group and a combination of one or more elements from the rare earth group with yttrium, the buffer layer of superconducting material characterized as having chemical and structural compatibility with the dielectric oxide substrate and the rare earth-barium-copper oxide superconducting film is provided.

  13. Superconducting Meissner effect bearings for cryogenic turbomachines. Phase 2. Final report, 1 November 1989-28 February 1994

    SciTech Connect

    Valenzuela, J.A.; Martin, J.L.

    1994-02-01

    This is the final report of a Phase II SBIR project to develop Meissner effect bearings for miniature cryogenic turbomachines. The bearing system was designed for use in miniature cryogenic turboexpanders in reverse-Brayton-cycle cryocoolers. These cryocoolers are designed to cool sensors on satellites. Existing gas bearings for this application must run relatively warm, so the heat leak from the bearings down the overhung shaft and into the cold process gas imposes a penalty on the cycle efficiency. By using cold Meissner effect bearings, this heat leak could be minimized and the input power per unit of cooling for these cryocoolers could be reduced. Two bearings concepts were explored in this project. The first used an all-magnetic passive radial suspension to position the shaft over a range of temperatures from room temperature to 77 K. This bearing concept was proven feasible, but impractical for the miniature high-speed turbine application since it lacked the required shaft positioning accuracy. A second bearing concept was then developed, in which the Meissner effect bearings are combined with self-acting gas bearings. The Meissner effect bearing provides the additional stiffness and damping required to stabilize the shaft at low temperature, while the gas bearing provides the necessary accuracy to allow very small turbine tip clearances (5mm) and high speeds (>500,000 rDm).

  14. Macroscopic Models of Superconductivity

    NASA Astrophysics Data System (ADS)

    Chapman, S. J.

    Available from UMI in association with The British Library. Requires signed TDF. After giving a description of the basic physical phenomena to be modelled, we begin by formulating a sharp -interface free-boundary model for the destruction of superconductivity by an applied magnetic field, under isothermal and anisothermal conditions, which takes the form of a vectorial Stefan model similar to the classical scalar Stefan model of solid/liquid phase transitions and identical in certain two-dimensional situations. This model is found sometimes to have instabilities similar to those of the classical Stefan model. We then describe the Ginzburg-Landau theory of superconductivity, in which the sharp interface is 'smoothed out' by the introduction of an order parameter, representing the number density of superconducting electrons. By performing a formal asymptotic analysis of this model as various parameters in it tend to zero we find that the leading order solution does indeed satisfy the vectorial Stefan model. However, at the next order we find the emergence of terms analogous to those of 'surface tension' and 'kinetic undercooling' in the scalar Stefan model. Moreover, the 'surface energy' of a normal/superconducting interface is found to take both positive and negative values, defining Type I and Type II superconductors respectively. We discuss the response of superconductors to external influences by considering the nucleation of superconductivity with decreasing magnetic field and with decreasing temperature respectively, and find there to be a pitchfork bifurcation to a superconducting state which is subcritical for Type I superconductors and supercritical for Type II superconductors. We also examine the effects of boundaries on the nucleation field, and describe in more detail the nature of the superconducting solution in Type II superconductors--the so-called 'mixed state'. Finally, we present some open questions concerning both the modelling and analysis of

  15. Superconducting wind turbine generators

    NASA Astrophysics Data System (ADS)

    Abrahamsen, A. B.; Mijatovic, N.; Seiler, E.; Zirngibl, T.; Træholt, C.; Nørgård, P. B.; Pedersen, N. F.; Andersen, N. H.; Østergård, J.

    2010-03-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  16. Midwest Superconductivity Consortium

    SciTech Connect

    Liedl, G.L.

    1992-01-01

    The Midwest Superconductivity Consortium's, MISCON, mission is to advance the science and understanding of high {Tc} superconductivity. Programmatic research focuses upon key materials-related problems: synthesis and processing; and limiting features in transport phenomena. During the past twenty-one projects produced over eighty-seven talks and seventy-two publications. Key achievements this past year expand our understanding of processing phenomena relating to crystallization and texture, metal superconductor composites, and modulated microstructures. Further noteworthy accomplishments include calculations on 2-D superconductor insulator transition, prediction of flux line lattice melting, and an expansion of our understanding and use of microwave phenomena as related to superconductors.

  17. Final Report - Development of a Multi-Spoke Superconducting Cavity for Nuclear Physics, Light Sources, and Driven Systems Applications (ODU Contribution)

    SciTech Connect

    Delayen, Jean

    2014-11-14

    This report summarizes the work done by Old Dominion University, in collaboration with the Thomas Jefferson National Accelerator Facility toward the development of high-velocity superconducting spoke cavities.

  18. Final report: DOE Grant ''Development of focusing monochromators for neutron scattering instruments'' (DE-FG02-96ER45599)

    SciTech Connect

    Popovici, Mihai P.

    2000-03-21

    Bent crystal monochromators were developed for the neutron scattering community: (1) doubly focusing bulk silicon, for high-resolution neutron diffraction; (2) doubly focusing multi-wafer silicon, for residual stress instruments; (3) silicon-wafer: (a) with pneumatic spherical bending, (b) with mechanical cylindrical bending, (c) with mechanical two-dimensional bending, for high-resolution three-axis spectrometry; (4) doubly focusing multi-wafer silicon, for epithermal (eV range) neutrons; (5) doubly focusing composite pyrolytic graphite (low-cost), for high-flux applications.

  19. Superconducting Memristors

    NASA Astrophysics Data System (ADS)

    Peotta, Sebastiano; Di Ventra, Massimiliano

    2014-09-01

    In his original work, Josephson predicted that a phase-dependent conductance should be present in superconducting tunnel junctions, an effect difficult to detect, mainly because it is hard to single it out from the usual nondissipative Josephson current. We propose a solution for this problem that consists of using different superconducting materials to realize the two junctions of a superconducting interferometer. According to the Ambegaokar-Baratoff relation the two junctions have different conductances if the critical currents are equal, thus the Josephson current can be suppressed by fixing the magnetic flux in the loop at half of a flux quantum without canceling the phase-dependent conductance. Our proposal can be used to study the phase-dependent conductance, an effect present in principle in all superconducting weak links. From the standpoint of nonlinear circuit theory, such a device is in fact an ideal memristor with possible applications to memories and neuromorphic computing in the framework of ultrafast and low-energy-consumption superconducting digital circuits.

  20. Characterization of superconducting and magnetic materials with muon spin rotation and neutron scattering. Progress report, March 1996--August 1997 and final report, June 1988--August 1997

    SciTech Connect

    Stronach, C.E.; Noakes, D.R.

    1997-09-01

    This report represents the culmination of over nine years of research activity in the study of superconducting and magnetically ordered materials using the muon spin rotation ({mu}SR) and neutron scattering techniques. Because all the activities that took place up until March 1996 have been covered in previous annual reports, this final report includes only a brief overview of activities prior to that date, and concentrates on the period from March 1996 through August 1997. The primary activity undertaken in this project has been studies of high-temperature superconductors and their close chemical relatives with the {mu}SR technique. These experiments extend from early work done with a relatively primitive muon beam at the AGS of Brookhaven National Laboratory and large polycrystalline samples of the earliest known high-{Tc} materials to studies of very small high-purity single crystals of the best high-{Tc} materials currently available using the highest quality surface muon beams and specially-designed low-background spectrometers at the Tri-University Meson Facility (TRIUMF) in the past three years. During the period since the last annual report five {mu}SR experiments were done at TRIUMF with DOE support. A study of single-crystal high-temperature superconductors was done in July 1996. A study of the quasicrystal materials Gd{sub 8}Mg{sub 42}Zn{sub 50} and Tb{sub 8}Mg{sub 42}Zn{sub 50} was done by D.R. Noakes in collaboration with G.M. Kalvius of the Technical University of Munich and R. Waeppling of Uppsala University during the first week of December 1996. During the second week of December 1996 a study of the cryocrystals CH{sub 4} and CF{sub 4} was done by D.R. Noakes in collaboration with S. Storchak of Moscow State University and J.H. Brewer of the University of British Columbia. A study of high-{Tc} superconductors was done at TRIUMF during the third week of December 1996 by C.E. Stronach and D.R. Noakes.

  1. Superconductive articles

    SciTech Connect

    Wu, X.D.; Muenchausen, R.E.

    1991-12-31

    An article of manufacture including a substrate, a patterned interlayer of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of oxides of Ce, Y, Cm, Dy, Er, Eu, Fe, Gd, Ho, In, La, Mn, Lu, Nd, Pr, Pu, Sm, Tb, Tl, Tm, Y, and Yb over the entire exposed surface of the intermediate article, and, a ceramic superconductive material layer as an overcoat upon the buffer layer whereby the ceramic superconductive material situated directly above the substrate has a crystal structure substantially different than the ceramic superconductive material situated above the overcoated patterned interlayer.

  2. Solenoid-based focusing in a proton linac

    SciTech Connect

    Terechkine, I; DiMarco, J.; Schappert, W.; Sergatskov, d.; Tartaglia, M.; /Fermilab

    2010-09-01

    Development of solenoid-based focusing lenses for the transport channel of an R&D linac front end at FNAL (HINS linac) is in its final stage. Superconducting lenses for the room temperature RF section of the linac are assembled into individual cryostats and certified using a dedicated test stand. During this certification process, the optical axis of each lens relative to the cryogenic vessel is found in the warm and cold state. Lenses for the superconducting RF sections are ready for production, and development of a cryomodule (which contains multiple superconducting lenses and RF cavities) is in progress. Studies have been conducted to measure fringe magnetic field of a lens in the cryomodule, to investigate a laser-based method of alignment, and to evaluate the extent of beam quality degradation due to imperfections in lens construction and alignment. This report presents some results of these studies.

  3. Investigation of Generation, Acceleration, Transport and Final Focusing of High-Intensity Heavy Ion Beams from Sources to Targets

    SciTech Connect

    Chiping Chen

    2006-10-26

    Under the auspices of the research grant, the Intense Beam Theoretical Research Goup at Massachusetts Institute of Technology's Plasma Science and Fusion Center made significant contributions in a number of important areas in the HIF and HEDP research, including: (a) Derivation of rms envelope equations and study of rms envelope dynamics for high-intensity heavy ion beams in a small-aperture AG focusing transport systems; (b) Identification of a new mechanism for chaotic particle motion, halo formation, and beam loss in high-intensity heavy ion beams in a small-aperture AG focusing systems; Development of elliptic beam theory; (d) Study of Physics Issues in the Neutralization Transport Experiment (NTX).

  4. High pressure studies of superconductivity

    NASA Astrophysics Data System (ADS)

    Hillier, Narelle Jayne

    Superconductivity has been studied extensively since it was first discovered over 100 years ago. High pressure studies, in particular, have been vital in furthering our understanding of the superconducting state. Pressure allows researchers to enhance the properties of existing superconductors, to find new superconductors, and to test the validity of theoretical models. This thesis presents a series of high pressure measurements performed in both He-gas and diamond anvil cell systems on various superconductors and on materials in which pressure-induced superconductivity has been predicted. Under pressure the alkali metals undergo a radical departure from the nearly-free electron model. In Li this leads to a superconducting transition temperature that is among the highest of the elements. All alkali metals have been predicted to become superconducting under pressure. Pursuant to this, a search for superconductivity has been conducted in the alkali metals Na and K. In addition, the effect of increasing electron concentration on Li1-xMgx alloys has been studied. Metallic hydrogen and hydrogen-rich compounds are believed to be good candidates for high temperature superconductivity. High pressure optical studies of benzene (C6H6) have been performed to 2 Mbar to search for pressure-induced metallization. Finally, cuprate and iron-based materials are considered high-Tc superconductors. These layered compounds exhibit anisotropic behavior under pressure. Precise hydrostatic measurements of dTc/dP on HgBa2CuO 4+delta have been carried out in conjunction with uniaxial pressure experiments by another group. The results obtained provide insight into the effect of each of the lattice parameters on Tc. Finally, a series of hydrostatic and non-hydrostatic measurements on LnFePO (Ln = La, Pr, Nd) reveal startling evidence that the superconducting state in the iron-based superconductors is highly sensitive to lattice strain.

  5. Superconducting Microelectronics.

    ERIC Educational Resources Information Center

    Henry, Richard W.

    1984-01-01

    Discusses superconducting microelectronics based on the Josephson effect and its advantages over conventional integrated circuits in speed and sensitivity. Considers present uses in standards laboratories (voltage) and in measuring weak magnetic fields. Also considers future applications in superfast computer circuitry using Superconducting…

  6. University Commission on Human Relations: Focusing on Racism & Other Forms of Discrimination. Final Report. Volume II: Transcripts of Public Hearings.

    ERIC Educational Resources Information Center

    James, Olive C. R., Ed.; Matson, Hollis N., Ed.

    This volume contains transcripts of six public hearings held by the San Francisco State University Commission on Human Relations between September and December 1989. The first hearing focused on Asian Pacific Americans and received testimony on higher education admissions policies, treatment in equity programs, student services, health issues,…

  7. An experimental investigation of high temperature superconducting microstrip antennas at K- and Ka-band frequencies. Ph.D. Thesis Final Report

    NASA Technical Reports Server (NTRS)

    Richard, Mark A.

    1993-01-01

    The recent discovery of high temperature superconductors (HTS) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS results in narrow bandwidths and high patch edge impedances of such antennas. To investigate the performance of superconducting microstrip antennas, three antenna architectures at K and Ka-band frequencies are examined. Superconducting microstrip antennas that are directly coupled, gap coupled, and electromagnetically coupled to a microstrip transmission line were designed and fabricated on lanthanum aluminate substrates using YBa2Cu3O7 superconducting thin films. For each architecture, a single patch antenna and a four element array were fabricated. Measurements from these antennas, including input impedance, bandwidth, patterns, efficiency, and gain are presented. The measured results show usable antennas can be constructed using any of the architectures. All architectures show excellent gain characteristics, with less than 2 dB of total loss in the four element arrays. Although the direct and gap coupled antennas are the simplest antennas to design and fabricate, they suffer from narrow bandwidths. The electromagnetically coupled antenna, on the other hand, allows the flexibility of using a low permittivity substrate for the patch radiator, while using HTS for the feed network, thus increasing the bandwidth while effectively utilizing the low loss properties of HTS. Each antenna investigated in this research is the first of its kind reported.

  8. Analysis and potential of once-through steam generators in line focus systems - Final results of the DUKE project

    NASA Astrophysics Data System (ADS)

    Feldhoff, Jan Fabian; Hirsch, Tobias; Pitz-Paal, Robert; Valenzuela, Loreto

    2016-05-01

    The direct steam generation in line focus systems such as parabolic troughs and linear Fresnel collectors is one option for providing `solar steam' or heat. Commercial power plants use the recirculation concept, in which the steam generation is separated from the superheating by a steam drum. This paper analyzes the once-through mode as an advanced solar field concept. It summarizes the results of the DUKE project on loop design, a new temperature control strategy, thermo-mechanical stress analysis, and an overall cost analysis. Experimental results of the temperature control concept at the DISS test facility at Plataforma Solar de Almería are presented.

  9. High temperature interface superconductivity

    NASA Astrophysics Data System (ADS)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  10. High temperature interface superconductivity

    DOE PAGESBeta

    Gozar, A.; Bozovic, I.

    2016-01-20

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. Here, wemore » conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.« less

  11. Superconducting pipes and levitating magnets.

    PubMed

    Levin, Yan; Rizzato, Felipe B

    2006-12-01

    Motivated by a beautiful demonstration of the Faraday and the Lenz laws in which a small neodymium magnet falls slowly through a conducting nonferromagnetic tube, we consider the dynamics of a magnet falling coaxially through a superconducting pipe. Unlike the case of normal conducting pipes, in which the magnet quickly reaches the terminal velocity, inside a superconducting tube the magnet falls freely. On the other hand, to enter the pipe the magnet must overcome a large electromagnetic energy barrier. For sufficiently strong magnets, the barrier is so large that the magnet will not be able to penetrate it and will be levitated over the mouth of the pipe. We calculate the work that must done to force the magnet to enter a superconducting tube. The calculations show that superconducting pipes are very efficient at screening magnetic fields. For example, the magnetic field of a dipole at the center of a short pipe of radius a and length L approximately > a decays, in the axial direction, with a characteristic length xi approximately 0.26a. The efficient screening of the magnetic field might be useful for shielding highly sensitive superconducting quantum interference devices. Finally, the motion of the magnet through a superconducting pipe is compared and contrasted to the flow of ions through a trans-membrane channel. PMID:17280160

  12. Superconducting pipes and levitating magnets

    NASA Astrophysics Data System (ADS)

    Levin, Yan; Rizzato, Felipe B.

    2006-12-01

    Motivated by a beautiful demonstration of the Faraday and the Lenz laws in which a small neodymium magnet falls slowly through a conducting nonferromagnetic tube, we consider the dynamics of a magnet falling coaxially through a superconducting pipe. Unlike the case of normal conducting pipes, in which the magnet quickly reaches the terminal velocity, inside a superconducting tube the magnet falls freely. On the other hand, to enter the pipe the magnet must overcome a large electromagnetic energy barrier. For sufficiently strong magnets, the barrier is so large that the magnet will not be able to penetrate it and will be levitated over the mouth of the pipe. We calculate the work that must done to force the magnet to enter a superconducting tube. The calculations show that superconducting pipes are very efficient at screening magnetic fields. For example, the magnetic field of a dipole at the center of a short pipe of radius a and length L≳a decays, in the axial direction, with a characteristic length ξ≈0.26a . The efficient screening of the magnetic field might be useful for shielding highly sensitive superconducting quantum interference devices. Finally, the motion of the magnet through a superconducting pipe is compared and contrasted to the flow of ions through a trans-membrane channel.

  13. Color superconductivity

    SciTech Connect

    Wilczek, F.

    1997-09-22

    The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken.

  14. SUPERCONDUCTING PHOTOINJECTOR

    SciTech Connect

    BEN-ZVI,I.; BURRILL, A.; CALAGA, R.; CHANG, X.; GROVER, R.; GUPTA, R.; HAHN, H.; HAMMONS, L.; KAYRAN, D.; KEWISCH, J.; LAMBIASE, R.; LITVINENKO, V.; MCINTYRE, G.; NAIK, D.; PATE, D.; PHILLIPS, D.; POZDEYEV, E.; RAO, T.; SMEDLEY, J.; THAN, R.; TODD, R.; WEISS, D.; WU, Q.; ZALTSMAN, A.; ET AL.

    2007-08-26

    One of the frontiers in FEL science is that of high power. In order to reach power in the megawatt range, one requires a current of the order of one ampere with a reasonably good emittance. The superconducting laser-photocathode RF gun with a high quantum efficiency photocathode is the most natural candidate to provide this performance. The development of a 1/2 cell superconducting photoinjector designed to operate at up to a current of 0.5 amperes and beam energy of 2 MeV and its photocathode system are the subjects covered in this paper. The main issues are the photocathode and its insertion mechanism, the power coupling and High Order Mode damping. This technology is being developed at BNL for DOE nuclear physics applications such as electron cooling at high energy and electron ion colliders..

  15. GYMNOS Modeling of Electron Beam Dynamics for the Injector and Final Focus Regions of the ETA-II Accelerator

    NASA Astrophysics Data System (ADS)

    Kueny, C. S.; Wang, L.-F.; Chen, Y.-J.; Hewett, D. W.

    1999-11-01

    The 2-D axisymmetric PIC code GYMNOS has been used to model electron beam dynamics in the ETA-II accelerator at LLNL. Experiments on ETA-II seek to produce a high-brightness, low-emittance electron beam and deliver it to an X-ray converter target. These experiments are relevant to the DARHT II (Dual Axis Radiography Hydrodynamic Test) and AHF (Advanced Hydrotest Facility) projects, which will provide X-ray radiography diagnostics as part of the US Science-Based Stockpile Stewardship Program. We present simulations of both the ETA-II injector which produces the initial beam, and of the target region where X-ray generation occurs. GYMNOS employs the Embedded Curved Boundary (ECB) model to provide accurate beam modeling near the injector cathode and the target surfaces, and was recently upgraded with a non-uniform mesh to efficiently model the beam over a range of spatial scales. Modeling of the ETA-II injector has provided guidance on experimental parameters necessary for producing a high-quality beam for transport through the accelerator. Simulations of the target region have modeled the effects of backstreaming ions and backscattered electrons on beam dynamics, and investigated possible measures to minimize degradation in beam quality and final spot size.

  16. FY06 LDRD Final Report Next-generation x-ray optics: focusing hard x-rays

    SciTech Connect

    Pivovaroff, M; Soufli, R

    2007-03-01

    The original goal of our research was to open up a new class of scientific experiments by increasing the power of newly available x-ray sources by orders of magnitude. This was accomplished by developing a new generation of x-ray optics, based on hard x-ray (10-200 keV) reflective and diffractive focusing elements. The optical systems we envision begin with a core reflective optic, which has the ability to capture and concentrate x-rays across a wide range of energies and angles band, combined with diffractive optics, based on large-scale multilayer structures, that will further enhance the spatial, spectral and temporal resolving power of the system. Enabling technologies developed at LLNL such as precise mounting of thermally formed substrates, smoothing techniques and multilayer films of ultra-high reflectance and precision were crucial in the development and demonstration of our research objectives. Highlights of this phase of the project include: the design and fabrication of a concentrator optic for the Pleiades Thomson X-ray source located at LLNL, smoothing of glass substrates through application of polyimide films, and the design, fabrication and testing of novel volume multilayers structures. Part of our research into substrate smooth led to the development of a new technique (patent pending) to construct high-quality, inexpensive x-ray optics. This innovation resulted in LLNL constructing a x-ray optic for the CERN Axion Solar Telescope (CAST) and allowed LLNL to join the international experiment.

  17. Improved Hydrogen Gas Getters for TRU Waste Transuranic and Mixed Waste Focus Area - Phase 2 Final Report

    SciTech Connect

    Stone, Mark Lee

    2002-04-01

    Alpha radiolysis of hydrogenous waste and packaging materials generates hydrogen gas in radioactive storage containers. For that reason, the Nuclear Regulatory Commission (NRC) limits the flammable gas (hydrogen) concentration in the Transuranic Package Transporter-II (TRUPACT-II) containers to 5 vol% of hydrogen in air, which is the lower explosion limit. Consequently, a method is needed to prevent the build up of hydrogen to 5 vol% during the storage and transport of the TRUPACT-II containers (up to 60 days). One promising option is the use of hydrogen getters. These materials scavenge hydrogen from the gas phase and irreversibly bind it in the solid phase. One proven getter is a material called 1,4-bis (phenylethynyl) benzene, or DEB. It has the needed binding rate and capacity, but some of the chemical species that might be present in the containers could interfere with its ability to remove hydrogen. This project is focused upon developing a protective polymeric membrane coating for the DEB getter material, which comes in the form of small, irregularly shaped particles. This report summarizes the experimental results of the second phase of the development of the materials.

  18. Superconducting quadrupoles

    SciTech Connect

    McInturff, A.D.

    1985-07-01

    The data base for this paper will represent the work from two different groups and two different Laboratories (Brookhaven National Laboratory and Fermi National Accelerator Laboratory). The majority of the data was that obtained by the Fermi National Accelerator Group and is the most recent, and is based on a larger number of coil windings. The coil winding sizes that will be discussed are 12 cm, (Figure 1) 7.6 cm and 5 cm, (Figure 2) for the inner diameter. The maximum gradients measured in the 5 cm sizes were 1.93 T/cm at 3.5 K and 1.79 T/cm at 4.2 K. In the 7.6 cm size were 1.35 T/cm at 2.0 K and 1.1 T/cm at 4.2 K and in the 12.0 cm size was 1.35 T/cm at 4.2 K. The 12 cm size used a cold iron shield, but had an older conductor, so one effect (increase due to Fe) offset the other (lower J/sub c/ (H) of the earlier superconductor). These gradients (especially the 12 cm measurements) can be improved using more modern conductors, (i.e., approx.20% + g/(cm A) and their higher current densities. These gradients represent an increase of 2 to 3+ times the value obtainable using conventional iron and copper magnets at a comparable aperature. The original purposes for these coils were for the 12 cm size, the Isabelle lattice, the 7.6 cm size, the Tevatron lattice and low ..beta.. insertion focus, and the 5 cm size, the final focus of SLC at SLAC and SSC size coils.

  19. US Navy superconductivity program

    NASA Technical Reports Server (NTRS)

    Gubser, Donald U.

    1991-01-01

    Both the new high temperature superconductors (HTS) and the low temperature superconductors (LTS) are important components of the Navy's total plan to integrate superconductivity into field operational systems. Fundamental research is an important component of the total Navy program and focuses on the HTS materials. Power applications (ship propulsion) use LTS materials while space applications (millimeter wave electronics) use HTS materials. The Space Experiment to be conducted at NRL will involve space flight testing of HTS devices built by industry and will demonstrate the ability to engineer and space qualify these devices for systems use. Another important component of the Navy's effort is the development of Superconducting Quantum Interference Device (SQUID) magnetometers. This program will use LTS materials initially, but plans to implement HTS materials as soon as possible. Hybrid HTS/LTS systems are probable in many applications. A review of the status of the Navy's HTS materials research is given as well as an update on the Navy's development efforts in superconductivity.

  20. Navy superconductivity efforts

    NASA Technical Reports Server (NTRS)

    Gubser, D. U.

    1990-01-01

    Both the new high temperature superconductors (HTS) and the low temperature superconductors (LTS) are important components of Navy's total plan to integrate superconductivity into field operational systems. Fundamental research is an important component of the total Navy program and focuses on the HTS materials. Power applications (ship propulsion, etc.) use LTS materials while space applications (MMW electronics, etc.) use HTS materials. The Space Experiment being conducted at NRL will involve space flight testing of HTS devices built by industry and will demonstrate the ability to engineer and space qualify these devices for systems use. Another important component of the Navy's effort is the development of Superconducting Quantum Interference Device (SQUID) magnetometers. This program will use LTS materials initially, but plans to implement HTS materials as soon as possible. Hybrid HTS/LTS systems are probable in many applications. A review of the status of the Navy's HTS materials research is given as well as an update on the Navy's development efforts in superconductivity, with particular emphasis on the related SDIO sponsored program on HTS applications.

  1. 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.

  2. Space applications of superconductivity

    NASA Technical Reports Server (NTRS)

    Sullivan, D. B.; Vorreiter, J. W.

    1979-01-01

    Some potential applications of superconductivity in space are summarized, e.g., the use of high field magnets for cosmic ray analysis or energy storage and generation, space applications of digital superconducting devices, such as the Josephson switch and, in the future, a superconducting computer. Other superconducting instrumentation which could be used in space includes: low frequency superconducting sensors, microwave and infrared detectors, instruments for gravitational studies, and high-Q cavities for use as stabilizing elements in clocks and oscillators.

  3. Superconducting electron and hole lenses

    NASA Astrophysics Data System (ADS)

    Cheraghchi, H.; Esmailzadeh, H.; Moghaddam, A. G.

    2016-06-01

    We show how a superconducting region (S), sandwiched between two normal leads (N), in the presence of barriers, can act as a lens for propagating electron and hole waves by virtue of the so-called crossed Andreev reflection (CAR). The CAR process, which is equivalent to Cooper pair splitting into two N electrodes, provides a unique possibility of constructing entangled electrons in solid state systems. When electrons are locally injected from an N lead, due to the CAR and normal reflection of quasiparticles by the insulating barriers at the interfaces, sequences of electron and hole focuses are established inside another N electrode. This behavior originates from the change of momentum during electron-hole conversion beside the successive normal reflections of electrons and holes due to the barriers. The focusing phenomena studied here are fundamentally different from the electron focusing in other systems, such as graphene p-n junctions. In particular, due to the electron-hole symmetry of the superconducting state, the focusing of electrons and holes is robust against thermal excitations. Furthermore, the effects of the superconducting layer width, the injection point position, and barrier strength are investigated on the focusing behavior of the junction. Very intriguingly, it is shown that by varying the barrier strength, one can separately control the density of electrons or holes at the focuses.

  4. Exotic Superconductivity in Correlated Electron Systems

    DOE PAGESBeta

    Mu, Gang; Sandu, Viorel; Li, Wei; Shen, Bing

    2015-05-25

    Over the past decades, the search for high-Tc superconductivity (SC) and its novel superconducting mechanisms is one of the most challenging tasks of condensed matter physicists and material scientists, wherein the most striking achievement is the discovery of high-c and unconventional superconductivity in strongly correlated 3d-electron systems, such as cuprates and iron pnictides/chalcogenides. Those exotic superconductors display the behaviors beyond the scope of the BCS theory (in the SC states) and the Landau-Fermi liquid theory (in the normal states). In general, such exotic superconductivity can be seen as correlated electron systems, where there are strong interplays among charge, spin, orbital,more » and lattice degrees of freedom. Thus, we focus on the exotic superconductivity in materials with correlated electrons in the present special issue.« less

  5. Exotic Superconductivity in Correlated Electron Systems

    SciTech Connect

    Mu, Gang; Sandu, Viorel; Li, Wei; Shen, Bing

    2015-05-25

    Over the past decades, the search for high-Tc superconductivity (SC) and its novel superconducting mechanisms is one of the most challenging tasks of condensed matter physicists and material scientists, wherein the most striking achievement is the discovery of high-c and unconventional superconductivity in strongly correlated 3d-electron systems, such as cuprates and iron pnictides/chalcogenides. Those exotic superconductors display the behaviors beyond the scope of the BCS theory (in the SC states) and the Landau-Fermi liquid theory (in the normal states). In general, such exotic superconductivity can be seen as correlated electron systems, where there are strong interplays among charge, spin, orbital, and lattice degrees of freedom. Thus, we focus on the exotic superconductivity in materials with correlated electrons in the present special issue.

  6. Recent Progress in the Superconductivity Research Field

    NASA Astrophysics Data System (ADS)

    Ichinose, Ataru

    Major developments in the research field of superconductivity have been achieved in 2008. Since the discovery of high-Tc superconductors, their practical application has been studied by many researchers. Coated conductors consisting of an YBa2Cu3Oy superconducting layer deposited on metal tapes buffered oxide layers were developed in the NEDO project between FY2003 and FY2007. These technologies for coated conductors are expected to be applicable to electrical power equipment. A new NEDO project that started in FY2008 is focusing on the development of superconducting electric power equipment such as power cables, superconducting magnetic energy storage devices (SMES) and transformers. Furthermore, a new family of high-Tc superconductors, Fe-As-O-based superconductors, has been discovered. The highest reported critical temperature, Tc, has rapidly increased owing to the considerable effort of many researchers. A new social environment based on superconductivity technology might indeed be realized in the near future.

  7. 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.

  8. Superconducting wire and cable for RHIC

    SciTech Connect

    Garber, M.; Ghosh, A.K.; Greene, A.; McChesney, D.; Morgillo, A.; Shah, R.; DelRe, S.; Epstein, G.; Hong, S.; Lichtenwalner, J.

    1994-06-01

    The superconducting dipole and quadrupole magnets in the RHIC accelerator ring are to be fabricated from 30-strand superconducting cable. The RHIC wire has a diameter of 0.65 mm, copper-to-superconductor ratio of 2.25, filament diameter of 6 {mu}m and high critical current density. Primary emphasis during manufacturing has been on uniformity of materials, processes and performance. Near final results are presented on a production program which has extended over two years. Measured parameters are described which are important for design of superconducting accelerator magnets.

  9. A PROCEDURE TO SET PHASE AND AMPLITUDE OF THE RF IN THE SNS LINAC'S SUPERCONDUCTING CAVITIES

    SciTech Connect

    L.M. YOUNG

    2001-06-01

    This paper describes a procedure to set the phase and amplitude of the RF fields in the Spallation Neutron Source (SNS) linac's superconducting cavities. The linac uses superconducting cavities to accelerate the H{sup -} ion beam from the normal conducting linac at 185 MeV to a final energy of {approx}1 GeV. There are two types of cavities in the linac, 33 cavities with a geometric beta of 0.61 and 48 cavities with a geometric beta of 0.81. The correct phase setting of any single superconducting cavity depends on the RF phase and amplitude of all the preceding superconducting cavities. For the beam to be properly accelerated it must arrive at each cavity with a relative phase ({phi}{sub s}), called the synchronous phase, of about -20 degrees. That is, it must arrive early with respect to the phase at which it would gain the maximum energy by 20 degrees. This timing provides the longitudinal focusing. Beam particles arriving slightly later gain more energy and move faster relative to the synchronous beam particle. The problem is to set the phase and amplitude of each cavity in the linac so that the synchronous particle arrives at each cavity with the correct phase. The amplitude of each superconducting cavity will be adjusted as high as possible constrained only by the available RF power and the breakdown field of the cavity.

  10. Superconductivity close to the Mott state: From condensed-matter systems to superfluidity in optical lattices

    SciTech Connect

    Le Hur, Karyn Maurice Rice, T.

    2009-07-15

    Since the discovery of high-temperature superconductivity in 1986 by Bednorz and Mueller, great efforts have been devoted to finding out how and why it works. From the d-wave symmetry of the order parameter, the importance of antiferromagnetic fluctuations, and the presence of a mysterious pseudogap phase close to the Mott state, one can conclude that high-T{sub c} superconductors are clearly distinguishable from the well-understood BCS superconductors. The d-wave superconducting state can be understood through a Gutzwiller-type projected BCS wavefunction. In this review article, we revisit the Hubbard model at half-filling and focus on the emergence of exotic superconductivity with d-wave symmetry in the vicinity of the Mott state, starting from ladder systems and then studying the dimensional crossovers to higher dimensions. This allows to confirm that short-range antiferromagnetic fluctuations can mediate superconductivity with d-wave symmetry. Ladders are also nice prototype systems allowing to demonstrate the truncation of the Fermi surface and the emergence of a Resonating Valence Bond (RVB) state with preformed pairs in the vicinity of the Mott state. In two dimensions, a similar scenario emerges from renormalization group arguments. We also discuss theoretical predictions for the d-wave superconducting phase as well as the pseudogap phase, and address the crossover to the overdoped regime. Finally, cold atomic systems with tunable parameters also provide a complementary insight into this outstanding problem.

  11. 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.

  12. Experimental Investigation of Magnetic, Superconducting, and other Phase Transitions in novel F-Electron Materials at Ultra-high Pressures - Final Progress Report

    SciTech Connect

    Maple, Brian; Jeffires, Jason

    2006-07-28

    This grant, entitled “Experimental investigation of magnetic, superconducting and other phase transitions in novel f-electron materials at ultrahigh pressures,” spanned the funding period from May 1st, 2003 until April 30th, 2006. The major goal of this grant was to develop and utilize an ultrahigh pressure facility—capable of achieving very low temperatures, high magnetic fields, and extreme pressures as well as providing electrical resistivity, ac susceptibility, and magnetization measurement capabilities under pressure—for the exploration of magnetic, electronic, and structural phases and any corresponding interactions between these states in novel f-electron materials. Realizing this goal required the acquisition, development, fabrication, and implementation of essential equipment, apparatuses, and techniques. The following sections of this report detail the establishment of an ultrahigh pressure facility (Section 1) and measurements performed during the funding period (Section 2), as well as summarize the research project (Section 3), project participants and their levels of support (Section 4), and publications and presentations (Section 5).

  13. Superconductivity in transuranium elements and compounds

    NASA Astrophysics Data System (ADS)

    Griveau, Jean-Christophe; Colineau, Éric

    2014-08-01

    We present here an overview of the properties of transuranium superconductors, but also of the (non-superconducting) transuranium analogues of uranium superconductors. We briefly review superconductivity in actinide elements and uranium compounds and focus in particular on the PuTX5 (T=Co,Rh; X=Ga,In) series, the largest superconducting system in actinides and NpPd5Al2, the so far unique neptunium superconductor. The effects of chemical substitution, ageing and pressure on the properties of transuranium superconductors are also discussed. xml:lang="fr"

  14. Superconductivity in Pd, Ir, and Pt chalcogenide

    NASA Astrophysics Data System (ADS)

    Oh, Yoon Seok; Yang, Junjie; Choi, Y. J.; Hogan, A.; Horibe, Y.; Cheong, S.-W.

    2012-02-01

    Large spin-orbit coupling in materials with heavy chalcogens can result in unique quantum states or functional properties such as topological insulator, giant thermoelectric power, and superconductivity. When materials contain heavy cations in addition to heavy chalcogens, spin-orbit coupling can be further enhanced. For these reasons, we have studied the superconductivity of Pd, Ir, and Pt tellurides and selenides. In the exploration of these chalcogenides, we have focused on the competition between superconductivity and charge density wave that is associated with superlattice reflections.

  15. Driven superconducting quantum circuits

    NASA Astrophysics Data System (ADS)

    Nakamura, Yasunobu

    2014-03-01

    Driven nonlinear quantum systems show rich phenomena in various fields of physics. Among them, superconducting quantum circuits have very attractive features such as well-controlled quantum states with design flexibility, strong nonlinearity of Josephson junctions, strong coupling to electromagnetic driving fields, little internal dissipation, and tailored coupling to the electromagnetic environment. We have investigated properties and functionalities of driven superconducting quantum circuits. A transmon qubit coupled to a transmission line shows nearly perfect spatial mode matching between the incident and scattered microwave field in the 1D mode. Dressed states under a driving field are studied there and also in a semi-infinite 1D mode terminated by a resonator containing a flux qubit. An effective Λ-type three-level system is realized under an appropriate driving condition. It allows ``impedance-matched'' perfect absorption of incident probe photons and down conversion into another frequency mode. Finally, the weak signal from the qubit is read out using a Josephson parametric amplifier/oscillator which is another nonlinear circuit driven by a strong pump field. This work was partly supported by the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST), Project for Developing Innovation Systems of MEXT, MEXT KAKENHI ``Quantum Cybernetics,'' and the NICT Commissioned Research.

  16. 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.

  17. Development work for a superconducting linear collider

    NASA Technical Reports Server (NTRS)

    Matheisen, Axel

    1995-01-01

    For future linear e(+)e(-) colliders in the TeV range several alternatives are under discussion. The TESLA approach is based on the advantages of superconductivity. High Q values of the accelerator structures give high efficiency for converting RF power into beam power. A low resonance frequency for the RF structures can be chosen to obtain a large number of electrons (positrons) per bunch. For a given luminosity the beam dimensions can be chosen conservatively which leads to relaxed beam emittance and tolerances at the final focus. Each individual superconducting accelerator component (resonator cavity) of this linear collider has to deliver an energy gain of 25 MeV/m to the beam. Today s.c. resonators are in use at CEBAF/USA, at DESY/Germany, Darmstadt/Germany KEK/Japan and CERN/Geneva. They show acceleration gradients between 5 MV/m and 10 MV/m. Encouraging experiments at CEA Saclay and Cornell University showed acceleration gradients of 20 MV/m and 25 MV/m in single and multicell structures. In an activity centered at DESY in Hamburg/Germany the TESLA collaboration is constructing a 500 MeV superconducting accelerator test facility (TTF) to demonstrate that a linear collider based on this technique can be built in a cost effective manner and that the necessary acceleration gradients of more than 15 MeV/m can be reached reproducibly. The test facility built at DESY covers an area of 3.000 m2 and is divided into 3 major activity areas: (1) The testlinac, where the performance ofthe modular components with an electron beam passing the 40 m long acceleration section can be demonstrated. (2) The test area, where all individual resonators are tested before installation into a module. (3) The preparation and assembly area, where assembly of cavities and modules take place. We report here on the design work to reach a reduction of costs compared to actual existing superconducting accelerator structures and on the facility set up to reach high acceleration gradients in

  18. Simple Superconducting "Permanent" Electromagnet

    NASA Technical Reports Server (NTRS)

    Israelson, Ulf E.; Strayer, Donald M.

    1992-01-01

    Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.

  19. Protective link for superconducting coil

    DOEpatents

    Umans, Stephen D.

    2009-12-08

    A superconducting coil system includes a superconducting coil and a protective link of superconducting material coupled to the superconducting coil. A rotating machine includes first and second coils and a protective link of superconducting material. The second coil is operable to rotate with respect to the first coil. One of the first and second coils is a superconducting coil. The protective link is coupled to the superconducting coil.

  20. PREFACE: 11th European Conference on Applied Superconductivity (EUCAS2013)

    NASA Astrophysics Data System (ADS)

    Farinon, Stefania; Pallecchi, Ilaria; Malagoli, Andrea; Lamura, Gianrico

    2014-05-01

    During the 11th edition of the European Conference on Applied Superconductivity, successfully held in Genoa from 15-19 September 2013, more than one thousand participants from over 40 countries were registered and contributions of 7 plenary lectures, 23 invited talks, 203 oral talks and 550 posters were presented. The present issue of Journal of Physics: Conference Series (JPCS) collects the 218 submitted papers that were peer reviewed and accepted in the Conference Proceedings. Similarly to the Superconductor Science and Technology Special issue: ''EUCAS 11th European Conference on Applied Superconductivity'' which contains some plenary and invited contributions, as well as some selected contributions, in this issue the papers are sorted according to the four traditional topics of interest of EUCAS, namely Materials (56 papers), Wires and Tapes (47 papers), Large Scale Applications (64 papers) and Electronics (51 papers). While the it Superconductors Science and Technology special issue focuses on the scientific and technological highlights of the conference, this collection provides an overall view of the worldwide research activity on applied superconductivity, mirroring the main guidelines and the hottest issues, which range from basic studies on newly discovered superconducting compounds to the state-of-the-art advances in large scale applications, wires and tapes fabrication and electronics. We would like to point out that, among the JPCS contributions, six papers present works financed by ongoing EU-Japan projects, three papers belong to the session on junctions and SQUIDs dedicated to the memory of Antonio Barone and one paper belongs to the session on pinning and flux dynamics dedicated to the memory of John Clem. Finally, we would like to thank all the people whose careful work contributed to the preparation of this JPCS issue, in particular the session chairs as well as the peer reviewers. The Editors Stefania Farinon (Editor in Chief, Large Scale

  1. Superconductivity in transition metals.

    PubMed

    Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

    2015-03-13

    A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. PMID:25666075

  2. High-temperature superconductivity in iron pnictides and chalcogenides

    NASA Astrophysics Data System (ADS)

    Si, Qimiao; Yu, Rong; Abrahams, Elihu

    2016-04-01

    Superconductivity develops in metals upon the formation of a coherent macroscopic quantum state of electron pairs. Iron pnictides and chalcogenides are materials that have high superconducting transition temperatures. In this Review, we describe the advances in the field that have led to higher superconducting transition temperatures in iron-based superconductors and the wide range of materials that are used to form these superconductors. We summarize the essential aspects of the normal state and the mechanism for superconductivity. We emphasize the degree of electron–electron correlations and their manifestation in properties of the normal state. We examine the nature of magnetism, analyse its role in driving the electronic nematicity and discuss quantum criticality at the border of magnetism in the phase diagram. Finally, we review the amplitude and structure of the superconducting pairing, and survey the potential material settings for optimizing superconductivity.

  3. A Course on Applied Superconductivity Shared by Four Departments

    ERIC Educational Resources Information Center

    Jensen, Bogi B.; Abrahamsen, Asger B.; Sorensen, Mads P.; Hansen, Jorn B.

    2013-01-01

    In this paper, a course on applied superconductivity is described. The course structure is outlined and the learning objectives and the learning activities are described. The teaching was multidisciplinary given by four departments each contributing with their expertise. Being applied superconductivity, the focus was on an application, which could…

  4. Superconductivity in the metallic elements at high pressures

    NASA Astrophysics Data System (ADS)

    Hamlin, J. J.

    2015-07-01

    Although the highest superconducting critical temperature, Tc , found in an elemental solid at ambient pressure is 9.2 K (niobium), under the application of ultra-high pressures, several elements exhibit Tc values near or above 20 K. This review includes a survey of the occurrence and understanding of pressure-induced superconductivity in the subset of elements that are metallic at ambient pressure. A particular focus is directed towards those elements that display the highest superconducting critical temperatures or exhibit substantial increases in Tc with pressure. A separate article in this issue by Shimizu will cover pressure-induced superconductivity in elements that are insulating at ambient pressure.

  5. Superconducting levitating bearing

    NASA Technical Reports Server (NTRS)

    Moon, Francis C. (Inventor)

    1996-01-01

    A superconducting bearing assembly includes a coil field source that may be superconducting and a superconducting structure. The coil field source assembly and superconducting structure are positioned so as to enable relative rotary movement therebetween. The structure and coil field source are brought to a supercooled temperature before a power supply induces a current in the coil field source. A Meissner-like effect is thereby obtained and little or no penetration of the field lines is seen in the superconducting structure. Also, the field that can be obtained from the superconducting coil is 2-8 times higher than that of permanent magnets. Since the magnetic pressure is proportioned to the square of the field, magnetic pressures from 4 to 64 times higher are achieved.

  6. High-Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  7. High Temperature Superconducting Materials Database

    National Institute of Standards and Technology Data Gateway

    SRD 149 NIST High Temperature Superconducting Materials Database (Web, free access)   The NIST High Temperature Superconducting Materials Database (WebHTS) provides evaluated thermal, mechanical, and superconducting property data for oxides and other nonconventional superconductors.

  8. Superconductive imaging surface magnetometer

    DOEpatents

    Overton, Jr., William C.; van Hulsteyn, David B.; Flynn, Edward R.

    1991-01-01

    An improved pick-up coil system for use with Superconducting Quantum Interference Device gradiometers and magnetometers involving the use of superconducting plates near conventional pick-up coil arrangements to provide imaging of nearby dipole sources and to deflect environmental magnetic noise away from the pick-up coils. This allows the practice of gradiometry and magnetometry in magnetically unshielded environments. One embodiment uses a hemispherically shaped superconducting plate with interior pick-up coils, allowing brain wave measurements to be made on human patients. another embodiment using flat superconducting plates could be used in non-destructive evaluation of materials.

  9. Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole.

    SciTech Connect

    He,P.; Anerella, M.; aydin, S.; Ganetis, G. Harrison, M.; Jain, A.; Parker, B.

    2007-06-25

    The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations in a spare RHIC quadrupole magnet under cryogenic conditions. Some preliminary results of these studies were limited in resolution due to a rather large motion of the laser head as well as the magnet. As a first step towards improving the measurement quality, a new set up was used that reduces the motion of the laser holder. The improved setup is described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, are presented.

  10. 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.

  11. Superconducting circuitry for quantum electromechanical systems

    NASA Astrophysics Data System (ADS)

    LaHaye, Matthew D.; Rouxinol, Francisco; Hao, Yu; Shim, Seung-Bo; Irish, Elinor K.

    2015-05-01

    Superconducting systems have a long history of use in experiments that push the frontiers of mechanical sensing. This includes both applied and fundamental research, which at present day ranges from quantum computing research and e orts to explore Planck-scale physics to fundamental studies on the nature of motion and the quantum limits on our ability to measure it. In this paper, we first provide a short history of the role of superconducting circuitry and devices in mechanical sensing, focusing primarily on efforts in the last decade to push the study of quantum mechanics to include motion on the scale of human-made structures. This background sets the stage for the remainder of the paper, which focuses on the development of quantum electromechanical systems (QEMS) that incorporate superconducting quantum bits (qubits), superconducting transmission line resonators and flexural nanomechanical elements. In addition to providing the motivation and relevant background on the physical behavior of these systems, we discuss our recent efforts to develop a particular type of QEMS that is based upon the Cooper-pair box (CPB) and superconducting coplanar waveguide (CPW) cavities, a system which has the potential to serve as a testbed for studying the quantum properties of motion in engineered systems.

  12. Superconductivity in bad metals

    SciTech Connect

    Emery, V.J.; Kivelson, S.A.

    1995-12-31

    It is argued that many synthetic metals, including high temperature superconductors are ``bad metals`` with such a poor conductivity that the usual mean-field theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. Some consequences for high temperature superconductors are described.

  13. Superconducting gyroscope research

    NASA Technical Reports Server (NTRS)

    Hendricks, J. B.; Karr, G. R.

    1985-01-01

    Four basic areas of research and development of superconducting gyroscopes are studied. Chapter 1 studies the analysis of a SQUID readout for a superconducting gyroscope. Chapter 2 studies the dependence of spin-up torque on channel and gas properties. Chapter 3 studies the theory of super fluid plug operation. And chapter 4 studies the gyro rotor and housing manufacture.

  14. Superconducting properties of protactinium.

    PubMed

    Smith, J L; Spirlet, J C; Müller, W

    1979-07-13

    The superconducting transition temperature and upper critical magnetic field of protactinium were measured by alternating-current susceptibility techniques. Since the superconducting behavior of protactinium is affected by its 5f electron character, it is clear now that protactinium is a true actinide element. PMID:17750320

  15. 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.

  16. Superconductivity of magnesium diboride

    SciTech Connect

    Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-15

    Over the past 14 years MgB2 has gone from a startling discovery to a promising, applied superconductor. In our article we present a brief overview of the synthesis and the basic superconducting properties of this remarkable compound. Specifically, the effect of pressure, substitutions and neutron irradiation on superconducting properties are discussed.

  17. Superconductivity of magnesium diboride

    NASA Astrophysics Data System (ADS)

    Bud'ko, Sergey L.; Canfield, Paul C.

    2015-07-01

    Over the past 14 years MgB2 has gone from a startling discovery to a promising, applied superconductor. In this article we present a brief overview of the synthesis and the basic superconducting properties of this remarkable compound. In particular, the effect of pressure, substitutions and neutron irradiation on superconducting properties are discussed.

  18. Superconductivity of magnesium diboride

    DOE PAGESBeta

    Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-15

    Over the past 14 years MgB2 has gone from a startling discovery to a promising, applied superconductor. In our article we present a brief overview of the synthesis and the basic superconducting properties of this remarkable compound. Specifically, the effect of pressure, substitutions and neutron irradiation on superconducting properties are discussed.

  19. Development of superconductive magnets

    NASA Technical Reports Server (NTRS)

    Laurence, J. C.

    1970-01-01

    Survey of superconductive magnets considers - stabilization problems, advances in materials and their uses, and design evolution. Uses of superconducting magnets in particle accelerators and bubble chambers, as well as possible applications in magnetohydrodynamic and thermonuclear power generation and levitation are discussed.

  20. Superconducting Graphene Nanoelectronic Devices

    NASA Astrophysics Data System (ADS)

    Wang, Joel; Zaffalon, Michele; Jarillo-Herrero, Pablo

    2010-03-01

    Graphene, a single atom-thick sheet of graphite discovered in recent years, has attracted tremendous attention due to its exotic electronic properties. At low energy, its gapless linear band structure results in transport properties described by the Dirac equation, making it an ideal system for the study of exotic quantum phenomena and other new physics. Graphene may also exhibit many novel transport characteristics in the superconducting regime. New phenomena, such as pseudo-diffusive dynamics of ballistic electrons, the relativistic Josephson effect, and specular Andreev reflection are predicted by theoretical models combining relativistic quantum mechanics and superconductivity. We study these phenomena experimentally with superconductor-graphene-superconductor junctions. The supercurrent in graphene is induced by the superconducting contacts through proximity effect. Various superconducting materials are considered for different explorations. Preliminary tests indicate clean electrical contact with graphene and superconducting properties as expected.

  1. Superconductivity in carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Dlugon, Katarzyna

    The purpose of this thesis is to explain the phenomenon of superconductivity in carbon nanomaterials such as graphene, fullerenes and carbon nanotubes. In the introductory chapter, there is a description of superconductivity and how it occurs at critical temperature (Tc) that is characteristic and different to every superconducting material. The discovery of superconductivity in mercury in 1911 by Dutch physicist Heike Kamerlingh Onnes is also mentioned. Different types of superconductors, type I and type II, low and high temperatures superconductors, as well as the BCS theory that was developed in 1957 by Bardeen, Cooper, and Schrieffer, are also described in detail. The BCS theory explains how Cooper's pairs are formed and how they are responsible for the superconducting properties of many materials. The following chapters explain superconductivity in doped fullerenes, graphene and carbon nanotubes, respectively. There is a thorough explanation followed by many examples of different types of carbon nanomaterials in which small changes in chemical structure cause significant changes in superconducting properties. The goal of this research was not only to take into consideration well known carbon based superconductors but also to search for the newest available materials such as the fullerene nanowhiskers discovered quite recently. There is also a presentation of fairly new ideas about inducing superconductivity in a monolayer of graphene which is more challenging than inducing superconductivity in graphite by simply intercalating metal atoms between its graphene sheets. An effort has been taken to look for any available information about carbon nanomaterials that have the potential to superconduct at room temperature, mainly because discovery of such materials would be a real revolution in the modern world, although no such materials have been discovered yet.

  2. Advantages and Challenges of Superconducting Accelerators

    NASA Astrophysics Data System (ADS)

    Krischel, Detlef

    After a short review of the history toward high-energy superconducting (SC) accelerators for ion beam therapy (IBT), an overview is given on material properties and technical developments enabling to use SC components in a medical accelerator for full body cancer treatment. The design concept and the assembly of a commercially available SC cyclotron for proton therapy (PT) are described and the potential advantages for applying superconductivity are assessed. The discussion includes the first years of operation experience with regard to cryogenic and magnetic performance, automated beam control, and maintenance aspects. An outlook is given on alternative machine concepts for protons-only or for heavier ions. Finally, it is discussed whether the application of superconductivity might be expanded in the future to a broader range of subsystems of clinical IBT accelerators such as SC magnets for transfer beam lines or gantries.

  3. Midwest Superconductivity Consortium. 1991 Progress report

    SciTech Connect

    Liedl, G.L.

    1992-01-01

    The Midwest Superconductivity Consortium`s, MISCON, mission is to advance the science and understanding of high {Tc} superconductivity. Programmatic research focuses upon key materials-related problems: synthesis and processing; and limiting features in transport phenomena. During the past twenty-one projects produced over eighty-seven talks and seventy-two publications. Key achievements this past year expand our understanding of processing phenomena relating to crystallization and texture, metal superconductor composites, and modulated microstructures. Further noteworthy accomplishments include calculations on 2-D superconductor insulator transition, prediction of flux line lattice melting, and an expansion of our understanding and use of microwave phenomena as related to superconductors.

  4. Midwest Superconductivity Consortium: 1994 Progress report

    SciTech Connect

    Not Available

    1995-01-01

    The mission of the Midwest Superconductivity Consortium, MISCON, is to advance the science and understanding of high {Tc} superconductivity. During the past year, 27 projects produced over 123 talks and 139 publications. Group activities and interactions involved 2 MISCON group meetings (held in August and January); with the second MISCON Workshop held in August; 13 external speakers; 79 collaborations (with universities, industry, Federal laboratories, and foreign research centers); and 48 exchanges of samples and/or measurements. Research achievements this past year focused on understanding the effects of processing phenomena on structure-property interrelationships and the fundamental nature of transport properties in high-temperature superconductors.

  5. Superconducting RFQ development at Los Alamos

    SciTech Connect

    Wangler, T.P.; Cimabue, A.; Merson, J.; Mills, R.S.; Wood, R.; Young, L.

    1992-10-01

    We are investigating the performance capabilities of a niobium, superconducting, radiofrequency-quadrupole (RFQ) accelerator for high- field continuous-wave operation, to provide greater acceleration and stronger focusing of low-velocity ion beams. We present the results of our RFQ beam-dynamics studies, which test new design methods for increasing the beam transmission, our cavity-design calculations, and some mechanical-design aspects of a short, superconducting RFQ 4-vane prototype structure that will be tested at high fields during the coming year.

  6. Superconducting RFQ development at Los Alamos

    SciTech Connect

    Wangler, T.P.; Cimabue, A.; Merson, J.; Mills, R.S.; Wood, R.; Young, L.

    1992-01-01

    We are investigating the performance capabilities of a niobium, superconducting, radiofrequency-quadrupole (RFQ) accelerator for high- field continuous-wave operation, to provide greater acceleration and stronger focusing of low-velocity ion beams. We present the results of our RFQ beam-dynamics studies, which test new design methods for increasing the beam transmission, our cavity-design calculations, and some mechanical-design aspects of a short, superconducting RFQ 4-vane prototype structure that will be tested at high fields during the coming year.

  7. Bulk Superconductivity and Disorder in Single Crystals of LaFePO

    SciTech Connect

    Analytis, James G.; Chu, Jiun-Haw; Erickson, Ann S.; Kucharczyk, Chris; Serafin, Alessandro; Carrington, Antony; Cox, Catherine; Kauzlarich, Susan M.; Hope, Hakon; /UC, Davis. Dept. Chem.

    2010-02-15

    We have studied the intrinsic normal and superconducting properties of the oxypnictide LaFePO. These samples exhibit bulk superconductivity and the evidence suggests that stoichiometric LaFePO is indeed superconducting, in contrast to other reports. We find that superconductivity is independent of the interplane residual resistivity {rho}{sub 0} and discuss the implications of this on the nature of the superconducting order parameter. Finally we find that, unlike T{sub c}, other properties in single-crystal LaFePO including the resistivity and magnetoresistance, can be very sensitive to disorder.

  8. Simulation of an HTS Synchronous Superconducting Generator

    NASA Astrophysics Data System (ADS)

    Zermeno, Victor M. R.; Abrahamsen, Asger B.; Mijatovic, Nenad; Sorensen, Mads Peter; Jensen, Bogi B.; Pedersen, Niels F.

    In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, mechanical torque fluctuations, etc. Unlike regular conductors, superconductors, experience high losses when exposed to AC fields. Thus, calculation of such losses is relevant for machine design to avoid quenches and increase performance. Superconducting coated conductors are well known to exhibit nonlinear resistivity, thus making the computation of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations.The chosen strategy for simulation is as follows: A mechanical torque signal together with an electric load is used to drive the finite element model of a synchronous generator where the current distribution in the rotor windings is assumed uniform. Then, a second finite element model for the superconducting material is linked to calculate the actual current distribution in the windings of the rotor. Finally, heating losses are computed as a response to the electric load. The model is used to evaluate the transient response of the generator.

  9. Metal optics and superconductivity

    SciTech Connect

    Golovashkin, A.L.

    1989-01-01

    The articles contained in this collection are dedicated to the study of the electron structure of transition metals and superconducting alloys and compounds based on them. The study of the electron structure of materials is one of the central problems of solid-state physics and defines the solution of a number of problems. One of them is the problem of high-temperature superconductivity which has attracted exceptional attention from physicists in connection with the discovery of new classes of ceramic oxides which are superconducting at liquid-nitrogen temperature. The electron structure is one of the three whales on which all of superconductivity rests. It is frequently our ignorance of the electronic properties of a metal, alloy or compound in its normal state which makes it impossible to predict superconductivity in the material, preventing use from calculating the parameters of the superconducting state. There are now a number of effective methods for investigation of the electron structure of the metals and allows. This collection discusses metal optics, tunneling and magnetic measurements in superconductors. These methods are quite informative and allow us to obtain many important electron characteristics and temperature relations. Various characteristics of the superconducting compounds Nb{sub 3}Ge, Nb{sub 3}Al, nb{sub 3}Sn and Nb{sub 3}Ga with A15 structure and NbN with B1 structure, having rather high critical temperatures, are experimentally studied.

  10. Ferromagnetic/Superconducting Multilayers

    NASA Astrophysics Data System (ADS)

    Bader, S. D.

    1998-03-01

    Although it is well known that magnetism influences superconductivity, the converse issue has been less well explored. Recent theoretical predictions for ferromagnetic/ superconducting/ ferromagnetic trilayers exhibiting interlayer magnetic coupling in the normal state indicate that the coupling should be suppressed below the superconducting transition temperature.(C.A. R. Sá de Melo, Phys. Rev. Lett. 79), 1933 (1997); O. Sipr, B.L. Györffy, J. Phys. Cond. Matt. 7, 5239 (1995). To realize such a situation, a requirement (when the magnetic layers are thick) is that the superconducting layer thickness must simultaneously be less than the range over which the magnetic interlayer coupling decays, but greater than the superconducting coherence length. This introduces serious materials constraints. The present work describes initial explorations of three sputtered multilayer systems in an attempt to observe coupling of the ferromagnetic layers across a superconducting spacer:((a) J.E. Mattson, R.M. Osgood III, C.D. Potter, C.H. Sowers, and S.D. Bader, J. Vac. Sci. Technol. A 15), 1774 (1997); (b) J.E. Mattson, C.D. Potter, M.J. Conover, C.H. Sowers, and S.D. Bader, Phys. Rev. B 55, 70 (1997), and (c) R.M. Osgood III, J.E. Pearson, C.H. Sowers, and S.D. Bader, submitted (1997). (a) Ni/Nb, (b) Fe_4N/NbN, and (c) GdN/NbN. In these systems we have retained thinner superconducting layers than had been achieved previously, but interlayer magnetic coupling is not observed even in the normal state. For Ni/Nb the interfacial Ni loses its moment, which also reduces the superconducting pair-breaking. GdN is an insulating ferromagnet, so itinerancy is sacrificed, and, probably as a result of this, no coupling is observed. Each system gives rise to interesting and anisotropic superconducting properties. Thus, although the goal remains elusive, our search highlights the challenges and opportunities.

  11. Superconductivity in doped insulators

    SciTech Connect

    Emery, V.J.; Kivelson, S.A.

    1995-12-31

    It is shown that many synthetic metals, including high temperature superconductors are ``bad metals``, with such a poor conductivity that the usual meanfield theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. It is argued that the supression of a first order phase transition (phase separation) by the long-range Coulomb interaction leads to high temperature superconductivity accompanied by static or dynamical charge inhomogeneIty. Evidence in support of this picture for high temperature superconductors is described.

  12. Structures behind superconductivity

    SciTech Connect

    Rotman, D.

    1988-07-01

    The previously reported preparation and structures of superconducting materials are reviewed. The two systems, Y-Ba-Cu-O and La-Cu-O, previously reported with high transition temperatures are discussed in some detail. The new systems introduced in 1987 that were not based on a rare earth but including Bi-Sr-Cu-O are also reviewed. Superconductive materials including thallium rather than bismuth that have been reported but not thoroughly studied are discussed briefly. It is pointed out that many superconducting materials have been prepared, but good documentation of the structures and properties of these materials need much more study.

  13. Superconducting active impedance converter

    DOEpatents

    Ginley, D.S.; Hietala, V.M.; Martens, J.S.

    1993-11-16

    A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductors allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology. 12 figures.

  14. Superconducting active impedance converter

    DOEpatents

    Ginley, David S.; Hietala, Vincent M.; Martens, Jon S.

    1993-01-01

    A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductor allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology.

  15. Tunneling in superconducting structures

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu. M.

    2010-12-01

    Here we review our results on the breakpoint features in the coupled system of IJJ obtained in the framework of the capacitively coupled Josephson junction model with diffusion current. A correspondence between the features in the current voltage characteristics (CVC) and the character of the charge oscillations in superconducting layers is demonstrated. Investigation of the correlations of superconducting currents in neighboring Josephson junctions and the charge correlations in neighboring superconducting layers reproduces the features in the CVC and gives a powerful method for the analysis of the CVC of coupled Josephson junctions. A new method for determination of the dissipation parameter is suggested.

  16. Line-focus solar central power system, Phase I. Final report, 29 September 1978 to 30 April 1980. Volume II. Text

    SciTech Connect

    Slemmons, A J

    1980-04-01

    The conceptual design, parametric analysis, cost and performance analysis, and a commercial assessment of a 100-MWe high-temperature line-focus central power system are presented. Parametric analyses and conceptual design of the heliostat subsystem, receiver subsystem, heat transport subsystem, energy storage subsystem, electrical power generating subsystem, and master control subsystem are included. A market analysis and development plan are given. (WHK)

  17. Teaching Core Courses with a Focus on Rural Health. An Instructor Resource Guide. Appendix to a Final Report on the Paraprofessional Rurally Oriented Family Home Health Training Program.

    ERIC Educational Resources Information Center

    Myer, Donna Foster, Ed.

    This instructor's resource guide, one in a series of products from a project to develop an associate degree program for paraprofessional rural family health promoters, deals with teaching courses that focus on rural health. Discussed in the first section of the guide are the role of core courses in rural health promotional training and the…

  18. Supertubes and Superconducting Membranes

    SciTech Connect

    Cordero, Ruben; Miguel-Pilar, Zelin

    2007-02-09

    We show the equivalence between configurations that arise from string theory of type IIA, called supertubes, and superconducting membranes at the bosonic level. We find equilibrium and oscillating configurations for a tubular membrane carrying a current along its axis.

  19. Superconducting thermoelectric generator

    SciTech Connect

    Metzger, J.D.; El-Genk, M.S.

    1998-05-05

    An apparatus and method for producing electricity from heat is disclosed. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device. 4 figs.

  20. Superconducting thermoelectric generator

    SciTech Connect

    Metzger, J.D.; El-Genk, M.S.

    1996-01-01

    An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.

  1. Superconducting thermoelectric generator

    DOEpatents

    Metzger, John D.; El-Genk, Mohamed S.

    1998-01-01

    An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.

  2. 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.

  3. Superconductive ceramic oxide combination

    SciTech Connect

    Chatterjee, D.K.; Mehrotra, A.K.; Mir, J.M.

    1991-03-05

    This patent describes the combination of a superconductive ceramic oxide which degrades in conductivity upon contact of ambient air with its surface and, interposed between the ceramic oxide surface and ambient air in the amount of at least 1 mg per square meter of surface area of the superconductive ceramic oxide, a passivant polymer selected from the group consisting of a polyester ionomer and an alkyl cellulose.

  4. Making Superconducting Welds between Superconducting Wires

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin I.; Eom, Byeong Ho

    2008-01-01

    A technique for making superconducting joints between wires made of dissimilar superconducting metals has been devised. The technique is especially suitable for fabrication of superconducting circuits needed to support persistent electric currents in electromagnets in diverse cryogenic applications. Examples of such electromagnets include those in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) systems and in superconducting quantum interference devices (SQUIDs). Sometimes, it is desirable to fabricate different parts of a persistent-current-supporting superconducting loop from different metals. For example, a sensory coil in a SQUID might be made of Pb, a Pb/Sn alloy, or a Cu wire plated with Pb/Sn, while the connections to the sensory coil might be made via Nb or Nb/Ti wires. Conventional wire-bonding techniques, including resistance spot welding and pressed contact, are not workable because of large differences between the hardnesses and melting temperatures of the different metals. The present technique is not subject to this limitation. The present technique involves the use (1) of a cheap, miniature, easy-to-operate, capacitor-discharging welding apparatus that has an Nb or Nb/Ti tip and operates with a continuous local flow of gaseous helium and (2) preparation of a joint in a special spark-discharge welding geometry. In a typical application, a piece of Nb foil about 25 m thick is rolled to form a tube, into which is inserted a wire that one seeks to weld to the tube (see figure). The tube can be slightly crimped for mechanical stability. Then a spark weld is made by use of the aforementioned apparatus with energy and time settings chosen to melt a small section of the niobium foil. The energy setting corresponds to the setting of a voltage to which the capacitor is charged. In an experiment, the technique was used to weld an Nb foil to a copper wire coated with a Pb/Sn soft solder, which is superconducting. The joint was evaluated as

  5. Line-focus solar central power system, Phase I. Final report, 29 September 1978 to 30 April 1980. Volume III. Appendices

    SciTech Connect

    Slemmons, A J

    1980-04-01

    The conceptual design, parametric analysis, cost and performance analysis, and commercial assessment of a 100-MWe line-focus solar central receiver power plant are reported. This volume contains the appendices: (a) methods of determination of molten salt heat-transfer coefficients and tube-wall temperatures, (b) inputs for STEAEC programs, (c) description of system analysis computer program, (d) receiver analysis program, and (e) heliostat production plan and design methodology. (WHK)

  6. Conceptual study of superconducting urban area power systems

    NASA Astrophysics Data System (ADS)

    Noe, Mathias; Bach, Robert; Prusseit, Werner; Willén, Dag; Gold-acker, Wilfried; Poelchau, Juri; Linke, Christian

    2010-06-01

    Efficient transmission, distribution and usage of electricity are fundamental requirements for providing citizens, societies and economies with essential energy resources. It will be a major future challenge to integrate more sustainable generation resources, to meet growing electricity demand and to renew electricity networks. Research and development on superconducting equipment and components have an important role to play in addressing these challenges. Up to now, most studies on superconducting applications in power systems have been concentrated on the application of specific devices like for example cables and current limiters. In contrast to this, the main focus of our study is to show the consequence of a large scale integration of superconducting power equipment in distribution level urban power systems. Specific objectives are to summarize the state-of-the-art of superconducting power equipment including cooling systems and to compare the superconducting power system with respect to energy and economic efficiency with conventional solutions. Several scenarios were considered starting from the replacement of an existing distribution level sub-grid up to a full superconducting urban area distribution level power system. One major result is that a full superconducting urban area distribution level power system could be cost competitive with existing solutions in the future. In addition to that, superconducting power systems offer higher energy efficiency as well as a number of technical advantages like lower voltage drops and improved stability.

  7. Electron pairing without superconductivity.

    PubMed

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C Stephen; Levy, Jeremy

    2015-05-14

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances-paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. PMID:25971511

  8. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P.; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C. Stephen; Levy, Jeremy

    2015-05-01

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity.

  9. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Levy, Jeremy

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. Support from AFOSR, ONR, ARO, NSF, DOE and NSSEFF is gratefully acknowledged.

  10. High temperature interfacial superconductivity

    SciTech Connect

    Bozovic, Ivan; Logvenov, Gennady; Gozar, Adrian Mihai

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.