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Sample records for temperature superconducting cable

  1. High Temperature Superconducting Underground Cable

    International Nuclear Information System (INIS)

    Farrell, Roger A.

    2010-01-01

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  2. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-01-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  3. Comparison study of cable geometries and superconducting tape layouts for high-temperature superconductor cables

    Science.gov (United States)

    Ta, Wurui; Shao, Tianchong; Gao, Yuanwen

    2018-04-01

    High-temperature superconductor (HTS) rare-earth-barium-copper-oxide (REBCO) tapes are very promising for use in high-current cables. The cable geometry and the layout of the superconducting tapes are directly related to the performance of the HTS cable. In this paper, we use numerical methods to perform a comparison study of multiple-stage twisted stacked-tape cable (TSTC) conductors to find better cable structures that can both improve the critical current and minimize the alternating current (AC) losses of the cable. The sub-cable geometry is designed to have a stair-step shape. Three superconducting tape layouts are chosen and their transport performance and AC losses are evaluated. The magnetic field and current density profiles of the cables are obtained. The results show that arrangement of the superconducting tapes from the interior towards the exterior of the cable based on their critical current values in descending order can enhance the cable's transport capacity while significantly reducing the AC losses. These results imply that cable transport capacity improvements can be achieved by arranging the superconducting tapes in a manner consistent with the electromagnetic field distribution. Through comparison of the critical currents and AC losses of four types of HTS cables, we determine the best structural choice among these cables.

  4. Southwire's High Temperature Superconducting Cable Development - Summary Report

    International Nuclear Information System (INIS)

    Sinha, Uday; Lindsay, David

    2005-01-01

    at ORNL for the DC Ic, voltage withstand, ac loss, and other properties using both the Vacuum and Pressure Terminations. The design concept was proven with the 5-m cables and the same design was used for the 30-m cables. Three 30-m cables were constructed during the first two quarters of 1999. The cables were made on flexible formers but they were introduced into three separate rigid vacuum jacketed pipes (VJP). The cables passed the DC Ic tests that were carried out at the manufacturing site. A site was developed at Southwire with a switch yard, liquid nitrogen tank, a cryogenic cooling and delivery system, and a control room with PLC control for the system. The HTS cables were installed by the third quarter of 1999. The HTS cables were energized Jan. 6, 2000. The official opening was carried out on Feb. 18, 2000. As of April 30, 2005 the HTS site has been operating at 100% load for >29,000 hours. Since June 1, 2001 the system has logged over 21,000 hours at full load without an operator on duty at the site. The cryogenic system has been under operation for more than two years and has proven very reliable. Southwire has developed World's First Industrial HTS cable and is continuing to prove its reliability. This report contains several sections outlined below that are related to Southwire's HTS cable development: (1) High Temperature Superconducting (HTS) Tapes; (2) Hand Wound 1-m Cables; (3) Development of Facilities for Construction and testing of HTS cables; (4) 5-m HTS Cables; (5) 30-m HTS Cables, Installation at Southwire; (6) Continued Developments; and (7) Publications. Each of the above sections provide only a short report. The details are given in separate volumes (Vol. 1 to Vol. 7) with separate appendices for each section. These are available at the Cofer Center Technical Library

  5. The Danish Superconducting Cable Project

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1997-01-01

    The design and construction of a superconducting cable is described. The cable has a room temperature dielectric design with the cryostat placed inside the electrical insulation.BSCCO 2223 superconducting tapes wound in helix form around a former are used as the cable conductor. Results from...

  6. The US market for high-temperature superconducting wire in transmission cable applications

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, D

    1996-04-01

    Telephone interviews were conducted with 23 utility engineers concerning the future prospects for high-temperature superconducting (HTS) transmission cables. All have direct responsibility for transmission in their utility, most of them in a management capacity. The engineers represented their utilities as members of the Electric Power Research Institute`s Underground Transmission Task Force (which has since been disbanded). In that capacity, they followed the superconducting transmission cable program and are aware of the cryogenic implications. Nineteen of the 23 engineers stated the market for underground transmission would grow during the next decade. Twelve of those specified an annual growth rate; the average of these responses was 5.6%. Adjusting that figure downward to incorporate the remaining responses, this study assumes an average growth rate of 3.4%. Factors driving the growth rate include the difficulty in securing rights-of-way for overhead lines, new construction techniques that reduce the costs of underground transmission, deregulation, and the possibility that public utility commissions will allow utilities to include overhead costs in their rate base. Utilities have few plans to replace existing cable as preventive maintenance, even though much of the existing cable has exceeded its 40-year lifetime. Ten of the respondents said the availability of a superconducting cable with the same life-cycle costs as a conventional cable and twice the ampacity would induce them to consider retrofits. The respondents said a cable with those characteristics would capture 73% of their cable retrofits.

  7. Characteristics of the joint mini-model high temperature superconducting cable

    International Nuclear Information System (INIS)

    Kim, H.; Sim, K.; Cho, J.; Kim, S.; Kim, J.H.; Jung, H.Y.

    2008-01-01

    To obtain realistic data on the high temperature superconducting (HTS) power cable, 3-phase 100 m long, 22.9 kV class HTS power transmission cable system have been developed by Korea Electrotechnology Research Institute (KERI) and LS cable Ltd. that is one of 21st Century Frontier Project in Korea. This cable was installed at Go-chang testing site of Korea Electric Power Corporation (KEPCO). For the application of the HTS power cable joint is very important to ensure the performance. Therefore, this paper gives some investigation of AC loss, critical current and joint resistance in jointed HTS tape. We experimentally showed that the influence of joint resistance on AC loss by using several joint methods. Finally, we are measured critical current, AC loss and jointed resistance for the manufactured mini-model cable

  8. Superconducting ac cable

    Science.gov (United States)

    Schmidt, F.

    1980-11-01

    The components of a superconducting 110 kV ac cable for power ratings or = 2000 MVA were developed. The cable design is of the semiflexible type, with a rigid cryogenic envelope containing a flexible hollow coaxial cable core. The cable core consists of spirally wound Nb-A1 composite wires electrically insulated by high pressure polyethylene tape wrappings. A 35 m long single phase test cable with full load terminals rated at 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of this cable design.

  9. Superconducting ac cable

    International Nuclear Information System (INIS)

    Schmidt, F.

    1980-01-01

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.) [de

  10. Design of a termination for a high temperature superconduction power cable

    DEFF Research Database (Denmark)

    Rasmussen, Carsten; Kühle (fratrådt), Anders Van Der Aa; Tønnesen, Ole

    1999-01-01

    ). This assembly is electrically insulated with an extruded polymer dielectric kept at room temperature. Cooling is provided by a flow of liquid nitrogen inside the former. The purpose of the termination is to connect the superconducting cable conductor at cryogenic temperature to the existing power grid at room...... temperatures, the transfer of liquid nitrogen over a high voltage drop and that of providing a well defined atmosphere inside the termination and around the cable conductor. Designs based on calculations and experiments will be presented. The solutions are optimized with respect to a low heat in-leak....

  11. Cryogenic System for a High-Temperature Superconducting Power Transmission Cable

    International Nuclear Information System (INIS)

    Demko, J.A.; Gouge, M.J.; Hughey, R.L.; Lue, J.W.; Martin, R.; Sinha, U.; Stovall, J.P.

    1999-01-01

    High-temperature superconducting (HTS) cable systems for power transmission are under development that will use pressurized liquid nitrogen to provide cooling of the cable and termination hardware. Southwire Company and Oak Ridge National Laboratory have been operating a prototype HTS cable system that contains many of the typical components needed for a commercial power transmission application. It is being used to conduct research in the development of components and systems for eventual commercial deployment. The cryogenic system was built by Air Products and Chemicals, Allentown, Pennsylvania, and can circulate up to 0.35 kg/s of liquid nitrogen at temperatures as low as 67 K at pressures of 1 to 10 bars. Sufficient cooling is provided for testing a 5-m-long HTS transmission cable system that includes the terminations required for room temperature electrical connections. Testing of the 5-m HTS transmission cable has been conducted at the design ac conditions of 1250 A and 7.5 kV line to ground. This paper contains a description of the essential features of the HTS cable cryogenic system and performance results obtained during operation of the system. The salient features of the operation that are important in large commercial HTS cable applications will be discussed

  12. The creation of high-temperature superconducting cables of megawatt range in Russia

    Science.gov (United States)

    Sytnikov, V. E.; Bemert, S. E.; Krivetsky, I. V.; Romashov, M. A.; Popov, D. A.; Fedotov, E. V.; Komandenko, O. V.

    2015-12-01

    Urgent problems of the power industry in the 21st century require the creation of smart energy systems, providing a high effectiveness of generation, transmission, and consumption of electric power. Simultaneously, the requirements for controllability of power systems and ecological and resource-saving characteristics at all stages of production and distribution of electric power are increased. One of the decision methods of many problems of the power industry is the development of new high-efficiency electrical equipment for smart power systems based on superconducting technologies to ensure a qualitatively new level of functioning of the electric power industry. The intensive research and development of new types of electrical devices based on superconductors are being carried out in many industrialized advanced countries. Interest in such developments has especially increased in recent years owing to the discovery of so-called high-temperature superconductors (HTS) that do not require complicated and expensive cooling devices. Such devices can operate at cooling by inexpensive and easily accessible liquid nitrogen. Taking into account the obvious advantages of superconducting cable lines for the transmission of large power flows through an electrical network, as compared with conventional cables, the Federal Grid Company of Unified Energy System (JSC FGC UES) initiated a research and development program including the creation of superconducting HTS AC and DC cable lines. Two cable lines for the transmitted power of 50 MVA/MW at 20 kV were manufactured and tested within the framework of the program.

  13. The creation of high-temperature superconducting cables of megawatt range in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Sytnikov, V. E., E-mail: vsytnikov@gmail.com; Bemert, S. E.; Krivetsky, I. V.; Romashov, M. A. [JSC NTTs FSC EES (Russian Federation); Popov, D. A.; Fedotov, E. V.; Komandenko, O. V. [JSC Irkutskkabel (Russian Federation)

    2015-12-15

    Urgent problems of the power industry in the 21st century require the creation of smart energy systems, providing a high effectiveness of generation, transmission, and consumption of electric power. Simultaneously, the requirements for controllability of power systems and ecological and resource-saving characteristics at all stages of production and distribution of electric power are increased. One of the decision methods of many problems of the power industry is the development of new high-efficiency electrical equipment for smart power systems based on superconducting technologies to ensure a qualitatively new level of functioning of the electric power industry. The intensive research and development of new types of electrical devices based on superconductors are being carried out in many industrialized advanced countries. Interest in such developments has especially increased in recent years owing to the discovery of so-called high-temperature superconductors (HTS) that do not require complicated and expensive cooling devices. Such devices can operate at cooling by inexpensive and easily accessible liquid nitrogen. Taking into account the obvious advantages of superconducting cable lines for the transmission of large power flows through an electrical network, as compared with conventional cables, the Federal Grid Company of Unified Energy System (JSC FGC UES) initiated a research and development program including the creation of superconducting HTS AC and DC cable lines. Two cable lines for the transmitted power of 50 MVA/MW at 20 kV were manufactured and tested within the framework of the program.

  14. Normal state resistance and low temperature magnetoresistance of superconducting cables for accelerator magnets

    International Nuclear Information System (INIS)

    Sampson, W.B.; Garber, M.; Ghosh, A.K.

    1988-01-01

    The normal state resistivity of the superconducting NbTi cable used in accelerator magnets is usually specified by the resistance per unit length at room temperature (295 K) and the residual resistance ratio (RRR). Using these resistance parameters, the amount of copper in the multifilamentary wire can be calculated. This method is consistent with the traditional etch and weigh technique, and as such is a alternative and convenient way of specifying the copper to superconductor ratio. In principle the magnetoresistance can be calculated from the RRR and the ''Kohler Plot'', for copper. In practice however, measurements of magnetoresistance for a wide variety of SSC inner cables show considerable disagreement with calculation. In this paper the magnetoresistance data on cables with RRR ranging from 50 to 175 are analyzed taking into account the conductor geometry and the effect of the small interfilamentary spacing on the resistivity of copper. 8 refs., 5 figs., 1 tab

  15. Measuring ac-loss in high temperature superconducting cable-conductors using four probe methods

    DEFF Research Database (Denmark)

    Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten; Olsen, Søren Krüger

    1999-01-01

    Measuring the ac-loss of superconducting cable conductors have many aspects in common with measuring the ac-loss of single superconducting tapes. In a cable conductor all tapes are connected to each other and to the test circuit through normal metal joints in each end. This makes such measurement...

  16. Design and construction of a high temperature superconducting power cable cryostat for use in railway system applications

    International Nuclear Information System (INIS)

    Tomita, M; Muralidhar, M; Suzuki, K; Fukumoto, Y; Ishihara, A; Akasaka, T; Kobayashi, Y

    2013-01-01

    The primary objective of the current effort was to design and test a cryostat using a prototype five-meter long high temperature Bi 2 Sr 2 Ca 2 Cu 3 O y (Bi-2223) superconducting dc power cable for railway systems. To satisfy the safety regulations of the Govt of Japan a mill sheet covered by super-insulation was used inside the walls of the cryostat. The thicknesses of various walls in the cryostat were obtained from a numerical analysis. A non-destructive inspection was utilized to find leaks under vacuum or pressure. The cryostat target temperature range was around 50 K, which is well below liquid nitrogen temperature, the operating temperature of the superconducting cable. The qualification testing was carried out from 77 down to 66 K. When using only the inner sheet wire, the maximum current at 77.3 K was 10 kA. The critical current (I c ) value increased with decreasing temperature and reached 11.79 kA at 73.7 K. This is the largest dc current reported in a Bi 2 Sr 2 Ca 2 Cu 3 O y or YBa 2 Cu 3 O y (Y-123) superconducting prototype cable so far. These results verify that the developed DC superconducting cable is reliable and fulfils all the requirements necessary for successful use in various power applications including railway systems. The key issues for the design of a reliable cryogenic system for superconducting power cables for railway systems are discussed. (paper)

  17. Operation experiences with a 30 kV/100 MVA high temperature superconducting cable system

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Däumling, Manfred; Jensen, Kim Høj

    2004-01-01

    of this demonstration project is to gain experience with HTS cables under realistic conditions in a live distribution network. Approximately 50 000 utility customers have their electric power supplied through the HTS cable. The cable system has delivered 226 GW h of energy and reached a maximum operating current......A superconducting cable based on Bi-2223 tape technology has been developed, installed and operated in the public network of Copenhagen Energy in a two-year period between May 2001 and May 2003. This paper gives a brief overview of the system and analyses some of the operation experiences. The aim...

  18. Operation experiences with a 30 kV/100 MVA high temperature superconducting cable system

    International Nuclear Information System (INIS)

    Toennesen, Ole; Daeumling, Manfred; Jensen, Kim H; Kvorning, Svend; Olsen, Soeren K; Traeholt, Chresten; Veje, Erling; Willen, Dag; Oestergaard, Jacob

    2004-01-01

    A superconducting cable based on Bi-2223 tape technology has been developed, installed and operated in the public network of Copenhagen Energy in a two-year period between May 2001 and May 2003. This paper gives a brief overview of the system and analyses some of the operation experiences. The aim of this demonstration project is to gain experience with HTS cables under realistic conditions in a live distribution network. Approximately 50 000 utility customers have their electric power supplied through the HTS cable. The cable system has delivered 226 GW h of energy and reached a maximum operating current of 1157 A. The operation experiences include over-currents of 6 kA due to faults on peripheral lines, commissioning, servicing and failure responses on the cooling system, continuous 24 h, 7 day per week monitoring and performance of the alarm system. The implications of these experiences for the future applications of HTS cable systems are analysed

  19. Analytical approximations for thermophysical properties of supercritical nitrogen (SCN) to be used in futuristic high temperature superconducting (HTS) cables

    Energy Technology Data Exchange (ETDEWEB)

    Dondapati, Raja Sekhar, E-mail: drsekhar@ieee.org [School of Mechanical Engineering, Lovely Professional University, Phagwara, Punjab 144401 (India); Ravula, Jeswanth [School of Mechanical Engineering, Lovely Professional University, Phagwara, Punjab 144401 (India); Thadela, S. [Department of Mechanical Engineering, Andhra University, Visakhapatnam, Andhra Pradesh (India); Usurumarti, Preeti Rao [Department of Mechanical Engineering, P.V.K. Institute of Technology, Anantapur, Andhra Pradesh (India)

    2015-12-15

    Future power transmission applications demand higher efficiency due to the limited resources of energy. In order to meet such demand, a novel method of transmission is being developed using High Temperature Superconducting (HTS) cables. However, these HTS cables need to be cooled below the critical temperature of superconductors used in constructing the cable to retain the superconductivity. With the advent of new superconductors whose critical temperatures having reached up to 134 K (Hg based), a need arises to find a suitable coolant which can accommodate the heating loads on the superconductors. The present work proposes, Supercritical Nitrogen (SCN) to be a feasible coolant to achieve the required cooling. Further, the feasibility of proposed coolant to be used in futuristic HTS cables is investigated by studying the thermophysical properties such as density, viscosity, specific heat and thermal conductivity with respect to temperature (T{sub C} + 10 K) and pressure (P{sub C} + 10 bar). In addition, few temperature dependent analytical functions are developed for thermophysical properties of SCN which are useful in predicting thermohydraulic performance (pressure drop, pumping power and cooling capacity) using numerical or computational techniques. Also, the developed analytical functions are used to calculate the pumping power and the temperature difference between inlet and outlet of HTS cable. These results are compared with those of liquid nitrogen (LN2) and found that the circulating pumping power required to pump SCN is significantly smaller than that to pump LN2. Further, it is found that the temperature difference between the inlet and outlet is smaller as compared to that when LN2 is used, SCN can be preferred to cool long length Hg based HTS cables. - Highlights: • Analytical functions are developed for thermophysical properties of Supercritical Nitrogen. • Error analysis shows extremely low errors in the developed analytical functions.

  20. Analytical approximations for thermophysical properties of supercritical nitrogen (SCN) to be used in futuristic high temperature superconducting (HTS) cables

    International Nuclear Information System (INIS)

    Dondapati, Raja Sekhar; Ravula, Jeswanth; Thadela, S.; Usurumarti, Preeti Rao

    2015-01-01

    Future power transmission applications demand higher efficiency due to the limited resources of energy. In order to meet such demand, a novel method of transmission is being developed using High Temperature Superconducting (HTS) cables. However, these HTS cables need to be cooled below the critical temperature of superconductors used in constructing the cable to retain the superconductivity. With the advent of new superconductors whose critical temperatures having reached up to 134 K (Hg based), a need arises to find a suitable coolant which can accommodate the heating loads on the superconductors. The present work proposes, Supercritical Nitrogen (SCN) to be a feasible coolant to achieve the required cooling. Further, the feasibility of proposed coolant to be used in futuristic HTS cables is investigated by studying the thermophysical properties such as density, viscosity, specific heat and thermal conductivity with respect to temperature (T_C + 10 K) and pressure (P_C + 10 bar). In addition, few temperature dependent analytical functions are developed for thermophysical properties of SCN which are useful in predicting thermohydraulic performance (pressure drop, pumping power and cooling capacity) using numerical or computational techniques. Also, the developed analytical functions are used to calculate the pumping power and the temperature difference between inlet and outlet of HTS cable. These results are compared with those of liquid nitrogen (LN2) and found that the circulating pumping power required to pump SCN is significantly smaller than that to pump LN2. Further, it is found that the temperature difference between the inlet and outlet is smaller as compared to that when LN2 is used, SCN can be preferred to cool long length Hg based HTS cables. - Highlights: • Analytical functions are developed for thermophysical properties of Supercritical Nitrogen. • Error analysis shows extremely low errors in the developed analytical functions.

  1. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    Energy Technology Data Exchange (ETDEWEB)

    Kalsia, Mohit [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Dondapati, Raja Sekhar, E-mail: drsekhar@ieee.org [School of Mechanical Engineering, Lovely Professional University, Phagwara, 144 401 (India); Usurumarti, Preeti Rao [Department of Mechanical Engineering, PVK Institute of Technology, Anantpur, 515 001 (India)

    2017-05-15

    Highlights: • The developed correlations can be integrated into thermohydraulic analysis of HTS cables. • This work also explains the phenomenon of flow with less pumping power and maximum heat transfer in HTS cables. • Pumping power required to circulate the SCAR for cooling of HTS cables would be significantly lower. • For Hg-based high temperature superconductors (T{sub c} > 134 K), SCAR found to be a suitable coolant. - Abstract: High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific

  2. Statistical correlations for thermophysical properties of Supercritical Argon (SCAR) used in cooling of futuristic High Temperature Superconducting (HTS) cables

    International Nuclear Information System (INIS)

    Kalsia, Mohit; Dondapati, Raja Sekhar; Usurumarti, Preeti Rao

    2017-01-01

    Highlights: • The developed correlations can be integrated into thermohydraulic analysis of HTS cables. • This work also explains the phenomenon of flow with less pumping power and maximum heat transfer in HTS cables. • Pumping power required to circulate the SCAR for cooling of HTS cables would be significantly lower. • For Hg-based high temperature superconductors (T_c > 134 K), SCAR found to be a suitable coolant. - Abstract: High Temperature Superconducting (HTS) cables are emerging as an alternative to conventional cables in efficient power transmission. However, these HTS cables require cooling below the critical temperature of superconductors used to transmit larger currents. With the invention of high temperature superconductors whose critical temperatures are up to 134 K (Hg based), it is a great challenge to identify a suitable coolant which can carry away the heating load on the superconductors. In order to accomplish such challenge, an attempt has been made in the present work to propose supercritical Argon (SCAR) as the alternative to cool the HTS cables. Further, a statistical correlation has been developed for the thermophysical properties such as density, viscosity, specific heat and thermal conductivity of SCAR. In addition, the accuracy of developed correlations is established with the help of few statistical parameters and validated with standard database available in the literature. These temperature dependent accurate correlations are useful in predicting the pressure drop and heat transfer behaviour in HTS cables using numerical or computational techniques. In recent times, with the sophistication of computer technology, solving of various complex transport equations along with the turbulence models became popular and hence the developed correlations would benefit the technological community. It is observed that, a decrease in pressure, density and viscosity are found to be decreasing whereas the thermal conductivity and specific heat

  3. Characterization of a high-temperature superconducting conductor on round core cables in magnetic fields up to 20 T

    Energy Technology Data Exchange (ETDEWEB)

    van der Laan, D. C.; Noyes, P. D.; Miller, G. E.; Weijers, H. W.; Willering, G. P.

    2013-02-13

    The next generation of high-ï¬eld magnets that will operate at magnetic ï¬elds substantially above 20 T, or at temperatures substantially above 4.2 K, requires high-temperature superconductors (HTS). Conductor on round core (CORC) cables, in which RE-Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE = rare earth) (REBCO) coated conductors are wound in a helical fashion on a flexible core, are a practical and versatile HTS cable option for low-inductance, high-field magnets. We performed the first tests of CORC magnet cables in liquid helium in magnetic fields of up to 20 T. A record critical current I{sub c} of 5021 A was measured at 4.2 K and 19 T. In a cable with an outer diameter of 7.5 mm, this value corresponds to an engineering current density J{sub e} of 114 A mm{sup -2} , the highest J{sub e} ever reported for a superconducting cable at such high magnetic fields. Additionally, the first magnet wound from an HTS cable was constructed from a 6 m-long CORC cable. The 12-turn, double-layer magnet had an inner diameter of 9 cm and was tested in a magnetic field of 20 T, at which it had an I{sub c} of 1966 A. The cables were quenched repetitively without degradation during the measurements, demonstrating the feasibility of HTS CORC cables for use in high-field magnet applications.

  4. AC loss in superconducting tapes and cables

    NARCIS (Netherlands)

    Oomen, M.P.

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers

  5. Superconducting power cables in Denmark - a case study

    DEFF Research Database (Denmark)

    Østergaard, Jacob

    1997-01-01

    A case study of a 450 MVA, 132 kV high temperature superconducting (HTS) power transmission cable has been carried out. In the study, a superconducting cable system is compared to a conventional cable system which is under construction for an actual transmission line in the Danish grid. The study...... that HTS cables will be less expensive for high power ratings, have lower losses for lines with a high load, and have a reduced reactive power production. The use of superconducting cables in Denmark accommodate plans by the Danish utility to make a substantial conversion of overhead lines to underground...

  6. Loss and Inductance Investigation in Superconducting Cable Conductors

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Tønnesen, Ole; Træholt, Chresten

    1999-01-01

    An important parameter in the design and optimization of a superconducting cable conductor is the control of the current distribution among single tapes and layers. This distribution is to a large degree determined by inductances, since the resistances are low. The self and mutual inductances...... of transport current and current distribution.This presentation is based on a number of experiments performed on prototype superconducting cable conductors. The critical current (1uV/cm) of the conductor at 77K was 1590 A (cable #1) and 3240 A (cable #2) respectively.At an rms current of 2 kA (50 Hz) the AC......-loss was measured on cable #2 to 0.6W/mxphase. This is, to our knowledge, the lowest AC-loss (at 2kA and 77K) of a high temperature superconducting cable conductor reported so far....

  7. Thermal Conductance and High-Frequency Properties of Cryogenic Normal or Superconducting Semi-rigid Coaxial Cables in the Temperature Range of 1-8 K

    Science.gov (United States)

    Kushino, A.; Kasai, S.; Ukibe, M.; Ohkubo, M.

    2018-04-01

    In this study, the characteristics of thin semi-rigid cables composed of different conductors and with outer diameters ranging from 0.86 to 1.19 mm were investigated at low temperatures. The thermal conductance was measured between approximately 1 and 8 K, and the frequency dependence of the attenuation in the cables was obtained at 3 K. The electrical conductors used in the cables were alloys: beryllium copper, brass, stainless steel (SUS304), phosphor bronze, cupronickel (CuNi), and niobium-titanium (NbTi). The thermal conductance of a commercial miniature coaxial cable with braided wires forming the outer electrical conductor was also examined for reference. The measured thermal conductance was compared to published data and that generated from material libraries and databases. Among the measured cables using normal metals, the semi-rigid cable composed of SUS304 conductors and a polytetrafluoroethylene insulator showed the lowest thermal conductance. The transmission performance of the semi-rigid cables using SUS304 or CuNi was improved by plating the central conductors with a silver coating of approximately 3 μm thickness, and their thermal conductance with the plating increased by approximately one order of magnitude. The superconducting NbTi semi-rigid cable exhibited the lowest thermal conductance of all the cables considered in the present study along with very small attenuation up to above 5 GHz.

  8. Electromagnetic losses in a three-phase high temperature superconducting cable determined by calorimetric measurements

    DEFF Research Database (Denmark)

    Traeholt, C.; Veje, E.; Tønnesen, Ole

    2002-01-01

    conventional phases (600 mm2 Cu) could be moved in the plane. It was possible to vary the inter-phase distance (centre to centre distance) from 9 to 48 cm. The HTS cable conductor was placed in a stainless steel cryostat and cooled with flowing liquid nitrogen (LN2). The losses were determined using...

  9. Development of scaling rules for Rutherford type superconducting cables

    International Nuclear Information System (INIS)

    Royet, J.M.; Scanlan, R.M.

    1991-01-01

    During the R and D phase of the Superconducting Supercollider (SSC) program, LBL was responsible for establishing the parameters for cables used in SSC dipole and quadrupole magnets. In addition, LBL has collaborated with Fermi National Accelerator Laboratory on the design and fabrication of a new cable for use in the Low Beta Quadrupoles. As a result of the development work on these and other cables, we have arrived a set of scaling rules which provide guidelines for choosing the parameters for a wide range of superconducting cables. These parameters include strand size, strand number, keystone angle, percent compaction, cable pitch and compacted cable dimensions. In addition, we have defined the tolerance ranges for the key cable manufacturing parameters such as mandrel size and shape, strand tension, and Turkshead temperature control. In this paper, the authors present the results on cables ranging from 8 strands to 36 strands of 0.65mm wire and from 8 strands to 30 strands of 0.8mm wire. The authors use these results to demonstrate the application of the scaling rules for Rutherford-type cable

  10. Development of scaling rules for Rutherford type superconducting cables

    International Nuclear Information System (INIS)

    Royet, J.M.; Scanlan, R.M.

    1990-09-01

    During the R ampersand D phase of the Superconducting Supercollider (SSC) program, LBL was responsible for establishing the parameters for cables used in SSC dipole and quadrupole magnets. In addition, the design and fabrication of a new cable for use in the Low Beta Quadrupoles. As a result of the development work on these and other cables, we have arrived a set of scaling rules which provide guidelines for choosing the parameters for a wide range of superconducting cables. These parameters include strand size, strand number, keystone angle, percent compaction, cable pitch and compacted cable dimensions. In addition, we have defined the tolerance ranges for the key cable manufacturing parameters such as mandrel size and shape, stand tension, and Turkshead temperature control. In this paper, we present the results on cables ranging from 8 strands to 36 strands of 0.65mm wire and from 8 strands to 30 strands of 0.8mm wire. We use these results to demonstrate the application of the scaling rules for Rutherford-type cable

  11. Development of innovative superconducting DC power cable

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Teruo; Kiuchi, Masaru [Dept. of Computer Science and Electronics Kyushu Institute of Technology, Iizuka (Japan)

    2017-09-15

    It is required to reduce the cost of superconducting cable to realize a superconducting DC power network that covers a wide area in order to utilize renewable energy. In this paper a new concept of innovative cable is introduced that can enhance the current-carrying capacity even though the same superconducting tape is used. Such a cable can be realized by designing an optimal winding structure in such a way that the angle between the tape and magnetic field becomes small. This idea was confirmed by preliminary experiments for a single layer model cable made of Bi-2223 tapes and REBCO coated conductors. Experiments of three and four layer cables of practical sizes were also done and it was found that the current-carrying capacity increased as theoretically predicted. If the critical current properties of commercial superconducting tapes are further improved in a parallel magnetic field, the enhancement will become pronounced and this technology will surely contribute to realization of superconducting DC power network.

  12. Superconducting flat tape cable magnet

    Science.gov (United States)

    Takayasu, Makoto

    2015-08-11

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

  13. Power applications for superconducting cables in Denmark

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Østergaard, Jacob; Olsen, S. Krüger

    1999-01-01

    In Denmark a growing concern for environmental protection has lead to wishes that the open country is kept free of overhead lines as far as possible. New lines under 100 kV and existing 60/50 kV lines should be established as underground cables. Superconducting cables represent an interesting...... in cases such as transmission of energy into cities and through areas of special interest. The planned large groups of windmills in Denmark generating up to 2000 MVA or more both on dry land and off-shore will be an obvious case for the application of superconducting AC or DC cables. These opportunities...... can be combined with other new technologies such as HVDC light transmission using isolated gate bipolar transistors (IGBTs). The network needed in a system with a substantial wind power generation has to be very strong in order to handle energy fluctuations. Such a network will be possible...

  14. Development of prototype DC superconducting cable for railway system

    International Nuclear Information System (INIS)

    Tomita, Masaru; Fukumoto, Yusuke; Suzuki, Kenji; Miryala, Muralidhar

    2010-01-01

    High Temperature Superconducting (HTSC) wire has significant potential for railway system applications. HTSC wire is currently a promising candidate for various engineering applications such as transformers and motors for railway system. HTSC direct current (DC) cable is ideal for a feeder of the overhead contact line system between the substation and the electric train. We completed a prototype Bi-2223 tape based direct current cable for trial purposes of several meters length. In the energizing experiment the current of 1720 A successfully constantly flew.

  15. Energy losses of superconducting power transmission cables in the grid

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Okholm, Jan; Lomholt, Karin

    2001-01-01

    One of the obvious motives for development of superconducting power transmission cables is reduction of transmission losses. Loss components in superconducting cables as well as in conventional cables have been examined. These losses are used for calculating the total energy losses of conventional...... as well as superconducting cables when they are placed in the electric power transmission network. It is concluded that high load connections are necessary to obtain energy saving by the use of HTSC cables. For selected high load connections, an energy saving of 40% is expected. It is shown...

  16. Young's moduli of cables for high field superconductive dipole magnet

    International Nuclear Information System (INIS)

    Yamada, Shunji; Shintomi, Takakazu.

    1983-01-01

    Superconductive dipole magnets for big accelerators are subjected to enormous electro-magnetic force, when they are operated with high field such as 10 Tesla. They should be constructed by means of superconductive cables, which have high Young's modulus, to obtain good performance. To develop such cables we measured the Young's moduli of cables for practical use of accelerator magnets. They are monolithic and compacted strand cables. We measured also Young's moduli of monolithic copper and brass cables for comparison. The obtained data showed the Young's moduli of 35 and 15 GPa for the monolithic and compacted strand cables, respectively. (author)

  17. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1987-07-01

    After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

  18. Improved cable insulation for superconducting magnets

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  19. Improved cable insulation for superconducting magnets

    International Nuclear Information System (INIS)

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

    1993-01-01

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

  20. Solid-cryogen-stabilized, cable-in-conduit (CIC) superconducting cables

    Science.gov (United States)

    Voccio, J. P.; Michael, P. C.; Bromberg, L.; Hahn, S.

    2015-12-01

    This paper considers the use of a solid cryogen as a means to stabilize, both mechanically and thermally, magnesium diboride (MgB2) superconducting strands within a dual-channel cable-in-conduit (CIC) cable for use in AC applications, such as a generator stator winding. The cable consists of two separate channels; the outer channel contains the superconducting strands and is filled with a fluid (liquid or gas) that becomes solid at the device operating temperature. Several options for fluid will be presented, such as liquid nitrogen, hydrocarbons and other chlorofluorocarbons (CFCs) that have a range of melting temperatures and volumetric expansions (from solid at operating temperature to fixed volume at room temperature). Implications for quench protection and conductor stability, enhanced through direct contact with the solid cryogen, which has high heat capacity and thermal conductivity (compared with helium gas), will be presented. Depending on the cryogen, the conductor will be filled initially either with liquid at atmospheric conditions or a gas at high pressure (∼100 atm). After cooldown, the cryogen in the stranded-channel will be solid, essentially locking the strands in place, preventing strand motion and degradation due to mechanical deformation while providing enhanced thermal capacity for stability and protection. The effect of cryogen porosity is also considered. The relatively high heat capacity of solid cryogens at these lower temperatures (compared to gaseous helium) enhances the thermal stability of the winding. During operation, coolant flow through the open inner channel will minimize pressure drop.

  1. High-Density Superconducting Cables for Advanced ACTPol

    Science.gov (United States)

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

    2016-07-01

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

  2. High-Density Superconducting Cables for Advanced ACTPol

    Science.gov (United States)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; hide

    2016-01-01

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

  3. Effect of thermo-mechanical processing on the material properties at low temperature of a large size Al-Ni stabilized Nb-Ti/Cu superconducting cable

    Science.gov (United States)

    Langeslag, S. A. E.; Curé, B.; Sgobba, S.; Dudarev, A.; ten Kate, H. H. J.; Neuenschwander, J.; Jerjen, I.

    2014-01-01

    For future high-resolution particle experiments, a prototype for a 60 kA at 5 T, 4.2 K class conductor is realized by co-extrusion of a large, 40-strand Nb-Ti/Cu superconducting cable with a precipitation type Al-0.1wt.%Ni stabilizer. Microalloying with nickel contributes to the strength of the stabilizer, and avoids significant degradation in residual resistivity ratio, owing to its low solid solubility in aluminum. Sections of the conductor are work hardened to increase the mechanical properties of the as-extruded temper. Mechanical and resistivity characteristics are assessed as function of the amount of work hardening, at room temperature as well as at 4.2 K. Thermal treatments, like resin curing after coil winding, can cause partial annealing of the cold-worked material and reverse the strengthening effect. However, targeted thermal treatments, applied at relatively low temperature can result in precipitation hardening. The depletion of nickel in the aluminum-rich matrix around the precipitates results in an increased strength and a decreased effect of nickel on the thermal and electrical resistivity of the material. The present work aims at identifying an optimal work hardening sequence, and an optimal thermal treatment, possibly coinciding with a suitable coil resin curing cycle, for the Al-Ni stabilized superconductor.

  4. Manufacture of keystoned flat superconducting cables for use in SSC [Superconducting Super Collider] dipoles

    International Nuclear Information System (INIS)

    Royet, J.; Scanlan, R.M.

    1986-09-01

    The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. In this paper we will emphasize the differences between the techniques for cabling conventional wires for cabling superconducting wires. Concepts for the tooling will be introduced. The effects of cabling parameters on critical current degradation are being evaluated in collaboration with NBS-Boulder

  5. Test of a cryogenic set-up for a 10 meter long liquid nitrogen cooled superconducting power cable

    DEFF Research Database (Denmark)

    Træholt, Chresten; Rasmussen, Carsten; Kühle (fratrådt), Anders Van Der Aa

    2000-01-01

    High temperature superconducting power cables may be cooled by a forced flow of sub-cooled liquid nitrogen. One way to do this is to circulate the liquid nitrogen (LN2) by means of a mechanical pump through the core of the cable and through a sub-cooler.Besides the cooling station, the cryogenics...... cable. We report on our experimental set-up for testing a 10 meter long high temperature superconducting cable with a critical current of 3.2 kA at 77K. The set-up consists of a custom designed cable end termination, current lead, coolant feed-through, liquid nitrogen closed loop circulation system...

  6. Superconducting Cable Development for Future High Energy Physics Detector Magnets

    Science.gov (United States)

    Horvath, I. L.

    1995-11-01

    Under the leadership of the Swiss Federal Institute of Technology (ETHZ) an international ad hoc collaboration for superconducting cables developed an aluminium stabilised superconducting cable for future detector magnets. With the financial support of the Swiss government, this R&D work was carried out for the European Organisation for Nuclear Research (CERN). In this report the manufacturing process is described and results of the quality control measurements are summarised. These tests showed that the industrial manufacturing of an aluminium stabilised superconducting cable is feasible.

  7. Feasibility study of superconducting power cables for DC electric railway feeding systems in view of thermal condition at short circuit accident

    Science.gov (United States)

    Kumagai, Daisuke; Ohsaki, Hiroyuki; Tomita, Masaru

    2016-12-01

    A superconducting power cable has merits of a high power transmission capacity, transmission losses reduction, a compactness, etc., therefore, we have been studying the feasibility of applying superconducting power cables to DC electric railway feeding systems. However, a superconducting power cable is required to be cooled down and kept at a very low temperature, so it is important to reveal its thermal and cooling characteristics. In this study, electric circuit analysis models of the system and thermal analysis models of superconducting cables were constructed and the system behaviors were simulated. We analyzed the heat generation by a short circuit accident and transient temperature distribution of the cable to estimate the value of temperature rise and the time required from the accident. From these results, we discussed a feasibility of superconducting cables for DC electric railway feeding systems. The results showed that the short circuit accident had little impact on the thermal condition of a superconducting cable in the installed system.

  8. Application of Superconducting Power Cables to DC Electric Railway Systems

    Science.gov (United States)

    Ohsaki, Hiroyuki; Lv, Zhen; Sekino, Masaki; Tomita, Masaru

    For novel design and efficient operation of next-generation DC electric railway systems, especially for their substantial energy saving, we have studied the feasibility of applying superconducting power cables to them. In this paper it is assumed that a superconducting power cable is applied to connect substations supplying electric power to trains. An analysis model line was described by an electric circuit, which was analyzed with MATLAB-Simulink. From the calculated voltages and currents of the circuit, the regenerative brake and the energy losses were estimated. In addition, assuming the heat loads of superconducting power cables and the cryogenic efficiency, the energy saving of the total system was evaluated. The results show that the introduction of superconducting power cables could achieve the improved use of regenerative brake, the loss reduction, the decreased number of substations, the reduced maintenance, etc.

  9. Technical Challenges and Potential Solutions for Cross-Country Multi-Terminal Superconducting DC Power Cables

    Science.gov (United States)

    Al-Taie, A.; Graber, L.; Pamidi, S. V.

    2017-12-01

    Opportunities for applications of high temperature superconducting (HTS) DC power cables for long distance power transmission in increasing the reliability of the electric power grid and to enable easier integration of distributed renewable sources into the grid are discussed. The gaps in the technology developments both in the superconducting cable designs and cryogenic systems as well as power electronic devices are identified. Various technology components in multi-terminal high voltage DC power transmission networks and the available options are discussed. The potential of ongoing efforts in the development of superconducting DC transmission systems is discussed.

  10. Analysis of Electrical Coupling Parameters in Superconducting Cables

    CERN Document Server

    Bottura, L; Rosso, C

    2003-01-01

    The analysis of current distribution and redistribution in superconducting cables requires the knowledge of the electric coupling among strands, and in particular the interstrand resistance and inductance values. In practice both parameters can have wide variations in cables commonly used such as Rutherford cables for accelerators or Cable-in-Conduits for fusion and SMES magnets. In this paper we describe a model of a multi-stage twisted cable with arbitrary geometry that can be used to study the range of interstrand resistances and inductances that is associated with variations of geometry. These variations can be due to cabling or compaction effects. To describe the variations from the nominal geometry we have adopted a cable model that resembles to the physical process of cabling and compaction. The inductance calculation part of the model is validated by comparison to semi-analytical results, showing excellent accuracy and execution speed.

  11. Stability of superconducting cables for use in large magnet systems

    International Nuclear Information System (INIS)

    Tateishi, Hiroshi; Schmidt, C.

    1992-01-01

    The construction of large superconducting magnets requires the development of complicated conductor types, which can fulfill the specific requirements of different types of magnets. A rather hard boundary condition for large magnets is the presence of fast changing magnetic fields. In the Institute of Technical Physics of the Karlsruhe Nuclear Research Center, Germany, a superconducting cable was developed for use in poloidal field coils in Tokamak experiments. This 'POLO'-cable exhibits low losses in a magnetic ac-field and a high stability margin. In the present article the requirements on a superconducting cable are described, as well as the mechanisms of ac-losses and the calculation of the stability limit. Calculated values are compared with experimental data. Some unresolved problems concerning the stability of large magnets are discussed taking the example of the POLO-cable. (author)

  12. metrological performance improvement of a superconducting cable test station

    CERN Document Server

    Montenero, Giuseppe; Ballarino, Amalia

    The work presented in this PhD thesis concerns the metrological performance improvement of a superconducting cable test station based on superconducting transformers. The main cable’s parameter to be assessed –as a function of temperature and magnetic field– is the critical current, i.e. beyond this limit the phase transition to the normal state occurs. Ramping the current at levels in the order of the tens of kA can be achieved with superconducting transformers at moderate capital and operational cost. But, issues such as (i) accurate/precise measurements and (ii) monitoring of the secondary current during the device operation have to be addressed. In this regard, the goals of the thesis are the design, prototyping, and validation of a new cryogenic current transducer and effective monitoring system for test stations transformer-based. Among the available transducers for current sensing at room temperature, the DC current transformer (DCCT) provides measurement accuracy in the order of the hundreds of ...

  13. Superconducting coaxial cable as a large capacity transmission medium for communication

    International Nuclear Information System (INIS)

    Mikoshiba, K.; Simohori, Y.; Ohmori, N.; Sone, F.

    1974-01-01

    In order to survey the feasibility of the superconducting communication system, the electrical performance of superconducting coaxial cable has been investigated experimentally. The results are as follows. The transmission loss can be described as a function of the frequency, a(f) = a 1 f 2 + a 2 f. Dielectric loss is dominant up to a few gigahertz. Improvement of the impedance irregularities due to dimensional imperfections along the cable smoothens the transmission loss versus frequency characteristics. The temperature dependence of the transmission loss agrees well with an approximate expression deduced using the Pippard temperature function. (author)

  14. Stationary operational behavior unsymmetrical superconducting three-phase cable

    Energy Technology Data Exchange (ETDEWEB)

    Iser, R.

    1974-01-01

    A superconducting cable with a coaxial conductor arrangement is electrically unsymmetrical. Voltage and current relationships are analyzed for such a cable where, as a result of reactance and capacitance matrices being unsymmetric, large voltage unsymmetry appears. This limits the practical length of this type of cable. It is shown that a significant gain in symmetry is attained by the use of two cables connected in parallel. The compensating current which then occurs involves no disadvantage. The circuit described permits overloads of up to 100 percent.

  15. High temperature superconductors as a technological discontinuity in the power cable industry

    International Nuclear Information System (INIS)

    Beales, T.P.; McCormack, J.S.

    1994-01-01

    The advent of superconductivity above 77 K represents to the power cable industry a technological discontinuity analogous to that seen in the copper telecommunications industry by the arrival of optical fibres. This phenomenon is discussed along with technical criteria and performance targets needed for high temperature superconducting wire to have an economic impact in transmission cables

  16. High temperature superconductors as a technological discontinuity in the power cable industry

    Energy Technology Data Exchange (ETDEWEB)

    Beales, T.P.; McCormack, J.S. [BICC Cables Ltd., Hebburn (United Kingdom)

    1994-12-31

    The advent of superconductivity above 77 K represents to the power cable industry a technological discontinuity analogous to that seen in the copper telecommunications industry by the arrival of optical fibres. This phenomenon is discussed along with technical criteria and performance targets needed for high temperature superconducting wire to have an economic impact in transmission cables.

  17. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Lynn, J.W.

    1990-01-01

    This book discusses development in oxide materials with high superconducting transition temperature. Systems with Tc well above liquid nitrogen temperature are already a reality and higher Tc's are anticipated. The author discusses how the idea of a room-temperature superconductor appears to be a distinctly possible outcome of materials research

  18. Wire rope superconducting cable for diurnal load leveling SMES

    International Nuclear Information System (INIS)

    Costello, G.A.

    1980-01-01

    The design of a wire rope cable for a superconducting magnetic energy storage (SMES) unit is discussed. The superconducting wires in the rope permit the passage of large currents in the relatively small conductors of the windings and hence cause large electromagnetic forces to act on the rope. The diameter of the rope, from a strength point of view, can be considerably reduced by supporting the rope at various points along its length

  19. Field Demonstration of a 24-kV Superconducting Cable at Detroit Edison

    International Nuclear Information System (INIS)

    Kelley, Nathan; Corsaro, Pietro

    2004-01-01

    Customer acceptance of high temperature superconducting (HTS) cable technology requires a substantial field demonstration illustrating both the system's technical capabilities and its suitability for installation and operation within the utility environment. In this project, the world's first underground installation of an HTS cable using existing ductwork, a 120 meter demonstration cable circuit was designed and installed between the 24 kV bus distribution bus and a 120 kV-24 kV transformer at Detroit Edison's Frisbie substation. The system incorporated cables, accessories, a refrigeration system, and control instrumentation. Although the system was never put in operation because of problems with leaks in the cryostat, the project significantly advanced the state-of-the-art in the design and implementation of Warm Dielectric cable systems in substation applications. Lessons learned in this project are already being incorporated in several ongoing demonstration projects

  20. Insulation systems for superconducting transmission cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1996-01-01

    the electrical insulation is placed outside both the superconducting tube and the cryostat. The superconducting tube is cooled by liquid nitrogen which is pumped through the hollow part of the tube.2) The cryogenic dielectric design, where the electrical insulation is placed inside the cryostat and thus is kept...

  1. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Tengming

    2018-01-02

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  2. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Science.gov (United States)

    Shen, Tengming

    2016-11-15

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  3. Advanced superconducting power cable for MV urban power supply

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Frank [Nexans Deutschland GmbH, Hannover (Germany); Merschel, Frank [RWE Deutschland AG, Essen (Germany); Noe, Mathias [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2015-07-01

    In recent years the technology of superconducting power cable systems has progressed such that the technical hurdles preparing for commercial applications have been mastered. Several field tests of large scale prototypes for the applications of superconducting cables as well as superconducting fault current limiters have been successfully accomplished and the technology of such systems is ready for commercialization. The presentation will give a detailed overview of the German AmpaCity project. An overview will be given on the development, manufacturing and installation of the 10 kV, 40 MVA HTS system consisting of a fault current limiter and of a 1 km cable in the city of Essen. Since it is the first time that a one kilometer HTS cable system is installed together with an HTS fault current limiter in a real grid application between two substations within a city center area, AmpaCity serves as a lighthouse project. In addition it is worldwide the longest installed HTS cable system so far. It is expected that relatively large technical advances will be made in the future of the comparatively new HTS technology, which in turn will bring associated cost reductions. For this reason, the AmpaCity pilot project in the downtown area of Essen in Germany will be an important step on the way to achieving more widespread application of HTS technology.

  4. Optimum copper to superconductor ratio in cables for superconducting magnets at 1.9 K

    International Nuclear Information System (INIS)

    Wolf, R.

    1994-01-01

    In this paper the optimum copper to superconducting ratio is calculated to prevent quenching for superconducting cables used in accelerator magnets like the LHC dipoles, operating in superfluid helium at 1.9K. The duration of the perturbations leading to a quench are estimated from flux measurements made with pickup coils in the LHC dipole models. The optimum copper to superconducting ratio is then found by studying the minimum quench energy and the influence of the length and the duration or the perturbation and heat transfer to the surroundings. A comparison is made of the behavior at temperatures of 1.9 and 4.3 K

  5. Detection of Local Temperature Change on HTS Cables via Time-Frequency Domain Reflectometry

    Science.gov (United States)

    Bang, Su Sik; Lee, Geon Seok; Kwon, Gu-Young; Lee, Yeong Ho; Ji, Gyeong Hwan; Sohn, Songho; Park, Kijun; Shin, Yong-June

    2017-07-01

    High temperature superconducting (HTS) cables are drawing attention as transmission and distribution cables in future grid, and related researches on HTS cables have been conducted actively. As HTS cables have come to the demonstration stage, failures of cooling systems inducing quench phenomenon of the HTS cables have become significant. Several diagnosis of the HTS cables have been developed but there are still some limitations of the experimental setup. In this paper, a non-destructive diagnostic technique for the detection of the local temperature change point is proposed. Also, a simulation model of HTS cables with a local temperature change point is suggested to verify the proposed diagnosis. The performance of the diagnosis is checked by comparative analysis between the proposed simulation results and experiment results of a real-world HTS cable. It is expected that the suggested simulation model and diagnosis will contribute to the commercialization of HTS cables in the power grid.

  6. Characterization and multi-scales modeling of the thermomechanical behaviour of a superconducting composite cable

    International Nuclear Information System (INIS)

    Gourdin, C.; Reytier, M.; Vedrine, P.

    2000-06-01

    The prediction of the superconducting cable mechanical properties (NbTi and Nb 3 Sn) becomes a great stake for the STCM applications. During the design phase of our magnets, the electromagnetic forces become considerable. Therefore, the control and the accuracy of the structural calculations need well known mechanical properties for each component. But, superconducting cables present, in compression, a non linear mechanical behaviour with a significant hysteresis, which will have to be taken into account in a near future. That is why a study is started in order to understand and to formulate this particular mechanical behaviour. In this paper, the NbTi and Nb 3 Sn cable structure is first presented as well as their manufacturing process. Then, a description of the experimental procedure used to realize the compression tests is made. Finally, the main results obtained at room temperature and also in liquid helium at 4.2 K are discussed. (author)

  7. Study of Nb3Sn cables for superconducting quadrupoles

    International Nuclear Information System (INIS)

    Otmani, R.

    1999-10-01

    In particle physics, the quest for higher energies may be satisfied by the use of niobium-tin superconducting magnets. Such magnets are made of Rutherford type cables which are wound from superconducting strands. The strands are made by the 'internal tin' method. The aim of this study is to determine the main parameters for the fabrication of a quadrupole. The two main requirements the cable must fulfill are high critical current and low losses. The main parameters were determined from different measurements and models. Thus, the key parameters for the current transport capacity are the number and the diameter of the filaments, the number of sub-elements, the surface of superconductor and the copper-to-non-copper ratio. For the hysteresis losses, the main parameters appear to be the effective filament diameter and the spacing of the filaments. For intra-strand losses, the main parameters appear to be the filaments' diameter, the filament spacing, the nature of the diffusion barrier and the Residual Resistivity Ratio (RRR) of the copper. The interstrand resistances for the cable are the key parameters for the losses. Thus, the nature of the strands coating or the presence of a stainless steel core can strongly diminish the cable losses. Finally, a design, for the strands and the cables for the fabrication of a quadrupole is proposed. (author)

  8. Superconducting cable cooling system by helium gas at two pressures

    International Nuclear Information System (INIS)

    Dean, J.W.

    1977-01-01

    Thermally contacting, oppositely streaming, cryogenic fluid streams in the same enclosure in a closed cycle changes the fluid from a cool high pressure helium gas to a cooler reduced pressure helium gas in an expander so as to be at different temperature ranges and pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T 1 . By first circulating the fluid from a refrigerator at one end of the line as a cool gas at a temperature range T 2 to T 3 in the go leg, then circulating the gas through an expander at the other end of the line where the gas becomes a cooler gas at a reduced pressure and at a reduced temperature T 4 and finally by circulating the cooler gas back again to the refrigerator in a return leg at a temperature range T 4 to T 5 , while in thermal contact with the gas in the go leg, and in the same enclosure therewith for compression into a higher pressure gas at T 2 in a closed cycle, where T 2 greater than T 3 and T 5 greater than T 4 , the fluid leaves the enclosure in the go leg as a gas at its coldest point in the go leg, and the temperature distribution is such that the line temperature decreases along its length from the refrigerator due to the cooling from the gas in the return leg

  9. Contributions to the study of superconducting multifilamentary composites and cables

    International Nuclear Information System (INIS)

    Turck, B.

    1992-03-01

    This report is a collection of published papers in French and in English on superconducting composites and cables. All domains concerning the behaviour of superconductors in coils for field generation have been covered: critical current, current distribution, instabilities, losses in varying field. This document provides with expressions and criteria for conductor design, with conditions for achieving given performances and with criteria for design and optimization of structures of multifilamentary composites and cables. These publications have played a determining role in the understanding of the behaviour of superconductors and in their use in high performing magnets

  10. High temperature interface superconductivity

    International Nuclear Information System (INIS)

    Gozar, A.; Bozovic, I.

    2016-01-01

    Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T_c 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-T_c 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.

  11. Cooling unit for a superconducting power cable. Two years successful operation

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, Friedhelm [Messer Group GmbH, Krefeld (Germany); Kutz, Thomas [Messer Industriegase GmbH, Bad Soden (Germany); Stemmle, Mark [Nexans Deutschland GmbH, Hannover (Germany); Kugel, Torsten [Westnetz GmbH, Essen (Germany)

    2016-07-01

    High temperature super conductors (HTS) can efficiently be cooled with liquid nitrogen down to a temperature of 64 K (-209 C). Lower temperatures are not practical, because nitrogen becomes solid at 63 K (-210 C). To achieve this temperature level the coolant has to be vaporized below atmospheric pressure. Messer has developed a cooling unit with an adequate vacuum subcooler, a liquid nitrogen circulation system, and a storage vessel for cooling an HTS power cable. The cooling unit was delivered in 2013 for the German AmpaCity project of RWE Deutschland AG, Nexans and Karlsruhe Institute of Technology. Within this project RWE and Nexans installed the worldwide longest superconducting power cable in the city of Essen, Germany. The cable is in operation since March 10th, 2014.

  12. Study on interstrand coupling losses in Rutherford-type superconducting cables

    International Nuclear Information System (INIS)

    Lei, Y.Z.; Shintomi, T.; Terashima, A.; Hirabayashi, H.

    1993-02-01

    Two sets of experimental apparatus for measuring the AC losses in superconducting strands and Rutherford-type cable conductors have been constructed. A few strand samples and a number of compacted cable samples with and without a CuMn matrix have been measured. The hysteresis loss, loss from coupling within strands and loss from coupling between strands in cables have been distinguished from each other. The results show that, even for Rutherford cables without any soldering and coating, their AC losses may be quite different from each other due to the variation of the interstrand coupling loss. For cables without a CuMn matrix, interstrand coupling loss increases nearly according to a geometrical series with an increase of curing temperature simulating coil fabrication. However, cables with the CuMn matrix show a relatively small curing temperature dependence. For most of the samples, losses do not show any evident dependence on the mechanical pressure. Interstrand resistances in one of these cables have also been measured; the results indicate that the tendency for a decrease in the interstrand resistances is consistent with the results of AC loss measurements. (author)

  13. Variable temperature superconducting microscope

    Science.gov (United States)

    Cheng, Bo; Yeh, W. J.

    2000-03-01

    We have developed and tested a promising type of superconducting quantum interference device (SQUID) microscope, which can be used to detect vortex motion and can operate in magnetic fields over a large temperature range. The system utilizes a single-loop coupling transformer, consisting of a patterned high Tc superconducting thin film. At one end of the transformer, a 20 μm diam detecting loop is placed close to the sample. At the other end, a large loop is coupled to a NbTi coil, which is connected to a low Tc SQUID sensor. Transformers in a variety of sizes have been tested and calibrated. The results show that the system is capable of detecting the motion of a single vortex. We have used the microscope to study the behavior of moving vortices at various positions in a YBa2Cu3O7 thin film bridge.

  14. Current Redistribution around the Superconducting-to-normal Transition in Superconducting Nb-Ti Rutherford Cables

    CERN Document Server

    Willering, G P; ten Kate, H H J

    2008-01-01

    Sufficient thermal-electromagnetic stability against external heat sources is an essential design criterion for superconducting Rutherford cables, especially if operated close to the critical current. Due to the complex phenomena contributing to stability such as helium cooling, inter-strand current and heat transfer, its level is difficult to quantify. In order to improve our understanding, many stability tests were performed on different cable samples, each incorporating several point-like heaters. The current redistribution around the heat front is measured after inducing a local normal zone in one strand of the cable. By using voltage taps, expansion of the normal zone is monitored in the initially quenched strand as well as in adjacent strands. An array of Hall probes positioned at the cable edge is used to scan the selffield generated by the cable by which it becomes possible to estimate the inter-strand current transfer. In this paper it is demonstrated that two different stability regimes can be disti...

  15. Development and fabrication of superconducting hybrid Cable-In-Conduit-Conductor (CICC) for indigenous fusion programme

    International Nuclear Information System (INIS)

    Singh, A.K.; Hussain, M.M.; Abdulla, K.K.; Singh, R.P.

    2011-01-01

    The Atomic Fuels Division has initiated development and fabrication of Cable-In-Conduit-Conductor (CICC) of various configurations, for superconducting fusion grade magnets required for their indigenous Fusion Programme. The process involves development of high grade superconducting multifilamentary wire, multi stage cabling of superconducting as well as copper wires and, finally, jacketing of the cables in SS316LN tubes. The overview of the development and fabrication of CICC is presented in this article. (author)

  16. Status of the LHC Superconducting Cable Mass Production

    CERN Document Server

    Adam, J D; Cavallari, Giorgio; Charifoulline, Z; Denarié, C H; Le Naour, S; Leroy, D F; Oberli, L R; Richter, D; Verweij, A P; Wolf, R

    2002-01-01

    Six contracts have been placed with industrial companies for the production of 1200 tons of the superconducting (SC) cables needed for the main dipoles and quadrupoles of the Large Hadron Collider (LHC). In addition, two contracts have been placed for the supply of 470 tons of NbTi and 26 tons of Nb sheets. The main characteristic of the specification is that it is functional. This means that the physical, mechanical and electrical properties of strands and cables are specified without defining the manufacturing processes. Facilities for the high precision measurements of the wire and cable properties have been implemented at CERN, such as strand and cable critical current, copper to superconductor ratio, interstrand resistance, magnetisation, RRR at 4.2 K and 1.9 K. The production has started showing that the highly demanding specifications can be fulfilled. This paper reviews the organisation of the contracts, the test facilities installed at CERN, the various types of measurements and the results of the ma...

  17. Explosive-emission cathode fabricated from superconducting cable

    International Nuclear Information System (INIS)

    Vavra, I.; Korenev, S.A.

    1989-01-01

    The authors describe on explosive-emission cathode that is based on stock superconducting cable - type NT-50, for example - that is bunched and held in a copper matrix. The copper matrix is partially etched away to create a multipoint structure for the cathode-plasma initiators. With 100-300 kV on the diode and a distance of 1 cm between the anode and cathode, electron currents of 20-80 and 60-300 A are obtained with cathode diameters of 0.5 and 1 cm, respectively

  18. Steady-state heat transfer in He II through porous superconducting cable insulation

    International Nuclear Information System (INIS)

    Baudouy, B.J.P.; Juster, F.P.; Meuris, C.; Vieillard, L.

    1996-01-01

    The LHC program includes the study of thermal behavior of the superconducting cables wound in the dipole magnet cooled by superfluid helium (He II). Insulation of these superconducting cables forms the major thermal shield hindering the He II cooling. This is particularly a problem in magnets which are subjected to thermal loads. To investigate He II heat transfer processes an experimental model has been realized which creates a one-dimensional heat transfer in such media. Insulation is generally realized by wrapping around the superconducting cable a combination of different kind of Kapton reg-sign tapes, fiber-glass impregnated by epoxy resin or Kevlar reg-sign fiber tapes. Steady-state heat transfer in He II through these multi-layer porous slabs has been analyzed. Experimental results for a range of heat flux show the existence of different thermal regimes related to He II. It is shown that the parameters of importance are a global geometrical factor which could be considered as an equivalent open-quotes permeabilityclose quotes related to He II heat transfer, the transfer function f(T) of He II and the thermal conductivity of the slab. The authors present and analyze results for different insulations as a function of the temperature

  19. Recent development of the Cu/Nb-Ti superconducting cables for SSC in Hitachi Cable, Ltd

    International Nuclear Information System (INIS)

    Sakai, S.; Iwaki, G.; Sawada, Y.; Moriai, H.; Ishigami, Y.

    1989-01-01

    In these few years, Cu/Nb-Ti superconducting cables for the dipole magnets of SSC projects have been developed in the industrial scale in Hitachi Cable, Ltd. The features of these developed conductors are as follows. (1) The diameter of Nb-Ti filaments is very small, 4-6 μm. (2) The critical current density (J c ) is very high, 2,850-3,050 A/mm 2 at 5 T on wires, 2750-2950 A/mm 2 at 5 T on cables in industrial scale. The champion J c of wires is 3,460 A/mm 2 at 5 T in the laboratory scale. (3) The RRR Residual Resistivity Ratio values of developed cables is very high, approximately 200, due to the newly developed high purity Oxygen Free Copper (OFC). (4) The conductors have been wound to the 1 m length dipole magnet in Hitachi Ltd., and it has generated 6.7 T in the central magnetic field at 6,595 A. The Cu/Cu-Mn/Nb-Ti composite wires which avoid the possibility of electrical coupling of the filaments have been produced in laboratory scale. The RRR of the copper stabilizer and J c properties have not degraded because of no metallurgical reactions between Cu and Mn, Nb-Ti and Mn. 7 refs., 9 figs., 4 tabs

  20. Loss and Inductance Investigations in a 4-layer Superconducting Prototype Cable Conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa

    1999-01-01

    One important issue in the design and optimization of a superconducting cable conductor is the control of the current distribution between single tapes and layers. This presentation is based on a number of experiments performed on a 4-layer three meter long prototype superconducting cable conductor......-losses are measured as a function of transport current and a given current distribution and compared with the monoblock model. Recommendations for design of future cable conductor prototypes are given....

  1. First tests of twisted-pair HTS 1 kA range cables for use in superconducting links

    CERN Document Server

    Ballarino, A; Hurte, J; Sitko, M; Willering, G

    2011-01-01

    The requirement at CERN for 1 kA range High Temperature Superconducting (HTS) cables optimized for long electrical transfer has led to the design and assembly of a novel type of cable that can be made from pre-reacted MgB2, Bi-2223 or YBCO tapes. The cable consists of an assembly of twisted pairs, each of which is made from three superconducting tapes with the required copper stabilizer. The twisted pair cable is designed to transfer a DC current of ± 600 A in helium gas environment. The paper reports on the results of the electrical tests performed on twisted-pair cables of identical structure and made from commercially available MgB2, Bi-2223 and YBCO tapes. The twist pitch of the cables is adapted to match the mechanical properties of the different superconductors. Critical current tests were performed at both liquid helium and liquid nitrogen temperature. The electrical performance of several cables made from different conductors is reported and compared.

  2. Elements of a specification for superconducting cable and why they are important for magnet construction

    International Nuclear Information System (INIS)

    Greene, A.F.; Scanlan, R.M.

    1989-01-01

    The purpose of this paper is to point out several features of the specification for SSC superconducting cable and its insulation that are important for fabrication of dipole magnet coils. Among these are the dimensions of the cable and insulation and their relevance for obtaining coils with appropriate overall dimensions, Other important cable properties are related to the twist direction of wire used to fabricate it and the opposite twist (or lay) direction of the cable. For some coils it is easier to work with cable of a particular lay direction. In conjunction with the ease of coil winding comes the requirement in the specification for superconducting cable which restricts the cable surface condition. The ease of winding coils is governed by the ability to bend and twist the cable at the coil ends without having wires come out of place, possibly later leading to insulation damage and a turn-to-turn short. 5 refs., 11 figs., 1 tab

  3. Modern high-temperature superconductivity

    International Nuclear Information System (INIS)

    Ching Wu Chu

    1988-01-01

    Ever since the discovery of superconductivity in 1911, its unusual scientific challenge and great technological potential have been recognized. For the past three-quarters of a century, superconductivity has done well on the science front. This is because sueprconductivity is interesting not only just in its own right but also in its ability to act as a probe to many exciting nonsuperconducting phenomena. For instance, it has continued to provide bases for vigorous activities in condensed matter science. Among the more recent examples are heavy-fermion systems and organic superconductors. During this same period of time, superconductivity has also performed admirably in the applied area. Many ideas have been conceived and tested, making use of the unique characteristics of superconductivity - zero resistivity, quantum interference phenomena, and the Meissner effect. In fact, it was not until late January 1987 that it became possible to achieve superconductivity with the mere use of liquid nitrogen - which is plentiful, cheap, efficient, and easy to handle - following the discovery of supercondictivity above 90 K in Y-Ba-Cu-O, the first genuine quaternary superconductor. Superconductivity above 90 K poses scientific and technological challenges not previously encountered: no existing theories can adequately describe superconductivity above 40 K and no known techniques can economically process the materials for full-scale applications. In this paper, therefore, the author recalls a few events leading to the discovery of the new class of quaternary compounds with a superconducting transition temperature T c in the 90 K range, describes the current experimental status of high-temperature superconductivity and, finally, discusses the prospect of very-high-temperature superconductivity, i.e., with a T c substantially higher than 100 K. 97 refs., 7 figs

  4. Residual Resistivity Ratio (RRR) Measurements of LHC Superconducting NbTi Cable Strands

    CERN Document Server

    Charifoulline, Z

    2006-01-01

    The Rutherford-type superconducting NbTi cables of the LHC accelerator are currently manufactured by six industrial companies. As a part of the acceptance tests, the Residual Resistivity Ratio (RRR) of superconducting strands is systematically measured on virgin strands to qualify the strands before cabling and on extracted strands to qualify the cables and to check the final heat treatment (controlled oxidation to control interstrand resistance). More than 12000 samples of virgin and extracted strands have been measured during last five years. Results show good correlation with the measurements done by the companies and reflect well the technological process of cable production (strand annealing, cabling, cable heat treatment). This paper presents a description of the RRR-test station and the measurement procedure, the summary of the results over all suppliers and finally the correlation between RRR-values of the cables and the magnets.

  5. Analytical Model of Thermo-electrical Behaviour in Superconducting Resistive Core Cables

    CERN Document Server

    Calvi, M; Breschi, M; Coccoli, M; Granieri, P; Iriart, G; Lecci, F; Siemko, A

    2006-01-01

    High field superconducting Nb$_{3}$Sn accelerators magnets above 14 T, for future High Energy Physics applications, call for improvements in the design of the protection system against resistive transitions. The longitudinal quench propagation velocity (vq) is one of the parameters defining the requirements of the protection. Up to now vq has been always considered as a physical parameter defined by the operating conditions (the bath temperature, cooling conditions, the magnetic field and the over all current density) and the type of superconductor and stabilizer used. It is possible to enhance the quench propagation velocity by segregating a percent of the stabilizer into the core, although keeping the total amount constant and tuning the contact resistance between the superconducting strands and the core. Analytical model and computer simulations are presented to explain the phenomenon. The consequences with respect to minimum quench energy are evidenced and the strategy to optimize the cable designed is di...

  6. Quench Property of Twisted-Pair MgB$_2$ Superconducting Cables in Helium Gas

    CERN Document Server

    Spurrell, J; Falorio, I; Pelegrin, J; Ballarino, A; Yang, Y

    2015-01-01

    CERN's twisted-pair superconducting cable is a novel design which offers filament transposition, low cable inductance and is particularly suited for tape conductors such as 2G YBCO coated conductors, Ag-sheathed Bi2223 tapes and Ni/Monel-sheathed MgB2 tapes. A typical design of such twistedpair cables consists of multiple superconducting tapes intercalated with thin copper tapes as additional stabilizers. The copper tapes are typically not soldered to the superconducting tapes so that sufficient flexibility is retained for the twisting of the tape assembly. The electrical and thermal contacts between the copper and superconducting tapes are an important parameter for current sharing, cryogenic stability and quench propagation. Using an MgB2 twisted-pair cable assembly manufactured at CERN, we have carried out minimum quench energy (MQE) and propagation velocity (vp) measurements with point-like heat deposition localized within a tape. Furthermore, different contacts between the copper and superconductor aroun...

  7. Flux-transfer losses in helically wound superconducting power cables

    International Nuclear Information System (INIS)

    Clem, John R; Malozemoff, A P

    2013-01-01

    Minimization of ac losses is essential for economic operation of high-temperature superconductor (HTS) ac power cables. A favorable configuration for the phase conductor of such cables has two counter-wound layers of HTS tape-shaped wires lying next to each other and helically wound around a flexible cylindrical former. However, if magnetic materials such as magnetic substrates of the tapes lie between the two layers, or if the winding pitch angles are not opposite and essentially equal in magnitude to each other, current distributes unequally between the two layers. Then, if at some point in the ac cycle the current of either of the two layers exceeds its critical current, a large ac loss arises from the transfer of flux between the two layers. A detailed review of the formalism, and its application to the case of paramagnetic substrates including the calculation of this flux-transfer loss, is presented. (paper)

  8. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    International Nuclear Information System (INIS)

    Krueger Olsen, S.; Kuehle, A.; Traeholt, C.; C Rasmussen, C.; Toennesen, O.; Daeumling, M.; Rasmussen, C.N.; Willen, D.W.A.

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current and the voltage over the cable close to 90 degrees. This has the effect that the loss cannot be derived directly using most commercial lock-in amplifiers due to their limited absolute accuracy. However, by using two lock-in amplifiers and an appropriate correction scheme the high relative accuracy of such lock-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce the inductive voltage. The 1 μV cm -1 critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6±0.15 W m -1 . This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far at these high currents. (author)

  9. Rotation analysis on large complex superconducting cables based on numerical modeling and experiments

    NARCIS (Netherlands)

    Qin, Jinggang; Yue, Donghua; Zhang, Xingyi; Wu, Yu; Liu, Xiaochuan; Liu, Huajun; Jin, Huan; Dai, Chao; Nijhuis, Arend; Zhou, Chao; Devred, Arnaud

    2018-01-01

    The conductors used in large fusion reactors, e.g. ITER, CFETR and DEMO, are made of cable-in-conduit conductor (CICC) with large diameters up to about 50 mm. The superconducting and copper strands are cabled around a central spiral and then wrapped with stainless-steel tape of 0.1 mm thickness. The

  10. Analytical studies on hotspot temperature of cable-in-conduit conductors

    International Nuclear Information System (INIS)

    Yoshida, Kiyoshi; Takigami, Hiroyoshi; Kubo, Hiroatsu

    2001-01-01

    This paper describes an analytical study to review the hotspot temperature design criteria of the cable-in-conduit conductors for the ITER magnet system. The ITER magnet system uses three kinds of cable-in-conduit conductors for the Toroidal Field (TF) coils, the Central Solenoid (CS) and the Poloidal Field (PF) coils. The amount of copper in the superconducting cable has been defined by using the classical hotspot temperature design criteria that is based on the adiabatic condition. In the current design, ITER superconducting cables include a large amount of pure copper strands to satisfy the classical criteria. However, temperature and stress in the conduit and insulations after quench can be simulated with the quench simulation program and stress analysis program using the latest analysis tools. This analysis shows that the strand temperature is dominated by the conduction along strands and the heat capacity of other conductor materials and coolant. The hotspot temperature depends strongly on the delay time for quench detection. This analysis provides an estimation of delay times for quench detection. The thermal and stress analysis can provide the maximum allowable temperature after quench by determination of a failure or a functional disorder condition of the jacket material and turn insulation. In conclusion, it is found that the current density of the cable space can be increased, by reducing the extra copper strand, thereby, allowing a reduction of the coil radial build. (author)

  11. Some theories of high temperature superconductivity

    International Nuclear Information System (INIS)

    Cohen, M.L.

    1990-01-01

    In this paper a brief review is given of some historical aspects of theoretical research on superconductivity including a discussion of BCS theory and some theoretical proposals for mechanisms which can cause superconductivity at high temperatures

  12. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current......-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce-the inductive...... voltage. The 1 mu V cm(-1) critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6 +/- 0.15 W m(-1). This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far...

  13. Thermo-Hydraulic behaviour of dual-channel superconducting Cable-In-Conduit Conductors for ITER

    International Nuclear Information System (INIS)

    Renard, B.

    2006-09-01

    In an effort to optimise the cryogenics of large superconducting coils for fusion applications (ITER), dual channel Cable-In-Conduit Conductors (CICC) are designed with a central channel spiral to provide low hydraulic resistance and faster helium circulation. The qualitative and economic rationale of the conductor central channel is here justified to limit the superconductor temperature increase, but brings more complexity to the conductor cooling characteristics. The pressure drop of spirals is experimentally evaluated in nitrogen and water and an explicit hydraulic friction model is proposed. Temperatures in the cable must be quantified to guarantee superconductor margin during coil operation under heat disturbance and set adequate inlet temperature. Analytical one-dimensional thermal models, in steady state and in transient, allow to better understand the thermal coupling of CICC central and annular channels. The measurement of a heat transfer characteristic space and time constants provides cross-checking experimental estimations of the internal thermal homogenization. A simple explicit model of global inter-channel heat exchange coefficient is proposed. The risk of thermosyphon between the two channels is considered since vertical portions of fusion coils are subject to gravity. The new hydraulic model, heat exchange model and gravitational risk ratio allow the thermohydraulic improvement of CICC central spirals. (author)

  14. AmpaCity. Superconducting cables and fault current limiters for the energy supply in conurbations

    International Nuclear Information System (INIS)

    Merschel, F.; Noe, M.; Stemmle, M.; Hobl, A.; Sauerbach, O.

    2013-01-01

    In 2013 RWE Germany is working jointly with cable manufacturer Nexans and with the scientific support of the Karlsruhe Institute of Technology (KIT) to install world's longest superconducting cable in the downtown area electricity grid of Essen. The AmpaCity project is partly funded by the German Federal Ministry of Economics and Technology and is playing an exemplary role in the further development of electricity grids in major cities worldwide. The project consortium presents AmpaCity as a convincing system solution especially with respect to economics and security of supply. Components of the system are a superconducting three-phase AC cable with two terminations and one connection joint in combination with a fault current limiter, which is also based on superconducting materials. The superconducting system is designed for 10 kV nominal voltage and 40 MW nominal power. It will replace a 110 kV cable system of equal capacity. At the same time, the project partners are paving the way for high failsafe performance, as the cable in conjunction with the fault current limiter cannot be overloaded by short circuit currents in the event of faults in the grid. Planning and follow up on the civil works in Essen posed a major challenge. Cable laying in the inner city, with various crossings of major highways, tramways, as well as already dense cable routes necessitated very thorough preparation and coordination. The civil works in Essen started in April 2013. At around the same time, after the cable had passed the type test, it went into production. Cable laying is scheduled for late summer. After commissioning, planned for the end of 2013, the field trial will run for at least two years under real grid conditions, to demonstrate this technology's suitability for wider deployment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sumption, Mike D. [Ohio State University, Columbia, OH (United States); Collings, Edward W. [Ohio State University, Columbia, OH (United States)

    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.

  16. The Consequence of Self-field and Non-uniform Current Distribution on Short Sample Tests of Superconducting Cables

    CERN Document Server

    Verweij, A P

    1998-01-01

    Electrical measurements on samples of superconducting cables are usually performed in order to determine the critical current $I_c$ and the n-value, assuming that the voltage U at the transition from the superconducting to the normal state follows the power law, U\\sim($I/I_c$)$^n$. An accurate measurement of $I_c$ and n demands, first of all, good control of temperature and field, and precise measurement of current and voltage. The critical current and n-value of a cable are influenced by the self-field of the cable, an effect that has to be known in order to compare the electrical characteristics of the cable with those of the strands from which it is made. The effect of the self-field is dealt with taking into account the orientation and magnitude of the applied field and the n-value of the strands. An important source of inaccuracy is related to the distribution of the currents among the strands. Non-uniform distributions, mainly caused by non-equal resistances of the connections between the strands of the...

  17. Development of a Novel Method for the Exploration of the Thermal Response of Superfluid Helium Cooled Superconducting Cables to Pulse Heat Loads

    Science.gov (United States)

    Winkler, T.; Koettig, T.; van Weelderen, R.; Bremer, J.; ter Brake, H. J. M.

    Management of transient heat deposition in superconducting magnets and its extraction from the aforementioned is becoming increasingly important to bring high energy particle accelerator performance to higher beam energies and intensities. Precise knowledge of transient heat deposition phenomena in the magnet cables will permit to push the operation of these magnets as close as possible to their current sharing limit, without unduly provoking magnet quenches. With the prospect of operating the Large Hadron Collider at CERN at higher beam energies and intensities an investigation into the response to transient heat loads of LHC magnets, operating in pressurized superfluid helium, is being performed. The more frequently used approach mimics the cable geometry by resistive wires and uses Joule-heating to deposit energy. Instead, to approximate as closely as possible the real magnet conditions, a novel method for depositing heat in cable stacks made out of superconducting magnet-cables has been developed. The goal is to measure the temperature difference as a function of time between the cable stack and the superfluid helium bath depending on heat load and heat pulse length. The heat generation in the superconducting cable and precise measurement of small temperature differences are major challenges. The functional principle and experimental set-up are presented together with proof of principle measurements.

  18. A General Model for Thermal, Hydraulic and Electric Analysis of Superconducting Cables

    CERN Document Server

    Bottura, L; Rosso, C

    2000-01-01

    In this paper we describe a generic, multi-component and multi-channel model for the analysis of superconducting cables. The aim of the model is to treat in a general and consistent manner simultaneous thermal, electric and hydraulic transients in cables. The model is devised for most general situations, but reduces in limiting cases to most common approximations without loss of efficiency. We discuss here the governing equations, and we write them in a matrix form that is well adapted to numerical treatment. We finally demonstrate the model capability by comparison with published experimental data on current distribution in a two-strand cable.

  19. Status of high temperature superconductor cable and fault current limiter projects at American Superconductor

    International Nuclear Information System (INIS)

    Maguire, J.F.; Yuan, J.

    2009-01-01

    This paper will describe the status of three key programs currently underway at American Superconductor Corp. The first program is the LIPA project which is a transmission voltage high temperature superconducting cable program, with funding support from the US Department of Energy. The 600 m cable, capable of carrying 574 MVA, was successfully installed and commissioned in LIPA grid on April 22, 2008. An overview of the project, system level design details and operational data will be provided. In addition, the status of the newly awarded LIPA II project will be described. The second program is Project Hydra, with funding support from the US Department of Homeland Security, to design, develop and demonstrate an HTS cable with fault current limiting functionality. The cable is 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The cable will be permanently installed and energized in Manhattan, New York in 2010. The initial status of Project Hydra will be presented. The final program to be discussed is a transmission voltage, high temperature superconducting fault current limiter funded by the US DOE. The project encompasses the design, construction and test of a 115 kV FCL for power transmission within a time frame of 4-5 years. Installation and testing are planned for a Southern California Edison substation. A project overview and progress under the first phase will be reported.

  20. Status of high temperature superconductor cable and fault current limiter projects at American Superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.F., E-mail: jmaguire@amsc.co [American Superconductor Co., 64 Jackson Road, Devens, MA 01434 (United States); Yuan, J. [American Superconductor Co., 64 Jackson Road, Devens, MA 01434 (United States)

    2009-10-15

    This paper will describe the status of three key programs currently underway at American Superconductor Corp. The first program is the LIPA project which is a transmission voltage high temperature superconducting cable program, with funding support from the US Department of Energy. The 600 m cable, capable of carrying 574 MVA, was successfully installed and commissioned in LIPA grid on April 22, 2008. An overview of the project, system level design details and operational data will be provided. In addition, the status of the newly awarded LIPA II project will be described. The second program is Project Hydra, with funding support from the US Department of Homeland Security, to design, develop and demonstrate an HTS cable with fault current limiting functionality. The cable is 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The cable will be permanently installed and energized in Manhattan, New York in 2010. The initial status of Project Hydra will be presented. The final program to be discussed is a transmission voltage, high temperature superconducting fault current limiter funded by the US DOE. The project encompasses the design, construction and test of a 115 kV FCL for power transmission within a time frame of 4-5 years. Installation and testing are planned for a Southern California Edison substation. A project overview and progress under the first phase will be reported.

  1. Status of high temperature superconductor cable and fault current limiter projects at American Superconductor

    Science.gov (United States)

    Maguire, J. F.; Yuan, J.

    2009-10-01

    This paper will describe the status of three key programs currently underway at American Superconductor Corp. The first program is the LIPA project which is a transmission voltage high temperature superconducting cable program, with funding support from the US Department of Energy. The 600 m cable, capable of carrying 574 MVA, was successfully installed and commissioned in LIPA grid on April 22, 2008. An overview of the project, system level design details and operational data will be provided. In addition, the status of the newly awarded LIPA II project will be described. The second program is Project Hydra, with funding support from the US Department of Homeland Security, to design, develop and demonstrate an HTS cable with fault current limiting functionality. The cable is 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The cable will be permanently installed and energized in Manhattan, New York in 2010. The initial status of Project Hydra will be presented. The final program to be discussed is a transmission voltage, high temperature superconducting fault current limiter funded by the US DOE. The project encompasses the design, construction and test of a 115 kV FCL for power transmission within a time frame of 4-5 years. Installation and testing are planned for a Southern California Edison substation. A project overview and progress under the first phase will be reported.

  2. Advanced refrigeration system for the Brookhaven superconducting cable project

    International Nuclear Information System (INIS)

    Jensen, J.E.

    1975-01-01

    A description is given of a basic supercritical refrigerator. The present status of the cable enclosure and the types of cooling schemes being considered are presented with some examples of laboratory results and computer analysis. (MOW)

  3. Superconducting critical temperature under pressure

    Science.gov (United States)

    González-Pedreros, G. I.; Baquero, R.

    2018-05-01

    The present record on the critical temperature of a superconductor is held by sulfur hydride (approx. 200 K) under very high pressure (approx. 56 GPa.). As a consequence, the dependence of the superconducting critical temperature on pressure became a subject of great interest and a high number of papers on of different aspects of this subject have been published in the scientific literature since. In this paper, we calculate the superconducting critical temperature as a function of pressure, Tc(P), by a simple method. Our method is based on the functional derivative of the critical temperature with the Eliashberg function, δTc(P)/δα2F(ω). We obtain the needed coulomb electron-electron repulsion parameter, μ*(P) at each pressure in a consistent way by fitting it to the corresponding Tc using the linearized Migdal-Eliashberg equation. This method requires as input the knowledge of Tc at the starting pressure only. It applies to superconductors for which the Migdal-Eliashberg equations hold. We study Al and β - Sn two weak-coupling low-Tc superconductors and Nb, the strong coupling element with the highest critical temperature. For Al, our results for Tc(P) show an excellent agreement with the calculations of Profeta et al. which are known to agree well with experiment. For β - Sn and Nb, we found a good agreement with the experimental measurements reported in several works. This method has also been applied successfully to PdH elsewhere. Our method is simple, computationally light and gives very accurate results.

  4. Detail of photo 7903109 stack of superconducting cables in the modulus measuring device

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    The picture shows an assembly of insulated superconducting cables of the type used in the Po dipole magnet inserted in the elastic modulus measuring device (photos 7903547X and 7903169) in order to measures its mechanical properties under azimuthal compression. See also 7903547X, 7903169, 8307552X.

  5. FY 2000 research and development of fundamental technologies for AC superconducting power devices. R and D of fundamental technologies for superconducting power cables and faults current limiters, R and D of superconducting magnets for power applications, and study on the total systems and related subjects; 2000 nendo koryu chodendo denryoku kiki kiban gijutsu kenkyu kaihatsu seika hokokusho. Chodendo soden cable kiban gijutsu no kenkyu kaihatsu, chodendo genryuki kiban gijutsu no kenkyu kaihatsu, denryokuyo chodendo magnet no kenkyu kaihatsu, total system nado no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The project for research and development of fundamental technologies for AC superconducting power devices has been started, and the FY 2000 results are reported. The R and D of fundamental technologies for superconducting power cables include grasping the mechanical characteristics associated with integration necessary for fabrication of large current capacity and long cables; development of barrier cable materials by various methods; and development of short insulated tubes as cooling technology for long superconducting cables, and grasping its thermal/mechanical characteristics. The R and D of faults current limiters include introduction of the unit for superconducting film fabrication, determination of the structures and layouts for large currents, and improvement of performance of each device for high voltages. R and D of superconducting magnets for power applications include grasping the fundamental characteristics of insulation at cryogenic temperature, completion of the insulation designs for high voltage/current lead bushing, and development of prototype sub-cooled nitrogen cooling unit for cooling each AC power device. Study on the total systems and related subjects include analysis for stabilization of the group model systems, to confirm improved voltage stability when the superconducting cable is in service. (NEDO)

  6. Development of superconducting wire and cable for the SSC project in Sumitomo Electric Industries

    International Nuclear Information System (INIS)

    Sashida, T.; Saito, S.; Oku, G.; Kurimoto, K.; Yamada, Y.; Yokota, M.; Ohmatsu, K.; Nagata, M.

    1991-01-01

    As a large production volume of NbTi superconducting wire and cable is required for the SSC project, a production process has been developed at Sumitomo Electric to optimize critical variables of wire properties. To achieve high electrical properties and a high overall yield of NbTi alloy in the fabrication process, the authors have employed carefully designed large size multifilament billets weighing more than 350kg to decrease the number of billets in large production scale. The collider dipole magnet consists of inner and outer cables, and the cable should be as uniform as possible to ensure the performance of the magnets. The authors studied two aspects to obtain such uniformity of superconducting wire; one is the selection of unit weight and the other is the property of critical current density of a strand

  7. Development of a superconducting cable for transmission of high electric power

    International Nuclear Information System (INIS)

    Moisson, F.; Leroux, J.M.

    1971-01-01

    The opportunities opened by the use of cryoresistive and superconducting materials in underground transmission systems have led to a cryocable program. A first set of problems associated with the development of cryogenic cables deals with the cable system, i.e., design, safety, terminal equipment including leads, cryogenic equipment, refrigerators, and problems related to overload capability and reliability. A second set concerns the cable itself, i.e., scientific and technological problems associated with the conductor, the electrical insulation, and the thermal exchange between conductor and helium. Useful experience is gained on the design problems and on the technological problems involved in the construction of a cryoconducting cable. A 20-M aluminum cable cooled down to 25 0 K with pressurized helium flow was built and tested with 3500-A dc under 20 Kv; results are presented. On this model the following types of problems were solved. First, mechanical problems concerning cooling of the cable, thermal contraction of the pipes, electrical insulation and conductors, construction of an invariable cable constituted by elementary helically wound conductors were solved. Second, thermal problems of reduction of heat leaks, conception of thermal insulation, and segmentation of vacuum jackets were solved. Third, electrical problems of design of 300 0 to 25 0 K leads were solved; this problem of losses at both ends is, in proportion, more important for the short model than for long cable. Finally, refrigeration problems of helium and nitrogen flows, thermal shields and design of refrigerators (optimal capacity and spacing) were solved

  8. Quality analysis of superconducting wire and cable for SSC dipole magnets

    International Nuclear Information System (INIS)

    Pollock, D.A.

    1992-01-01

    This paper reports that a critical component of the SSC collider dipole magnets is superconducting cable. The uniformity and reliability requirements for the dipoles place stringent demands on the cable. These needs have been defined as various contract requirements in the material specifications for NbTi alloy, superconducting wire and cable. A supplied qualification program is being started by the SSCL with industry to establish reliable sources of superconductor cable. Key to this qualification program is the establishment by industry of detailed process methods and controls for wire and cable manufacture. To monitor conductor performance, a computer database is being developed by the SSCL Magnet Systems Division Quality Assurance Department. The database is part of a program for ensuring superconductor uniformity by focusing on the understanding and control of variation. A statistical and graphical summary of current data for key performance variables will be presented in light of the specification requirement for uniformity. Superconductor material characteristics to be addressed will include Wire Critical Current (I c ), Copper Ratio (Cu:SC), Wire Diameter, Wire Piece Length, and Cable Dimensional Control

  9. Steady state heat transfer experimental studies of LHC superconducting cables operating in cryogenic environment of superfluid helium

    CERN Document Server

    Santandrea, Dario; Tuccillo, Raffaele; Granieri, Pier Paolo

    The heat management is a basic and fundamental aspect of the superconducting magnets used in the CERN Large Hadron Collider. Indeed, the coil temperature must be kept below the critical value, despite the heat which can be generated or deposited in the magnet during the normal operations. Therefore, this thesis work aims at determining the heating power which can be extracted from the superconducting cables of the LHC, specially through their electrical insulation which represents the main thermal barrier. An experimental measurement campaign in superfluid helium bath was performed on several samples reproducting the main LHC magnets. The heating power was generated in the sample by Joule heating and the temperature increase was measured by means of Cernox bare chip and thermocouples. An innovative instrumentation technique which also includes the in-situ calibration of the thermocouples was developed. A thorough uncertainty analysis on the overall measurement chain concluded the experimental setup. The prese...

  10. Analysis of eddy current loss in high-Tc superconducting power cables with respect to various structure of stabilizer

    International Nuclear Information System (INIS)

    Choi, S. J.; Song, M. K.; Lee, S. J.; Cho, J. W.; Sim, K. D.

    2005-01-01

    The High-Tc superconducting power cable consists of a multi-layer high-Tc superconducting cable core and a stabilizer which is used to bypass the current at fault time. Eddy current loss is generated in the stabilizer in normal operating condition and affects the whole system. In this paper, the eddy current losses are analyzed with respect to various structure of stabilizer by using opera-3d. Moreover, optimal conditions of the stabilizer are derived to minimize the eddy current losses from the analyzed results. The obtained results could be applied to the design and manufacture of the high-Tc superconducting power cable system.

  11. A unique cabling designed to produce Rutherford-type superconducting cable for the SSC project

    International Nuclear Information System (INIS)

    Grisel, J.; Royet, J.M.; Scanlan, R.M.; Armer, R.

    1988-08-01

    Up to 25,000 Km of keystoned flat cable must be produced for the SSC project. Starting from a specification developed by Lawrence Berkeley Laboratory (LBL), a special cabling machine has been designed by Dour Metal. It has been designed to be able to run at a speed corresponding to a maximum production rate of 10 m/min. This cabling machine is the key part of the production line which consists of a precision Turkshead equipped with a variable power drive, a caterpillar, a dimensional control bench, a data acquisition system, and a take-up unit. The main features of the cabling unit to be described are a design with nearly equal path length between spool and assembling point for all the wires, and the possibility to run the machine with several over- or under-twisting ratios between cable and wires. These requirements led Dour Metal to the choice of an unconventional mechanical concept for a cabling machine. 4 refs., 2 figs

  12. High temperature superconductor cable concepts for fusion magnets

    CERN Document Server

    AUTHOR|(CDS)2078397

    2013-01-01

    Three concepts of high temperature superconductor cables carrying kA currents (RACC, CORC and TSTC) are investigated, optimized and evaluated in the scope of their applicability as conductor in fusion magnets. The magnetic field and temperature dependence of the cables is measured; the thermal expansion and conductivity of structure, insulation and filling materials are investigated. High temperature superconductor winding packs for fusion magnets are calculated and compared with corresponding low temperature superconductor cases.

  13. Analysis of the electrodynamics of subcable current distribution in the superconducting POLO coil cable

    International Nuclear Information System (INIS)

    Sihler, C.; Heller, R.; Maurer, W.; Ulbricht, A.; Wuechner, F.

    1995-10-01

    Unexpected ramp rate limitations (RRL) found in superconducting magnets during the development of magnet systems can be attributed to a current imbalance amongst the cabled strands which leads to a lower than expected quench current. In superconducting magnets the current distribution in the cable during ramping depends mainly on the electromagnetic properties of the system. A detailed analysis of principle causes for RRL phenomena was performed with a model for one half of the POLO coil considering the complete inductance matrix of the cable and the fact that all turns are mutually coupled. The main results of these calculations are that unequal contact resistances can not be responsible for RRL phenomena in coils with parameters comparable to those of the POLO coil and that already minor geometrical disturbances in the cable structure can lead to major and lasting imbalances in the current distribution of cables with insulated and non-insulated strands. During the POLO experiment the half-coil model was employed to get a better understanding of the measured compensated subcable voltages during quench. The good agreement of the calculated and measured results demonstrates the validity of the model for RRL analyses. (orig.)

  14. Protection for low current superconducting coils wound with insulated strand cable

    International Nuclear Information System (INIS)

    Satti, J.

    1980-09-01

    The insulated strand cable concept for winding of low current superconducting coil leads to an ideal quench protection by induction coupling. A superconducting secondary loop was made within a cable of a 6.2 Henry dipole coil. When quenching occurred, current was induced in the secondary strand above the critical value. The normal strand quenched the whole cable due to good thermal contact. The secondary loop works as a heater turned on as the wire becomes normal throughout the coil. With a well spread quench, the energy dissipation density is decreased thus preventing local burnout. The mechanism is possible because of close coupling that is present in the insulated cable as in bifilar winding. For the coil tested a 12 strand cable was used, thus a favorable 11 to 1 turn ratio was obtained for the primary to secondary. The superconductor in the secondary had a lower resistance until the critical current was achieved. A theoretical explanation is described for a simplified circuit. Test on the dipole coil with four individual shells showed that the one shell protected with the induced coupling heater always had a more rapid reduction of current. The induced coupling heater tested and explained in this paper works automatically and does not rely on mechanical or electrical devices

  15. Experiment of 200-meter superconducting DC cable system in Chubu University

    International Nuclear Information System (INIS)

    Yamaguchi, S.; Kawahara, T.; Hamabe, M.; Watanabe, H.; Ivanov, Yu.; Sun, J.; Iiyoshi, A.

    2011-01-01

    We designed and constructed the experimental device of 200-meter superconducting DC cable system in the beginning of 2010 and did the first experiment until March, 2010, and the second experiment has been done from August to October 2010. This experimental device is called CASER-2, and the main aim of the experiment is to demonstrate high performance of DC superconducting cable system for comparing the copper cable system. Thermal contraction and expansion during the thermal cycle are discussed in the paper because if the thermal stress of the HTS tape conductor is high, the critical current of the HTS tape is reduced. Therefore, it is the first priority to keep the system in high performance and safety. We also mentioned several experiments and ideas in the paper, such as the low heat leaks of the terminal cryostat and the cryogenic pipe, and the low circulation power, energy storage function of the cable system. In this paper, we present the experimental results of the CASER-2, and discuss and estimate the performance of the system and several ideas. These discussions include the specification of the future long cable system, and show the subjects to solve for the future system.

  16. Helium flow dynamics and heat transfer in a cable in conduit conductor of superconducting magnets: a review

    International Nuclear Information System (INIS)

    Vaghela, Hitensinh; Sarkar, Biswanath; Lakhera, Vikas

    2016-01-01

    Superconducting (SC) magnets with Cable in Conduit Conductor (CICC) winding, cooled by helium at 4 K temperature are employed for many applications which require high magnetic field and high current densities. The construction of CICC aims to maintain superconductivity state by optimization of various parameters, i.e., thermal stability, ratio of normal conductor to superconductor material, mechanical strength, low hydraulic impedance, current density, magnetic field, etc. The cryogenic thermal stability of the CICC is of prime importance for the safe, stable and reliable operation of SC magnets. The prediction of thermal and hydraulic behaviour of CICC in large SC magnets is difficult due to the complex geometry, variation of fluid properties, various heat in-flux incidences over the long length of CICC and a complex heat transport phenomenon. A systematic review of the thermal and hydraulic studies of CICC has been presented in the paper highlighting the challenges and opportunities for further improvement in its design and performance. (author)

  17. Stability of superconducting Rutherford cables for accelerator magnets

    NARCIS (Netherlands)

    Willering, G.P.

    2009-01-01

    The stability of superconducting magnets has a high priority for particle accelerators, since the operational time and operational collision energy depend strongly on it. Local heat dissipation due to beam loss and conductor movement is inevitable, causing local hot spots in the conductor, possibly

  18. Proposal for the award of a contract, without competitive tendering, for the supply of two cabling machines for the manufacture of superconducting cable for the LHC main magnets

    CERN Document Server

    2001-01-01

    This document concerns the award of a contract, without competitive tendering, for the supply of two cabling machines for the production of superconducting cable for the LHC main magnets. These cables are of two different types, hereafter referred as Cable 1 and Cable 2. For the reasons set out in this document, the Finance Committee is invited to agree to the negotiation of a contract with SETIC (FR) for the supply of two cabling machines, for a total amount not exceeding 3 200 000 euros (4 948 800 Swiss francs), not subject to revision. The rate of exchange which has been used is that stipulated in the tender. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: FR - 100%.

  19. Characteristic Analysis of DC Electric Railway Systems with Superconducting Power Cables Connecting Power Substations

    Science.gov (United States)

    Ohsaki, H.; Matsushita, N.; Koseki, T.; Tomita, M.

    2014-05-01

    The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

  20. Characteristic analysis of DC electric railway systems with superconducting power cables connecting power substations

    International Nuclear Information System (INIS)

    Ohsaki, H; Matsushita, N; Koseki, T; Tomita, M

    2014-01-01

    The application of superconducting power cables to DC electric railway systems has been studied. It could leads to an effective use of regenerative brake, improved energy efficiency, effective load sharing among the substations, etc. In this study, an electric circuit model of a DC feeding system is built and numerical simulation is carried out using MATLAB-Simulink software. A modified electric circuit model with an AC power grid connection taken into account is also created to simulate the influence of the grid connection. The analyses have proved that a certain amount of energy can be conserved by introducing superconducting cables, and that electric load distribution and concentration among the substations depend on the substation output voltage distribution.

  1. A new scheme for critical current measurements on straight superconducting cables in a large solenoid

    International Nuclear Information System (INIS)

    Rossi, L.; Volpini, G.

    1991-01-01

    The precision of I c measurement of straight superconducting cables in solenoids can be limited by the magnetic field inhomogeneity. A solution in order to improve the field homogeneity based on iron shims is presented here. A conceptual design for the experimental lay-out of a test station to be used in connection with the SOLEMI-I solenoid at the Milan INFN Section (LASA Laboratory) is given

  2. Electrical Insulation of 500-m High-Tc Superconducting Power Cable

    International Nuclear Information System (INIS)

    Takahashi, T; Ichikawa, M; Suzuki, H; Okamoto, T; Akita, S; Mukoyama, S; Yagi, M; Maruyama, S; Kimura, A

    2006-01-01

    Electrical insulation is one of the essential technologies for the electric power apparatus. Determination of testing voltages and design method of the electrical insulation layer are inextricably linked each other, and are critical to developing and realizing a cold dielectric (CD) type high-Tc superconducting (HTS) power cable. The authors had proposed the electrical insulation design method with concepts of partial discharge-free designs for ac voltage condition. This paper discusses the testing voltages for a 77 kV 1000 A HTS power cable with a length of 500 m, and describes results of various voltage withstand test. As a result, it is concluded that the proposed electrical insulation design method is appropriate for the HTS power cable

  3. Current distribution inside Rutherford-type superconducting cables and impact on performance of LHC dipoles

    CERN Document Server

    Schreiner, T

    2002-01-01

    The windings of high--field superconducting accelerator magnets are usually made of Rutherford--type cables. The magnetic field distribution along the axis of such magnets exhibits a periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. Such a Periodic Field Pattern (PFP) has already been observed in number of superconducting accelerator magnets. Additional unbalanced currents in individual strands of the cable appear to be causing this effect. The present thesis describes the investigation of the PFPs performed with a Hall probes array inserted inside the aperture of the LHC superconducting dipoles, both in the small--scale model magnets with a length of one meter and in full--scale prototypes and pre--series magnets with fifteen meters of length. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the magnet current history. One of the main parameters influencing the properties of the PFP is the cross--...

  4. The Electrical Aspects of the choice of Former in a High T-c Superconducting Power Cable

    DEFF Research Database (Denmark)

    Däumling, Manfred; Kühle (fratrådt), Anders Van Der Aa; Olsen, Søren Krüger

    1999-01-01

    Centrally located in a superconducting power cable the former supplies a rigid means onto which to wind the superconducting tapes and enables a continuous supply of cooling power via a flow of liquid cryogen through it. Therefore, the choice of former has a broad impact on the construction and de...

  5. Superconducting magnets

    International Nuclear Information System (INIS)

    1994-08-01

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

  6. Textured YBCO films grown on wires: application to superconducting cables

    International Nuclear Information System (INIS)

    Dechoux, N; Jiménez, C; Chaudouët, P; Rapenne, L; Sarigiannidou, E; Robaut, F; Petit, S; Garaudée, S; Porcar, L; Soubeyroux, J L; Odier, P; Bruzek, C E; Decroux, M

    2012-01-01

    Efforts to fabricate superconducting wires made of YBa 2 Cu 3 O 7 (YBCO) on La 2 Zr 2 O 7 (LZO) buffered and biaxially textured Ni-5 at.%W (NiW) are described. Wires were manually shaped from LZO buffered NiW tapes. Different diameters were produced: 1.5, 2 and 3 mm. The wires were further covered with YBCO grown by metal organic chemical vapor deposition (MOCVD). We developed an original device in which the round substrate undergoes an alternated rotation of 180° around its axis in addition to a reel-to-reel translation. This new approach allows covering the whole circumference of the wire with a YBCO layer. This was confirmed by energy dispersive x-ray spectroscopy (EDX) analysis coupled to a scanning electron microscope (SEM). For all wire diameters, the YBCO layer thickness varied from 300 to 450 nm, and the cationic composition was respected. Electron backscattering diffraction (EBSD) measurements were performed directly on an as-deposited wire without surface preparation allowing the investigation of the crystalline quality of the film surface. Combining EBSD with XRD results we show that YBCO grows epitaxially on the LZO buffered NiW wires. For the first time, superconductive behaviors have been detected on round substrates in both the rolling and circular direction. J c reached 0.3 MA cm −2 as measured at 77 K by transport and third-harmonic detection. Those preliminary results confirm the effectiveness of the MOCVD for complex geometries, especially for YBCO deposition on small diameter wires. This approach opens huge perspectives for the elaboration of a new generation of YBCO-based round conductors. (paper)

  7. Theory of high temperature superconductivity

    International Nuclear Information System (INIS)

    Srivastava, C.M.

    1989-01-01

    This paper develops a semi-empirical electronic band structure for a high T c superconductor like YBa 2 Cu 3 O 6 - δ . The author accounts for the electrical transport properties on the model based on the correlated electron transfer arising from the electron-phonon interaction. The momentum pairing leading to the superconducting phase amongst the mobile charge carriers is shown

  8. Supercritical helium cooled, cabled, superconducting hollow conductors for large high field magnets

    International Nuclear Information System (INIS)

    Hoenig, M.O.; Iwasa, Y.; Montgomery, D.B.; Bejan, A.

    1976-01-01

    Within the last two years a new concept of cabled superconducting hollow conductors has been developed which are able to recover from transient instabilities by virtue of on-going, single-phase helium cooling. It has been possible to correlate small scale experimental results with an iterative computer program. The latter has been recently upgraded to include axial as well as radial heat transfer and predict more closely the chances of recovery. Nearly 1 g/s of supercritical helium has been circulated in a closed loop using a high speed centrifugal fan and up to 10 g/s using a reciprocating single pulse bellows pump. The loop is now being adapted to a 3 m length of a tightly wound 5000 A cabled hollow conductor equipped with pulse coils designed to fit inside a water cooled Bitter magnet. The combination will allow for a steady background field of 7.5 t with a 2 t superimposed pulse. (author)

  9. Qualification of Fiber Optic Cables for Martian Extreme Temperature Environments

    Science.gov (United States)

    Ramesham, Rajeshuni; Lindensmith, Christian A.; Roberts, William T.; Rainen, Richard A.

    2011-01-01

    Means have been developed for enabling fiber optic cables of the Laser Induced Breakdown Spectrometer instrument to survive ground operations plus the nominal 670 Martian conditions that include Martian summer and winter seasons. The purpose of this development was to validate the use of the rover external fiber optic cabling of ChemCam for space applications under the extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission. Flight-representative fiber optic cables were subjected to extreme temperature thermal cycling of the same diurnal depth (or delta T) as expected in flight, but for three times the expected number of in-flight thermal cycles. The survivability of fiber optic cables was tested for 600 cumulative thermal cycles from -130 to +15 C to cover the winter season, and another 1,410 cumulative cycles from -105 to +40 C to cover the summer season. This test satisfies the required 3 times the design margin that is a total of 2,010 thermal cycles (670 x 3). This development test included functional optical transmission tests during the course of the test. Transmission of the fiber optic cables was performed prior to and after 1,288 thermal cycles and 2,010 thermal cycles. No significant changes in transmission were observed on either of the two representative fiber cables subject through the 3X MSL mission life that is 2,010 thermal cycles.

  10. Temperature rise of cyclicly loaded power cables

    Energy Technology Data Exchange (ETDEWEB)

    Brakelmann, H

    1984-09-01

    A calculation method for the current ratings of cyclicly loaded power cables is introduced, taking into account optional shapes of the load cycle as well as the drying-out of the soil. The method is based on the Fourier-analysis of the loss cycle, representing an extension of the calculation method of VDE 0298. It is shown, that the ''VDE-method'' gives good results for the thermal resistances, if an ''utility load cycle'' in accordance with VDE 0298 is supposed. Only for cycles deviating essentially from the utility load cycle, the thermal resistances calculated by the ''VDE-method'' may be too great. In these cases the represented method is advantageous and can be processed by the aid of microcomputers.

  11. The discovery of high temperature superconductivity

    International Nuclear Information System (INIS)

    Muller, K. A.; Bednorz, J.G.

    1988-01-01

    This article recalls the different stages which led to the display of high temperature superconductivity for Ba, La, Cu, O and the following avalanche of discoveries for other oxides; the numerous theoretical models which tentatively explain the current experimental results are also reviewed. 30 refs

  12. The discovery of high temperature superconductivity

    International Nuclear Information System (INIS)

    Muller, K.A.; Bednorz, J.G.

    1988-01-01

    This article recalls the different stages which led to the display of high temperature superconductivity for Ba La Cu O, and the following avalanche of discoveries for other oxides; the numerous theoretical models which tentatively explain the current experimental results are also reviewed [fr

  13. Study of Nb{sub 3}Sn cables for superconducting quadrupoles; Etude de cables Nb{sub 3}Sn pour quadripoles supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Otmani, R

    1999-10-01

    In particle physics, the quest for higher energies may be satisfied by the use of niobium-tin superconducting magnets. Such magnets are made of Rutherford type cables which are wound from superconducting strands. The strands are made by the 'internal tin' method. The aim of this study is to determine the main parameters for the fabrication of a quadrupole. The two main requirements the cable must fulfill are high critical current and low losses. The main parameters were determined from different measurements and models. Thus, the key parameters for the current transport capacity are the number and the diameter of the filaments, the number of sub-elements, the surface of superconductor and the copper-to-non-copper ratio. For the hysteresis losses, the main parameters appear to be the effective filament diameter and the spacing of the filaments. For intra-strand losses, the main parameters appear to be the filaments' diameter, the filament spacing, the nature of the diffusion barrier and the Residual Resistivity Ratio (RRR) of the copper. The interstrand resistances for the cable are the key parameters for the losses. Thus, the nature of the strands coating or the presence of a stainless steel core can strongly diminish the cable losses. Finally, a design, for the strands and the cables for the fabrication of a quadrupole is proposed. (author)

  14. Contributions to the study of superconducting multifilamentary composites and cables; Contributions a l`etude du comportement des composites et cables supraconducteurs

    Energy Technology Data Exchange (ETDEWEB)

    Turck, B

    1992-03-01

    This report is a collection of published papers in French and in English on superconducting composites and cables. All domains concerning the behaviour of superconductors in coils for field generation have been covered: critical current, current distribution, instabilities, losses in varying field. This document provides with expressions and criteria for conductor design, with conditions for achieving given performances and with criteria for design and optimization of structures of multifilamentary composites and cables. These publications have played a determining role in the understanding of the behaviour of superconductors and in their use in high performing magnets.

  15. The quality assurance of superconducting wire and cable for SSC magnets

    International Nuclear Information System (INIS)

    Pollock, D.; Baggett, P.; Capone, D.

    1991-03-01

    The success of the SSC depends on the consistency and uniformity of the superconducting magnets used in the main collider rings and the high energy booster. To a great extent the success of the magnets depends upon the quality of the superconductor wire and cable used in coil windings. As the SSC project has begun its transition from Research to Development, a new laboratory organization has been established to carry the design requirements from concept to reality. The SSCL Magnet Systems Division Quality Assurance Group has been working on the development of a quality management and analysis system for insuring superconductor uniformity through the understanding and control of manufacturing variation. Key areas of the QA activity include: the design and development of a computer database and analysis system for the collection and statistical analysis of superconductor materials data (containing: source physical and chemical properties, billet process history, and final product performance data); and the development of wire and cable product specifications which focus on the control of variation. As a result of this work several new concepts have been developed which will affect the traditional approach to superconductor wire and cable production. 18 refs., 5 figs., 1 tab

  16. Short-circuit experiments on a high Tc-superconducting cable conductor

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Jensen, E.H.; Traholt, C.

    2002-01-01

    A high temperature superconductor (HTS) cable conductor (CC) with a critical current of 2.1 kA was tested over a range of short-circuit currents up to 20 kA. The duration of the short-circuit currents is 1 s. Between each short-circuit test the critical current of the HTS CC was measured in order...

  17. High transition temperature superconducting integrated circuit

    International Nuclear Information System (INIS)

    DiIorio, M.S.

    1985-01-01

    This thesis describes the design and fabrication of the first superconducting integrated circuit capable of operating at over 10K. The primary component of the circuit is a dc SQUID (Superconducting QUantum Interference Device) which is extremely sensitive to magnetic fields. The dc SQUID consists of two superconductor-normal metal-superconductor (SNS) Josephson microbridges that are fabricated using a novel step-edge process which permits the use of high transition temperature superconductors. By utilizing electron-beam lithography in conjunction with ion-beam etching, very small microbridges can be produced. Such microbridges lead to high performance dc SQUIDs with products of the critical current and normal resistance reaching 1 mV at 4.2 K. These SQUIDs have been extensively characterized, and exhibit excellent electrical characteristics over a wide temperature range. In order to couple electrical signals into the SQUID in a practical fashion, a planar input coil was integrated for efficient coupling. A process was developed to incorporate the technologically important high transition temperature superconducting materials, Nb-Sn and Nb-Ge, using integrated circuit techniques. The primary obstacles were presented by the metallurgical idiosyncrasies of the various materials, such as the need to deposit the superconductors at elevated temperatures, 800-900 0 C, in order to achieve a high transition temperature

  18. Measurement of the temperature distribution inside the power cable using distributed temperature system

    Science.gov (United States)

    Jaros, Jakub; Liner, Andrej; Papes, Martin; Vasinek, Vladimir; Mach, Veleslav; Hruby, David; Kajnar, Tomas; Perecar, Frantisek

    2015-01-01

    Nowadays, the power cables are manufactured to fulfill the following condition - the highest allowable temperature of the cable during normal operation and the maximum allowable temperature at short circuit conditions cannot exceed the condition of the maximum allowable internal temperature. The distribution of the electric current through the conductor leads to the increase of the amplitude of electrons in the crystal lattice of the cables material. The consequence of this phenomenon is the increase of friction and the increase of collisions between particles inside the material, which causes the temperature increase of the carrying elements. The temperature increase is unwanted phenomena, because it is causing losses. In extreme cases, the long-term overload leads to the cable damaging or fire. This paper deals with the temperature distribution measurement inside the power cables using distributed temperature system. With cooperation with Kabex company, the tube containing optical fibers was installed into the center of power cables. These fibers, except telecommunications purposes, can be also used as sensors in measurements carrying out with distributed temperature system. These systems use the optical fiber as a sensor and allow the continual measurement of the temperature along the whole cable in real time with spatial resolution 1 m. DTS systems are successfully deployed in temperature measurement applications in industry areas yet. These areas include construction, drainage, hot water etc. Their advantages are low cost, resistance to electromagnetic radiation and the possibility of real time monitoring at the distance of 8 km. The location of the optical fiber in the center of the power cable allows the measurement of internal distribution of the temperature during overloading the cable. This measurement method can be also used for prediction of short-circuit and its exact location.

  19. Use of high-temperature superconducting films in superconducting bearings

    International Nuclear Information System (INIS)

    Cansiz, A.

    1999-01-01

    We have investigated the effect of high-temperature superconductor (HTS) films deposited on substrates that are placed above bulk HTSs in an attempt to reduce rotational drag in superconducting bearings composed of a permanent magnet levitated above the film/bulk HTS combination. According to the critical state model, hysteresis energy loss is inversely proportional to critical current density, J c , and because HTS films typically have much higher J c than that of bulk HTS, the film/bulk combination was expected to reduce rotational losses by at least one order of magnitude in the coefficient of fiction, which in turn is a measure of the hysteresis losses. We measured rotational losses of a superconducting bearing in a vacuum chamber and compared the losses with and without a film present. The experimental results showed that contrary to expectation, the rotational losses are increased by the film. These results are discussed in terms of flux drag through the film, as well as of the critical state model

  20. Superconductivity

    International Nuclear Information System (INIS)

    Onnes, H.K.

    1988-01-01

    The author traces the development of superconductivity from 1911 to 1986. Some of the areas he explores are the Meissner Effect, theoretical developments, experimental developments, engineering achievements, research in superconducting magnets, and research in superconducting electronics. The article also mentions applications shown to be technically feasible, but not yet commercialized. High-temperature superconductivity may provide enough leverage to bring these applications to the marketplace

  1. Measuring ac losses in superconducting cables using a resonant circuit:Resonant current experiment (RESCUE)

    DEFF Research Database (Denmark)

    Däumling, Manfred; Olsen, Søren Krüger; Rasmussen, Carsten

    1998-01-01

    be recorded using, for example, a digital oscilloscope. The amplitude decay of the periodic voltage or current accurately reflects the power loss in the system. It consists of two components-an ohmic purely exponential one (from leads, contacts, etc.), and a nonexponential component originating from......A simple way to obtain true ac losses with a resonant circuit containing a superconductor, using the decay of the circuit current, is described. For the measurement a capacitor is short circuited with a superconducting cable. Energy in the circuit is provided by either charging up the capacitors...... with a certain voltage, or letting a de flow in the superconductor. When the oscillations are started-either by opening a switch in case a de is flowing or by closing a switch to connect the charged capacitors with the superconductor-the current (via a Rogowski coil) or the voltage on the capacitor can...

  2. Theory and modelling of quench in cable-in-conduit superconducting magnets

    International Nuclear Information System (INIS)

    Shajii, A.

    1994-04-01

    A new simple, self consistent theoretical model is presented that describes the phenomena of quench propagation in Cable-In-Conduit superconducting magnets. The model (Quencher) circumvents many of the difficulties associated with obtaining numerical solutions in more general existing models. Specifically, a factor of 30-50 is gained in CPU time over the general, explicit time dependent codes used to study typical quench events. The corresponding numerical implementation of the new model is described and the numerical results are shown to agree very well with those of the more general models, as well as with experimental data. Further, well justified approximations lead to the MacQuench model that is shown to be very accurate and considerably more efficient than the Quencher model. The MacQuench code is suitable for performing quench studies on a personal computer, requiring only several minutes of CPU time. In order to perform parametric studies on new conductor designs it is required to utilize a model such as MacQuench because of the high computational efficiency of this model. Finally, a set of analytic solutions for the problem of quench propagation in Cable-In-Conduit Conductors is presented. These analytic solutions represent the first such results that remain valid for the long time scales of interest during a quench process. The assumptions and the resulting simplifications that lead to the analytic solutions are discussed, and the regimes of validity of the various approximations are specified. The predictions of the analytic results are shown to be in very good agreement with numerical as well as experimental results. Important analytic scaling relations are verified by such comparisons, and the consequences of some of these scalings on currently designed superconducting magnets are discussed

  3. Research briefing on high-temperature superconductivity

    Science.gov (United States)

    1987-10-01

    The research briefing was prepared in response to the exciting developments in superconductivity in ceramic oxide materials announced earlier in 1987. The panel's specific charge was to examine not only the scientific opportunities in high-temperature superconductivity but also the barriers to commercial exploitation. While the base of experimental knowledge on the superconductors is growing rapidly, there is as yet no generally accepted theoretical explanation of their behavior. The fabrication and processing challenges presented by the materials suggest that the period or precommercial exploration for applications will probably extend for a decade or more. Near term prospects for applications include magnetic shielding, the voltage standard, superconducting quantum interference devices, infrared sensors, microwave devices, and analog signal processing. The panel also identified a number of longer-term prospects in high-field and large-scale applications, and in electronics. The United States' competitive position in the field is discussed, major scientific and technological objectives for research and development identified, and concludes with a series of recommendations.

  4. Superconductivity

    International Nuclear Information System (INIS)

    Palmieri, V.

    1990-01-01

    This paper reports on superconductivity the absence of electrical resistance has always fascinated the mind of researchers with a promise of applications unachievable by conventional technologies. Since its discovery superconductivity has been posing many questions and challenges to solid state physics, quantum mechanics, chemistry and material science. Simulations arrived to superconductivity from particle physics, astrophysic, electronics, electrical engineering and so on. In seventy-five years the original promises of superconductivity were going to become reality: a microscopical theory gave to superconductivity the cloth of the science and the level of technological advances was getting higher and higher. High field superconducting magnets became commercially available, superconducting electronic devices were invented, high field accelerating gradients were obtained in superconductive cavities and superconducting particle detectors were under study. Other improvements came in a quiet progression when a tornado brought a revolution in the field: new materials had been discovered and superconductivity, from being a phenomenon relegated to the liquid Helium temperatures, became achievable over the liquid Nitrogen temperature. All the physics and the technological implications under superconductivity have to be considered ab initio

  5. Low AC Loss in a 3 kA HTS Cable of the Dutch Project

    DEFF Research Database (Denmark)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan

    2012-01-01

    Requirements for a 6km long high temperature superconducting (HTS) AC power cable of the Amsterdam project are: a cable has to fit in an annulus of 160mm, with two cooling stations at the cable ends only. Existing solutions for HTS cables would lead to excessively high coolant pressure drop in th...

  6. High temperature superconductivity and cold fusion

    International Nuclear Information System (INIS)

    Rabinowitz, M.

    1990-01-01

    There are numerous historical and scientific parallels between high temperature superconductivity (HTSC) and the newly emerging field of cold fusion (CF). Just as the charge carrier effective mass plays an important role in SC, the deuteron effective mass may play a vital role in CF. A new theory including effects of proximity, electron shielding, and decreased effective mass of the fusing nuclei can account for the reported CF results. A quantum-gas model that covers the range from low temperature to superhigh temperature SC indicates an increased T c with reduced dimensionality. A reduced dimensionality effect may also enhance CF. A relation is shown between CF and the significant cluster-impact fusion experiments

  7. Superconducting magnets 1992

    International Nuclear Information System (INIS)

    1993-06-01

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

  8. Superconductivity

    International Nuclear Information System (INIS)

    Kakani, S.L.; Kakani, Shubhra

    2007-01-01

    The monograph provides readable introduction to the basics of superconductivity for beginners and experimentalists. For theorists, the monograph provides nice and brief description of the broad spectrum of experimental properties, theoretical concepts with all details, which theorists should learn, and provides a sound basis for students interested in studying superconducting theory at the microscopic level. Special chapter on the theory of high-temperature superconductivity in cuprates is devoted

  9. High temperature superconductivity space experiment (HTSSE)

    International Nuclear Information System (INIS)

    Nisenoff, M.; Gubser, D.V.; Wolf, S.A.; Ritter, J.C.; Price, G.

    1991-01-01

    The Naval Research Laboratory (NRL) is exploring the feasibility of deploying high temperature superconductivity (HTS) devices and components in space. A variety of devices, primarily passive microwave and millimeter wave components, have been procured and will be integrated with a cryogenic refrigerator system and data acquisition system to form the space package, which will be launched late in 1992. This Space Experiment will demonstrate that this technology is sufficiently robust to survive the space environment and has the potential to significantly improved space communications systems. The devices for the initial launch (HTSSE-I) have been received by NRL and evaluated electrically, thermally and mechanically and will be integrated into the final space package early in 1991. In this paper the performance of the devices are summarized and some potential applications of HTS technology in space system are outlined

  10. High temperature superconducting Maglev equipment on vehicle

    Science.gov (United States)

    Wang, S. Y.; Wang, J. S.; Ren, Z. Y.; Zhu, M.; Jiang, H.; Wang, X. R.; Shen, X. M.; Song, H. H.

    2003-04-01

    Onboard high temperature superconducting (HTS) Maglev equipment is a heart part of a HTS Maglev vehicle, which is composed of YBaCuO bulks and rectangle-shape liquid nitrogen vessel and used successfully in the first manned HTS Maglev test vehicle. Arrangement of YBaCuO bulks in liquid nitrogen vessel, structure of the vessel, levitation forces of a single vessel and two vessels, and total levitation force are reported. The first manned HTS Maglev test vehicle in the world has operated well more than one year after it was born on Dec. 31, 2000, and more than 23,000 passengers have taken the vehicle till now. Well operation of more than one year proves the reliability of the onboard HTS Maglev equipment.

  11. Analysis of thermodynamic properties for high-temperature superconducting oxides

    International Nuclear Information System (INIS)

    Kushwah, S.S.; Shanker, J.

    1993-01-01

    Analysis of thermodynamic properties such as specific heat, Debye temperature, Einstein temperature, thermal expansion coefficient, bulk modulus, and Grueneisen parameter is performed for rare-earth-based, Tl-based, and Bi-based superconducting copper oxides. Values of thermodynamic parameters are calculated and reported. The relationship between the Debye temperature and the superconducting transition temperature is used to estimate the values of T c using the interaction parameters from Ginzburg. (orig.)

  12. Realisation and instrumentation of high current power station for superconducting cables testing

    International Nuclear Information System (INIS)

    Regnaud, S.

    2000-05-01

    This report deals with the designing of a high current station able to test electric properties of superconductors. This test station will be used for testing the superconducting wires of large hadron collider detectors in CERN. The high current test station will have to generate high intensity continuous current in a magnetic field of 0 to 5 tesla and in temperature conditions of 4.2 K. The length of wire samples submitted to the uniform magnetic field is 300 mm and the installation is fitted with equipment able to measure the magnetic field perpendicular to either faces of the wire. The peculiarity of this station is to use a superconducting transformer in order to generate the high current. The first part of this work recalls important notions concerning superconductivity. The second part presents the high current station by describing the superconducting transformer and the sample-holder. We have studied the designing of a transformer able to yield a secondary current whose intensity reaches 100 kA, such intensity generates powerful electromagnetic forces (566 kN/m) in case of defect, so the sample-holder has to be carefully design to bear them. The third part presents the cryogenic component of the station, the instrumentation of the sample-holder and the method used to measure secondary currents. In the last part we present the performance of a prototype transformer, this prototype is able to deliver a 22 kA secondary current for a 160 A primary current, the uncertainty on the measured value of the secondary current is about 3%

  13. Superconductivity

    International Nuclear Information System (INIS)

    Caruana, C.M.

    1988-01-01

    Despite reports of new, high-temperature superconductive materials almost every day, participants at the First Congress on Superconductivity do not anticipate commercial applications with these materials soon. What many do envision is the discovery of superconducting materials that can function at much warmer, perhaps even room temperatures. Others hope superconductivity will usher in a new age of technology as semiconductors and transistors did. This article reviews what the speakers had to say at the four-day congress held in Houston last February. Several speakers voiced concern that the Reagan administration's apparent lack of interest in funding superconductivity research while other countries, notably Japan, continue to pour money into research and development could hamper America's international competitiveness

  14. Japan. Superconductivity for Smart Grids

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.

    2012-11-15

    Currently, many smart grid projects are running or planned worldwide. These aim at controlling the electricity supply more efficiently and more stably in a new power network system. In Japan, especially superconductivity technology development projects are carried out to contribute to the future smart grid. Japanese cable makers such as Sumitomo Electric and Furukawa Electric are leading in the production of high-temperature superconducting (HTS) power cables. The world's largest electric current and highest voltage superconductivity proving tests have been started this year. Big cities such as Tokyo will be expected to introduce the HTS power cables to reduce transport losses and to meet the increased electricity demand in the near future. Superconducting devices, HTS power cables, Superconducting Magnetic Energy Storage (SMES) and flywheels are the focus of new developments in cooperations between companies, universities and research institutes, funded by the Japanese research and development funding organization New Energy and Industrial Technology Development Organization (NEDO)

  15. Alternating current loss calculation in a high-TC superconducting transmission cable considering the magnetic field distribution

    International Nuclear Information System (INIS)

    Noji, H; Haji, K; Hamada, T

    2003-01-01

    We have calculated the alternating current (ac) losses of a 114 MVA high-T C superconducting (HTS) transmission cable using an electric-circuit (EC) model. The HTS cable is fabricated by Tokyo Electric Power Company and Sumitomo Electric Industries, Ltd. The EC model is comprised of a resistive part and an inductive part. The resistive part is obtained by the approximated Norris equation for a HTS tape. The Norris equation indicates hysteresis losses due to self-fields. The inductive part has two components, i.e. inductances related to axial fields and those related to circumferential fields. The layer currents and applied fields of each layer were calculated by the EC model. By using both values, the ac losses of the one-phase HTS cable were obtained by calculation considering the self-field, the axial field and the circumferential field of the HTS tape. The measured ac loss transporting 1 kA rms is 0.7 W m -1 ph -1 , which is equal to the calculation. The distribution of each layer loss resembles in shape the distribution of the circumferential field in each layer, which indicates that the circumferential fields strongly influence the ac losses of the HTS cable

  16. The impact of high temperature superconductivity on the electric power sector

    International Nuclear Information System (INIS)

    Wolsky, A.M.

    1996-01-01

    The progress and prospects for the application of high temperature superconductivity to the Electric Power Sector has been the topic of an IEA Implementing Agreement, begun in 1990. The present Task Members are Canada, Denmark, Finland, Germany, Israel, Italy, Japan, Netherlands, Norway, Sweden, Switzerland, Turkey, United Kingdom and the United States. As a result of the Implementing Agreement, work has been done by the Operating Agent with the full participation of all the member countries. This work has facilitated the exchange of information among experts in all countries and has documented relevant assessments. Further, this work has examined the status of high amperage conductor, fault-current limiters, superconducting magnetic energy storage, cables, rotating machines, refrigeration, and studies of the power system. The Task Members find more progress toward applications than many expected five years ago and the grounds for further international collaboration to hasten the use of superconductors in the power sector, early in the 21st century

  17. Study of Transient Heat Transport Mechanisms in Superfluid Helium Cooled Rutherford-Cables

    CERN Document Server

    AUTHOR|(CDS)2100615

    The Large Hadron Collider leverages superconducting magnets to focus the particle beam or keep it in its circular track. These superconducting magnets are composed of NbTi-cables with a special insulation that allows superfluid helium to enter and cool the superconducting cable. Loss mechanisms, e.g. continuous random loss of particles escaping the collimation system heating up the magnets. Hence, a local temperature increase can occur and lead to a quench of the magnets when the superconductor warms up above the critical temperature. A detailed knowledge about the temperature increases in the superconducting cable (Rutherford type) ensures a secure operation of the LHC. A sample of the Rutherford cable has been instrumented with temperature sensors. Experiments with this sample have been performed within this study to investigate the cooling performance of the helium in the cable due to heat deposition. The experiment uses a superconducting coil, placed in a cryostat, to couple with the magnetic field loss m...

  18. Low AC-Loss Superconducting Cable Technology for Electric Aircraft Propulsion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The availability of low AC loss magnesium diboride (MgB2) superconducting wires enables much lighter weight superconducting stator coils than with any other metal or...

  19. Electromagnetic analysis of a superconducting transformer for high current characterization of cable in conduit conductors in background magnetic field

    Science.gov (United States)

    Wu, Xiangyang; Tan, Yunfei; Fang, Zhen; Jiang, Donghui; Chen, Zhiyou; Chen, Wenge; Kuang, Guangli

    2017-10-01

    A large cable-in-conduit-conductor (CICC) test facility has been designed and fabricated at the High Magnetic Field Laboratory of the Chinese Academy of Sciences (CHMFL) in order to meet the test requirement of the conductors which are applied to the future fusion reactor. The critical component of the test facility is an 80 kA superconducting transformer which consists of a multi-turn primary coil and a minor-turn secondary coil. As the current source of the conductor samples, the electromagnetic performance of the superconducting transformer determines the stability and safety of the test facility. In this paper, the key factors and parameters, which have much impact on the performance of the transformer, are analyzed in detail. The conceptual design and optimizing principles of the transformer are discussed. An Electromagnetic-Circuit coupled model built in ANSYS Multiphysics is successfully used to investigate the electromagnetic characterization of the transformer under the dynamic operation condition.

  20. High critical temperature superconducting composite and fabrication process

    International Nuclear Information System (INIS)

    Dubots, P.; Legat, D.

    1989-01-01

    The core comprises a high temperature superconducting sintered oxide coated with alumina or barium oxide covered with a first sheath in aluminum, a second sheath in niobium and a third sheath in copper [fr

  1. Leaders in high temperature superconductivity commercialization win superconductor industry award

    CERN Multimedia

    2007-01-01

    CERN's Large Hadron Collider curretn leads project head Amalia Ballarino named superconductor industry person of the year 2006. Former high temperature superconductivity program manager at the US Department of energy James Daley wins lifetime achievement award. (1,5 page)

  2. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

    2016-10-05

    The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

  3. Materials Science of High-Temperature Superconducting Coated Conductor Materials

    National Research Council Canada - National Science Library

    Beasley, M. R

    2007-01-01

    This program was broadly focused on the materials science of high temperature superconducting coated conductors, which are of potential interest for application in electric power systems of interest to the Air Force...

  4. Calculation of temperature rise for cable conductor of DCS cabinet power based on theory of numerical thermal transfer

    International Nuclear Information System (INIS)

    Tian Yong; Zhang Longqiang; Yang Zhen; Yu Bin

    2014-01-01

    In order to ensure a long-term reliable operation of the DCS cabinet's 220 V AC power cable, it was needed to confirm whether the conductor temperature rise of power cable meet the requirement of the cable specification. Based on the actual data in site and the theory of numerical heat transfer, conservative model was established, and the conductor temperature was calculated. The calculation results show that the cable arrangement on the cable tray will not lead to the conductor temperature rise of power cable over than the required temperature in technical specification. (authors)

  5. A high temperature superconducting impulse generator

    International Nuclear Information System (INIS)

    Locker, J.R.; Geers, S.

    1992-01-01

    A mechanism based upon the Superconducting Vector Switch (SVS) effect displays the property of impulse generation. In this paper the principle of operation of this impulse generator is discussed. Experimental results and analytical predictions are presented

  6. Model for electromagnetic field analysis of superconducting power transmission cable comprising spiraled coated conductors

    International Nuclear Information System (INIS)

    Takeuchi, Katsutoku; Amemiya, Naoyuki; Nakamura, Taketsune; Maruyama, Osamu; Ohkuma, Takeshi

    2011-01-01

    Since the superconductor layers of YBCO-coated conductors are very thin, the ac loss of coated conductors is dominated by the magnetic flux density normal to the conductor face. In cables, most of the normal magnetic flux component is generated near gaps between coated conductors. Although the effects of gaps are significant, there are few reports on the electromagnetic field analysis of cables with spiral structures carried out while taking the gap effect into consideration. In a finitely long cable with a spiral structure, the electromagnetic field is naturally periodic along the cable axis. In a two-layer cable, the simplest period along the cable axis is the least common multiple of the spiral pitches in the inner and outer layers. However, we verified that there is a shorter period, and the same electromagnetic field distribution appears in all conductors of the same layer. Using these periodicities, we developed a three-dimensional model for the analysis of two-layer cables with a spiral structure. Current distributions of cables were analyzed using this model, and ac losses were calculated. In addition, these results were compared with ac losses calculated by two-dimensional analysis performed on the cross section of a cable. It was verified that the ac loss in a cable is correctly calculated by the 2D model when the spiral pitch is long enough. However, in the case of a tightly twisted cable, the ac losses calculated by the 2D model include some errors caused by an approximation in which the spiral structure is ignored.

  7. Long-term test of the 22.9kV HTS power cable system in LS Cable Ltd

    International Nuclear Information System (INIS)

    Jang, Hyun Man; Lee, Chang Young; Kim, Choon Dong; Kim, Do Hyung; Park, In Son; Ji, Bong Ki; Kim, Dong Wook; Cho, Jeonwook

    2006-01-01

    Since 2001, LS cable Ltd. has been developing the design, manufacturing and evaluation technologies for high temperature superconducting (HTS) power cable system as a member of DAPAS (Dream for Advanced Power system by Applied Superconductivity technology) program in Korea. The 30 m HTS cable system that is rated at 22.9 kV and 1.2 kA giving a rated capacity of 50 MVA had been developed and tested. The cable was designed as a cold dielectric type employing Bi-2223 HTS tapes and polypropylene (PP) laminated paper as the conductor and electrical insulation, respectively. The cable is cooled with sub-cooled liquid nitrogen at temperature from 75 to 77 K. The manufacturing and the installation of the cable system were completed in 2004. Long-term performance test of the cable system has been conducted for six months to verify its electric and mechanical properties in 2005

  8. Nuclear grade cable thermal life model by time temperature superposition algorithm based on Matlab GUI

    International Nuclear Information System (INIS)

    Lu Yanyun; Gu Shenjie; Lou Tianyang

    2014-01-01

    Background: As nuclear grade cable must endure harsh environment within design life, it is critical to predict cable thermal life accurately owing to thermal aging, which is one of dominant factors of aging mechanism. Purpose: Using time temperature superposition (TTS) method, the aim is to construct nuclear grade cable thermal life model, predict cable residual life and develop life model interactive interface under Matlab GUI. Methods: According to TTS, nuclear grade cable thermal life model can be constructed by shifting data groups at various temperatures to preset reference temperature with translation factor which is determined by non linear programming optimization. Interactive interface of cable thermal life model developed under Matlab GUI consists of superposition mode and standard mode which include features such as optimization of translation factor, calculation of activation energy, construction of thermal aging curve and analysis of aging mechanism., Results: With calculation result comparison between superposition and standard method, the result with TTS has better accuracy than that with standard method. Furthermore, confidence level of nuclear grade cable thermal life with TTS is higher than that with standard method. Conclusion: The results show that TTS methodology is applicable to thermal life prediction of nuclear grade cable. Interactive Interface under Matlab GUI achieves anticipated functionalities. (authors)

  9. Alternative designs of high-temperature superconducting synchronous generators

    OpenAIRE

    Goddard, K. F.; Lukasik, B.; Sykulski, J. K.

    2010-01-01

    This paper discusses the different possible designs of both cored and coreless superconducting synchronous generators using high-temperature superconducting (HTS) tapes, with particular reference to demonstrators built at the University of Southampton using BiSCCO conductors. An overview of the electromagnetic, thermal, and mechanical issues is provided, the advantages and drawbacks of particular designs are highlighted, the need for compromises is explained, and practical solutions are offer...

  10. Modelling of Dynamic Transmission Cable Temperature Considering Soil-Specific Heat, Thermal Resistivity, and Precipitation

    DEFF Research Database (Denmark)

    Olsen, Rasmus; Anders, George J.; Holboell, Joachim

    2013-01-01

    This paper presents an algorithm for the estimation of the time-dependent temperature evolution of power cables, when real-time temperature measurements of the cable surface or a point within its vicinity are available. The thermal resistivity and specific heat of the cable surroundings are varied...... as functions of the moisture content which is known to vary with time. Furthermore, issues related to the cooling effect during rainy weather are considered. The algorithm is based on the lumped parameters model and takes as input distributed temperature sensing measurements as well as the current and ambient...... temperature. The concept is verified by studying a laboratory setup of a 245 kV cable system....

  11. Unusual temperature evolution of superconductivity in LiFeAs

    Energy Technology Data Exchange (ETDEWEB)

    Nag, Pranab Kumar; Schlegel, Ronny; Baumann, Danny; Grafe, Hans-Joachim; Beck, Robert [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Wurmehl, Sabine [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Institute for Solid State Physics, TU Dresden (Germany); Buechner, Bernd [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Institute for Solid State Physics, TU Dresden (Germany); Center for Transport and Devices, TU Dresden (Germany); Hess, Christian [Leibniz Institute for Solid State and Materials Research Dresden, IFW Dresden (Germany); Center for Transport and Devices, TU Dresden (Germany)

    2016-07-01

    We have performed temperature dependent scanning tunneling spectroscopy on an impurity-free surface area of a LiFeAs single crystal. Our data reveal a highly unusual temperature evolution of superconductivity: at T{sub c}{sup *}=18 K a partial superconducting gap opens, as is evidenced by subtle, yet clear features in the tunneling spectra, i.e. particle-hole symmetric coherence peaks and dip-hump structures. At T{sub c}=16 K, these features substantiate dramatically and become characteristic of full superconductivity. Remarkably, this is accompanied by an almost jump-like increase of the gap energy at T{sub c} to about 87% of its low-temperature gap value. The energy of the dip as measured by its distance to the coherence peak remains practically constant in the whole temperature regime T ≤ T{sub c}{sup *}. We compare these findings with established experimental and theoretical results.

  12. High-temperature superconducting phase in rare earth alloys

    International Nuclear Information System (INIS)

    Vedyaev, A.V.; Molodykh, O.Eh.; Savchenko, M.A.; Stefanovich, A.V.

    1984-01-01

    A possibility of high-temperature superconducting phase existence in rare e arth alloys with aluminium: TbAl-NdAl is predicted. Such a phase is shown t o exist at t approximately 40 k, however its existence is possible only in a nar row temperature range and it might be metastable. A possibility of a supercondu cting phase occurrence in spin glass is studied. It is shown that the first kin d phase transition to superconducting state may first occur under definite condi tions in the system. But the phase in question will be a low-temperature one be cause of rather inefficient elctron-phonon interaction. Further temperature dec rease would lead to an appearance of magnetic order and to disappearance of the superconductivity

  13. High temperature superconductivity the road to higher critical temperature

    CERN Document Server

    Uchida, Shin-ichi

    2015-01-01

    This book presents an overview of material-specific factors that influence Tc and give rise to diverse Tc values for copper oxides and iron-based high- Tc superconductors on the basis of more than 25 years of experimental data, to most of which the author has made important contributions. The book then explains why both compounds are distinct from others with similar crystal structure and whether or not one can enhance Tc, which in turn gives a hint on the unresolved pairing mechanism. This is an unprecedented new approach to the problem of high-temperature superconductivity and thus will be inspiring to both specialists and non-specialists interested in this field.   Readers will receive in-depth information on the past, present, and future of high-temperature superconductors, along with special, updated information on what the real highest Tc values are and particularly on the possibility of enhancing Tc for each member material, which is important for application. At this time, the highest Tc has not been...

  14. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  15. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  16. High temperature superconductive flux gate magnetometer

    International Nuclear Information System (INIS)

    Gershenson, M.

    1991-01-01

    This paper proposes a different type of HTS superconducting magnetometer based on the non-linear magnetic behavior of bulk HTS materials. The device design is based on the generation of second harmonics which arise as a result of non-linear magnetization observed in Type-II superconductors. Even harmonics are generated from the non-linear interaction of an ac excitation signal with an external DC magnetic field which acts as a bias signal

  17. Superconductivity in power engineering

    International Nuclear Information System (INIS)

    1989-01-01

    This proceedings volume presents 24 conference papers and 15 posters dealing with the following aspects: 1) Principles and elementary aspects of high-temperature superconductivity (3 plenary lectures); 2) Preparation, properties and materials requirements of metallic or oxide superconductors (critical current behaviour, soldered joints, structural studies); 3) Magnet technology (large magnets for thermonuclear fusion devices; magnets for particle accelerators and medical devices); 4) Magnetic levitation and superconductivity; 5) Cryogenics; 6) Energy storage systems using superconducting coils (SMES); 7) Superconducting power transmission cables, switches, transformers, and generator systems for power plant; 8) Supporting activities, industrial aspects, patents. There are thirty-eight records in the ENERGY database relating to individual conference papers. (MM) [de

  18. Superconducting generators and motors and methods for employing same

    Energy Technology Data Exchange (ETDEWEB)

    Tomsic, Michael J.; Long, Larry

    2017-08-29

    A superconducting electrical generator or motor having a plurality of cryostats is described. The cryostats contain coolant and a first cryostat encloses at least one of a plurality of superconducting coils. A first coil is in superconducting electrical communication with a second coil contained in a second cryostat through a superconducting conduction cooling cable enclosing a conductor. The first cryostat and the second cryostat may be in fluid communication through at least one cryogen channel within the at least one superconducting conduction cooling cable. In other embodiments, none of the plurality of cryostats may be in fluid communication and the cable may be cooled by conduction along the conductor from the first or second cryostat, or from both. The conductor may have different segments at temperatures equal to or above the temperature of the coolant and the superconducting conduction cooling cables may be connected through quick connect fittings.

  19. Possibility of high temperature superconducting phases in PdH

    Science.gov (United States)

    Tripodi, Paolo; Di Gioacchino, Daniele; Borelli, Rodolfo; Vinko, Jenny Darja

    2003-05-01

    Possible new superconducting phases with a high critical transition temperature (Tc) have been found in stable palladium-hydrogen (PdHx) samples for stoichiometric ratio x=H/Pd⩾1, in addition to the well-known low critical transition temperature (0⩽Tc⩽9) when x is in the range (0.75⩽x⩽1.00). Possible new measured superconducting phases with critical temperature in the range 51⩽Tc⩽295 K occur. This Tc varies considerably with every milli part of x when x exceeds unit. A superconducting critical current density Jc⩾6.1×104 A cm-2 has been measured at 77 K with HDC=0 T.

  20. Possibility of high temperature superconducting phases in PdH

    Energy Technology Data Exchange (ETDEWEB)

    Tripodi, Paolo; Di Gioacchino, Daniele; Borelli, Rodolfo; Vinko, Jenny Darja

    2003-05-15

    Possible new superconducting phases with a high critical transition temperature (T{sub c}) have been found in stable palladium-hydrogen (PdH{sub x}) samples for stoichiometric ratio x=H/Pd{>=}1, in addition to the well-known low critical transition temperature (0{<=}T{sub c}{<=}9) when x is in the range (0.75{<=}x{<=}1.00). Possible new measured superconducting phases with critical temperature in the range 51{<=}T{sub c}{<=}295 K occur. This T{sub c} varies considerably with every milli part of x when x exceeds unit. A superconducting critical current density J{sub c}{>=}6.1x10{sup 4} A cm{sup -2} has been measured at 77 K with H{sub DC}=0 T.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sumption, Mike D. [The Ohio State Univ., Columbus, OH (United States). Center for Superconducting and Magnetic Materials (CSMM); Collings, Edward W. [The Ohio State Univ., Columbus, OH (United States). Center for Superconducting and Magnetic Materials (CSMM)

    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.

  2. Superconductivity

    CERN Document Server

    Poole, Charles P; Creswick, Richard J; Prozorov, Ruslan

    2014-01-01

    Superconductivity, Third Edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Widely used theoretical approaches are explained in detail. Topics of special interest include high temperature superconductors, spectroscopy, critical states, transport properties, and tunneling. This book covers the whole field of superconductivity from both the theoretical and the experimental point of view. This third edition features extensive revisions throughout, and new chapters on second critical field and iron based superconductors.

  3. DC Cable for Railway

    Science.gov (United States)

    Tomita, Masaru

    The development of a superconducting cable for railways has commenced, assuming that a DC transmission cable will be used for electric trains. The cable has been fabricated based on the results of current testing of a superconducting wire, and various evaluation tests have been performed to determine the characteristics of the cable. A superconducting transmission cable having zero electrical resistance and suitable for railway use is expected to enhance regeneration efficiency, reduce power losses, achieve load leveling and integration of sub-stations, and reduce rail potential.

  4. Improvement of a high current DC power supply system for testing the large scaled superconducting cables and magnets

    International Nuclear Information System (INIS)

    Yamada, Shuichi; Chikaraishi, Hirotaka; Tanahashi, Shugo

    1993-11-01

    A dc 75 kA power supply system was constructed to test the superconducting (SC) R and D cables and magnets for the Large Helical Device. It consists of three 25 kA unit banks. A unit bank has two double-star-rectifier connections with the inter-phase reactors. A digital feedback control method is applied to the automatic current regulation (ACR) in each unit bank. For shortening the dead time of the feedback process, a new algorithm of a digital phase controller for the ACR is investigated. A Bode diagram of the feedback process is directly measured. It is confirmed that the dead time of the feedback process is reduced to one sixth, and that the feedback gain of PID compensation is improved by a factor of two from the original method. (author)

  5. A dielectric approach to high temperature superconductivity

    International Nuclear Information System (INIS)

    Mahanty, J.; Das, M.P.

    1989-01-01

    The dielectric response of an electron-ion system to the presence of a pair of charges is investigated. From the nature of the dielectric function, it is shown that a strong attractive pair formation is possible depending on the dispersion of the ion branches. The latter brings a reduction to the sound velocity which is used as a criterion for the superconductivity. By solving the BCS equation with the above dielectric function, we obtain a reasonable value of T/sub c/. 17 refs., 1 fig

  6. Superconductivity - applications

    International Nuclear Information System (INIS)

    The paper deals with the following subjects: 1) Electronics and high-frequency technology, 2) Superconductors for energy technology, 3) Superconducting magnets and their applications, 4) Electric machinery, 5) Superconducting cables. (WBU) [de

  7. Quench characteristics of a two-strand superconducting cable and the influence of its length

    NARCIS (Netherlands)

    Mulder, G.B.J.; Mulder, G.B.J.; Krooshoop, Hendrikus J.G.; Vysotski, V.S.; Vysotski, V.S.; van de Klundert, L.J.M.; van de Klundert, L.J.M.

    1992-01-01

    The quench process of a multi-strand cable was investigated using the simplest system: two twisted wires. Several properties of the quench, such as the commutation of currents, the time scale, the resistance rate, and the maximum voltage, were determined experimentally or by calculation. Particular

  8. Development of superconducting strand and cable with improved properties for use in SSC [Superconducting Super Collider] magnets

    International Nuclear Information System (INIS)

    Scanlan, R.M.

    1989-02-01

    The critical current requirement for the NbTi superconductor strand was set at 2750 A/mm 2 (5 T, 4.2 K) in the SSC Conceptual Design, compared with a value of 1800 A/mm 2 which was specified for the strand used in the Tevatron dipoles. In addition, a filament diameter of 5 μm, instead of the 9 μm diameter used in the Tevatron, was chosen to reduce field distortion at injection. In order to meet the requirements for field homogeneity, the dimensional requirements for both strand and cable were also tightened. The technical solutions employed to achieve these improved properties and the resulting specifications will be discussed. 9 refs

  9. Conduction cooled high temperature superconducting dipole magnet for accelerator applications

    DEFF Research Database (Denmark)

    Zangenberg, N.; Nielsen, G.; Hauge, N.

    2012-01-01

    A 3T proof-of-principle dipole magnet for accelerator applications, based on 2nd generation high temperature superconducting tape was designed, built, and tested by a consortium under the lead of Danfysik. The magnet was designed to have a straight, circular bore with a good field region of radius...

  10. Memory effect in the high-temperature superconducting bulks

    International Nuclear Information System (INIS)

    Zhang, Xing-Yi; Zhou, Jun; Zhou, You-He

    2013-01-01

    Highlights: •Effects of temperature cycles on levitation force relaxation are investigated. •Memory effect of the YBCO bulks is observed in experiments. •With an increase of temperature, memory of the superconductor is gradually lost. -- Abstract: We present an experimental investigation of the relaxation of vertical force components in a high-temperature superconducting levitation system with different temperature cycle processes. For a selected ambient temperature (T 1 ) of the system, the experimental results show that the relaxations of the levitation forces are strongly dependent on the initial temperature. When the sample was submitted to temperature jumps around T 1 , the sample temperature was regulated at T 2 , and there were two cases of the experiments, ΔT = T 2 − T 1 0 (positive temperature cycle). It was found that in the case of negative temperature cycle, the superconducting samples have memory effect. And for the positive temperature cycle, with the experimental temperature increase, the memory effect of samples is gradually losing. Additionally, with the increase of temperature, the influences of the negative and positive temperature cycle on the levitation force relaxation are unsymmetrical. All the results are interpreted by using the characteristics of the free energy ‘ground’ plot of the Spin-glasses qualitatively

  11. Fabrication process of a superconducting multifilament conductor of a cable and resulting electric conductor

    International Nuclear Information System (INIS)

    Fevrier, A.; Verhaege, T.; Bonnet, P.

    1990-01-01

    Elementary conductors constituted of a plurality of superconducting filaments in a metallic matrix are prepared and then twisted. Elementary conductors with a diameter between 0.05 and 0.25 mm without electric insulation are twisted after heating with a pitch of four time the diameter, finally the conductor is insulated [fr

  12. A continuous winding scheme for superconducting tokamak coils with cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Kim, Sang-ho; Chung, Kie-hyung; Lee, Deok Kyo

    2001-01-01

    Superconducting magnet coils are essential for steady-state or long-pulse operation of tokamaks. In an advanced tokamak, the central solenoid (CS) coils are usually divided into several pairs of modules to provide for an extra plasma shaping capability in addition to those available from the shaping (poloidal field) coils. In the conventional pancake winding scheme of superconducting coils, each coil consists of separate superconducting 'double-pancake' coils connected together in series; however, such joints are not superconducting, which is one of the major disadvantages, especially in pulsed operations. A new type of winding was adopted for the ITER CS coil, which consists of cylindrical shell 'layers' joined in series. A disadvantage of this layer winding is its inability to yield modular coils that can provide certain degree of plasma shaping. Joints can be removed in a coil winding pack with the conventional pancake winding scheme, if the conductor is sufficiently long and the winding machine is properly equipped. The compactness, however, cannot be preserved with this scheme. The winding compactness is important since the radial build of the CS coils is one of the major parameters that determine the machine size. In this paper, we present a continuous winding scheme that requires no joints, allows coil fabrication at minimum dimension, and meets the flux swing requirement and other practical aspects

  13. AC loss in the superconducting cables of the CERN Fast Cycled Magnet Prototype

    NARCIS (Netherlands)

    Borgnolutti, F.; Bottura, L.; Nijhuis, Arend; Zhou, Chao; Liu, Bo; Miyoshi, Y.; Krooshoop, Hendrikus J.G.; Richter, D.

    2011-01-01

    Fast Cycled Superconducting Magnets (FCM's) are an option of interest for the long-term consolidation and upgrade plan of the LHC accelerator complex. The economical advantage of FCM's in the range of 2 T bore field, continuously cycled at 0.5 Hz repetition rate, depends critically on the AC loss

  14. Analysis of mechanical characteristics of superconducting field coil for 17 MW class high temperature superconducting synchronous motor

    International Nuclear Information System (INIS)

    Kim, J. H.; Park, S. I.; Im, S. H.; Kim, H. M.

    2013-01-01

    Superconducting field coils using a high-temperature superconducting (HTS) wires with high current density generate high magnetic field of 2 to 5 [T] and electromagnetic force (Lorentz force) acting on the superconducting field coils also become a very strong from the point of view of a mechanical characteristics. Because mechanical stress caused by these powerful electromagnetic force is one of the factors which worsens the critical current performance and structural characteristics of HTS wire, the mechanical stress analysis should be performed when designing the superconducting field coils. In this paper, as part of structural design of superconducting field coils for 17 MW class superconducting ship propulsion motor, mechanical stress acting on the superconducting field coils was analyzed and structural safety was also determined by the coupling analysis system that is consists of commercial electromagnetic field analysis program and structural analysis program.

  15. Contribution to the study of superconducting magnets using high transition temperature superconducting materials

    International Nuclear Information System (INIS)

    Lecrevisse, Thibault

    2012-01-01

    The new industrial superconductors using high critical temperature compounds offer new possibilities for superconducting magnetism. Indeed they allow higher magnetic field with the same classical cryogenics at 4.2 K on one hand, and on the other hand they also pave the way for superconducting magnets working between 10 K and 30 K. The high temperature superconductors are then needed in order to produce magnetic fields higher than 16 T (case of HTS dipole insert for Large Hadron Collider at CERN) or to increase the specific density stored in one SMES (Superconducting Magnetic Energy Storage, in the case of the SuperSMES ANR Project).Nevertheless the indisputable assets (critical temperature, critical magnetic field, mechanical stresses) brought by the use of High critical temperature superconductors like YBCO, used in superconducting magnets, require to solve some challenges. Their behavior is still badly understood, especially during the resistive transitions. To succeed in protecting these conductors we need a new reflection on protection schemes designed to avoid the thermal and mechanical damages. The answer to the question: 'Can we use those materials in the long run inside superconducting magnets?' is now inescapable.Some answers are given here. The use of the conductors is approached through various experimental studies to understand the material (electrical characterization and modeling of the critical surface) and to define the key stages of high critical temperature superconducting magnets manufacturing (work on the junctions between conductors and pancakes). This study led to the creation of two coils in order to identify the issues related to the use of YBCO tapes. A numerical thermo-electrical model of the high critical temperature superconductor has been developed and a numerical code based on the CEA software CASTEM (Finish Elements Model) allowed to study the resistive transition (or quench) behavior of those conductor and coil. The code has been

  16. Theory of the superconducting proximity effect below the transition temperature

    International Nuclear Information System (INIS)

    Silvert, W.

    1975-01-01

    The form of the low-temperature theory of the superconducting proximity effect depends on whether the non-linear terms are assumed to depend only on the local value of the gap or on its average value over some finite range. The local assumption leads to smaller values of the gap and to unphysical results at low temperatures. The effect of non-locality is significant even in the Ginsburg-Landau regime. (author)

  17. Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields

    Science.gov (United States)

    Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

    2018-01-01

    High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (Hc2) and critical temperature (Tc). The critical current (Ic) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new Ic measurement system that can carry out accurate Ic measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The Ic measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa2Cu3O7-x(YBCO) tapes Ic determination with different temperatures and magnetic fields.

  18. Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields.

    Science.gov (United States)

    Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

    2018-01-01

    High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (H c2 ) and critical temperature (T c ). The critical current (I c ) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new I c measurement system that can carry out accurate I c measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The I c measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa 2 Cu 3 O 7-x (YBCO) tapes I c determination with different temperatures and magnetic fields.

  19. Structural features that optimize high temperature superconductivity

    International Nuclear Information System (INIS)

    Jorgensen, J.D.; Argonne Nat. Lab., IL; Hinks, D.G.; Argonne Nat. Lab., IL; Chmaissem, O.; Argonne Nat. Lab., IL; Argyriou, D.N.; Argonne Nat. Lab., IL; Mitchell, J.F.; Argonne Nat. Lab., IL; Dabrowski, B.

    1996-01-01

    Studies of a large number of compounds have provided a consistent picture of what structural features give rise to the highest T c 's in copper-oxide superconductors. For example, various defects can be introduced into the blocking layer to provide the optimum carrier concentration, but defects that form in or adjacent to the CuO 2 layers will lower T c and eventually destroy superconductivity. After these requirements are satisfied, the highest T c 's are observed for compounds (such as the HgBa 2 Ca n-1 Cu n O 2n+2+x family) that have flat and square CuO 2 planes and long apical Cu-O bonds. This conclusion is confirmed by the study of materials in which the flatness of the CuO 2 plane can be varied in a systematic way. In more recent work, attention has focused on how the structure can be modified, for example, by chemical substitution, to improve flux pinning properties. Two strategies are being investigated: (1) Increasing the coupling of pancake vortices to form vortex lines by shortening or ''metallizing'' the blocking layer; and (2) the formation of defects that pin flux. (orig.)

  20. Structural features that optimize high temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, J.D.; Hinks, D.G. Chmaissem, O.; Argyriou, D.N.; Mitchell, J.F. [Argonne National Lab., IL (United States); Dabrowski, B. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Physics

    1996-01-01

    For example, various defects can be introduced into the blocking layer to provide the optimum carrier concentration, but defects that form in or adjacent to the CuO{sub 2} layers will lower T{sub c} and eventually destroy superconductivity. After these requirements are satisfied, the highest T{sub c}`s are observed for compounds (such as the HgBa{sub 2}Ca{sub n-1}CuO{sub 2n{plus}2{plus}x} family) that have flat and square CuO{sub 2} planes and long apical Cu-O bonds. This conclusion is confirmed by the study of materials in which the flatness of the CuO{sub 2} plane can be varied in a systematic way. In more recent work, attention has focused on how the structure can be modified, for example, by chemical substitution, to improve flux pinning properties. Two strategies are being investigated: (1) Increasing the coupling of pancake vortices to form vortex-lines by shortening or ``metallizing`` the blocking layer; and (2) the formation of defects that pin flux.

  1. Structural features that optimize high temperature superconductivity

    International Nuclear Information System (INIS)

    Jorgensen, J.D.; Hinks, D.G. Chmaissem, O.; Argyriou, D.N.; Mitchell, J.F.; Dabrowski, B.

    1996-01-01

    For example, various defects can be introduced into the blocking layer to provide the optimum carrier concentration, but defects that form in or adjacent to the CuO 2 layers will lower T c and eventually destroy superconductivity. After these requirements are satisfied, the highest T c 's are observed for compounds (such as the HgBa 2 Ca n-1 CuO 2n+2+x family) that have flat and square CuO 2 planes and long apical Cu-O bonds. This conclusion is confirmed by the study of materials in which the flatness of the CuO 2 plane can be varied in a systematic way. In more recent work, attention has focused on how the structure can be modified, for example, by chemical substitution, to improve flux pinning properties. Two strategies are being investigated: (1) Increasing the coupling of pancake vortices to form vortex-lines by shortening or ''metallizing'' the blocking layer; and (2) the formation of defects that pin flux

  2. Abstracts of The First Polish-US Conference on High Temperature Superconductivity

    International Nuclear Information System (INIS)

    1995-01-01

    The current problems in high temperature superconductivity science have been presented at the conference. The two main topics have been mostly represented: superconducting material research and fundamental physical research on superconductivity mechanisms. Superconducting material preparation, chemical composition, magnetic and electrical properties of different type of high temperature superconductors, material structure and its influence on superconducting properties and related problems were included in the first of the general topics. In the range of second general topic of the two listed above, many theoretical models being applied for explanation of superconductivity mechanism in different systems up and below transition temperature were presented

  3. Seismic Responses of a Cable-Stayed Bridge with Consideration of Uniform Temperature Load

    Directory of Open Access Journals (Sweden)

    Junjun Guo

    2016-12-01

    Full Text Available The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. This paper discusses the effects of uniform temperature changes on the seismic responses of a cable-stayed bridge. A three dimensional finite element model of a cable-stayed bridge using OpenSees is established for nonlinear time history analysis, and uniform temperature load is applied to the prototype bridge before the conducting of seismic excitation. Three ground motion records are selected from the PEER strong motion database based on the design spectrum. Case studies are then performed considering the varying temperature and the connections between the deck and pylons of the bridge. The result shows that the seismic responses of the bridge are significantly increased with the consideration of temperature load. Meanwhile, the types between the deck and pylon also have notable impacts on the seismic responses of the bridge with and without temperature changes. This research could provide a reference for designers during the design phase of cable-stayed brides.

  4. Applications of high-temperature superconductivity

    International Nuclear Information System (INIS)

    Malozemoff, A.P.; Gallagher, W.J.; Schwall, R.E.

    1987-01-01

    The new high temperature superconductors open up possibilities for applications in magnets, power transmission, computer interconnections, Josephson devices and instrumentation, among many others. The success of these applications hinges on many interlocking factors, including critical current density, critical fields, allowable processing temperatures, mechanical properties and chemical stability. An analysis of some of these factors suggests which applications may be the easiest to realize and which may have the greatest potential

  5. Superconductivity

    International Nuclear Information System (INIS)

    Taylor, A.W.B.; Noakes, G.R.

    1981-01-01

    This book is an elementray introduction into superconductivity. The topics are the superconducting state, the magnetic properties of superconductors, type I superconductors, type II superconductors and a chapter on the superconductivity theory. (WL)

  6. A Snapshot View of High Temperature Superconductivity 2002

    Energy Technology Data Exchange (ETDEWEB)

    Schuller, Ivan K. [Univ. of California, San Diego, CA (United States); Bansil, Arun [Northeastern Univ., Boston, MA (United States); Basov, Dimitri N. [Univ. of California, San Diego, CA (United States)

    2002-04-05

    This report outlines the conclusions of a workshop on High Temperature Superconductivity held April 5-8, 2002 in San Diego. The purpose of this report is to outline and highlight some outstanding and interesting issues in the field of High Temperature Superconductivity. The range of activities and new ideas that arose within the context of High Temperature Superconductors is so vast and extensive that it is impossible to summarize it in a brief document. Thus, this report does not pretend to be all-inclusive and cover all areas of activity. It is a restricted snapshot and it only presents a few viewpoints. The complexity and difficulties with high temperature superconductivity are well illustrated by the Buddhist parable of the blind men trying to describe “experimentally” an elephant. These very same facts clearly illustrate that this is an extremely active field, with many unanswered questions, and with a great future potential for discoveries and progress in many (sometimes unpredictable) directions. It is very important to stress that, independently of any current or future applications, this is a very important area of basic research.

  7. A Snapshot View of High Temperature Superconductivity 2002

    International Nuclear Information System (INIS)

    Schuller, Ivan K.; Bansil, Arun; Basov, Dimitri N.

    2002-01-01

    This report outlines the conclusions of a workshop on High Temperature Superconductivity held April 5-8, 2002 in San Diego. The purpose of this report is to outline and highlight some outstanding and interesting issues in the field of High Temperature Superconductivity. The range of activities and new ideas that arose within the context of High Temperature Superconductors is so vast and extensive that it is impossible to summarize it in a brief document. Thus, this report does not pretend to be all-inclusive and cover all areas of activity. It is a restricted snapshot and it only presents a few viewpoints. The complexity and difficulties with high temperature superconductivity are well illustrated by the Buddhist parable of the blind men trying to describe ''experimentally'' an elephant. These very same facts clearly illustrate that this is an extremely active field, with many unanswered questions, and with a great future potential for discoveries and progress in many (sometimes unpredictable) directions. It is very important to stress that, independently of any current or future applications, this is a very important area of basic research.

  8. Energy storage via high temperature superconductivity (SMES)

    Energy Technology Data Exchange (ETDEWEB)

    Mikkonen, R. [Tampere Univ. of Technology (Finland)

    1998-10-01

    The technology concerning high temperature superconductors (HTS) is matured to enabling different kind of prototype applications including SMES. Nowadays when speaking about HTS systems, attention is focused on the operating temperature of 20-30 K, where the critical current and flux density are fairly close to 4.2 K values. In addition by defining the ratio of the energy content of a novel HTS magnetic system and the required power to keep the system at the desired temperature, the optimum settles to the above mentioned temperature range. In the frame of these viewpoints a 5 kJ HTS SMES system has been designed and tested at Tampere University of Technology with a coil manufactured by American Superconductor (AMSC). The HTS magnet has inside and outside diameters of 252 mm and 317 mm, respectively and axial length of 66 mm. It operates at 160 A and carries a total of 160 kA-turns to store the required amount of energy. The effective magnetic inductance is 0.4 H and the peak axial field is 1.7 T. The magnet is cooled to the operating temperature of 20 K with a two stage Gifford-McMahon type cryocooler with a cooling power of 60 W at 77 K and 8 W at 20 K. The magnetic system has been demonstrated to compensate a short term loss of power of a sensitive consumer

  9. The origins of macroscopic quantum coherence in high temperature superconductivity

    International Nuclear Information System (INIS)

    Turner, Philip; Nottale, Laurent

    2015-01-01

    Highlights: • We propose a new theoretical approach to superconductivity in p-type cuprates. • Electron pairing mechanisms in the superconducting and pseudogap phases are proposed. • A scale free network of dopants is key to macroscopic quantum coherence. - Abstract: A new, theoretical approach to macroscopic quantum coherence and superconductivity in the p-type (hole doped) cuprates is proposed. The theory includes mechanisms to account for e-pair coupling in the superconducting and pseudogap phases and their inter relations observed in these materials. Electron pair coupling in the superconducting phase is facilitated by local quantum potentials created by static dopants in a mechanism which explains experimentally observed optimal doping levels and the associated peak in critical temperature. By contrast, evidence suggests that electrons contributing to the pseudogap are predominantly coupled by fractal spin waves (fractons) induced by the fractal arrangement of dopants. On another level, the theory offers new insights into the emergence of a macroscopic quantum potential generated by a fractal distribution of dopants. This, in turn, leads to the emergence of coherent, macroscopic spin waves and a second associated macroscopic quantum potential, possibly supported by charge order. These quantum potentials play two key roles. The first involves the transition of an expected diffusive process (normally associated with Anderson localization) in fractal networks, into e-pair coherence. The second involves the facilitation of tunnelling between localized e-pairs. These combined effects lead to the merger of the super conducting and pseudo gap phases into a single coherent condensate at optimal doping. The underlying theory relating to the diffusion to quantum transition is supported by Coherent Random Lasing, which can be explained using an analogous approach. As a final step, an experimental program is outlined to validate the theory and suggests a new

  10. Heat transfer through the flat surface of Rutherford superconducting cable samples with novel pattern of electrical insulation immersed in He II

    Science.gov (United States)

    Strychalski, M.; Chorowski, M.; Polinski, J.

    2014-05-01

    Future accelerator magnets will be exposed to heat loads that exceed even by an order of magnitude presently observed heat fluxes transferred to superconducting magnet coils. To avoid the resistive transition of the superconducting cables, the efficiency of heat transfer between the magnet structure and the helium must be significantly increased. This can be achieved through the use of novel concepts of the cable’s electrical insulation wrapping, characterized by an enhanced permeability to helium while retaining sufficient electrical resistivity. This paper presents measurement results of the heat transfer through Rutherford NbTi cable samples immersed in a He II bath and subjected to the pressure loads simulating the counteracting of the Lorentz forces observed in powered magnets. The Rutherford cable samples that were tested used different electrical insulation wrapping schemes, including the scheme that is presently used and the proposed scheme for future LHC magnets. A new porous polyimide cable insulation with enhanced helium permeability was proposed in order to improve the evacuation of heat form the NbTi coil to He II bath. These tests were performed in a dedicated Claudet-type cryostat in pressurized He II at 1.9 K and 1 bar.

  11. Vitaly Ginzburg and high temperature superconductivity: Personal reminiscences

    International Nuclear Information System (INIS)

    Mazin, Igor I.

    2008-01-01

    This article is an attempt to give Western readers, as well as young researchers in Russia, a glance at the atmosphere in one of the leading physics institutions in the USSR from 1977-1988, through the eye of a graduate student and later a posdoc in the theory group led by Vitaly Ginzburg, arguably the most enthusiatic proponent of high-temperature superconductivity before the discovery of Bednorz and Muller. This is a very personal narration, wherein the events of my own life and career are inevitably intertwined with scientific events and with my reminiscences of great Russian physicists whom I had the pleasure to meet with while working in the 'High-Temperature Superconductivity Section' at the Lebedev Institute within the aforementioned 12 years

  12. Charge imbalance induced by a temperature gradient in superconducting aluminum

    International Nuclear Information System (INIS)

    Mamin, H.J.; Clarke, J.; Van Harlingen, D.J.

    1984-01-01

    The quasiparticle transport current induced in a superconducting aluminum film by a temperature gradient has been measured by means of the spatially decaying charge imbalance generated near the end of the sample where the current is divergent. The magnitude and decay length of the charge imbalance are in good agreement with the predictions of a simple model that takes into account the nonuniformity of the temperature gradient. The inferred value of the thermopower in the superconducting state agrees reasonably well with the value measured in the normal state. Measurements of the decay length of charge imbalance induced by current injection yield a value of the inelastic relaxation time tau/sub E/ of about 2 ns. This value is substantially smaller than that obtained from other measurements for reasons that are not known

  13. High temperature superconductivity: Hope of a new technology

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Following the sensational report in 1986 from the IBM laboratory in Rueschlikon, Switzerland, that superconductivity - that permanent flow of current at temperatures close to absolute zero - is also possible at higher temperatures, the waves of enthusiasm among scientists at first rose high. They talked of a revolution in electrotechnology, especially since superconductors at room temperature seemed to have almost come within reach. In the meantime their thoughts on the matter are much more down to earth. What are the realistic fields of application for the 'new superconductors'? The questions are discussed by scientists, politicians and engineers. (orig.) [de

  14. Solar radiative heating of fiber-optic cables used to monitor temperatures in water

    Science.gov (United States)

    Neilson, Bethany T.; Hatch, Christine E.; Ban, Heng; Tyler, Scott W.

    2010-08-01

    In recent years, applications of distributed temperature sensing (DTS) have increased in number and diversity. Because fiber-optic cables used for DTS are typically sheathed in dark UV-resistant materials, the question arises as to how shortwave solar radiation penetrating a water column influences the accuracy of absolute DTS-derived temperatures in aquatic applications. To quantify these effects, we completed a modeling effort that accounts for the effects of radiation and convection on a submersed cable to predict when solar heating may be important. Results indicate that for cables installed at shallow depths in clear, low-velocity water bodies, measurable heating of the cable is likely during peak solar radiation. However, at higher velocities, increased turbidity and/or greater depths, the effects of solar heating are immeasurable. A field study illustrated the effects of solar radiation by installing two types of fiber-optic cable at multiple water depths (from 0.05 to 0.8 m) in the center and along the sidewall of a trapezoidal canal. Thermistors were installed at similar depths and shielded from solar radiation to record absolute water temperatures. During peak radiation, thermistor data showed small temperature differences (˜0.003°C-0.04°C) between depths suggesting minor thermal stratification in the canal center. DTS data from cables at these same depths show differences of 0.01°C-0.17°C. The DTS differences cannot be explained by stratification alone and are likely evidence of additional heating from solar radiation. Sidewall thermistor strings also recorded stratification. However, corresponding DTS data suggested that bed conduction overwhelmed the effects of solar radiation.

  15. Proceedings of a high temperature superconductivity strategy workshop

    International Nuclear Information System (INIS)

    Kurzfeld, A.

    1987-07-01

    The paper contains the proceedings of a high temperature superconductivity strategy workshop, held at the Rutherford Appleton Laboratory, United Kingdom, 1987. The purpose of the meeting was to consider the U.K. strategy to be adopted for the high Tsub(c) superconductors and their application. The notes are presented of five Working Groups examining the following subjects: materials preparation, structural evaluation, physical properties, theoretical studies, and applications. (UK)

  16. Finite element modeling of temperature load effects on the vibration of local modes in multi-cable structures

    Science.gov (United States)

    Treyssède, Fabien

    2018-01-01

    Understanding thermal effects on the vibration of local (cable-dominant) modes in multi-cable structures is a complicated task. The main difficulty lies in the modification by temperature change of cable tensions, which are then undetermined. This paper applies a finite element procedure to investigate the effects of thermal loads on the linear dynamics of prestressed self-weighted multi-cable structures. Provided that boundary conditions are carefully handled, the discretization of cables with nonlinear curved beam elements can properly represent the thermoelastic behavior of cables as well as their linearized dynamics. A three-step procedure that aims to replace applied pretension forces with displacement continuity conditions is used. Despite an increase in the computational cost related to beam rotational degrees of freedom, such an approach has several advantages. Nonlinear beam finite elements are usually available in commercial codes. The overall method follows a thermoelastic geometrically non-linear analysis and hereby includes the main sources of non-linearities in multi-cable structures. The effects of cable bending stiffness, which can be significant, are also naturally accounted for. The accuracy of the numerical approach is assessed thanks to an analytical model for the vibration of a single inclined cable under temperature change. Then, the effects of thermal loads are investigated for two cable bridges, highlighting how natural frequencies can be affected by temperature. Although counterintuitive, a reverse relative change of natural frequency may occur for certain local modes. This phenomenon can be explained by two distinct mechanisms, one related to the physics intrinsic to cables and the other related to the thermal deflection of the superstructure. Numerical results show that cables cannot be isolated from the rest of the structure and the importance of modeling the whole structure for a quantitative analysis of temperature effects on the

  17. High temperature superconducting YBCO microwave filters

    Science.gov (United States)

    Aghabagheri, S.; Rasti, M.; Mohammadizadeh, M. R.; Kameli, P.; Salamati, H.; Mohammadpour-Aghdam, K.; Faraji-Dana, R.

    2018-06-01

    Epitaxial thin films of YBCO high temperature superconductor are widely used in telecommunication technology such as microwave filter, antenna, coupler and etc., due to their lower surface resistance and lower microwave loss than their normal conductor counterparts. Thin films of YBCO were fabricated by PLD technique on LAO substrate. Transition temperature and width were 88 K and 3 K, respectively. A filter pattern was designed and implemented by wet photolithography method on the films. Characterization of the filter at 77 K has been compared with the simulation results and the results for a made gold filter. Both YBCO and gold filters show high microwave loss. For YBCO filter, the reason may be due to the improper contacts on the feedlines and for gold filter, low thickness of the gold film has caused the loss increased.

  18. Preparation of high-temperature superconducting ceramics

    International Nuclear Information System (INIS)

    Causa, M.T.; Dutrus, S.M.; Esparza, Daniel; Fainstein, Carlos; Malachevsky, M.T.; Salva, Horacio; Sanchez, Rodolfo; Steren, L.B.; Tovar, Manuel; Veglio, Nestor

    1987-01-01

    We have prepared samples of the family ABa2Cu3Ox (A=Y, Gd, Eu, Dy, Sm, Er). The powdered samples were characterized by X-ray diffraction at room temperature. We have also studied the effect of Fe impurities in YBa2Cu3Ox and EuBa2Cu3Ox. Moreover, single crystals of YBa2Cu3Ox and La(1-x)SrxCuO4 were grown using cooper oxide flux. (Author) [es

  19. High-temperature superconducting current leads

    Science.gov (United States)

    Hull, J. R.

    1992-07-01

    The use of high-temperature superconductors (HTSs) for current leads to deliver power to devices at liquid helium temperature is near commercial realization. The use of HTSs in this application has the potential to reduce refrigeration requirements and helium boiloff to values significantly lower than the theoretical best achievable with conventional leads. Considerable advantage is achieved by operating these leads with an intermediate temperature heat sink. The HTS part of the lead can be made from pressed and sintered powder. Powder-in-tube fabrication is also possible, however, the normal metal part of the lead acts as a thermal short and cannot provide much stabilization without increasing the refrigeration required. Lead stability favors designs with low current density. Such leads can be manufactured with today's technology, and lower refrigeration results from the same allowable burnout time. Higher current densities result in lower boiloff for the same lead length, but bumout times can be very short. In comparing experiment to theory, the density of helium vapor needs to be accounted for in calculating the expected boiloff. For very low-loss leads, two-dimensional heat transfer and the state of the dewar near the leads may play a dominant role in lead performance.

  20. Superconducting energy store

    International Nuclear Information System (INIS)

    Elsel, W.

    1986-01-01

    The advantages obtained by the energy store device according to the invention with a superconducting solenoid system consist of the fact that only relatively short superconducting forward and return leads are required, which are collected into cables as far as possible. This limits the coolant losses of the cables. Only one relatively expensive connecting part with a transition of its conductors from room temperature to a low temperature is required, which, like the normal conducting current switch, is easily accessible. As the continuation has to be cooled independently of the upper part solenoid, cooling of this continuation part can prevent the introduction of large quantities of heat into the connected part solenoid. Due to the cooling of the forward and return conductors of the connecting cable with the coolant of the lower part solenoid, there are relatively few separations between the coolant spaces of the part solenoids. (orig./MM) [de

  1. Superconductivity

    CERN Document Server

    Poole, Charles P; Farach, Horacio A

    1995-01-01

    Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

  2. Design and application consideration of high temperature superconducting current leads

    International Nuclear Information System (INIS)

    Wu, J.L.

    1994-01-01

    As a potential major source of heat leak and the resultant cryogen boiloff, cryogenic current leads can significantly affect the refrigeration power requirement of cryogenic power equipment. Reduction of the heat leak associated with current leads can therefore contribute to the development and application of this equipment. Recent studies and tests have demonstrated that, due to their superconducting and low thermal conductivity properties, ceramic high temperature superconductor (HTSC) can be employed in current leads to significantly reduce the heat leak. However, realization of this benefit requires special design considerations pertaining to the properties and the fabrication technology of the relatively new ceramic superconductor materials. Since processing and fabrication technology are continuously being developed in the laboratories, data on material properties unrelated to critical states are quite limited. Therefore, design analysis and experiments have to be conducted in tandem to achieve a successful development. Due to the rather unique combination of superconducting and thermal conductivities which are orders of magnitude lower than copper, ceramic superconductors allow expansion of the operating scenarios of current leads. In addition to the conventional vapor-cooled lead type application, low heat leak conduction-cooled type current leads may be practical and are being developed. Furthermore, a current lead with an intermediate heat leak intercept has been successfully demonstrated in a multiple current lead assembly employing HTSC. These design and application considerations of high temperature superconducting current leads are addressed here

  3. Field quality of LHC superconducting dipole magnets

    International Nuclear Information System (INIS)

    Mishra, R.K.

    2003-01-01

    The author reports here the main results of field measurements performed so far on the LHC superconducting dipoles at superfluid helium temperature. The main field strength at injection, collision conditions and higher order multipoles are discussed. Superconducting magnets exhibit additional field imperfections due to diamagnetic properties of superconducting cables, apart from geometric error, saturation of iron yoke and eddy currents error. Dynamic effects on field harmonics, such as field decay at injection and subsequent snap back are also discussed. (author)

  4. Design prospect of remountable high-temperature superconducting magnet

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, Hidetoshi, E-mail: hidetoshi.hashizume@qse.tohoku.ac.jp; Ito, Satoshi

    2014-10-15

    The remountable (mountable and demountable repeatedly) high-temperature superconducting (HTS) magnet has been proposed for huge and complex superconducting magnets in future fusion reactors to fabricate and repair easily the magnet and access inner structural components. This paper summarizes progress in R and D activities of mechanical joints of HTS conductors in terms of the electrical resistance and heat transfer performance at the joint region. The latest experimental results show the low joint resistance, 4 nΩ under 70 kA current condition using REBCO HTS conductor with mechanical lap joint system, and for the cooling system the maximum heat flux of 0.4 MW/m{sup 2} is removed by using bronze sintered porous media with sub-cooled liquid nitrogen. These values indicate that there is large possibility to design the remountable HTS magnet for fusion reactors.

  5. Effects evaluation of artificial aging by temperature and gamma radiation on cables for Laguna Verde nuclear power plant (LVNPP)

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez C, R. M.; Bonifacio M, J.; Garcia H, E. E.; Loperena Z, J. A. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia M, C., E-mail: raulmario.vazquez@inin.gob.m [CFE, Central Nuclear Laguna Verde, Km. 42.5 Carretera Cardel-Nautla, Veracruz (Mexico)

    2010-10-15

    A set of tests has been carried out at the Equipment Qualification Laboratory at National Institute of Nuclear Research to perform accelerated aging up to 60 years under temperature and gamma radiation environment for electrical cables. The results obtained from such tests are the base line data for comparison to with the current cable conditions at the plant. This work is intended for establishing the cable aging management program for the Laguna Verde nuclear power plant (LVNPP). For such purpose, the Institute has prepared methodologies and procedures to apply condition monitoring techniques in accelerated aging tests on samples of new cables drawn from the LVNPP warehouse. The condition indicators of the material selected for condition monitoring and the aging management process of cables were: Elongation at Break (EAB) and Oxidation Induction Time (OIT). A cable aging management program includes activities for cable selection, determination of condition indicators of the cable materials (EAB, OIT, Ind enter), accelerated aging of cable samples at the laboratory, analysis of maintenance history, operational experience of the plant and analysis of the environmental and service conditions (temperature and gamma radiation), as well as the establishment of a condition monitoring plan for cables in the plant. Two cable model samples were thermally aged and gamma irradiated with doses corresponding to differential operational periods. EAB and OIT values of cable insulating material (ethylene propylene and cross linked polyethylene) were obtained. It was found that the EAB and OIT data correlation is very closed, and it could be applied to infer values that are not possible to measure directly at the plant and be used for cable aging evaluation and remaining life time determination. (Author)

  6. Superconducting transition temperature and the formation of closed electron shells in the atoms of superconducting compounds

    International Nuclear Information System (INIS)

    Chapnik, I.M.

    1985-01-01

    The relationship between the regularities in the tansition temperature (T/sub c/) values in analogous compounds (having the same structure and stoichiometry) and the formation of the closed electron shells outside inert gas shells in the atoms of the variable component of the 158 intermetallic superconducting compounds has been discussed. The T/sub c/ data for compounds of the elements from the first long period of the Periodic Table (K to Se) are compared with the T/sub c/ data for the analogous compounds of the elements from the second long period (Rb to Te)

  7. Colloquium: High pressure and road to room temperature superconductivity

    Science.gov (United States)

    Gor'kov, Lev P.; Kresin, Vladimir Z.

    2018-01-01

    This Colloquium is concerned with the superconducting state of new high-Tc compounds containing hydrogen ions (hydrides). Recently superconductivity with the record-setting transition temperature of Tc=203 K was reported for sulfur hydrides under high pressure. In general, high pressure serves as a path finding tool toward novel structures, including those with very high Tc . The field has a rich and interesting history. Currently, it is broadly recognized that superconductivity in sulfur hydrides owes its origin to the phonon mechanism. However, the picture differs from the conventional one in important ways. The phonon spectrum in sulfur hydride is both broad and has a complex structure. Superconductivity arises mainly due to strong coupling to the high-frequency optical modes, although the acoustic phonons also make a noticeable contribution. A new approach is described, which generalizes the standard treatment of the phonon mechanism and makes it possible to obtain an analytical expression for Tc in this phase. It turns out that, unlike in the conventional case, the value of the isotope coefficient (for the deuterium-hydrogen substitution) varies with the pressure and reflects the impact of the optical modes. The phase diagram, that is the pressure dependence of Tc , is rather peculiar. A crucial feature is that increasing pressure results in a series of structural transitions, including the one which yields the superconducting phase with the record Tc of 203 K. In a narrow region near P ≈150 GPa the critical temperature rises sharply from Tc≈120 to ≈200 K . It seems that the sharp structural transition, which produces the high-Tc phase, is a first-order phase transition caused by interaction between the order parameter and lattice deformations. A remarkable feature of the electronic spectrum in the high-Tc phase is the appearance of small pockets at the Fermi level. Their presence leads to a two-gap spectrum, which can, in principle, be observed with the

  8. Superconductivity

    International Nuclear Information System (INIS)

    2007-01-01

    During 2007, a large amount of the work was centred on the ITER project and related tasks. The activities based on low-temperature superconducting (LTS) materials included the manufacture and qualification of ITER full-size conductors under relevant operating conditions, the design of conductors and magnets for the JT-60SA tokamak and the manufacture of the conductors for the European dipole facility. A preliminary study was also performed to develop a new test facility at ENEA in order to test long-length ITER or DEMO full-size conductors. Several studies on different superconducting materials were also started to create a more complete database of superconductor properties, and also for use in magnet design. In this context, an extensive measurement campaign on transport and magnetic properties was carried out on commercially available NbTi strands. Work was started on characterising MgB 2 wire and bulk samples to optimise their performance. In addition, an intense experimental study was started to clarify the effect of mechanical loads on the transport properties of multi-filamentary Nb 3 Sn strands with twisted or untwisted superconducting filaments. The experimental activity on high-temperature superconducting (HTS) materials was mainly focussed on the development and characterisation of YBa 2 Cu 3 O 7-X (YBCO) based coated conductors. Several characteristics regarding YBCO deposition, current transport performance and tape manufacture were investigated. In the framework of chemical approaches for YBCO film growth, a new method, developed in collaboration with the Technical University of Cluj-Napoca (TUCN), Romania, was studied to obtain YBCO film via chemical solution deposition, which modifies the well-assessed metallic organic deposition trifluoroacetate (MOD-TFA) approach. The results are promising in terms of critical current and film thickness values. YBCO properties in films with artificially added pinning sites were characterised in collaboration with

  9. High temperature superconducting films by rf magnetron sputtering

    International Nuclear Information System (INIS)

    Kadin, A.M.; Ballentine, P.H.

    1989-01-01

    The authors have produced sputtered films of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O by rf magnetron sputtering from an oxide target consisting of loose reacted powder. The use of a large 8-inch stoichiometric target in the magnetron mode permits films located above the central region to be free of negative-ion resputtering effects, and hence yields reproducible, uniform stoichiometric compositions for a wide range of substrate temperatures. Superconducting YBCO films have been obtained either by sputtering at low temperatures followed by an 850 0 C oxygen anneal, or alternatively by depositing onto substrates heated to ∼600 - 650 0 C and cooling in oxygen. Films prepared by the former method on cubic zirconia substrate consist of randomly oriented crystallites with zero resistance above 83 K. Those deposited on zirconia at medium temperatures without the high-temperature anneal contain smooth partially oriented crystallites, with a slightly depressed T/sub c/ ∼75K. Finally, superconducting films have been deposited on MgO using a BiSrCaCu/sub 2/O/sub x/ powder target

  10. Proposal for the award of a contract for the supply of superconducting cables for the LHC low-current insertion (mqm) and wide-aperture insertion (mqy) quadrupoles

    CERN Document Server

    1999-01-01

    This document concerns the award of a contract for the supply of the superconducting cables for the LHC low-current insertion (MQM) and wide-aperture insertion (MQY) quadrupoles. A call for tenders (IT-2631/LHC/LHC) was sent to four firms in four Member States, three firms in Japan and two firms in the USA on 3 June 1999. By the closing date, CERN had received seven tenders. The Finance Committee is invited to agree to the negotiation of a contract with the firm VACUUMSCHMELZE (DE) for the supply of all superconducting cables for the LHC MQM and MQY quadrupoles for a total net price of 3 240 257 euros, subject to revision after 31 December 2000, with an option to procure additional cables representing 10% of the initial quantity for a total net price of 324 026 euros, bringing the total to an amount of 3 564 283 euros, subject to revision after 31 December 2000. At the exchange rate given in the tender, these amounts correspond to 5 192 720 Swiss francs, 519 272 Swiss francs and 5 711 992 Swiss francs respect...

  11. JETC (Japanese Technology Evaluation Center) Panel Report on High Temperature Superconductivity in Japan

    Science.gov (United States)

    Shelton, Duane; Gamota, George

    1989-01-01

    The Japanese regard success in R and D in high temperature superconductivity as an important national objective. The results of a detailed evaluation of the current state of Japanese high temperature superconductivity development are provided. The analysis was performed by a panel of technical experts drawn from U.S. industry and academia, and is based on reviews of the relevant literature and visits to Japanese government, academic and industrial laboratories. Detailed appraisals are presented on the following: Basic research; superconducting materials; large scale applications; processing of superconducting materials; superconducting electronics and thin films. In all cases, comparisons are made with the corresponding state-of-the-art in the United States.

  12. Superconductivity

    International Nuclear Information System (INIS)

    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

  13. Progress in DOE high temperature superconductivity electric power applications program

    International Nuclear Information System (INIS)

    Daley, J.G.; Sheahn, T.P.

    1992-01-01

    The Department of Energy (DOE) leads national R and D effort to develop US industry's capability to produce a wide range of advanced energy-efficient electric power products. The immediate need is to make high temperature superconductivity (HTS) wire. Wire developers at the DOE National laboratories are working wit industrial partners toward this objective. In this paper, the authors describe the progress to date, citing both the difficulties associated with making wire from these ceramic materials, and achievements at several organizations. Results for progress over the next five years are stated

  14. High-temperature superconducting passive microwave devices, filters and antennas

    International Nuclear Information System (INIS)

    Ohshima, S.

    2000-01-01

    High-temperature superconducting (HTS) passive microwave devices, such as filters and antennas, are promising devices. In particular, HTS filters may be successfully marketed in the near future. Cross-coupled filters, ring filters, and coplanar waveguide filters are good options to reduce filter size. On the other hand, HTS patch antennas which can be cooled by a cryo-cooler are also promising devices as well, since they show higher efficiency than normal antennas. This paper examines the design process and filter properties of HTS filters as well as the gains, directivity, and cooling system of HTS patch antennas. (author)

  15. Superconductivity

    International Nuclear Information System (INIS)

    Andersen, N.H.; Mortensen, K.

    1988-12-01

    This report contains lecture notes of the basic lectures presented at the 1st Topsoee Summer School on Superconductivity held at Risoe National Laboratory, June 20-24, 1988. The following lecture notes are included: L.M. Falicov: 'Superconductivity: Phenomenology', A. Bohr and O. Ulfbeck: 'Quantal structure of superconductivity. Gauge angle', G. Aeppli: 'Muons, neutrons and superconductivity', N.F. Pedersen: 'The Josephson junction', C. Michel: 'Physicochemistry of high-T c superconductors', C. Laverick and J.K. Hulm: 'Manufacturing and application of superconducting wires', J. Clarke: 'SQUID concepts and systems'. (orig.) With 10 tabs., 128 figs., 219 refs

  16. Thermal properties of superconducting bulk metallic glasses at ultralow temperatures

    International Nuclear Information System (INIS)

    Rothfuss, Daniel Simon

    2013-01-01

    This thesis describes the first investigation of thermal properties of superconducting bulk metallic glasses in the range between 6mK and 300K. Measuring the thermal conductivity provides the possibility to probe the fundamental interactions governing the heat flow in solids. At ultralow temperatures a novel contactless measuring technique was used, which is based on optical heating and paramagnetic temperature sensors that are read out by a SQUID magnetometer. Below the critical temperature T c the results can be described by resonant scattering of phonons by tunneling systems. Above T c the phonon contribution to the thermal conductivity can be described successfully within a model considering not only electrons and phonons but also localized modes as scattering centres. To expand the accessible temperature range for experiments an adiabatic nuclear demagnetization refrigerator was set up. For measuring the base temperature a novel noise thermometer was developed which enables continuous measuring of the temperature in this temperature range for the first time. Therefore the magnetic Johnson noise of a massive copper cylinder is simultaneously monitored by two SQUID magnetometers. A subsequent cross-correlation suppresses the amplifier noise by more than one order of magnitude. The thermometer was characterized between 42μK and 0.8K showing no deviation from the expected linear behaviour between the power spectral density of the thermal noise and the temperature.

  17. Numerical analysis of the stability of HTS power cable under fault current considering the gaps in the cable

    International Nuclear Information System (INIS)

    Fang, J.; Li, H.F.; Zhu, J.H.; Zhou, Z.N.; Li, Y.X.; Shen, Z.; Dong, D.L.; Yu, T.; Li, Z.M.; Qiu, M.

    2013-01-01

    Highlights: •The equivalent circuit equations and the heat balance equations were established. •The current distributions of the HTS cable under fault current were obtained. •The temperature curves of conductor layers under fault current were obtained. •The effect of the gap liquid nitrogen on the thermal characteristics was studied. -- Abstract: During the operation of a high temperature superconducting power cable in a real grid, the power cable can be impacted inevitably by large fault current. The study on current distribution and thermal characteristics in the cable under fault current is the foundation to analyze its stability. To analyze the operation situation of 110 kV/3 kA class superconducting cable under the fault current of 25 kA rms for 3 s, the equivalent circuit equations and heat balance equations were established. The current distribution curves and the temperature distribution curves were obtained. The liquid nitrogen which exists in the gaps of HTS cable was taken into consideration, the influence of gap liquid nitrogen on the thermal characteristics was investigated. The analysis results can be used to estimate the security and stability of the superconducting cable

  18. Numerical analysis of the stability of HTS power cable under fault current considering the gaps in the cable

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J., E-mail: fangseer@sina.com [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li, H.F. [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhu, J.H.; Zhou, Z.N. [China Electric Power Research Institute, Beijing 100192 (China); Li, Y.X.; Shen, Z.; Dong, D.L.; Yu, T. [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China); Li, Z.M.; Qiu, M. [China Electric Power Research Institute, Beijing 100192 (China)

    2013-11-15

    Highlights: •The equivalent circuit equations and the heat balance equations were established. •The current distributions of the HTS cable under fault current were obtained. •The temperature curves of conductor layers under fault current were obtained. •The effect of the gap liquid nitrogen on the thermal characteristics was studied. -- Abstract: During the operation of a high temperature superconducting power cable in a real grid, the power cable can be impacted inevitably by large fault current. The study on current distribution and thermal characteristics in the cable under fault current is the foundation to analyze its stability. To analyze the operation situation of 110 kV/3 kA class superconducting cable under the fault current of 25 kA{sub rms} for 3 s, the equivalent circuit equations and heat balance equations were established. The current distribution curves and the temperature distribution curves were obtained. The liquid nitrogen which exists in the gaps of HTS cable was taken into consideration, the influence of gap liquid nitrogen on the thermal characteristics was investigated. The analysis results can be used to estimate the security and stability of the superconducting cable.

  19. Superconductivity

    CERN Document Server

    Thomas, D B

    1974-01-01

    A short general review is presented of the progress made in applied superconductivity as a result of work performed in connection with the high-energy physics program in Europe. The phenomenon of superconductivity and properties of superconductors of Types I and II are outlined. The main body of the paper deals with the development of niobium-titanium superconducting magnets and of radio-frequency superconducting cavities and accelerating structures. Examples of applications in and for high-energy physics experiments are given, including the large superconducting magnet for the Big European Bubble Chamber, prototype synchrotron magnets for the Super Proton Synchrotron, superconducting d.c. beam line magnets, and superconducting RF cavities for use in various laboratories. (0 refs).

  20. Research on material of high temperature cable and wire insulation by γ-rays

    International Nuclear Information System (INIS)

    Jia Shaojin; Zhang Zhicheng; Xu Xiangling; Ge Xuewu; Ye qiang; Wang Feng

    2000-01-01

    Radiation-crosslinking improves a number of essential properties of polymers, so the high -temperature-resistance of polyethylene (PE) was increased by irradiation. The national products of High -density-polyethylene (HDPE), crosslinking promoters, flame-retardant, antioxidants, Si rubber, and Ethylene-propylene-monomer (EPDM) were used as cable insulation. After -irradiation, thermal-endurance can get above 135, and high flame retardance was firmed, Oxygen index can get above 32 by crosslinking

  1. Sample of superconducting wiring (Niobium Titanium)

    CERN Multimedia

    About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resistan...

  2. Sample of superconducting wiring (Niobium Titanium)

    CERN Multimedia

    About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resista...

  3. What is strange about high-temperature superconductivity in cuprates?

    Science.gov (United States)

    Božović, I.; He, X.; Wu, J.; Bollinger, A. T.

    2017-10-01

    Cuprate superconductors exhibit many features, but the ultimate question is why the critical temperature (Tc) is so high. The fundamental dichotomy is between the weak-pairing, Bardeen-Cooper-Schrieffer (BCS) scenario, and Bose-Einstein condensation (BEC) of strongly-bound pairs. While for underdoped cuprates it is hotly debated which of these pictures is appropriate, it is commonly believed that on the overdoped side strongly-correlated fermion physics evolves smoothly into the conventional BCS behavior. Here, we test this dogma by studying the dependence of key superconducting parameters on doping, temperature, and external fields, in thousands of cuprate samples. The findings do not conform to BCS predictions anywhere in the phase diagram.

  4. Superconductors for the medium-voltage grid. A superconducting power cable running through the inner city of Essen passes a two-year field test; Supraleiter fuer das Mittelspannungsnetz. Ein supraleitendes Stromkabel quer durch die Essener Innenstadt besteht zweijaehrigen Feldtest

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Franz

    2017-04-01

    Scientists are testing the longest high-temperature superconducting cable in the world under real conditions in Essen. One kilometre long, it connects two substations in the inner city. It replaces a conventional 110 kV line and renders one substation in the inner city obsolete. After two years of testing, it has passed the field test. It could be a blueprint for the future power supply system in urban areas. [German] Wissenschaftler testen in Essen das laengste Hochtemperatur-Supraleiterkabel der Welt unter realen Bedingungen. Mit einer Laenge von einem Kilometer verbindet es zwei Umspannstationen quer durch die Innenstadt. Es ersetzt eine konventionelle 110-kV-Leitung und macht eine Umspannanlage im Stadtzentrum ueberfluessig. In einer zweijaehrigen Erprobung hat es den Praxistest bestanden. Es koennte eine Blaupause fuer die kuenftige Stromversorgung in Ballungsraeumen sein.

  5. High-temperature superconducting fault-current limiter - optimisation of superconducting elements

    International Nuclear Information System (INIS)

    2004-01-01

    This report summarises the findings of a study initiated to continue the work of a DTI-LINK Collaborative Research Programme 'Enhancing the Properties of Bulk High Temperature Superconductors and their Potential Application as Fault Current Limiters (FCL). Details are given of computer modelling of the quenching process involving the transition from superconducting to normal conducting states undergone by the material when large currents are present. The design of compound elements, and a multi-element model are described along with FCL design covering distribution bus-coupler, embedded generator connection, larger generator connection, hazardous area safety, and interconnection to fault-prone network. The evaluation of thermal loss, test equipment and schedule, the optimised element, installed cost data, and the UK market are considered

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

    Science.gov (United States)

    Boom, R. W. (Inventor)

    1967-01-01

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

  7. Design and study of new cables for superconducting accelerator magnets: Synchrotron SIS 100 at GSI and NICA collider at JINR*

    International Nuclear Information System (INIS)

    Khodzhibagiyan, H G; Drobin, V M; Kovalenko, A D; Vladimirova, N M; Fischer, E; Pantsyrny, V I; Potanina, L V; Shikov, A K

    2010-01-01

    Recent data from the design of new optimized options of NbTi composite wires and hollow cables for fast cycling synchrotron SIS100 at GSI and NICA collider at JINR are presented. The SIS100 new cable is proposed to be used for manufacturing of single-layer coil for dipole magnet with maximal amplitude of pulsed magnetic field up to 2 T. The cable should provide continues pulsed operation at the current amplitude of I = 13 kA and magnetic field ramp rate of dB/dt = 4 T/s. The results of experimental study of energy losses in the new wire and cable samples for SIS100 magnets are presented. The design cable parameters for the NICA 4 T dipole magnet are fixed at the level of I = 17 kA and dB/dt = 1 T/s. The status of the work is presented and discussed.

  8. Superconducting pulsed magnets

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mechanisms and calculation of total losses in the magnet. The need for cooling to minimize temperature rise in a magnet. Measuring ac losses in wires and in magnets. Lecture 5. Stab...

  9. Design, processing, and properties of Bi 2212\\/Ag Rutherford cables

    CERN Document Server

    Collings, E W; Scanlan, R M; Dietderich, D R; Motowidlo, L R; Sokolowski, R S; Aoki, Y; Hasegawa, T

    1999-01-01

    In a program intended to explore the use of high temperature superconducting (HTSC) cables in high field synchrotron dipole magnets model Bi:2212/Ag Rutherford cables were designed bearing in mind the needs for mechanical integrity, relatively high tensile strength, and low coupling losses. To satisfy these needs a core-type cable design was selected and a readily available heat-resistant core material acquired. Cables were wound for critical current- and AC loss measurement. Both winding-induced (mechanical) and core-induced (chemical) critical current degradation was examined. Interstrand coupling loss was measured calorimetrically on model cable samples with bare- and oxide-coated cores. From the results it was predicted that the losses of full-scale Bi:2212/Ag-wound LHC-type Rutherford cables would fall close to the acceptability range for the windings of high-field accelerator dipoles. (10 refs).

  10. Transient analysis of an HTS DC power cable with an HVDC system

    Science.gov (United States)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

    2013-11-01

    The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

  11. Application of high temperature superconductivity to electric motor design

    International Nuclear Information System (INIS)

    Edmonds, J.S.; Sharma, D.K.; Jordan, H.E.; Edick, J.D.; Schiferl, R.F.

    1992-01-01

    This paper reports on progress made in a joint project conducted by the Electric Power Research Institute and Reliance Electric Company to study the possible application of High Temperature Super Conductors (HTSC), materials to electric motors. Specific applications are identified which can be beneficially served by motors constructed with HTSC materials. A summary is presented of the components and design issues related to HTSC motors designed for these applications. During the course of this development program, a three tier HTSC wire performance specification has evolved. The three specifications and the rationale behind these three levels of performance are explained. A description of a test motor that has been constructed to verify the electromagnetic analytical techniques of HTSC motor design is given. Finally, a DC motor with an HTSC field coil is described. Measured data with the motor running is presented showing that the motor is operating with the field winding in the superconducting state

  12. Shock-induced synthesis of high temperature superconducting materials

    Science.gov (United States)

    Ginley, D.S.; Graham, R.A.; Morosin, B.; Venturini, E.L.

    1987-06-18

    It has now been determined that the unique features of the high pressure shock method, especially the shock-induced chemical synthesis technique, are fully applicable to high temperature superconducting materials. Extraordinarily high yields are achievable in accordance with this invention, e.g., generally in the range from about 20% to about 99%, often in the range from about 50% to about 90%, lower and higher yields, of course, also being possible. The method of this invention involves the application of a controlled high pressure shock compression pulse which can be produced in any conventional manner, e.g., by detonation of a high explosive material, the impact of a high speed projectile or the effect of intense pulsed radiation sources such as lasers or electron beams. Examples and a discussion are presented.

  13. Operation and design selection of high temperature superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2004-01-01

    Axial and radial high temperature superconducting (HTS) magnetic bearings are evaluated by their parameters. Journal bearings possess advantages over thrust bearings. High magnetic gradients in a multi-pole permanent magnet (PM) configuration, the surrounding melt textured YBCO stator and adequate designs are the key features for increasing the overall bearing stiffness. The gap distance between rotor and stator determines the specific forces and has a strong impact on the PM rotor design. We report on the designing, building and measuring of a 200 mm prototype 100 kg HTS bearing with an encapsulated and thermally insulated melt textured YBCO ring stator. The encapsulation requires a magnetically large-gap (4-5 mm) operation but reduces the cryogenic effort substantially. The bearing requires 3 l of LN 2 for cooling down, and about 0.2 l LN 2 h -1 under operation. This is a dramatic improvement of the efficiency and in the practical usage of HTS magnetic bearings

  14. The DARPA manufacturing initiative in high temperature superconductivity

    International Nuclear Information System (INIS)

    Adams, K.R.

    1989-01-01

    The Defense Advanced Research Projects Agency (DARPA) has a very aggressive Technology Base program in high temperature superconductivity. This program is expected to provide the basis for a specialized set of military products - passive microwave and millimeter wave devices - within the next three years. In order to get these high leverage products into military systems, a manufacturing base must be developed for HTSC components. A plan for DARPA in HTSC manufacturing is directly coupled with the ongoing DARPA materials and device oriented R and D program. In essence, this plan recommends a three phased effort: 1. Phase I (two years); Fund companies through R and D contracts for specialized HTSC components; prepare a detailed plan and develop an HTSC consortium. 2. Phase II (six years): Establish an HTSC Sematech initiative for electronic applications, including active devices. 3. Phase III (optional): Continue the HTSC Sematech with emphasis on high power applications

  15. Calculation of the superconducting transition temperature in niobium

    International Nuclear Information System (INIS)

    Perlov, C.M.

    1982-01-01

    The author presents calculations of the superconducting transition temperature, T/sub c/, the electron-phonon coupling constant, lambda, and the spectral function, α 2 f(ω), for niobium. The author's calculations are based on an empirical pseudopotential method (EPM) band structure. Phonon linewidths are also given for longitudinal and transverse branches along different directions. The necessary electron-phonon matrix elements are evaluated using only the rigid-ion approximation by applying Green's theorem. The calculated value of T/sub c/ is 8.4 K which differs from the measured value by only 9%; the calculated lambda is 1.02. The spectral function and linewidths are compared to experimental and previous theoretical results

  16. High-temperature superconducting nanowires for photon detection

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, R. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg (Sweden); CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Fisica, Università degli Studi di Napoli ‘Federico II’, I-80125 Napoli (Italy); Ejrnaes, M. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Parlato, L. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Fisica, Università degli Studi di Napoli ‘Federico II’, I-80125 Napoli (Italy); Tafuri, F. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, I-81031 Aversa, CE (Italy); Cristiano, R. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Golubev, D. [Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto (Finland); Sobolewski, Roman, E-mail: roman.sobolewski@rochester.edu [Institute of Electron Technology, PL-02668 Warszawa (Poland); Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester, NY 14627-0231 (United States); Bauch, T.; Lombardi, F. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg (Sweden); and others

    2015-02-15

    Highlights: • Homogeneous YBCO nanowires have been fabricated for photon detection applications. • Serial-parallel nanowire configuration leads to a large detector active area. • The YBCO nanowires exhibit critical current densities up to 106 A/cm{sup 2}. • The devices have been excited using a 1550-nm wavelength, pulsed laser irradiation. • Photoresponse signals have been measured and analyzed from 4 K up to the device T{sub c}. - Abstract: The possible use of high-temperature superconductors (HTS) for realizing superconducting nanowire single-photon detectors is a challenging, but also promising, aim because of their ultrafast electron relaxation times and high operating temperatures. The state-of-the-art HTS nanowires with a 50-nm thickness and widths down to 130 nm have been fabricated and tested under a 1550-nm wavelength laser irradiation. Experimental results presenting both the amplitude and rise times of the photoresponse signals as a function of the normalized detector bias current, measured in a wide temperature range, are discussed. The presence of two distinct regimes in the photoresponse temperature dependence is clearly evidenced, indicating that there are two different response mechanisms responsible for the HTS photoresponse mechanisms.

  17. Complete Fiber/Copper Cable Solution for Long-Term Temperature and Pressure Measurement in Supercritical Reservoirs and EGS Wells

    Energy Technology Data Exchange (ETDEWEB)

    Pastouret, Alan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Gooijer, Frans [Draka Cableteq USA, Inc., North Dighton, MA (United States); Overton, Bob [Draka Cableteq USA, Inc., North Dighton, MA (United States); Jonker, Jan [Draka Cableteq USA, Inc., North Dighton, MA (United States); Curley, Jim [Draka Cableteq USA, Inc., North Dighton, MA (United States); Constantine, Walter [Draka Cableteq USA, Inc., North Dighton, MA (United States); Waterman, Kendall Miller [Draka Cableteq USA, Inc., North Dighton, MA (United States)

    2015-11-13

    High Temperature insulated wire and optical fiber cable is a key enabling technology for the Geothermal Technologies Program (GTP). Without insulated electrical wires and optical fiber, downhole temperature and pressure sensors, flow meters and gauges cannot communicate with the surface. Unfortunately, there are currently no insulated electrical wire or fiber cable constructions capable of surviving for extended periods of deployment in a geothermal well (240-325°C) or supercritical (374°C) reservoir. This has severely hindered engineered reservoir creation, management and utilization, as hot zones and cool water intrusions cannot be understood over time. The lack of a insulated electrical wire and fiber cable solution is a fundamental limitation to the viability of this energy source. The High Temperature Downhole Tools target specification is development of tools and sensors for logging and monitoring wellbore conditions at depths of up to 10,000 meters and temperatures up to 374oC. It well recognized in the industry that no current electronic or fiber cable can be successfully deployed in a well and function successfully for more a few days at temperatures over 240oC. The goal of this project was to raise this performance level significantly. Prysmian Group’s objective in this project was to develop a complete, multi-purpose cable solution for long-term deployment in geothermal wells/reservoirs that can be used with the widest variety of sensors. In particular, the overall project objective was to produce a manufacturable cable design that can perform without serious degradation: • At temperatures up to 374°C; • At pressures up to 220 bar; • In a hydrogen-rich environment; and • For the life of the well (> 5 years). This cable incorporates: • Specialty optical fibers, with specific glass chemistry and high temperature and pressure protective coatings for data communication and distributed temperature and pressure sensing, and • High-temperature

  18. High-temperature study of superconducting hydrogen and deuterium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Durajski, A.P. [Institute of Physics, Czestochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Czestochowa (Poland); Szczesniak, R. [Institute of Physics, Czestochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Czestochowa (Poland); Institute of Physics, Jan Dlugosz University, Ave. Armii Krajowej 13/15, 42-200 Czestochowa (Poland); Pietronero, L. [Sapienza, Universita di Roma, Dip. Fisica, P. le A. Moro 2, 00185 Roma (Italy); Institute of Complex Systems, CNR, Via dei Taurini 19 Roma (Italy); London Institute for Mathematical Sciences, South Street 22, Mayfair London (United Kingdom)

    2016-05-15

    Hydrogen-rich compounds are extensively explored as candidates for a high-temperature superconductors. Currently, the measured critical temperature of 203 K in hydrogen sulfide (H{sub 3}S) is among the highest over all-known superconductors. In present paper, using the strong-coupling Eliashberg theory of superconductivity, we compared in detail the thermodynamic properties of two samples containing different hydrogen isotopes H{sub 3}S and D{sub 3}S at 150 GPa. Our research indicates that it is possible to reproduce the measured values of critical temperature 203 K and 147 K for H{sub 3}S and D{sub 3}S by using a Coulomb pseudopotential of 0.123 and 0.131, respectively. However, we also discuss a scenario in which the isotope effect is independent of pressure and the Coulomb pseudopotential for D{sub 3}S is smaller than for H{sub 3}S. For both scenarios, the energy gap, specific heat, thermodynamic critical field and related dimensionless ratios are calculated and compared with other conventional superconductors. We shown that the existence of the strong-coupling and retardation effects in the systems analysed result in significant differences between values obtained within the framework of the Eliashberg formalism and the prediction of the Bardeen-Cooper-Schrieffer theory. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Comparison of Conductor-Temperature Calculations Based on Different Radial-Position-Temperature Detections for High-Voltage Power Cable

    Directory of Open Access Journals (Sweden)

    Lin Yang

    2018-01-01

    Full Text Available In this paper, the calculation of the conductor temperature is related to the temperature sensor position in high-voltage power cables and four thermal circuits—based on the temperatures of insulation shield, the center of waterproof compound, the aluminum sheath, and the jacket surface are established to calculate the conductor temperature. To examine the effectiveness of conductor temperature calculations, simulation models based on flow characteristics of the air gap between the waterproof compound and the aluminum are built up, and thermocouples are placed at the four radial positions in a 110 kV cross-linked polyethylene (XLPE insulated power cable to measure the temperatures of four positions. In measurements, six cases of current heating test under three laying environments, such as duct, water, and backfilled soil were carried out. Both errors of the conductor temperature calculation and the simulation based on the temperature of insulation shield were significantly smaller than others under all laying environments. It is the uncertainty of the thermal resistivity, together with the difference of the initial temperature of each radial position by the solar radiation, which led to the above results. The thermal capacitance of the air has little impact on errors. The thermal resistance of the air gap is the largest error source. Compromising the temperature-estimation accuracy and the insulation-damage risk, the waterproof compound is the recommended sensor position to improve the accuracy of conductor-temperature calculation. When the thermal resistances were calculated correctly, the aluminum sheath is also the recommended sensor position besides the waterproof compound.

  20. Ultra high-current superconducting cables for a 2.2-Tesla, 300-kilojoule energy storage magnet

    International Nuclear Information System (INIS)

    Miranda, G.A.; Rhodenizer, R.; Rackov, P.; Punchard, W.F.B.; de Winter, T.A.

    1976-01-01

    These 2.2-T, 300-kJ magnets are to operate at 10 to 12 kA with a safety factor in critical current of about 50 percent at 10 kA. The conductor must exhibit low losses in addition to being stable. Magnetic Corporation of America (MCA) designed a flat conductor using 1224 copper-matrix, monofilament wires combined in two stages of cabling followed by two stages of flat braiding. Two of these conductors were constructed, one with wire already on hand and the second using wire made specifically for this application. Intermagnetics General Corporation (IGC) designed two rectangular conductors using 315 and 319 mixed-matrix multifilament wires combined in three stages of cabling followed by compaction in a Turk's head. The maximum transport current capabilities (I/sub t/) of these cables were measured in hairpin shaped samples with the straight section under test in perpendicularly applied fields. The measured results at 2.5 T for the two MCA cables were 11.7 kA and 15.4 kA, and for the IGC cables were 18.2 kA and 19.3 kA (extrapolated). In addition, samples of the compacted and uncompacted major strands from the IGC cables were tested. The results of these measurements are compred with values of I/sub t/ from the single-wire critical currents taking into account the adjacent conductor fields and the cable self-fields.Several causes of degradation of I/sub t/ in the compacted cable are discussed including those due to experimental factors

  1. The infinite range Heisenberg model and high temperature superconductivity

    Science.gov (United States)

    Tahir-Kheli, Jamil

    1992-01-01

    The thesis deals with the theory of high temperature superconductivity from the standpoint of three-band Hubbard models.Chapter 1 of the thesis proposes a strongly coupled variational wavefunction that has the three-spin system of an oxygen hole and its two neighboring copper spins in a doublet and the background Cu spins in an eigenstate of the infinite range antiferromagnet. This wavefunction is expected to be a good "zeroth order" wavefunction in the superconducting regime of dopings. The three-spin polaron is stabilized by the hopping terms rather than the copper-oxygen antiferromagnetic coupling Jpd. Considering the effect of the copper-copper antiferromagnetic coupling Jdd, we show that the three-spin polaron cannot be pure Emery (Dg), but must have a non-negligible amount of doublet-u (Du) character for hopping stabilization. Finally, an estimate is made for the magnitude of the attractive coupling of oxygen holes.Chapter 2 presents an exact solution to a strongly coupled Hamiltonian for the motion of oxygen holes in a 1-D Cu-O lattice. The Hamiltonian separates into two pieces: one for the spin degrees of freedom of the copper and oxygen holes, and the other for the charge degrees of freedom of the oxygen holes. The spinon part becomes the Heisenberg antiferromagnet in 1-D that is soluble by the Bethe Ansatz. The holon piece is also soluble by a Bethe Ansatz with simple algebraic relations for the phase shifts.Finally, we show that the nearest neighbor Cu-Cu spin correlation increases linearly with doping and becomes positive at x [...] 0.70.

  2. Radiation Shielding Utilizing A High Temperature Superconducting Magnet

    Data.gov (United States)

    National Aeronautics and Space Administration — Project objective is to evaluate human radiation protection and architecture utilizing existing superconducting magnet technology while attempting to significantly...

  3. Superconductivity

    CERN Document Server

    Ketterson, John B

    2008-01-01

    Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

  4. Semiannual report for the period April 1 to September 30, 1978 of work on: (1) superconducting power transmission system development; (2) cable insulation development. Power Transmission Project technical note No. 83

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-07

    Progress in the development, fabrication and testing of superconductors for HVAC power transmission systems is reported. Information is included on the materials evaluation of superconducting alloys, production of tapes from these alloys, principally Nb/sub 3/Sn cable insulation requirements and development, and the cryogenic equipment used in this research program. (LCL)

  5. Influence of pulse electric current on structure and superconducting properties of high temperature superconductor

    International Nuclear Information System (INIS)

    Rajchenko, A.I.; Flis, A.A.; Chernenko, L.I.; Kryuchkova, N.I.

    1998-01-01

    The influence of high-density pulse current treatment at room temperature on structure and superconducting properties of HTSC Y Ba 2 Cu 3 O x ceramics is studied. The structures of the samples are found to undergo appreciable changes as the density of pulse current is gradually increased from its minimum value; as a certain threshold value is attained, there occurs a melting-off of coarse grains with a partial destroying of intergrain contact areas followed by superconductivity loss. A further increase in the treatment current density results in a restoration of the superconducting properties probably due to the occurrence of aligned-with-current superconducting bridges between the melted-off grains. The superconducting transition temperature in the samples does not charge but subsequent thermal treatment causes this temperature to increase

  6. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    International Nuclear Information System (INIS)

    Liu Fusui; Chen Wanfang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He II is only a criterion for microscopic superfluidity of 4 He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-T c cuprates

  7. Theory of high-T{sub C} superconductivity: transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Harshman, Dale R [Physikon Research Corporation, Lynden, WA 98264 (United States); Fiory, Anthony T [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Dow, John D, E-mail: drh@physikon.net [Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

    2011-07-27

    It is demonstrated that the transition temperature (T{sub C}) of high-T{sub C} superconductors is determined by their layered crystal structure, bond lengths, valency properties of the ions, and Coulomb coupling between electronic bands in adjacent, spatially separated layers. Analysis of 31 high-T{sub C} materials (cuprates, ruthenates, ruthenocuprates, iron pnictides, organics) yields the universal relationship for optimal compounds, k{sub B}T{sub C0} ={beta}/{iota}{zeta}, where {iota} is related to the mean spacing between interacting charges in the layers, {zeta} is the distance between interacting electronic layers, {beta} is a universal constant and T{sub C0} is the optimal transition temperature (determined to within an uncertainty of {+-} 1.4 K by this relationship). Non-optimum compounds, in which sample degradation is evident, e.g. by broadened superconducting transitions and diminished Meissner fractions, typically exhibit reduced T{sub C} < T{sub C0}. It is shown that T{sub C0} may be obtained from an average of the Coulomb interaction forces between the two layers.

  8. Effect of thermal phonons on the superconducting transition temperature

    International Nuclear Information System (INIS)

    Leavens, C.R.; Talbot, E.

    1983-01-01

    There is no consensus in the literature on whether or not thermal phonons depress the superconducting transition temperature T/sub c/. In this paper it is shown by accurate numerical solution of the real-frequency Eliashberg equations for the pairing self-energy phi and renormalization function Z that thermal phonons in the kernel for phi raise T/sub c/ but those in Z lower it by a larger amount so that the net effect is to depress T/sub c/. (A previous calculation which ignored the effect of thermal phonons in phi overestimated the suppression of T/sub c/ by at least a factor of 3.) It is shown how to switch off the thermal phonons in the imaginary-frequency Eliashberg equations, exactly for Z and approximately for phi. The real-frequency and approximate imaginary-frequency results for the depression of T/sub c/ by thermal phonons are in very satisfactory agreement. Thermal phonons are found to depress the transition temperature of Nb 3 Sn by only 2%. It is estimated that the suppression of T/sub c/ by thermal phonons saturates at about 50% in the limit of very strong electron-phonon coupling

  9. A liquid nitrogen temperature SSC [Superconducting Super Collider

    International Nuclear Information System (INIS)

    McAshan, M.S.; VanderArend, P.

    1987-04-01

    Under the assumption that new developments in the science of superconductivity will lead to dipole magnets suitable for the SSC that have the same properties with regard to field, field quality, size and cost as those in the present conception of the collider, but operating at 77 K rather than 4.35 K; the initial cost of the collider facility is found to be less by $213 M out of the $2,000 M actual construction cost for the collider technical systems and the conventional facilities estimated in the Conceptual Design Report. EDI and contingency is not included in these figures. Operation at the higher temperature is not, however, an unequivocal advantage. The beam line vacuum system in the 77 K case presents problems that will require a larger magnet aperture for satisfactory solution. The costs of this together with the cost of the development and construction of the new vacuum system required is estimated to be $156 M. The net capital cost saving associated with the higher temperature operation is thus found to be $57 M or about 3% of the estimated cost. In addition it is estimated that the operating cost of the facility will under conditions be less by $27.5 M per year in the steady-state including an allowance for the greater availability of the simpler cryogenic system. 14 refs., 1 fig., 4 tabs

  10. Stability analysis of high temperature superconducting coil in liquid hydrogen

    International Nuclear Information System (INIS)

    Nakayama, T.; Yagai, T.; Tsuda, M.; Hamajima, T.

    2007-01-01

    Recently, it is expected that hydrogen plays an important role in energy source including electric power in near future. Liquid hydrogen has high potential for cooling down superconducting coil wound with high temperature superconductors (HTS), such as BSCCO, YBCO. In this paper, we study stabilities of the coils wound with BSCCO tapes, which are immersed in the liquid hydrogen, and compare stability results with those cooled by liquid helium. We treat a minimum propagation zone (MPZ) theory to evaluate the coil stability considering boiling heat flux of the liquid hydrogen, and specific heat, heat conduction and resistivity of HTS materials as a function of temperature. It is found that the coil cooled by the liquid hydrogen has higher stability margin than that cooled by the liquid helium. We compare the stability margins of both coils wound with Bi-2223/Ag tape and Bi-2212/Ag tape in liquid hydrogen. As a result, it is found that the stability of Bi-2212 coil is equivalent to that of Bi-2223 coil in low and high magnetic field, while the maximum current of Bi-2212 coil exceeds a little bit that of Bi-2223 coil in both magnetic fields

  11. Magnet cable manufacturing

    International Nuclear Information System (INIS)

    Royet, J.

    1985-07-01

    The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. The superconducting strands are mostly circular but a design of a cable made of preflattened wires was proposed a few years ago under the name of Berkeley flat; such cable shows some interesting characteristics. Another design consists of a few smaller precabled wires (e.g. 6 around 1). This configuration allows smaller filaments and a better transposition of the current elements. The Superconducting Super Collider project involves the largest amount of superconducting cable ever envisaged for a single machine. Furthermore, the design calls for exceptional accuracy and improved characteristics of the cable. A part of the SSC research and development program is focused on these important questions. In this paper we emphasize the difference between the conventional cabling and wires with superconducting. A new concept for the tooling will be introduced as well as the necessary characteristics of a specialized cabler. 5 figs

  12. Assessment and study of existing concepts and methods of cryogenic refrigeration for superconducting transmission cables. Final report. Draft

    International Nuclear Information System (INIS)

    Kadi, F.J.; Longsworth, R.C.

    1976-02-01

    A review of current programs to develop superconducting power transmission shows that current plans require helium refrigerators operating at 5 to 13 0 K and 3 to 15 atm pressure with compressor power input in the range of 1300 to 3500 HP. Future requirements will probably trend towards slightly higher temperatures and larger refrigerators. Present large helium refrigerators and APCI standard nitrogen plants were studied and average outage frequency of about 18 per year is found to be typical for both. Cost and reliability studies of alternate refrigeration systems based on studies of components shows that the best current system which would have a failure rate of once in 20 y would consist of two full size oil flooded screw compressors in parallel, manifolded to two full size cold boxes and a liquid helium back up dewar. The principal area of development needed to implement this system is in the switch over mechanisms. These include switching to an auxillary power source in the event of power interruption, switching to the standby compressor, and switching to the back up liquid helium dewar. Costs are projected as being only slightly greater than preliminary estimates

  13. Assessment and study of existing concepts and methods of cryogenic refrigeration for superconducting transmission cables. Final report

    International Nuclear Information System (INIS)

    Kadi, F.J.; Longsworth, R.C.

    1976-02-01

    A review of current programs to develop superconducting power transmission shows that current plans require helium refrigerators operating at 5 to 13 0 K and 3 to 15 atm pressure with compressor power input in the range of 1,300 to 3,500 HP. Future requirements will probably trend toward slightly higher temperatures and larger refrigerators. Present large helium refrigerators and APCI standard nitrogen plants were studied and an average outage frequency of about 18 per year is found to be typical for both. Cost and reliability studies of alternate refrigeration systems based on studies of components shows that the best current system which would have a failure rate of once in 20 years would consist of two full size oil flooded screw compressors in parallel, manifolded to two full size cold boxes and a liquid helium back up dewar. The principal area of development needed to implement this system is in the switch over mechanisms. These include switching to an auxillary power source in the event of power interruption, switching to the standby compressor, and switching to the back up liquid helium dewar. Costs are projected as being only slightly greater than preliminary estimates

  14. Low-temperature synthesis of superconducting nanocrystalline MgB2

    International Nuclear Information System (INIS)

    Lu, J.; Xiao, Z.; Lin, Q.; Claus, H.; Fang, Z.Z.

    2010-01-01

    Magnesium diboride (MgB 2 ) is considered a promising material for practical application in superconducting devices, with a transition temperature near 40 K. In the present paper, nanocrystalline MgB 2 with an average particle size of approximately 70 nm is synthesized by reacting LiBH 4 with MgH 2 at temperatures as low as 450 C. This synthesis approach successfully bypasses the usage of either elemental boron or toxic diborane gas. The superconductivity of the nanostructures is confirmed by magnetization measurements, showing a superconducting critical temperature of 38.7 K.

  15. Measuring the microwave response of superconducting Nb:STO and Ti at mK temperatures using superconducting resonators

    Energy Technology Data Exchange (ETDEWEB)

    Thiemann, Markus; Beutel, Manfred; Dressel, Martin; Scheffler, Marc [1. Physikalisches Institut, Universitaet Stuttgart (Germany); Fillis-Tsirakis, Evangelos; Boschker, Hans; Mannhart, Jochen [Max Planck Institute for Solid State Research, Stuttgart (Germany)

    2016-07-01

    Niobium doped SrTiO{sub 3} is a superconductor, with the lowest charge carrier density among all superconductors. It shows a dome in the transition temperature as a function of doping concentration with a maximum T{sub c} ∼ 0.3 K. The superconducting dome may originate from the different bands being occupied depending on the doping level. The low energy scales of the system, as indicated by the low T{sub c} are within the GHz-regime. Therefore microwave measurements are a powerful technique to reveal the electronic properties of these superconductors. We preformed microwave measurements on Nb:STO of different doping levels in a dilution refrigerator, using superconducting stripline resonators. Measurements were done in a temperature and frequency range from 40-400 mK and 1-20 GHz, covering the normal and superconducting states. For comparison we also measured the temperature dependence of the surface impedance of superconducting titanium (T{sub c} ∼ 0.5 K), which can be well described by the Mattis-Bardeen equations with a ratio (2Δ)/(k{sub B}T{sub c}) = 3.56. Therefore titanium is an ideal reference sample representing a conventional BCS-superconductor.

  16. The Application of High Temperature Superconducting Materials to Power Switches

    CERN Document Server

    March, S A; Ballarino, A

    2009-01-01

    Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

  17. Experimental and analytical study of the DC breakdown characteristics of polypropylene laminated paper with a butt gap condition considering the insulation design of superconducting cable

    Science.gov (United States)

    Seo, In-jin; Choi, Won; Seong, Jae-gyu; Lee, Bang-wook; Koo, Ja-yoon

    2014-08-01

    It has been reported that the insulation design under DC stress is considered as one of the critical factors in determining the performance of high-voltage direct current (HVDC) superconducting cable. Therefore, it is fundamentally necessary to investigate the DC breakdown characteristics of the composite insulation system consisting of liquid nitrogen (LN2)/polypropylene-laminated-paper (PPLP). In particular, the insulation characteristics under DC polarity reversal condition should be verified to understand the polarity effect of the DC voltage considering the unexpected incidents taking place at line-commutated-converters (LCC) under service at a DC power grid. In this study, to examine the variation of DC electric field strength, the step voltage and polarity reversal breakdown tests are performed under DC stress. Also, we investigate the electric field distributions in a butt gap of the LN2/PPLP condition considering the DC polarity reversal by using simulation software.

  18. Trial manufacture of liquid nitrogen cooling High Temperature Superconductivity Motor

    International Nuclear Information System (INIS)

    Sugimoto, H; Nishikawa, T; Tsuda, T; Hondou, Y; Akita, Y; Takeda, T; Okazaki, T; Ohashi, S; Yoshida, Y

    2006-01-01

    We present a new high temperature superconductivity (HTS) synchronous motor using the liquid nitrogen as the refrigerant in this paper. This motor is designed to be used as the propulsion motor in ship. Because we use the liquid nitrogen as the refrigerant, it is possible to simplify the cooling equipments in the motor. And in our design, we apply the axial flux type of motor to simplify the cryostat of the HTS wires used to make the field coils. Here, the fields using the bismuth HTS wire for the HTS coils are fixed. Moreover, the cores used in the fields are separated from cryostat, and the armature applies the core-less structure. According to various the electromagnetic field analysis results, the new motor was designed and produced. The diameter of the motor is 650mm, and the width of the motor is 360mm. The motor's rated output is 8.8kW at 100rpm, while the overload output is 44kW, and the maximum efficiency is 97.7%. Also, in order to further miniaturize the motor, other magnetic field analysis have been done when the high-current-density type HTS wire was used and the permendur was used instead of magnetic steel plates. In this case, the motor's rated output is 12kW, and the overload output is 60kW

  19. Ambient temperature field measuring system for LHC superconducting dipoles

    International Nuclear Information System (INIS)

    Billan, J.; De Panfilis, S.; Giloteaux, D.; Pagano, O.

    1996-01-01

    It is foreseen to perform acceptance tests including field measurements of the collared coils assembly of the LHC superconducting dipoles to estimate, at an early production stage, the possible significant deviations from the expected multipole component value of these magnets. A sensitive measuring probe and efficient data acquisition are the consequence of a low magnetizing current necessary to limit the coils heating. This demands a high signals sensitivity and an enhanced signal-to-noise ratio to retrieve the higher multipole component. Moreover, the correlation with the multipoles content of the magnets at cryogenic temperature and nominal excitation current need to be identified before the manufacturing process may continue. The field probe of the mole-type is equipped with three radial rotating search coils, an angular encoder and gravity sensor. It has been designed to slide inside the bore of the dipole coils and to measure the local field at fixed positions. The field analysis resulting in terms of multipole components, field direction and field integrals, measured on four 10 m long, twin-aperture LHC dipole prototypes, will be described together with the performance of the measuring method

  20. Miniaturized high-temperature superconducting multiplexer with cascaded quadruplet structure

    Science.gov (United States)

    Xu, Zhang; Jingping, Liu; Shaolin, Yan; Lan, Fang; Bo, Zhang; Xinjie, Zhao

    2015-06-01

    In this paper, compact high temperature superconducting (HTS) multiplexers are presented for satellite communication applications. The first multiplexer consists of an input coupling node and three high-order bandpass filters, which is named triplexer. The node is realized by a loop microstrip line instead of conventional T-junction to eliminate the redundant susceptance due to combination of three filters. There are two eight-pole band-pass filters and one ten-pole band-pass filter with cascaded quadruplet structure for realizing high isolation. Moreover, the triplexer is extended to a multiplexer with six channels so as to verify the expansibility of the suggested approach. The triplexer is fabricated using double-sided YBa2Cu3O7 thin films on a 38 × 25 mm2 LaAlO3 substrate. The experimental results, when compared with those ones from the T-junction multiplexer, show that our multiplexer has lower insertion loss, smaller sizes and higher isolation between any two channels. Also, good agreement has been achieved between simulations and measurements, which illustrate the effectiveness of our methods for the design of high performance HTS multiplexers.

  1. Construction and 1st Experiment of the 500-meter and 1000-meter DC Superconducting Power Cable in Ishikari

    Science.gov (United States)

    Yamaguchi, S.; Ivanov, Y.; Watanabe, H.; Chikumoto, N.; Koshiduka, H.; Hayashi, K.; Sawamura, T.

    Ishikari project constructs two lines. The length of the Line 1 is 500 m, and connects the photovoltaic cell to the internet-data center. The other line is 1 km length, and it is a test facility and called Line 2. The structures of the cable systems are not same to test their performance. The construction was started from 2014 in the field, the Line 1 was completed in May 2015, and it was cooled down and do the current experiment, and warmed up. The Line 2 is almost complete in October 2015. It will be tested in November and December, 2015. In order to reduce the stress of the cable induced by the thermal expansion and contraction, we adopted the way of the helical deformation of the cable. The force of the cable is reduced to 1/3 of an usual cable test. Because the cryogenic pipes are welded in the field and we cannot use the baking of the vacuum chamber of the cryogenic pipe, a new vacuum pumping method was proposed and tested for the cryogenic pipe. Since the straight pipes are used to compose the cryogenic pipe, the pressure drop of the circulation would be 1/100 of the corrugated pipe in the present condition, and it is suitable for longer cable system. The heat leak of the cryogenic pipe is ∼1.4W/m including the cable pipe's and the return pipe's. The heat leak of the current lead is ∼30W/kA in the test bench. Finally the current of 6kA/3 sec and the current of 5kA/15 min were achieved in Line 1. The reduction of heat leak will be a major subject of the longer cable system. The cost of the construction will be almost twice higher than that of the copper and aluminum over-head line with the iron tower in the present Japan. The cost construction of the over-head line is an average value, and depends on the newspaper.

  2. NMR initiatives on understanding high-temperature superconductivity

    International Nuclear Information System (INIS)

    Kitaoka, Y.; Mukuda, H.; Shimizu, S.; Abe, M.; Iyo, A.; Tanaka, Y.; Kito, H.; Tokiwa, K.; Watanabe, T.

    2007-01-01

    We review a recent progress of NMR studies [H. Mukuda, et al., Phys. Rev. Lett 96 (2006) 087001; S. Shimizu, et al., submitted for publication.] on multi-layered cuprates. This work has shed new light to a generic phase diagram of high-temperature superconductivity (HTSC) which suggests a competition between antiferromagnetism (AFM) and superconductivity (SC). The multi-layered cuprates include two types of CuO 2 planes, an outer CuO 2 plane (OP) in a pyramidal coordination and an inner CuO 2 plane (IP) in a square one with no apical oxygen. Remarkable feature of the multi-layered systems is the presence of ideally flat CuO 2 planes that are homogeneously doped. Systematic Cu-NMR studies on the optimally-doped five-layered HgBa 2 Ca 4 Cu 5 O 12+δ (Hg-1245(OPT)) and slightly overdoped Tl-1245(OVD) have revealed the coexistent phase of SC and AFM in a unit cell [H. Kotegawa, et al., Phys. Rev. B 64 (2001) 064515; H. Kotegawa, et al., Phys. Rev. B 69 (2004) 014501.]. The optimally doped two OPs are predominantly superconducting with T c =108 and 100K, whereas the under-doped three IPs show the AFM order below T N =60 and 45K for Hg-1245(OPT) and Tl-1245(OVD), respectively. Recently exciting is the finding of the uniform mixing of AFM and HTSC in a single CuO 2 layer in the under-doped Hg-1245(UD) and the heavily underdoped four-layered Ba 2 Ca 3 Cu 4 O 8 F 2 (0234F(2.0)) that has fluorine ions (F 1- ) as apical ions [H. Mukuda, et al., Phys. Rev. Lett 96 (2006) 087001; S. Shimizu, et al., submitted for publication.]. In Hg-1245(UD) with T c =72K and T N =290K, the OPs exhibit the uniform mixing of AFM and HTSC with AFM moment of M AFM (OP)=0.1μ B , whereas the IPs are possibly AFM insulators with a small doping [H. Mukuda, et al., Phys. Rev. Lett 96 (2006) 087001.]. In 0234F(2.0) with T c =55K and T N =100K, the uniform mixing of AFM and HTSC is demonstrated to take place in electron (n)-doped IPs [S. Shimizu, et al., submitted for publication.], thanks to insight

  3. The Effect of CuSn Intermetallics on the Interstrand Contact Resistance in Superconducting Cables for the Large Hadron Collider (LHC)

    CERN Document Server

    Scheuerlein, C; Jacob, P; Leroy, D; Oberli, L R; Taborelli, M

    2005-01-01

    The LHC superconducting cables are submitted to a 200°C heat-treatment in air in order to increase the resistance between the crossing strands (RC) within the cable. During this treatment the as-applied Sn-Ag alloy strand coating is transformed into a CuSn intermetallic compound layer. The microstructure, the surface topography and the surface chemistry of the non-reacted and reacted coatings have been characterised by different techniques, notably focused ion beam (FIB), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Based on the results obtained by these techniques the different influences that the intermetallics have on RC are discussed. The desired RC is obtained only when a continuous Cu3Sn layer is formed, i.e. a sufficient wetting of the Cu substrate by the tinning alloy is crucial. Among other effects the formation of the comparatively hard intermetallics roughens the surface and, thus, reduces the true contact area and i...

  4. Multipoint Pressure and Temperature Sensing Fiber Optic Cable for Monitoring CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Challener, William [General Electric Company, Niskayuna, NY (United States)

    2015-02-10

    This report describes the work completed on contract DE-FE0010116. The goal of this two year project was to develop and demonstrate in the laboratory a highly accurate multi-point pressure measurement fiber optic cable based on MEMS pressure sensors suitable for downhole deployment in a CO2 sequestration well. The sensor interrogator was also to be demonstrated in a remote monitoring system and environmental testing was to be completed to indicate its downhole survivability over a lengthy period of time (e.g., 20 years). An interrogator system based on a pulsed laser excitation was shown to be capable of multiple (potentially 100+) simultaneous sensor measurements. Two sensors packages were completed and spliced in a cable onto the same fiber and measured. One sensor package was subsequently measured at high temperatures and pressures in supercritical CO2, while the other package was measured prior and after being subjected to high torque stresses to mimic downhole deployment. The environmental and stress tests indicated areas in which the package design should be further improved.

  5. Exciton interaction: its possible role in high temperature superconductivity

    International Nuclear Information System (INIS)

    Little, W.A.

    1987-01-01

    The recent remarkable developments in superconductivity has forced the group of physicists in the main stream of superconductivity research to re-examine the possible role of what has been referred to in the conference as novel mechanisms of superconductivity. The exciton mechanism is one such. While the many studies and developments in this subject are relatively well known to those involved in studies of organic superconductors and superconductors of reduced dimension, it appears that it is not well known to that large body of physicists involved in the more conventional mainstream of superconductivity. The salient features of the mechanism are reviewed and what it can and cannot do is discussed. Remarks are based on the most recent and most comprehensive review of the subject published in 1979, plus a few key papers since that time

  6. Pair Fermi contour and high-temperature superconductivity

    CERN Document Server

    Belyavsky, V I

    2002-01-01

    The holes superconducting coupling with the pair high summarized pulse and the relative motion low pulses is considered with an account of the quasi-two-dimensional electron structure of the HTSC-cuprates with the clearly-pronounced nesting of the Fermi contour. The superconducting energy gap and the condensation energy are determined and their dependences on the doping level are qualitatively studied. It is shown that the energy gap takes place in some holes concentration area, limited on both sides. The superconducting state, whereby the condensation energy is positive, originates in the more narrower doping interval inside this area. The hole pair redistribution in the pulse space constitutes the cause of the superconducting state origination by the holes repulsive screened Coulomb interaction. The coupling mechanism discussed hereby, males it possible to explain qualitatively not only the phase diagram basic peculiarities but also the key experimental facts, related to the cuprate HTSC-materials

  7. Ceramic insulation for superconducting Nb{sub 3}Sn cables; Isolation ceramique pour cables supraconducteurs en Nb{sub 3}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Puigsegur, A

    2005-01-15

    Nb{sub 3}Sn is the best superconductor candidate for the realization of high field magnets (>11 Tesla), its implementation remains delicate because of the great brittleness of material after the heat treatment necessary to the formation of Nb{sub 3}Sn compounds. The conventional insulation for Nb{sub 3}Sn requires to perform, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We have proposed an innovating ceramic insulation deposited directly on the unreacted conducting cable. After the heat treatment of the niobium tin, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. After a rheological study, to characterize the impregnated suspension, we have shown that using this insulation in a coil manufacture process does not affect the electrical properties of the Nb{sub 3}Sn wires. A solenoid of small dimensions was tested with success in high external magnetic fields and has produced a magnetic field of 3.8 T under 740 A. (author)

  8. Photoemission and the origin of high temperature superconductivity

    International Nuclear Information System (INIS)

    Norman, M. R.; Randeria, M.; Janko, B.; Campuzano, J. C.

    2000-01-01

    The condensation energy can be shown to be a moment of the change in the occupied part of the spectral function when going from the normal to the superconducting state. As a consequence, there is a one to one correspondence between the energy gain associated with forming the superconducting ground state, and the dramatic changes seen in angle resolved photoemission spectra. Some implications this observation has are offered

  9. Magnetic ordering at low temperatures in some random superconducting and insulating compounds

    International Nuclear Information System (INIS)

    Hueser, D.

    1985-01-01

    This thesis presents the results of some investigations on the magnetic ordering phenomena in some random superconducting and insulating materials. The results are described of an investigation of the coexistence of superconductivity and random magnetic freezing in (Th,Nd)Ru 2 . On the basis of various measurements as function of temperature and external magnetic field the author found that spin glass-like freezing can occur far below the superconductivity and even that a sample may re-enter the superconducting state below a freezing temperature. Associated with the isothermal remanent magnetization of a random magnetic material he observed strong anomalies in the critical field versus temperature curves. Also a magnetic field memory effect has been found. (Auth.)

  10. Infinite-range Heisenberg model and high-temperature superconductivity

    Science.gov (United States)

    Tahir-Kheli, Jamil; Goddard, William A., III

    1993-11-01

    A strongly coupled variational wave function, the doublet spin-projected Néel state (DSPN), is proposed for oxygen holes in three-band models of high-temperature superconductors. This wave function has the three-spin system of the oxygen hole plus the two neighboring copper atoms coupled in a spin-1/2 doublet. The copper spins in the neighborhood of a hole are in an eigenstate of the infinite-range Heisenberg antiferromagnet (SPN state). The doublet three-spin magnetic polaron or hopping polaron (HP) is stabilized by the hopping terms tσ and tτ, rather than by the copper-oxygen antiferromagnetic coupling Jpd. Although, the HP has a large projection onto the Emery (Dg) polaron, a non-negligible amount of doublet-u (Du) character is required for optimal hopping stabilization. This is due to Jdd, the copper-copper antiferromagnetic coupling. For the copper spins near an oxygen hole, the copper-copper antiferromagnetic coupling can be considered to be almost infinite ranged, since the copper-spin-correlation length in the superconducting phase (0.06-0.25 holes per in-plane copper) is approximately equal to the mean separation of the holes (between 2 and 4 lattice spacings). The general DSPN wave function is constructed for the motion of a single quasiparticle in an antiferromagnetic background. The SPN state allows simple calculations of various couplings of the oxygen hole with the copper spins. The energy minimum is found at symmetry (π/2,π/2) and the bandwidth scales with Jdd. These results are in agreement with exact computations on a lattice. The coupling of the quasiparticles leads to an attraction of holes and its magnitude is estimated.

  11. Termination for a superconducting power transmission line including a horizontal cryogenic bushing

    Science.gov (United States)

    Minati, Kurt F.; Morgan, Gerry H.; McNerney, Andrew J.; Schauer, Felix

    1984-01-01

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminates the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  12. Superconductivity

    International Nuclear Information System (INIS)

    Narlikar, A.V.

    1993-01-01

    Amongst the numerous scientific discoveries that the 20th century has to its credit, superconductivity stands out as an exceptional example of having retained its original dynamism and excitement even for more than 80 years after its discovery. It has proved itself to be a rich field by continually offering frontal challenges in both research and applications. Indeed, one finds that a majority of internationally renowned condensed matter theorists, at some point of their career, have found excitement in working in this important area. Superconductivity presents a unique example of having fetched Nobel awards as many as four times to date, and yet, interestingly enough, the field still remains open for new insights and discoveries which could undeniably be of immense technological value. 1 fig

  13. Nonlinear vibration behaviors of suspended cables under two-frequency excitation with temperature effects

    Science.gov (United States)

    Zhao, Yaobing; Huang, Chaohui; Chen, Lincong; Peng, Jian

    2018-03-01

    The aim of this paper is to investigate temperature effects on the nonlinear vibration behaviors of suspended cables under two-frequency excitation. For this purpose, two combination and simultaneous resonances are chosen and studied in detail. First of all, based on the assumptions of the temperature effects, the partial differential equations of the in-plane and out-of-plane motions with thermal effects under multi-frequency excitations are obtained. The Galerkin method is adopted to discretize the nonlinear dynamic equations, and the single-mode planar discretization is considered. Then, in the absence of the primary and internal resonances, the frequency response equations are obtained by using the multiple scales method. The stability analyses are conducted via investigating the nature of the singular points of equations. After that, temperature effects on nonlinear vibration characteristics of the first symmetric mode are studied. Parametric investigations of temperature effects on corresponding non-dimensional factors and coefficients of linear and nonlinear terms are performed. Numerical results are presented to show the temperature effects via the frequency-response curves and detuning-phase curves of four different sag-to-span ratios. It is found out that effects of temperature variations would lead to significant quantitative and/or qualitative changes of the nonlinear vibration properties, and these effects are closely related to the sag-to-span ratio and the degree of the temperature variation. Specifically, the softening/hardening-type spring behaviors, the response amplitude, the range of the resonance, the intersection and number of branches, the number and phase of the steady-state solutions are all affected by the temperature changes.

  14. Superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This book profiles the research activity of 42 companies in the superconductivity field, worldwide. It forms a unique and comprehensive directory to this emerging technology. For each research site, it details the various projects in progress, analyzes the level of activity, pinpoints applications and R and D areas, reviews strategies and provides complete contact information. It lists key individuals, offers international comparisons of government funding, reviews market forecasts and development timetables and features a bibliography of selected articles on the subject

  15. Superconductivity

    International Nuclear Information System (INIS)

    Buller, L.; Carrillo, F.; Dietert, R.; Kotziapashis, A.

    1989-01-01

    Superconductors are materials which combine the property of zero electric resistance with the capability to exclude any adjacent magnetic field. This leads to many large scale applications such as the much publicized levitating train, generation of magnetic fields in MHD electric generators, and special medical diagnostic equipment. On a smaller-scale, superconductive materials could replace existing resistive connectors and decrease signal delays by reducing the RLC time constants. Thus, a computer could operate at much higher speeds, and consequently at lower power levels which would reduce the need for heat removal and allow closer spacing of circuitry. Although technical advances and proposed applications are constantly being published, it should be recognized that superconductivity is a slowly developing technology. It has taken scientists almost eighty years to learn what they now know about this material and its function. The present paper provides an overview of the historical development of superconductivity and describes some of the potential applications for this new technology as it pertains to the electronics industry

  16. Current high-temperature superconducting coils and applications in Japan

    International Nuclear Information System (INIS)

    Matsushita, T.

    2000-01-01

    In Japan, four projects for the application of Bi-based superconducting magnets to practical apparatus are currently underway. These projects involve the development of an insert magnet for a 1 GHz nuclear magnetic resonance spectrometer, a magnet for a silicon single-crystal pulling apparatus, a magnet for a magnetic separation system, and a 1 T pulse magnet for a superconducting magnet energy storage system. For example, the magnet for the silicon single-crystal pulling apparatus is of the class with stored energy of 1 MJ to be operated at around 20 K. This review focuses on the present status of the development of these magnets, followed by a discussion of the problems of the present superconducting tapes that need to be overcome for future applications. (author)

  17. The power processor of a high temperature superconducting energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Ollila, J. [Power Electronics, Tampere University of Technology, Tampere (Finland)

    1997-12-31

    This report introduces the structure and properties of a power processor unit for a high temperature superconducting magnetic energy storage system which is bused in an UPS demonstration application. The operation is first demonstrated using simulations. The software based operating and control system utilising combined Delta-Sigma and Sliding-Mode control is described shortly. Preliminary test results using a conventional NbTi superconducting energy y storage magnet operating at 4.2 K is shown. (orig.)

  18. The pressure effect on the superconducting transition temperature of black phosphorus

    CERN Document Server

    Karuzawa, M; Endo, S

    2002-01-01

    We have measured the pressure effect on the superconducting transition temperature T sub c of black phosphorus up to 160 GPa using a superconducting quantum interference device vibrating coil magnetometer. It was found that T sub c had a maximum value of about 9.5 K at about 32 GPa, began decreasing with pressure and reached about 4.3 K at about 100 GPa.

  19. Advances in Fiber Optic Sensors Technology Development for temperature and strain measurements in Superconducting magnets and devices

    CERN Document Server

    Chiuchiolo, A.; Bajko, M.; Bottura, L.; Consales, M.; Cusano, A.; Giordano, M.; Perez, J. C.

    2016-01-01

    The luminosity upgrade of the Large Hadron Collider (HL-LHC) requires the development of a new generation of superconducting magnets based on Nb$_{3}$Sn technology. In order to monitor the magnet thermo-mechanical behaviour during its service life, from the coil fabrication to the magnet operation, reliable sensing systems need to be implemented. In the framework of the FP7 European project EUCARD, Nb$_{3}$Sn racetrack coils are developed as test beds for the fabrication validation, the cable characterization and the instrumentation development. Fiber optic sensors (FOS) based on Fiber Bragg Grating (FBG) technology have been embedded in the coils of the Short Model Coil (SMC) magnet. The FBG sensitivity to both temperature and strain required the development of a solution able to separate the mechanical and temperature effects. This work presents the feasibility study of the implementation of embedded FBG sensors for the temperature and strain monitoring of the 11 T type conductor. We aim to monitor and regi...

  20. Superconducting permanent magnets for high-temperature operation

    Czech Academy of Sciences Publication Activity Database

    Jirsa, Miloš; Muralidhar, M.

    2004-01-01

    Roč. 54, Suppl. D (2004), D441-D444 ISSN 0011-4626. [Czech and Slovak Conference on Magnetism. Košice, 12.07.2004-15.07.2004] Institutional research plan: CEZ:AV0Z1010914 Keywords : superconducting magnets * ternary LRE-123 compounds * mesoscopic defects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.292, year: 2004

  1. Deposition of superconducting (Cu, C)-Ba-O films by pulsed laser deposition at moderate temperature

    International Nuclear Information System (INIS)

    Yamamoto, Tetsuro; Kikunaga, Kazuya; Obara, Kozo; Terada, Norio; Kikuchi, Naoto; Tanaka, Yasumoto; Tokiwa, Kazuyasu; Watanabe, Tsuneo; Sundaresan, Athinarayanan; Shipra

    2007-01-01

    Superconducting (Cu, C)-Ba-O thin films have been epitaxially grown on (100) SrTiO 3 at a low growth temperature of 500-600 deg. C by pulsed laser deposition. The dependences of their crystallinity and transport properties on preparation conditions have been investigated in order to clarify the dominant parameters for carbon incorporation and the emergence of superconductivity. It has been revealed that the CO 3 content in the films increases with increasing both the parameters of partial pressure of CO 2 during film growth and those of growth rate and enhancement of superconducting properties. The present study has also revealed that the structural and superconducting properties of the (Cu, C)-Ba-O films are seriously deteriorated by the irradiation of energetic particles during deposition. Suppression of the radiation damage is another key for a high and uniform superconducting transition. By these optimizations, a superconducting onset temperature above 50 K and a zero-resistance temperature above 40 K have been realized

  2. Frequency-domain cascading microwave superconducting quantum interference device multiplexers; beyond limitations originating from room-temperature electronics

    Science.gov (United States)

    Kohjiro, Satoshi; Hirayama, Fuminori

    2018-07-01

    A novel approach, frequency-domain cascading microwave multiplexers (MW-Mux), has been proposed and its basic operation has been demonstrated to increase the number of pixels multiplexed in a readout line U of MW-Mux for superconducting detector arrays. This method is an alternative to the challenging development of wideband, large power, and spurious-free room-temperature (300 K) electronics. The readout system for U pixels consists of four main parts: (1) multiplexer chips connected in series those contain U superconducting resonators in total. (2) A cryogenic high-electron-mobility transistor amplifier (HEMT). (3) A 300 K microwave frequency comb generator based on N(≡U/M) parallel units of digital-to-analog converters (DAC). (4) N parallel units of 300 K analog-to-digital converters (ADC). Here, M is the number of tones each DAC produces and each ADC handles. The output signal of U detectors multiplexed at the cryogenic stage is transmitted through a cable to the room temperature and divided into N processors where each handles M pixels. Due to the reduction factor of 1/N, U is not anymore dominated by the 300 K electronics but can be increased up to the potential value determined by either the bandwidth or the spurious-free power of the HEMT. Based on experimental results on the prototype system with N = 2 and M = 3, neither excess inter-pixel crosstalk nor excess noise has been observed in comparison with conventional MW-Mux. This indicates that the frequency-domain cascading MW-Mux provides the full (100%) usage of the HEMT band by assigning N 300 K bands on the frequency axis without inter-band gaps.

  3. Transient analysis of an HTS DC power cable with an HVDC system

    International Nuclear Information System (INIS)

    Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo

    2013-01-01

    Highlights: •A model of an HTS DC power cable was developed using real time digital simulator. •The simulations of the HTS DC power cable in connection with an HVDC system were performed. •The transient analysis results of the HTS DC power cable were presented. -- Abstract: The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system

  4. Transient analysis of an HTS DC power cable with an HVDC system

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, Minh-Chau, E-mail: thanchau7787@gmail.com [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@cwnu.ac.kr [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yang, Byeongmo [Korea Electric Power Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejon 305-760 (Korea, Republic of)

    2013-11-15

    Highlights: •A model of an HTS DC power cable was developed using real time digital simulator. •The simulations of the HTS DC power cable in connection with an HVDC system were performed. •The transient analysis results of the HTS DC power cable were presented. -- Abstract: The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.

  5. Effect of the annealing temperature for the hydrogen Q-degradation on superconducting cavities

    International Nuclear Information System (INIS)

    Ota, Tomoko; Sukenobu, Satoru; Tanabe, Yoshio; Onishi, Yoshimichi; Noguchi, Shuichi; Ono, Masaaki; Saito, Kenji; Shishido, Toshio; Yamazaki, Yoshishige

    1997-01-01

    Hydrogen Q-degradation was studied in niobium superconducting cavities prepared by barrel polishing, and electropolishing without annealing, though a fast cooling down of cavities. Cavity performance with various annealing temperature were tested using a 1.3GHz single-cell cavity to compare the effects of annealing temperature for hydrogen Q-degradation. (author)

  6. Pressure behaviour of the superconducting transition temperature of lanthanum

    International Nuclear Information System (INIS)

    Glocker, R.

    1977-01-01

    The dissertation has the following chapters: 1) Introduction, 2) Fundamentals of the microscopic theory of superconductivity, 3) Calculation of the first momentum of the Eliashberg function, 4) Determination of the average values of frequency, 5) The relativistic cellular method and its application to lanthanum, 6) Results of the calculation of the electron-phonon coupling cosntants for f.c.c. lanthanum, 7) Phonon dispersion and phonon state density. (orig.) [de

  7. Investigation on maximum transition temperature of phonon mediated superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Fusui, L; Yi, S; Yinlong, S [Physics Department, Beijing University (CN)

    1989-05-01

    Three model effective phonon spectra are proposed to get plots of {ital T}{sub {ital c}}-{omega} adn {lambda}-{omega}. It can be concluded that there is no maximum limit of {ital T}{sub {ital c}} in phonon mediated superconductivity for reasonable values of {lambda}. The importance of high frequency LO phonon is also emphasized. Some discussions on high {ital T}{sub {ital c}} are given.

  8. Recovery time of high temperature superconducting tapes exposed in liquid nitrogen

    International Nuclear Information System (INIS)

    Sheng, Jie; Zeng, Weina; Yao, Zhihao; Zhao, Anfeng; Hu, Daoyu; Hong, Zhiyong

    2016-01-01

    Highlights: • A novel method based on a sequence of AC pulses is presented. • Liquid nitrogen temperature is used as criterion to judge whether the sample has recovered. • Recovery time of some tape doesn't increase with the amplitude of fault current. • This phenomenon is caused by boiling heat transfer process of liquid nitrogen. • This phenomenon can be used in optimizing both the limiting rate and reclosing system. - Abstract: The recovery time is a crucial parameter to high temperature superconducting tapes, especially in power applications. The cooperation between the reclosing device and the superconducting facilities mostly relies on the recovery time of the superconducting tapes. In this paper, a novel method is presented to measure the recovery time of several different superconducting samples. In this method criterion used to judge whether the sample has recovered is the liquid nitrogen temperature, instead of the critical temperature. An interesting phenomenon is observed during the testing of superconducting samples exposed in the liquid nitrogen. Theoretical explanations of this phenomenon are presented from the aspect of heat transfer. Optimization strategy of recovery characteristics based on this phenomenon is also briefly discussed.

  9. Superconducting magnet technology for particle accelerators and detectors seminar

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    This lecture is an introduction to superconducting magnets for particle accelerators and detectors, the aim being to explain the vocabulary and describe the basic technology of modern superconducting magnets, and to explore the limits of the technology. It will include the following: - Why we need superconducting magnets - Properties of superconductors, critical field, critical temperature - Why accelerators need fine filaments and cables; conductor manufacture - Temperature rise and temperature margin: the quench process, training - Quench protection schemes. Protection in the case of the LHC. - Magnets for detectors - The challenges of state-of-the-art magnets for High Energy Physics

  10. The temperature and tension characteristics of the FBGs embedded in the polythene sheath of an optical cable

    Science.gov (United States)

    Chen, Guanghui; Zhao, Ming; Sha, Jianbo; Zhang, Jun; Wu, Bingyan; Lin, Chen; Zhang, Mingliang; Gao, Kan

    2015-10-01

    The five of FBG were embedded in the PE sheath of a tether optical cable, which has about 18mm diameter and 7000mm length. The temperature and tension characteristics of the FBGs embedded in the polythene (PE) sheath had been demonstrated quantitatively. The Bragg wavelength of the embedded FBG shift linearly with the change of pulling force loaded on the tether optical cable and its tension sensitivity is about 3.75 pm/kg. The results of temperature experiment suggest the embedded FBG have been sensitized by PE material, so that its temperature sensitivity increase from 9.37pm/°C to about 12.51pm/°C.

  11. High temperature superconducting compounds II; Proceedings of the Second Symposium, Anaheim, CA, Feb. 20, 21, 1990

    International Nuclear Information System (INIS)

    Whang, S.H.; Dasgupta, A.; Laibowitz, R.

    1990-01-01

    Various topics relevant to the production and implementation of high-temperature superconducting compounds are highlighted including critical current; texturing; ceramics and novel processing; composites; deformation and consolidation; thin films; microstructures; tapes, filaments, and ribbons; and thermodynamics. The thermally activated flux creep, critical current density and current enhancement in high-temperature superconductors are addressed. Also discussed are the phase stability and microstructure of doped superconductors, mechanical considerations in the processing of high-Tc superconductors, fabrication and application of high current density, high RTc superconducting thin films and devices, the effect of substrate temperature and RF biasing on the composition of sputtered Bi-based superconducting thin films, and optical electron microanalysis of cuprate superconductors. The microstructure dependence of critical current density and fabrication of double-layered ribbons from cuprate are also discussed

  12. Test results of full-scale high temperature superconductors cable models destined for a 36 kV, 2 kA(rms) utility demonstration

    DEFF Research Database (Denmark)

    Daumling, M.; Rasmussen, C.N.; Hansen, F.

    2001-01-01

    Power cable systems using high temperature superconductors (HTS) are nearing technical feasibility. This presentation summarises the advancements and status of a project aimed at demonstrating a 36 kV, 2 kA(rms) AC cable system by installing a 30 m long full-scale functional model in a power...

  13. A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Jiang, Y; Pei, R; Coombs, T A [Electronic, Power and Energy Conversion Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Ye, L [Department of Electrical Power Engineering, CAU, P. O. Box 210, Beijing 100083 (China); Campbell, A M [Interdisciplinary Research Centre in Superconductivity, University of Cambridge, CB3 0HE (United Kingdom)], E-mail: Zh223@cam.ac.uk

    2008-02-15

    In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB{sub 2} wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB{sub 2} wires. The results demonstrate that the multi-element MgB{sub 2} wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement.

  14. High temperature superconducting current lead test facility with heat pipe intercepts

    International Nuclear Information System (INIS)

    Blumenfeld, P.E.; Prenger, C.; Roth, E.W.; Stewart, J.A.

    1998-01-01

    A high temperature superconducting (HTS) current lead test facility using heat pipe thermal intercepts is under development at the Superconducting Technology Center at Los Alamos National Laboratory. The facility can be configured for tests at currents up to 1,000 A. Mechanical cryocoolers provide refrigeration to the leads. Electrical isolation is maintained by intercepting thermal energy from the leads through cryogenic heat pipes. HST lead warm end temperature is variable from 65 K to over 90 K by controlling heat pipe evaporator temperature. Cold end temperature is variable up to 30 K. Performance predictions in terms of heat pipe evaporator temperature as a function of lead current are presented for the initial facility configuration, which supports testing up to 200 A. Measurements are to include temperature and voltage gradient in the conventional and HTS lead sections, temperature and heat transfer rate in the heat pipes. as well as optimum and off-optimum performance of the conventional lead sections

  15. Proposal for the award of a contract for the supply of polyimide film for cable and ground insulation of the LHC superconducting magnets

    CERN Document Server

    1999-01-01

    This document concerns the award of a contract for the supply of up to 79 tonnes of polyimide film, of three different types, for cable and ground insulation of the LHC superconducting magnets. A call for tenders (IT-2679/LHC/LHC) was sent on 21 September 1999 to two firms in Japan and one firm in the USA. By the closing date, CERN had received three tenders. The Finance Committee is invited to agree to the negotiation of a contract with the firm KANEKA (JP), the lowest bidder, for the supply of 79 tonnes of polyimide film of three different types for an amount of 5 425 541 USD (8 123 284 Swiss francs) for the polyimide film produced in the USA, not subject to revision, and 725 726 546 Japanese yen (10 109 020 Swiss francs) for the polyimide film produced in Japan, not subject to revision, with an option for the supply of up to 20% additional polyimide film of each type, for an amount of 1 085 108 USD (1 624 657 Swiss francs) and 145 145 309 Japanese yen (2 021 804 Swiss francs) respectively, not subject to r...

  16. Capital and operating cost estimates for high temperature superconducting magnetic energy storage

    International Nuclear Information System (INIS)

    Schoenung, S.M.; Meier, W.R.; Fagaly, R.L.; Heiberger, M.; Stephens, R.B.; Leuer, J.A.; Guzman, R.A.

    1992-01-01

    Capital and operating costs have been estimated for mid-scale (2 to 200 Mwh) superconducting magnetic energy storage (SMES) designed to use high temperature superconductors (HTS). Capital costs are dominated by the cost of superconducting materials. Operating costs, primarily for regeneration, are significantly reduced for HTS-SMES in comparison to low temperature, conventional systems. This cost component is small compared to other O and M and capital components, when levelized annual costs are projected. In this paper, the developments required for HTS-SMES feasibility are discussed

  17. Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet

    Directory of Open Access Journals (Sweden)

    Satoshi Fukui, Yoshihiro Shoji, Jun Ogawa, Tetsuo Oka, Mitsugi Yamaguchi, Takao Sato, Manabu Ooizumi, Hiroshi Imaizumi and Takeshi Ohara

    2009-01-01

    Full Text Available We present numerical simulation of separating magnetic particles with different magnetic susceptibilities by magnetic chromatography using a high-temperature superconducting bulk magnet. The transient transport is numerically simulated for two kinds of particles having different magnetic susceptibilities. The time evolutions were calculated for the particle concentration in the narrow channel of the spiral arrangement placed in the magnetic field. The field is produced by the highly magnetized high-temperature superconducting bulk magnet. The numerical results show the flow velocity difference of the particle transport corresponding to the difference in the magnetic susceptibility, as well as the possible separation of paramagnetic particles of 20 nm diameter.

  18. Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet.

    Science.gov (United States)

    Fukui, Satoshi; Shoji, Yoshihiro; Ogawa, Jun; Oka, Tetsuo; Yamaguchi, Mitsugi; Sato, Takao; Ooizumi, Manabu; Imaizumi, Hiroshi; Ohara, Takeshi

    2009-02-01

    We present numerical simulation of separating magnetic particles with different magnetic susceptibilities by magnetic chromatography using a high-temperature superconducting bulk magnet. The transient transport is numerically simulated for two kinds of particles having different magnetic susceptibilities. The time evolutions were calculated for the particle concentration in the narrow channel of the spiral arrangement placed in the magnetic field. The field is produced by the highly magnetized high-temperature superconducting bulk magnet. The numerical results show the flow velocity difference of the particle transport corresponding to the difference in the magnetic susceptibility, as well as the possible separation of paramagnetic particles of 20 nm diameter.

  19. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography

    International Nuclear Information System (INIS)

    Hirsch, J.E.

    2013-01-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. - Highlights: • A new property of superconducting particles is predicted. • Electron holography will show an apparent increase in thickness at low temperatures. • This will result from a predicted increase in the mean inner potential. • This will originate in expulsion of electrons from the interior to the surface. • This is not predicted by the conventional BCS theory of superconductivity

  20. Temperature dependence of the superconducting proximity effect quantified by scanning tunneling spectroscopy

    Directory of Open Access Journals (Sweden)

    A. Stępniak

    2015-01-01

    Full Text Available Here, we present the first systematic study on the temperature dependence of the extension of the superconducting proximity effect in a 1–2 atomic layer thin metallic film, surrounding a superconducting Pb island. Scanning tunneling microscopy/spectroscopy (STM/STS measurements reveal the spatial variation of the local density of state on the film from 0.38 up to 1.8 K. In this temperature range the superconductivity of the island is almost unaffected and shows a constant gap of a 1.20 ± 0.03 meV. Using a superconducting Nb-tip a constant value of the proximity length of 17 ± 3 nm at 0.38 and 1.8 K is found. In contrast, experiments with a normal conductive W-tip indicate an apparent decrease of the proximity length with increasing temperature. This result is ascribed to the thermal broadening of the occupation of states of the tip, and it does not reflect an intrinsic temperature dependence of the proximity length. Our tunneling spectroscopy experiments shed fresh light on the fundamental issue of the temperature dependence of the proximity effect for atomic monolayers, where the intrinsic temperature dependence of the proximity effect is comparably weak.

  1. Understanding and application of superconducting materials

    International Nuclear Information System (INIS)

    Moon, Byeong Mu; Lee, Chun Heung

    1997-02-01

    This book deals with superconducting materials, which contains from basic theory to application of superconducting materials. The contents of this book are mystery of superconducting materials, properties of superconducting materials, thermodynamics of superconducting materials, theoretical background of superconducting materials, tunnelling and quantum interference, classification and properties of superconducting materials, high temperature superconducting materials, production and analysis of superconducting materials and application of superconducting materials.

  2. Low-temperature properties of a superconducting disordered metal

    International Nuclear Information System (INIS)

    Graebner, J.E.; Golding, B.; Schutz, R.J.; Hsu, F.S.L.; Chen, H.S.

    1977-01-01

    Specific heat C/sub p/ and thermal conductivity kappa measurements between 0.1 and 10 K on the superconducting (T/sub c/ = 2.53 K) and structurally disordered metal Zr/sub 0.7/Pd/sub 0.3/ exhibit an approximately linear term in C/sub p/ and a T/sup 1.9/ dependence of kappa below T/sub c/. The magnitudes of these terms are close to those found for insulating glasses, thereby suggesting that disorder-induced localized excitations exist at similar densities in very different classes of disordered solids

  3. Problems of high temperature superconductivity in three-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Geilikman, B T

    1973-01-01

    A review is given of more recent papers on this subject. These papers have dealt mainly with two-dimensional systems. The present paper extends the treatment to three-dimensional systems, under the following headings: systems with collective electrons of one group and localized electrons of another group (compounds of metals with non-metals-dielectrics, organic substances, undoped semiconductors, molecular crystals); experimental investigations of superconducting compounds of metals with organic compounds, dielectrics, semiconductors, and semi-metals; and systems with two or more groups of collective electrons. Mechanics are considered and models are derived. 86 references.

  4. A conceptual design of high-temperature superconducting isochronous cyclotron magnet

    International Nuclear Information System (INIS)

    Jiao, F.; Tang, Y.; Li, J.; Ren, L.; Shi, J.

    2011-01-01

    A design of High-temperature superconducting (HTS) isochronous cyclotron magnet is proposed. The maximum magnetic field of cyclotron main magnet reaches 3 T. Laying the HTS coil aboard the magnetic pole will raise the availability of the magnetic Field. Super-iron structure can provide a high uniformity and high gradient magnetic field. Super-iron structure can raise the availability of the HTS materials. Along with the development of High-temperature superconducting (HTS) materials, the technology of HTS magnet is becoming increasingly important in the Cyclotron, which catches growing numbers of scholars' attentions. Based on the analysis of the problems met in the process of marrying superconducting materials with ferromagnetic materials, this article proposes a design of HTS isochronous cyclotron magnet. The process of optimization of magnet and the methods of realizing target parameters are introduced after taking finite element software as analyzing tools.

  5. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography.

    Science.gov (United States)

    Hirsch, J E

    2013-10-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Temperature Profiles During Quenches in LHC Superconducting Dipole Magnets Protected by Quench Heaters

    OpenAIRE

    Maroussov, V; Sanfilippo, S; Siemko, A

    1999-01-01

    The efficiency of the magnet protection by quench heaters was studied using a novel method which derives the temperature profile in a superconducting magnet during a quench from measured voltage signals. In several Large Hadron Collider single aperture dipole models, temperature profiles and temperature gradients in the magnet coil have been evaluated in the case of protection by different sets of quench heaters and different powering and protection parameters. The influence of the insulation...

  7. Use of a High-Temperature Superconducting Coil for Magnetic Energy Storage

    International Nuclear Information System (INIS)

    Fagnard, J-F; Crate, D; Jamoye, J-F; Laurent, Ph; Mattivi, B; Cloots, R; Ausloos, M; Genon, A; Vanderbemden, Ph

    2006-01-01

    A high temperature superconducting magnetic energy storage device (SMES) has been realised using a 350 m-long BSCCO tape wound as a ''pancake'' coil. The coil is mounted on a cryocooler allowing temperatures down to 17.2 K to be achieved. The temperature dependence of coil electrical resistance R(T) shows a superconducting transition at T = 102.5 K. Measurements of the V(I) characteristics were performed at several temperatures between 17.2 K and 101.5 K to obtain the temperature dependence of the critical current (using a 1 μV/cm criterion). Critical currents were found to exceed 100 A for T < 30 K. An electronic DC-DC converter was built in order to control the energy flow in and out of the superconducting coil. The converter consists of a MOS transistor bridge switching at a 80 kHz frequency and controlled with standard Pulse Width Modulation (PWM) techniques. The system was tested using a 30 V squared wave power supply as bridge input voltage. The coil current, the bridge input and output voltages were recorded simultaneously. Using a 10 A setpoint current in the superconducting coil, the whole system (coil + DC-DC converter) can provide a stable output voltage showing uninterruptible power supply (UPS) capabilities over 1 s

  8. Characterization of high temperature superconductor cables for magnet toroidal field coils of the DEMO fusion power plant

    CERN Document Server

    Bayer, Christoph M

    2017-01-01

    Nuclear fusion is a key technology to satisfy the basic demand for electric energy sustainably. The official EUROfusion schedule foresees a first industrial DEMOnstration Fusion Power Plant for 2050. In this work several high temperature superconductor sub-size cables are investigated for their applicability in large scale DEMO toroidal field coils. Main focus lies on the electromechanical stability under the influence of high Lorentz forces at peak magnetic fields of up to 12 T.

  9. Characterization of high temperature superconductor cables for magnet toroidal field coils of the DEMO fusion power plant

    Energy Technology Data Exchange (ETDEWEB)

    Bayer, Christoph M.

    2017-05-01

    Nuclear fusion is a key technology to satisfy the basic demand for electric energy sustainably. The official EUROfusion schedule foresees a first industrial DEMOnstration Fusion Power Plant for 2050. In this work several high temperature superconductor sub-size cables are investigated for their applicability in large scale DEMO toroidal field coils. Main focus lies on the electromechanical stability under the influence of high Lorentz forces at peak magnetic fields of up to 12 T.

  10. Development of superconducting power devices in Europe

    International Nuclear Information System (INIS)

    Tixador, Pascal

    2010-01-01

    Europe celebrated last year (2008) the 100-year anniversary of the first liquefaction of helium by H. Kammerling Onnes in Leiden. It led to the discovery of superconductivity in 1911. Europe is still active in the development of superconducting (SC) devices. The discovery of high critical temperature materials in 1986, again in Europe, has opened a lot of opportunities for SC devices by broking the 4 K cryogenic bottleneck. Electric networks experience deep changes due to the emergence of dispersed generation (renewable among other) and to the advances in ICT (Information Communication Technologies). The networks of the future will be 'smart grids'. Superconductivity will offer 'smart' devices for these grids like FCL (Fault Current Limiter) or VLI (Very Low Inductance) cable and would certainly play an important part. Superconductivity also will participate to the required sustainable development by lowering the losses and enhancing the mass specific powers. Different SC projects in Europe will be presented (Cable, FCL, SMES, Flywheel and Electrical Machine) but the description is not exhaustive. Nexans has commercialized the first two FCLs without public funds in the European grid (UK and Germany). The Amsterdam HTS cable is an exciting challenge in term of losses for long SC cables. European companies (Nexans, Air Liquide, Siemens, Converteam, ...) are also very active for projects outside Europe (LIPA, DOE FCL, ...).

  11. Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo [ed.

    2005-07-01

    Research on superconductivity at ENEA is mainly devoted to projects related to the ITER magnet system. In this framework, ENEA has been strongly involved in the design, manufacturing and test campaigns of the ITER toroidal field model coil (TFMC), which reached a world record in operating current (up to 80 kA). Further to this result, the activities in 2004 were devoted to optimising the ITER conductor performance. ENEA participated in the tasks launched by EFDA to define and produce industrial-scale advanced Nb3Sn strand to be used in manufacturing the ITER high-field central solenoid (CS) and toroidal field (TF) magnets. As well as contributing to the design of the new strand and the final conductor layout, ENEA will also perform characterisation tests, addressing in particular the influence of mechanical stress on the Nb3Sn performance. As a member of the international ITER-magnet testing group, ENEA plays a central role in the measurement campaigns and data analyses for each ITER-related conductor and coil. The next phase in the R and D of the ITER magnets will be their mechanical characterisation in order to define the fabrication route of the coils and structures. During 2004 the cryogenic measurement campaign on the Large Hadron Collider (LHC) by-pass diode stacks was completed. As the diode-test activity was the only LHC contract to be finished on schedule, the 'Centre Europeenne pour la Recherche Nucleaire' (CERN) asked ENEA to participate in an international tender for the cold check of the current leads for the LHC magnets. The contract was obtained, and during 2004, the experimental setup was designed and realised and the data acquisition system was developed. The measurement campaign was successfully started at the end of 2004 and will be completed in 2006.

  12. Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator

    NARCIS (Netherlands)

    Song, X.; Polinder, H.; Liu, D.; Mijatovic, Nenad; Holbøll, Joachim; Jensen, Bogi Bech

    Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen at

  13. Electric field dependence of excess electrical conductivity below transition temperature in thin superconducting lead films

    Energy Technology Data Exchange (ETDEWEB)

    Ashwini Kumar, P K; Duggal, V P [Delhi Univ. (India). Dept. of Physics and Astrophysics

    1976-01-26

    Results of measurements of the electric field dependence of the excess electrical conductivity are reported in thin superconducting lead films below the transition temperature. It is observed that the normal state sheet resistance has some effect on the nonlinearity but the theory of Yamaji still fits well to the experimental data.

  14. Pressure dependence of the superconducting transition temperature of Rb3C60 up to 20 kbar

    International Nuclear Information System (INIS)

    Bud'ko, S.L.; Meng, R.L.; Chu, C.W.; Hor, P.H.

    1991-01-01

    AC susceptibility measurements of Rb 3 C 60 under hydrostatic pressure up to 20 kbar are reported. The superconducting transition temperature (T c ) decreases linearly under pressure with the pressure derivative dT c /dP = -0.78 K degrees/kbar

  15. Many-body problems in high temperature superconductivity

    International Nuclear Information System (INIS)

    Yu Lu.

    1991-10-01

    In this brief review the basic experimental facts about high T c superconductors are outlined. The superconducting properties of these superconductors are not very different from those of the ordinary superconductors. However, their normal state properties cannot be described by the standard Fermi liquid (FL) theory. Our current understanding of the strongly correlated models is summarized. In one dimension these systems behave like a ''Luttinger liquid'', very much distinct from the FL. In spite of the enormous efforts made in two-dimensional studies, the question of FL vs non-FL behaviour is still open. The numerical results as well as various approximation schemes are discussed. Both the single hole problem in a quantum antiferromagnet and finite doping regime are considered. (author). 104 refs, 9 figs

  16. submitter Geometrical Behavior of Nb$_{3}$Sn Rutherford Cables During Heat Treatment

    CERN Document Server

    Durante, Maria; Ferracin, Paolo; Manil, Pierre; Perez, Juan Carlos; Rifflet, Jean-Michel; Rondeaux, Francoise

    2016-01-01

    In Nb$_{3}$Sn accelerator magnets, non-superconducting precursor cables are wound into their final coil shape and then heat treated at a high temperature to form the A15 superconducting phase. The growth of cable strands during reaction and the differential thermal dilatation in the coil components lead to both stress in the cable and geometrical deformations of the winding, with possible consequences on magnet performances. An experimental campaign on different types of Rutherford cables has been carried out at CEA Saclay, in collaboration with CERN, in order to measure cable dimension changes in all directions, with respect to cable configuration and winding geometry. A 700-mm-long versatile test bench has been designed for several cable topologies up to 22 mm in width. This paper describes the tooling and presents the results of the experimental campaign led on the cables, made of powder-in-tube and restacked-rod-process strands, of FRESCA2, a 13-T dipole magnet

  17. Low-temperature rapid synthesis and superconductivity of Fe-based oxypnictide superconductors.

    Science.gov (United States)

    Fang, Ai-Hua; Huang, Fu-Qiang; Xie, Xiao-Ming; Jiang, Mian-Heng

    2010-03-17

    Fe-based oxypnictide superconductors were successfully synthesized at lower reaction temperatures and with shorter reaction times made possible by starting with less stable compounds, which provide a larger driving force for reactions. Using ball-milled powders of intermediate compounds, phase-pure superconductors with T(c) above 50 K were synthesized at 1173 K in 20 min. This method is particularly advantageous for retaining F, a volatile dopant that enhances superconductivity. Bulk superconductivity and high upper critical fields up to 392 T in Sm(0.85)Nd(0.15)FeAsO(0.85)F(0.15) were demonstrated.

  18. Generation of coherent electromagnetic radiation by superconducting films at nitrogen temperatures

    CERN Document Server

    Lykov, A N

    2001-01-01

    One detected generation of coherent electromagnetic radiation by GdBa sub 2 Cu sub 3 O sub 7 sub - sub x superconducting films within 1-10 MHz range at temperature of liquid nitrogen boiling. This type generation is caused by synchronization realized due to the feedback of abrupt changes of the Abrikosov's vortices produced by the external low-frequency magnetic field. Possibility to reach more intensive radiation due to increase of the area of superconducting film, as well as, via increase of amplitude and of frequency of electromagnetic field exciting a vortex system in films is the most important advantage of the given technique of generation

  19. AC Losses and Their Thermal Effect in High Temperature Superconducting Machines

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Zou, Shengnan

    2015-01-01

    In transient operations or fault conditions, high temperature superconducting (HTS) machines suffer AC losses which have an influence on the thermal stability of superconducting windings. In this paper, a method to calculate AC losses and their thermal effect in HTS machines is presented....... The method consists of three sub-models that are coupled only in one direction. The magnetic field distribution is first solved in a machine model, assuming a uniform current distribution in HTS windings. The magnetic fields on the boundaries are then used as inputs for an AC loss model which has...

  20. Integrated high-transition temperature magnetometer with only two superconducting layers

    DEFF Research Database (Denmark)

    Kromann, R.; Kingston, J.J.; Miklich, A.H.

    1993-01-01

    We describe the fabrication and testing of an integrated YBa2Cu3O7-x thin-film magnetometer consisting of a dc superconducting quantum interference device (SQUID), with biepitaxial grain boundary junctions, integrated with a flux transformer on a single substrate. Only two superconducting layers...... are required, the SQUID body serving as the crossunder that completes the multiturn flux transformer. The highest temperature at which any of the magnetometers functioned was 76 K. At 60 K the magnetic field gain of this device was 63, and the magnetic field noise was 160 fT Hz-1/2 at 2 kHz, increasing to 3...

  1. Superconducting technology

    International Nuclear Information System (INIS)

    2010-01-01

    Superconductivity has a long history of about 100 years. Over the past 50 years, progress in superconducting materials has been mainly in metallic superconductors, such as Nb, Nb-Ti and Nb 3 Sn, resulting in the creation of various application fields based on the superconducting technologies. High-T c superconductors, the first of which was discovered in 1986, have been changing the future vision of superconducting technology through the development of new application fields such as power cables. On basis of these trends, future prospects of superconductor technology up to 2040 are discussed. In this article from the viewpoints of material development and the applications of superconducting wires and electronic devices. (author)

  2. Routes to High-Temperature Superconductivity: A Lesson from FeSe/SrTiO3

    Science.gov (United States)

    Lee, Dung-Hai

    2018-03-01

    Raising the superconducting transition temperature to a point where applications are practical is one of the most important challenges in science. In this review, we aim at gaining insights on the Tc controlling factors for a particular high-temperature superconductor family - the FeSe-based superconductors. In particular, we discuss the mechanisms by which the Cooper pairing temperature is enhanced from ˜8 K in bulk FeSe to ˜80 K in the interface between an atomic layer of FeSe and SrTiO3. This includes the experimental hints and the theoretical simulation of the involved mechanisms. We end by applying these insights to suggest some possible high-temperature superconducting systems.

  3. Direct Observation of High-Temperature Superconductivity in One-Unit-Cell FeSe Films

    International Nuclear Information System (INIS)

    Zhang Wen-Hao; Zhang Jin-Song; Li Fang-Sen; Guo Ming-Hua; Ding Hao; Tang Chen-Jia; Wang Qing-Yan; He Ke; Ji Shuai-Hua; Chen Xi; Sun Yi; Zhao Yan-Fei; Xing Ying; Wang Hui-Chao; Zhang Hui-Min; Peng Jun-Ping; Li Zhi; Wang Meng; Fujita Takeshi; Hirata Akihiko

    2014-01-01

    We prepared one-unit-cell (1-UC) thick FeSe films on insulating SrTiO 3 substrates with non-superconducting FeTe protection layers by molecular beam epitaxy for ex situ studies. By direct transport and magnetic measurements, we provide definitive evidence for high temperature superconductivity in the 1-UC FeSe films with an onset T C above 40 K and an extremely large critical current density J C ∼1.7×10 6 A/cm 2 at 2 K, which are much higher than T C ∼8 K and J C ∼10 4 A/cm 2 for bulk FeSe, respectively. Our work may pave the way to enhancing and tailoring superconductivity by interface engineering. (express letter)

  4. Magnetic levitation using high temperature superconducting pancake coils as composite bulk cylinders

    International Nuclear Information System (INIS)

    Patel, A; Hopkins, S C; Baskys, A; Glowacki, B A; Kalitka, V; Molodyk, A

    2015-01-01

    Stacks of superconducting tape can be used as composite bulk superconductors for both trapped field magnets and for magnetic levitation. Little previous work has been done on quantifying the levitation force behavior between stacks of tape and permanent magnets. This paper reports the axial levitation force properties of superconducting tape wound into pancake coils to act as a composite bulk cylinder, showing that similar stable forces to those expected from a uniform bulk cylinder are possible. Force creep was also measured and simulated for the system. The geometry tested is a possible candidate for a rotary superconducting bearing. Detailed finite element modeling in COMSOL Multiphysics was also performed including a full critical state model for induced currents, with temperature and field dependent properties and 3D levitation force models. This work represents one of the most complete levitation force modeling frameworks yet reported using the H-formulation and helps explain why the coil-like stacks of tape are able to sustain levitation forces. The flexibility of geometry and consistency of superconducting properties offered by stacks of tapes, make them attractive for superconducting levitation applications. (paper)

  5. Cryogenic cooling system for HTS cable

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Shigeru [Taiyo Nippon Sanso, Tsukuba (Japan)

    2017-06-15

    Recently, Research and development activity of HTS (High Temperature Superconducting) power application is very progressive worldwide. Especially, HTS cable system and HTSFCL (HTS Fault current limiter) system are proceeding to practical stages. In such system and equipment, cryogenic cooling system, which makes HTS equipment cooled lower than critical temperature, is one of crucial components. In this article, cryogenic cooling system for HTS application, mainly cable, is reviewed. Cryogenic cooling system can be categorized into conduction cooling system and immersion cooling system. In practical HTS power application area, immersion cooling system with sub-cooled liquid nitrogen is preferred. The immersion cooling system is besides grouped into open cycle system and closed cycle system. Turbo-Brayton refrigerator is a key component for closed cycle system. Those two cooling systems are focused in this article. And, each design and component of the cooling system is explained.

  6. Electronic and magnetic interactions in high temperature superconducting and high coercivity materials. Final performance report

    International Nuclear Information System (INIS)

    Cooper, B.R.

    1997-01-01

    The issue addressed in the research was how to understand what controls the competition between two types of phase transition (ordering) which may be present in a hybridizing correlated-electron system containing two transition-shell atomic species; and how the variation of behavior observed can be used to understand the mechanisms giving the observed ordered state. This is significant for understanding mechanisms of high-temperature superconductivity and other states of highly correlated electron systems. Thus the research pertains to magnetic effects as related to interactions giving high temperature superconductivity; where the working hypothesis is that the essential feature governing the magnetic and superconducting behavior of copper-oxide-type systems is a cooperative valence fluctuation mechanism involving the copper ions, as mediated through hybridization effects dominated by the oxygen p electrons. (Substitution of praseodymium at the rare earth sites in the 1·2·3 material provides an interesting illustration of this mechanism since experimentally such substitution strongly suppresses and destroys the superconductivity; and, at 100% Pr, gives Pr f-electron magnetic ordering at a temperature above 16K). The research was theoretical and computational and involved use of techniques aimed at correlated-electron systems that can be described within the confines of model hamiltonians such as the Anderson lattice hamiltonian. Specific techniques used included slave boson methodology used to treat modification of electronic structure and the Mori projection operator (memory function) method used to treat magnetic response (dynamic susceptibility)

  7. Temperature dependence of the current to sustain a normal hotspot in superconducting microbridges

    International Nuclear Information System (INIS)

    Yamaguchi, Y.; Ishii, C.

    1981-01-01

    A modification of the boundary condition to determine the SN boundary in the hotspot model of superconducting microbridges is proposed and successfully applied to the interpretation of recent measurements of the hotspot-sustaining current by Mizuno and Aomine. It is shown that suppression of the order parameter due to the applied current gives rise to an additional temperature dependence of the hotspot-sustaining current in the extreme vicinity of the transition temperature. (orig.)

  8. A simple technique for measuring the superconducting critical temperature of small (>= 10 μg) samples

    International Nuclear Information System (INIS)

    Pereira, R.F.R.; Meyer, E.; Silveira, M.F. da.

    1983-01-01

    A simple technique for measuring the superconducting critical temperature of small (>=10μg) samples is described. The apparatus is built in the form of a probe, which can be introduced directly into a liquid He storage dewar and permits the determination of the critical temperature, with an imprecision of +- 0.05 K above 4.2 K, in about 10 minutes. (Author) [pt

  9. 14 CFR 23.689 - Cable systems.

    Science.gov (United States)

    2010-01-01

    ... in cable tension throughout the range of travel under operating conditions and temperature variations... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cable systems. 23.689 Section 23.689... Systems § 23.689 Cable systems. (a) Each cable, cable fitting, turnbuckle, splice, and pulley used must...

  10. Superconducting Accelerator Magnets

    CERN Document Server

    Mess, K H; Wolff, S

    1996-01-01

    The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements ...

  11. Problems with conductors and dielectrics for cryogenic cables

    Energy Technology Data Exchange (ETDEWEB)

    Bogner, G; Penczynski, P [Siemens A.G., Erlangen (F.R. Germany). Abt. Reaktortechnik

    1976-06-01

    The most important problems which need to be solved if superconducting power cables are to be used on a large scale are connected with the superconducting cable materials and the dielectrics used for insulation. Research work on superconducting materials for ac and dc cables is briefly reviewed together with stabilization problems for these materials. Three types of insulation are considered - vacuum, subcooled or supercritical helium, and foil wound insulation. The merits and problems encountered in each case are discussed.

  12. Semiannual report for the period October 1, 1979-March 31, 1980 of work on: (1) superconducting power transmission system development; (2) cable insulation development. Power Transmission Project Technical Note No. 106

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-07

    Progress is reported in a program whose objective is to develop an underground superconducting power transmission system which is economical and technically attractive to the utility industry. The system would be capable of carrying very large blocks of electric power, and would supplant overhead lines in urban and suburban areas and regions of natural beauty. The program consisted initially of work in the laboratory to develop suitable materials, cryostats, and cable concepts. The materials work covers the development and testing of suitable superconductors and dielectric insulation. The laboratory work has now been extended to an outside test facility which represents an intermediate step between the laboratory scale and a full-scale system. The facility will allow cables several hundred feet long to be tested under realistic conditions. In addition, the refrigerator has been designed for optimum service for utility applications.

  13. ac superconducting articles

    International Nuclear Information System (INIS)

    Meyerhoff, R.W.

    1977-01-01

    A noval ac superconducting cable is described. It consists of a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface

  14. Summaries of reports of the 30. Conference on low-temperature physics. Pt. 1. Fundamental questions of superconductivity including HTSC

    International Nuclear Information System (INIS)

    1994-01-01

    Thesis of reporsts of the 30th Conference on low-temperature physics are presented. Fundamental problems of superconductivity are discussed including HTSC in bulk crystals, in thin films of Josephson junctions, ceramics and heterostructures. Specific features of superconductor structure and magnetic properties and also different mechanisms of superconductivity are analyzed

  15. Performance of a conduction-cooled high-temperature superconducting bearing

    International Nuclear Information System (INIS)

    Strasik, M.; Hull, J.R.; Johnson, P.E.; Mittleider, J.; McCrary, K.E.; McIver, C.R.; Day, A.C.

    2008-01-01

    We report rotational loss measurements for a high-temperature superconducting (HTS) bearing whose cooling consists of a thermal conduction path to the cold head of a cryocooler. Losses have been measured for rotational rates up to 14,500 rpm at different HTS temperatures. The rotational losses decrease with decreasing HTS temperature. For temperatures that can be obtained in a liquid-nitrogen thermosiphon system, at a given speed and gap, the loss of the conduction-cooled HTS bearing is not significantly higher than the loss of a nearly identical HTS bearing cooled by flowing nitrogen from the thermosiphon

  16. High-temperature superconductivity in solid solutions based on mixed yttrium and barium cuprate

    International Nuclear Information System (INIS)

    Bazuev, G.V.; Kirsanov, N.A.; Makarova, O.V.; Zubkov, V.G.; Shveikin, G.P.

    1990-01-01

    The discovery of high-temperature superconductivity (T c = 30-40 K) in mixed lanthanum and alkaline earth cuprates La 2-x M x CuO 4 , where M = Ba and Ca (1-3) stimulated an extensive search for new superconducting phases based on mixed oxides of these elements. The superconducting transition temperature T c in LnBa 2 Cu 3 O 7-z phases is practically independent of the REE and lies between 90-96 K. The crystal structure of superconducting YBa 2 Cu 3 O 7-z is similar to perovskite, has orthorhombic symmetry (4,5), and is related to the lanthanum barium cuprite tetragonal defect structure La 3 Ba 3 Cu 6 O 14.1 (8). A study of possible solid solutions (SS) based on YBa 2 Cu 3 O 7-z through iso- or heterovalent substitution for Y 3+ and Ba 2+ and of their electrical properties seems warranted. In the present work, the authors report the synthesis, x-ray diffraction study, and specific electric resistivity of SS Y 1-x M x (Ba 1-y M y ') 2 Cu 3 O 7-z , where M = La, Lu, Sc, In, K, Zr, and Ce and M' = Ca, Sr, Mg, K, and La

  17. Macroscopic Magnetic Coupling Effect: The Physical Origination of a High-Temperature Superconducting Flux Pump

    Science.gov (United States)

    Wang, Wei; Coombs, Tim

    2018-04-01

    We have uncovered at the macroscopic scale a magnetic coupling phenomenon in a superconducting YBa2Cu3O7 -δ (YBCO) film, which physically explains the mechanism of the high-temperature superconducting flux pump. The coupling occurs between the applied magnetic poles and clusters of vortices induced in the YBCO film, with each cluster containing millions of vortices. The coupling energy is verified to originate from the inhomogeneous field of the magnetic poles, which reshapes the vortex distribution, aggregates millions of vortices into a single cluster, and accordingly moves with the poles. A contrast study is designed to verify that, to provide the effective coupling energy, the applied wavelength must be short while the field amplitude must be strong, i.e., local-field inhomogeneity is the crucial factor. This finding broadens our understanding of the collective vortex behavior in an applied magnetic field with strong local inhomogeneity. Moreover, this phenomenon largely increases the controlled vortex flow rate by several orders of magnitude compared with existing methods, providing motivation for and physical support to a new branch of wireless superconducting dc power sources, i.e., the high-temperature superconducting flux pump.

  18. The thermal relay design to improve power system security for the HTS cables in Icheon substation

    International Nuclear Information System (INIS)

    Lee, Hansang; Yang, Byeong-Mo; Jang, Gilsoo

    2013-01-01

    Highlights: •It is important to study thermal characteristics of the HTS cable. •The thermal relay in the Icheon substation has been developed. •Well-designed thermal relay has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes a model for thermal protection relay for the high temperature superconducting (HTS) cables and thermal protection scheme in Icheon substation in Korea. The thermal protection is one of the most important factors to guarantee the reliability of the HTS cable as well as power system security. The superconductivity of the HTS cables, which can be guaranteed by the liquid nitrogen near 70 K, can be threatened by the large fault current. To avoid the overheating in HTS cable and to secure the power system operation with the HTS cable, the thermal protection relay should be considered. To find the optimal thermal-protection scheme, the model for the superconducting power system has been achieved in Icheon substation and the thermal protection scheme has been verified through PSCAD/EMTDC simulation

  19. The thermal relay design to improve power system security for the HTS cables in Icheon substation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hansang, E-mail: hslee80@kiu.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-11-15

    Highlights: •It is important to study thermal characteristics of the HTS cable. •The thermal relay in the Icheon substation has been developed. •Well-designed thermal relay has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes a model for thermal protection relay for the high temperature superconducting (HTS) cables and thermal protection scheme in Icheon substation in Korea. The thermal protection is one of the most important factors to guarantee the reliability of the HTS cable as well as power system security. The superconductivity of the HTS cables, which can be guaranteed by the liquid nitrogen near 70 K, can be threatened by the large fault current. To avoid the overheating in HTS cable and to secure the power system operation with the HTS cable, the thermal protection relay should be considered. To find the optimal thermal-protection scheme, the model for the superconducting power system has been achieved in Icheon substation and the thermal protection scheme has been verified through PSCAD/EMTDC simulation.

  20. High voltage dc cables

    Energy Technology Data Exchange (ETDEWEB)

    Bjustrom, B

    1965-12-01

    How stress distribution in dc cables varies with temperature and stress level, influence of polarity reversals and space charges, and different types of overvoltage to which dc cable may be subjected are discussed. Design problems, especially as related to corrosion protection and to mechanical stress caused by wire armoring during manufacturing and laying, accessories and work done on test methods, and the possibility of designing 400 to 600 kV dc cables for transmitting 2000 to 4000 MW are described.

  1. A Cryogenic Magnetostrictive Actuator Using a Persistent High Temperature Superconducting Magnet. Part 1; Concept and Design

    Science.gov (United States)

    Horner, Garnett; Bromberg, Leslie; Teter, J. P.

    2000-01-01

    Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSCCO 2212 with a magnetostrictive element will be discussed.

  2. Copper Metallic Substrates for High Temperature Superconducting Coated Conductors

    National Research Council Canada - National Science Library

    Yust, Nicholas A; Nekkanti, Rama; Brunke, Lyle B; Srinivasan, Raghavan; Barnes, Paul N

    2006-01-01

    .... Detailed x-ray diffraction (XRD) studies and orientation imaging microscopy (OIM) were performed to measure the in-plane alignment, out-of-plane alignment, and microtexture at various deformation levels and annealing temperatures...

  3. Irradiation effect of the insulating materials for fusion superconducting magnets at cryogenic temperature

    Science.gov (United States)

    Kobayashi, Koji; Akiyama, Yoko; Nishijima, Shigehiro

    2017-09-01

    In ITER, superconducting magnets should be used in such severe environment as high fluence of fast neutron, cryogenic temperature and large electromagnetic forces. Insulating material is one of the most sensitive component to radiation. So radiation resistance on mechanical properties at cryogenic temperature are required for insulating material. The purpose of this study is to evaluate irradiation effect of insulating material at cryogenic temperature by gamma-ray irradiation. Firstly, glass fiber reinforced plastic (GFRP) and hybrid composite were prepared. After irradiation at room temperature (RT) or liquid nitrogen temperature (LNT, 77 K), interlaminar shear strength (ILSS) and glass-transition temperature (Tg) measurement were conducted. It was shown that insulating materials irradiated at room temperature were much degraded than those at cryogenic temperature.

  4. Influence of disorder on the superconducting critical temperature in indium-opal nanocomposites

    Science.gov (United States)

    Zakharchuk, I.; Januzaj, A.; Mikhailin, N. Yu.; Traito, K. B.; Chernyaev, A. V.; Romanov, S. G.; Safonchik, M.; Shamshur, D. V.; Lähderanta, E.

    2018-06-01

    Transport properties of bulk indium-opal and indium-porous glass superconducting nanocomposites possessing moderate and strong disorder are investigated. A strongly nonmonotonous dependence of the global critical temperature Tc versus normal state conductivity of samples is found. The maximum, which is observed at moderate disorder, has Tc higher than that of clean bulk indium. The increasing part can be explained by the Eliashberg equations with disorder and an additional mechanism of interaction between superconducting and dielectric granules. The descending part of the maximum at higher disorder can be explained by the increasing of long-range Coulomb repulsion due to diffusion of charges. Negative slope in magnetic field dependence of resistivity and a peak in the temperature dependence of resistivity, observed in the sample near the proximity to the disorder-induced superconductor-insulator transition (SIT). A large difference between the onset temperature of superconducting fluctuations, Tcon , and global critical temperature Tc is found and considered in the framework of the weak multifractal theory. Slow time-logarithmic relaxation of the resistivity between Tc and Tcon is observed, which assumes existence of the precursor state near the SIT. This unusual state is discussed in the scope of the many-body localization theory.

  5. A review of basic phenomena and techniques for sputter-deposition of high temperature superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Auciello, O. (Microelectronics Center of North Carolina, Research Triangle Park, NC (USA) North Carolina State Univ., Raleigh, NC (USA). Dept. of Materials Science and Engineering); Ameen, M.S.; Kingon, A.I.; Lichtenwalner, D.J. (North Carolina State Univ., Raleigh, NC (USA). Dept. of Materials Science and Engineering); Krauss, A.R. (Argonne National Lab., IL (USA))

    1990-01-01

    The processes involved in plasma and ion beam sputter-deposition of high temperature superconducting thin films are critically reviewed. Recent advances in the development of these techniques are discussed in relation to basic physical phenomena, specific to each technique, which must be understood before high quality films can be produced. Control of film composition is a major issue in sputter-deposition of multicomponent materials. Low temperature processing of films is a common goal for each technique, particularly in relation to integrating high temperature superconducting films with the current microelectronics technology. It has been understood for some time that for Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} deposition, the most intensely studied high-{Tc} compound, incorporation of sufficient oxygen into the film during deposition is necessary to produce as-deposited superconducting films at relatively substrate temperatures. Recent results have shown that with the use of suitable buffer layers, high quality Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} sputtered films can be obtained on Si substrates without the need for post-deposition anneal processing. This review is mainly focussed on issues related to sputter-deposition of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} thin films, although representative results concerning the bismuth and thallium based compounds are included. 143 refs., 11 figs.

  6. Numerical calculation of transient field effects in quenching superconducting magnets

    CERN Document Server

    Schwerg, Nikolai; Russenschuck, Stephan

    2009-01-01

    The maximum obtainable magnetic induction of accelerator magnets, relying on normal conducting cables and iron poles, is limited to around 2 T because of ohmic losses and iron saturation. Using superconducting cables, and employing permeable materials merely to reduce the fringe field, this limit can be exceeded and fields of more than 10 T can be obtained. A quench denotes the sudden transition from the superconducting to the normal conducting state. The drastic increase in electrical resistivity causes ohmic heating. The dissipated heat yields a temperature rise in the coil and causes the quench to propagate. The resulting high voltages and excessive temperatures can result in an irreversible damage of the magnet - to the extend of a cable melt-down. The quench behavior of a magnet depends on numerous factors, e.g. the magnet design, the applied magnet protection measures, the external electrical network, electrical and thermal material properties, and induced eddy current losses. The analysis and optimizat...

  7. Tunneling observation at very low temperature of impurity bands within the gap of the Kondo superconducting system CuFe/Pb(T(K)>T(c))

    International Nuclear Information System (INIS)

    Dumoulin, Louis; Le Fur, Daniel

    1976-01-01

    Very low temperature superconducting tunneling experiments on CuFe(12.10 -6 ) backed by superconducting lead show a band of localized states next to the gap edge. There is no quantitative agreement with the perturbative approach of Mueller-Hartmann Zittartz in this system where the Kondo temperature is larger than the superconductive T(c) [fr

  8. Low AC Loss in a 3 kA HTS Cable of the Dutch Project

    Science.gov (United States)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan; Willén, Dag; Lentge, Heidi; Thidemann, Carsten; Traeholt, Chresten; Melnik, Irina; Geschiere, Alex

    Requirements for a 6 km long high temperature superconducting (HTS) AC power cable of the Amsterdam project are: a cable has to fit in an annulus of 160 mm, with two cooling stations at the cable ends only. Existing solutions for HTS cables would lead to excessively high coolant pressure drop in the cable, potentially affecting public acceptance of the project. A way out would be to substantially reduce AC losses from 1 down to about 0.1 W/m per phase at rated current of 3 kArms, frequency of 50 Hz and temperature of 77 K. In this paper we discuss a strategy towards this ambitious goal, a concept design of the single phase cable 3 kA conductor made of YBCO tapes and present corresponding experimental and simulation data supporting the developed approach leading directly to this goal. HTS cable model was made that show a drastically reduced AC loss. The low loss was achieved by using appropriate pitch angles for two-layer cable conductor of relatively large diameter, by minimizing the gaps between the HTS tapes, and by using narrow HTS tapes that conform well to the roundness of the underlying former. AC loss of 0.12 W/m at 3 kArms was measured at a frequency of 60 Hz and at a temperature of 77 K.

  9. Experimental demonstration of superconducting critical temperature increase in electromagnetic metamaterials.

    Science.gov (United States)

    Smolyaninova, Vera N; Yost, Bradley; Zander, Kathryn; Osofsky, M S; Kim, Heungsoo; Saha, Shanta; Greene, R L; Smolyaninov, Igor I

    2014-12-04

    A recent proposal that the metamaterial approach to dielectric response engineering may increase the critical temperature of a composite superconductor-dielectric metamaterial has been tested in experiments with compressed mixtures of tin and barium titanate nanoparticles of varying composition. An increase of the critical temperature of the order of ΔT ~ 0.15 K compared to bulk tin has been observed for 40% volume fraction of barium titanate nanoparticles. Similar results were also obtained with compressed mixtures of tin and strontium titanate nanoparticles.

  10. Experimental demonstration of superconducting critical temperature increase in electromagnetic metamaterials

    Science.gov (United States)

    Smolyaninova, Vera N.; Yost, Bradley; Zander, Kathryn; Osofsky, M. S.; Kim, Heungsoo; Saha, Shanta; Greene, R. L.; Smolyaninov, Igor I.

    2014-12-01

    A recent proposal that the metamaterial approach to dielectric response engineering may increase the critical temperature of a composite superconductor-dielectric metamaterial has been tested in experiments with compressed mixtures of tin and barium titanate nanoparticles of varying composition. An increase of the critical temperature of the order of ΔT ~ 0.15 K compared to bulk tin has been observed for 40% volume fraction of barium titanate nanoparticles. Similar results were also obtained with compressed mixtures of tin and strontium titanate nanoparticles.

  11. Analysis of Voltage Signals from Superconducting Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-30

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

  12. Finding new superconductors: the spin-fluctuation gateway to high Tc and possible room temperature superconductivity.

    Science.gov (United States)

    Pines, David

    2013-10-24

    We propose an experiment-based strategy for finding new high transition temperature superconductors that is based on the well-established spin fluctuation magnetic gateway to superconductivity in which the attractive quasiparticle interaction needed for superconductivity comes from their coupling to dynamical spin fluctuations originating in the proximity of the material to an antiferromagnetic state. We show how lessons learned by combining the results of almost three decades of intensive experimental and theoretical study of the cuprates with those found in the decade-long study of a strikingly similar family of unconventional heavy electron superconductors, the 115 materials, can prove helpful in carrying out that search. We conclude that, since Tc in these materials scales approximately with the strength of the interaction, J, between the nearest neighbor local moments in their parent antiferromagnetic state, there may not be a magnetic ceiling that would prevent one from discovering a room temperature superconductor.

  13. Low temperature x-ray analysis and electron microscopy of a new family of superconducting materials

    International Nuclear Information System (INIS)

    Ossipyan, Yu.A.; Borodin, V.A.; Goncharov, V.A.; Kondakov, S.F.; Khasanov, S.S.; Chernyshova, L.M.; Shekhtman, V.S.; Shmyt'ko, I.M.; Stchegolev, N.F.

    1987-01-01

    Recent findings in the field of high temperature superconductivity require that structural aspects of the behavior of this class of materials be investigated in detail in a wide temperature interval. A series of superconducting ceramics on the base of lanthanum and yttrium oxides (La/sub 2-x/Sr/sub x/CuO 4 ; x = 0, 2 and YBaCuO) have been obtained in the solid state Physics Institute of the Academy of Sciences of the USSR. This paper presents the results of the analysis of powder and sintered materials, using X-ray diffractometers (DRON), scanning electron microscope and special devices, enabling the investigations to be carried out within 4.2 K - 573 K

  14. Relativistic BCS-BEC crossover at finite temperature and its application to color superconductivity

    International Nuclear Information System (INIS)

    He Lianyi; Zhuang Pengfei

    2007-01-01

    The nonrelativistic G 0 G formalism of BCS-BEC crossover at finite temperature is extended to relativistic fermion systems. The uncondensed pairs contribute a pseudogap to the fermion excitations. The theory recovers the BCS mean field approximation at zero temperature and the nonrelativistic results in a proper limit. For massive fermions, when the coupling strength increases, there exist two crossovers from the weak coupling BCS superfluid to the nonrelativistic BEC state and then to the relativistic BEC state. For color superconductivity at moderate baryon density, the matter is in the BCS-BEC crossover region, and the behavior of the pseudogap is quite similar to that found in high temperature superconductors

  15. Design and Test of a Thermal Triggered Persistent Current System using High Temperature Superconducting Tapes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Keun [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Kang, Hyoungku [Electro-Mechanical Research Institute, Hyundai Heavy Industries, Yongin (Korea, Republic of); Ahn, Min Cheol [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Yang, Seong Eun [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Yoon, Yong Soo [Department of Electrical Engineering, Ansan College of Technology, 671 Choji-Dong, Danwon-Gu, Ansan, 425-792 (Korea, Republic of); Lee, Sang Jin [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Ko, Tae Kuk [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of)

    2006-06-01

    A superconducting magnet which is operated in persistent current mode in SMES, NMR, MRI and MAGLEV has many advantages such as high uniformity of magnetic field and reduced thermal loss. A high temperature superconducting (HTS) persistent current switch (PCS) system was designed and tested in this research. The HTS PCS was optimally designed using two different HTS tapes, second generation coated conductor (CC) HTS tape and Bi-2223 HTS tape by the finite element method (FEM) in thermal quench characteristic view. The CC tape is more prospective applicable wire in these days for its high n value and critical current independency from external magnetic field than Bi-2223 tape. Also a prototype PCS system using Bi-2223 tape was manufactured and tested. The PCS system consists of a PCS part, a heater which induces the PCS to quench, and a superconducting magnet. The test was performed in various conditions of transport current. An initial current decay appeared when the superconducting magnet was energized in a PCS system was analyzed. This paper would be foundation of HTS PCS researches.

  16. A vibrating wire parallel to a high temperature superconducting slab. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Saif, A G; El-sabagh, M A [Department of Mathematic and Theoretical physics, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The power losses problem for an idealized high temperature type II superconducting system of a simple geometry is studied. This system is composed of a vibrating normal conducting wire (two wires) carrying a direct current parallel to an uniaxial anisotropic type II superconducting slab (moving slab). First, the electromagnetic equation governing the dynamics of this system, and its solutions are obtained. Secondly, a modified anisotropic london equation is developed to study these systems in the case of the slab moving. Thirdly, it is found that, the power losses is dependent on the frequency, london penetration depth, permeability, conductivity, velocity, and the distance between the normal conductors and the surfaces of the superconducting slab. Moreover, the power losses decreases as the distance between the normal conductors and the surface of the superconducting slab decreases; and increases as the frequency, the london penetration depth, permeability, conductivity, and velocity are increased. These losses along the versor of the anisotropy axis is increased as {lambda}{sub |}| increases. Moreover, it is greater than the power losses along the crystal symmetry direction. In the isotropic case as well as the slab thickness tends to infinity, agreement with previous results are obtained. 2 figs.

  17. High-temperature superconducting oxide synthesis and the chemical doping of the Cu-O planes

    International Nuclear Information System (INIS)

    Tarascon, J.M.; Barboux, P.; Bagley, B.G.; Greene, L.H.; McKinnon, W.R.; Hull, G.W.

    1987-01-01

    Different synthesis techniques for the preparation of dense superconducting ceramics are discussed, and a sol-gel process is shown to be very promising. The effect of oxygen content, and the effect of substitution of Ni and Zn for copper, on the structural, transport and superconducting properties of the La-Sr-Cu-O and Y-Ba-Cu-O systems are presented. The authors find that substitution on the copper sites destroys T/sub c/ in the La-Sr-Cu-O system and decreases it in the Y-Ba-Cu-O system, and this effect is insensitive as to whether the 3d metal is magnetic (Ni) or diamagnetic (Zn). A detailed study of the YBa/sub 2/Cu/sub 3/O/sub 7-y/ system as a function of oxygen content (y) shows that superconductivity can be destroyed in these materials by the removal of oxygen and restored by reinjecting oxygen; either thermally at 500 0 C or at temperatures (80 0 C) compatible with device processing by means of a novel plasma oxidation process. Of scientific interest, the plasma process induces bulk superconductivity in the undoped La/sub 2/CuO/sub 4/

  18. Microchip-calorimetry of organic charge transfer complex which shows superconductivity at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, Yuki [Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan); Yamashita, Satoshi [RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Yamamoto, Takashi [Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan); Nakazawa, Yasuhiro, E-mail: nakazawa@chem.sci.osaka-u.ac.jp [Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama 1-1, Toyonaka, Osaka 560-0043 (Japan); Institute for Molecular Science, Nishigonaka 38, Myodaiji, Okazaki 444-8585 (Japan)

    2012-03-20

    Highlights: Black-Right-Pointing-Pointer Organic charge transfer salt of {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br shows superconductivity. Black-Right-Pointing-Pointer We succeeded to detect thermal anomaly microchip device TCG3880. Black-Right-Pointing-Pointer Development details of the calorimeter and the detection system is presented. Black-Right-Pointing-Pointer The magnetic fields dependence shows typical character of layered superconductor. - Abstract: We carried out thermodynamic measurements of organic charge transfer complex of {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene by TCG3880 chip device in order to examine capability of the chip calorimeter at low temperature region and under magnetic fields. TCG3880 chip is mounted on a {sup 3}He cryostat available in combination with a superconductive magnet up to 7 T. Thermal anomalies related to the glass-like freezing of ethylene groups of BEDT-TTF molecules and the superconductive transition were observed. A frequency dependence of the thermal anomaly of the glass formation and a magnetic fields dependence of the thermal anomaly of the superconductive transition are reported. The results presented in this work demonstrate that the TCG3880 is quite useful for thermodynamic investigations of the organic charge transfer complex with much reduced sample quantity as compared with those of relaxation and adiabatic calorimetry.

  19. Nonlocal fluctuational electromagnetic response and neutron magnetic scattering near the superconducting transition temperature

    International Nuclear Information System (INIS)

    Barash, Yu.S.; Galaktionov, A.V.

    1992-01-01

    A general expression is found for superconducting fluctuation contribution to transverse permittivity c tr f (Ω, Q) of a standard massive isotopic metal near T c at Ω c and Qζ 0 0 is the coherence length at zero temperature, Q is the external electromagnetic field pulse), depending on frequency and wave vector. Differential cross section of magnetic scattering of neutrons near T c in the region of comparatively small angles is considered

  20. 6. Trilateral German-Russian-Ukrainian seminar on high-temperature superconductivity

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Kornilov, E.I.

    1993-01-01

    The proceedings of the 6. Trilateral German-Russian-Ukrainian seminar on high-temperature superconductivity are reported. Nuclear methods (neutron diffraction, neutron polarization, Raman scattering, ESR) applied to study rare earth cuprates are described. The reports dealing with fundamental experimental studies and theoretical investigations are presented. The source materials for preparation of high-tc superconductors and the ways of their preparation, as well as their physico-chemical properties are considered

  1. Thin Film Technology of High-Critical-Temperature Superconducting Electronics.

    Science.gov (United States)

    1985-12-11

    ANALISIS OF THIN-FILM SUPERCONDUCTORS J. Talvacchio, M. A. Janocko, J. R. Gavaler, and A...in the areas of substrate preparation, niobum nitride, nlobium-tin, and molybdenum-rhenium. AN INTEGRATED DEPOSITION AND ANALISI - FACILITT The four...mobility low (64). The voids are separating 1-3 nm clusters of dense deposit. At low deposition temperatures this microstructure will persist near

  2. Theory of the transition temperature of superconducting amorphous transition metals

    International Nuclear Information System (INIS)

    Zwicknagel, G.

    1979-11-01

    In the present paper first the transition temperature Tsub(c) is shown to be a local quantity, which depends on the (average) short range order, and second it is demonstrated how to calculate local electronic properties in the framework of a short range order model and the transition temperature of amorphous systems based on accepted structure models of the amorphous state. In chapter I the theoretical basis of this work is presented in brief. The model used to study the role of short range order (in periodically ordered as well as in disordered system) is described in chapter II. The results of this model for the periodically ordered case are compared in chapter III with band structure calculations. In chapter IV it is shown how to establish short range order models for disordered systems and what kind of information can be obtained with respect to the electronic properties. Finally in chapter V it is discussed to what extend the interpretation of the transition temperature Tsub(c) as being determined by short range order effects can be supported by the electronic properties, which are calculated in the chapters III and IV. (orig.) [de

  3. Development of Nb3Sn AC superconducting wire. Pt. 2

    International Nuclear Information System (INIS)

    Kasahara, Hobun; Torii, Shinji; Akita, Shirabe; Ueda, Kiyotaka; Kubota, Yoji; Yasohama, Kazuhiko; Kobayashi, Hisayasu; Ogasawara, Takeshi.

    1993-01-01

    For the realization of superconducting power apparatus, it is important that the development of highly stable superconducting cables. Nb 3 Sn wire has higher critical temperature than NbTi wire. Therefore, it is possible to make highly stable superconducting wires. In this report, we examine a manufacturing process of Ac Nb 3 Sn wire. This manufacturing process has four times higher critical current density than conventional processes. We have made a 400 kVA class AC coil with React and Wind method. The loss density of this coil was 20MW/m 3 at just before the quench. In this case, the temperature of cable increased about 3.8 K. This means that the Nb 3 Sn coil has a very high stability. (author)

  4. SCMS-1, Superconducting Magnet System for an MHD generator

    International Nuclear Information System (INIS)

    Zenkevich, V.B.; Kirenin, I.A.; Tovma, V.A.

    1977-01-01

    The research and development effort connected with the building of the superconducting magnet systems for MHD generators at the Institute for High Temperatures of the U.S.S.R. Academy of Sciences included the designing, fabrication and testing of the superconducting magnet system for an MHD generator (SCMS-1), producing a magnetic field up to 4 Tesla in a warm bore tube 300 mm in diameter and 1000 mm long (the nonuniformity of the magnetic field in the warm bore did not exceed +-5%. The superconducting magnet system is described. The design selected consisted of a dipole, saddle-form coil, wound around a tube. The cooling of the coils is of the external type with helium access to each layer of the winding. For winding of the superconducting magnet system a 49-strand cable was used consisting of 42 composition conductors, having a diameter of 0.3 mm each, containing six superconducting strands with a niobium-titanium alloy base (the superconducting strands were 70 microns in diameter), and seven copper conductors of the same diameter as the composite conductors. The cable is made monolithic with high purity indium and insulated with lavsan fiber. The cable diameter with insulation is 3.5 mm

  5. Investigation of the mechanical and electrical properties of superconducting coils

    International Nuclear Information System (INIS)

    Saito, T.; Yamagiwa, T.; Hara, K.; Kojima, Y.; Hosoyama, K.; Mori, A.; Nojima, K.; Okamoto, Y.; Takabayashi, S.; Tanaka, T.

    1994-01-01

    Measurement of elastic (Young's) modulus of the superconducting coil and electrical punch-through test have been performed at LBL to understand the mechanical and electrical properties of the superconducting coils. The authors have investigated the elastic modulus of the superconducting coils with six kinds of insulators (made with polyimide-fiberglass-epoxy and all polyimide insulation with epoxy/polyimide adhesive) at room and liquid nitrogen temperatures using samples made of 10 stacks of superconducting cables. The samples are cured under varying compression to investigate the curing pressure dependence of Young's modulus of the coils with six kinds of the insulation system. The electrical punch-through test has also performed under compression at room and liquid nitrogen temperatures to investigate electrical integrity of the insulated coils. The tensile strength test of four kinds of polyimide films has been performed at various temperatures (between cryogenic and coil curing temperatures) to understand the mechanical properties of the films

  6. Compilation of NRL Publications on High Temperature Superconductivity.

    Science.gov (United States)

    1987-01-01

    Fig. 2. The upper critical field as a function of .R. Beasley: Phys. Rev 11(1979) 4545. temperature for Ial.8Sro.2Cu04 (left) and 10) A. Junod , A...commuication 10) T.P. Orlando. E.J. McNiff. Jr.. S. Foner. and M.R. Beasley: Fhys. Rev 9(1979) 4545.-,, 11) A. Junod . A. Bezinge. T. Graf. J.L. Jorda. J...of MRS meeting (Anaheim, i Uchida et al. Jpn. J. of Apph Phys. 26, L443 (1987). -s 1987; in press). 12. H. Junod et al. (preprint

  7. A visualization instrument to investigate the mechanical-electro properties of high temperature superconducting tapes under multi-fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei; Zhang, Xingyi, E-mail: zhangxingyi@lzu.edu.cn; Liu, Cong; Zhang, Wentao; Zhou, Jun; Zhou, YouHe [Key Laboratory of Mechanics on Disaster and Environment in Western China Attached to the Ministry of Education of China, Lanzhou University, Lanzhou, Gansu 730000, People’s Republic of China and Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2016-07-15

    We construct a visible instrument to study the mechanical-electro behaviors of high temperature superconducting tape as a function of magnetic field, strain, and temperature. This apparatus is directly cooled by a commercial Gifford-McMahon cryocooler. The minimum temperature of sample can be 8.75 K. A proportion integration differentiation temperature control is used, which is capable of producing continuous variation of specimen temperature from 8.75 K to 300 K with an optional temperature sweep rate. We use an external loading device to stretch the superconducting tape quasi-statically with the maximum tension strain of 20%. A superconducting magnet manufactured by the NbTi strand is applied to provide magnetic field up to 5 T with a homogeneous range of 110 mm. The maximum fluctuation of the magnetic field is less than 1%. We design a kind of superconducting lead composed of YBa2Cu3O7-x coated conductor and beryllium copper alloy (BeCu) to transfer DC to the superconducting sample with the maximum value of 600 A. Most notably, this apparatus allows in situ observation of the electromagnetic property of superconducting tape using the classical magnetic-optical imaging.

  8. Surface temperature measurements on superconducting cavities in superfluid helium

    International Nuclear Information System (INIS)

    Fouaidy, T.; Junquera, T.; Caruette, A.

    1991-01-01

    Two thermometry systems have been developed: a scanning thermometer system routinely used for the 1.5 GHz monocell cavity studies and a fixed thermometer array used to investigate spatial surface resistance distribution on various SC removable endplates of a cylindrical TE011mode cavity. Thermometers used in these systems are thermally insulated from the surrounding HeII bath by an epoxy housing ('epoxy'thermometers). Accurate calibration of the fixed thermometers was conducted by using different test cells and the experimental results were compared to model calculations performed with a finite element computational code. Measured thermometer efficiency and linearity are in good agreement with numerical results. Some typical temperature maps of different Nb samples obtained with the TE011 array (40 epoxy thermometers) are discussed. On the basis of numerical modelling results, a new type of thermometer with an improved efficiency has been designed. The thermal insulation against Helium II has been drastically improved by placing the sensitive part of the thermometer in a small vacuum jacket ('vacuum' thermometers). Two main goals have been reached with the first prototypes: improved efficiency by a factor of 2.5 - 3, and a bath temperature dependence of the thermal response in good agreement with the expected Kapitza conductance behaviour. Fitting experimental results with numerical modelling data, allow us to estimate the Kapitza conductance. The obtained values are in good agreement with the previous results reported by several authors using a different measurement method. The 'vacuum' thermometers are currently used on the TE011 mode cavity with Nb and NbTiN plates and the first results are presented

  9. Method and apparatus for forming high-critical-temperature superconducting layers on flat and/or elongated substrates

    Science.gov (United States)

    Ciszek, Theodore F.

    1994-01-01

    An elongated, flexible superconductive wire or strip is fabricated by pulling it through and out of a melt of metal oxide material at a rate conducive to forming a crystalline coating of superconductive metal oxide material on an elongated, flexible substrate wire or strip. A coating of crystalline superconductive material, such as Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8, is annealed to effect conductive contact between adjacent crystalline structures in the coating material, which is then cooled to room temperature. The container for the melt can accommodate continuous passage of the substrate through the melt. Also, a second pass-through container can be used to simultaneously anneal and overcoat the superconductive coating with a hot metallic material, such as silver or silver alloy. A hollow, elongated tube casting method of forming an elongated, flexible superconductive wire includes drawing the melt by differential pressure into a heated tubular substrate.

  10. Research and development project for flywheel energy storage system using high-temperature superconducting magnetic bearing

    International Nuclear Information System (INIS)

    Shinagawa, Jiro; Ishikawa, Fumihiko

    1996-01-01

    Recent progress in the research and development of an yttrium-based oxide high-temperature superconductor has enabled the production of a large-diameter bulk with a strong flux-pinning force. A combination of this superconductor and a permanent magnet makes it feasible to fabricate a non-contact, non-controlled superconducting magnetic bearing with a very small rotational loss. Use of the superconducting magnetic bearing for a flywheel energy storage system may pave the way to the development of a new energy storage system that has great energy storage efficiency. >From relevant data measured with a miniature model of the high-temperature superconducting magnetic bearing, a conceptual design of an 8 MWh flywheel energy storage system was developed, using the new bearing which proved to be potentially capable of achieving a high energy storage efficiency of 84%. A 100 Wh-class experimental system was install that attained a high revolution rate of 17.000 rpm. (author)

  11. Application of a phenomenological model for the surface impedance in high temperature superconducting films

    International Nuclear Information System (INIS)

    Mosquera, A.S.; Landinez Tellez, D.A.; Roa-Rojas, J.

    2007-01-01

    We report the application of a phenomenological model for the microwave surface impedance in high temperature superconducting films. This model is based on the modified two-fluid model, in which the real and imaginary parts of the surface impedance use the modelling parameter γ. This is responsible for the superconducting and normal charge carrier density and is used for the description of the temperature dependence of the London penetration depth λ L (T) including λ L (0). The relaxation time model also uses the γ parameter in combination with the residual resistance parameter α. The parameter δ 1 1 , γ, α, and δ 2 . The parameter δ 2 n (T) is a result of the competition between the increase of the relaxation time and the decrease of the normal charge-carrier density. We applied this model to analyze experimental results of MgB 2 , YBa 2 Cu 3 O 7-δ and GdBa 2 Cu 3 O 7-δ superconducting material. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. An investigation of texturing by magnetic and mechanical techniques in high critical temperature superconducting ceramics

    International Nuclear Information System (INIS)

    Deschanels, X.

    1992-11-01

    The principal goal of this work is to quantify the influence of texture of ceramic superconductors ReBaCuO (Re=Dy, Y) on their critical current density (Jc). The magnetic alignment of particles at ambient temperature is the first technique who has allowed us to produce superconducting (Meissner effect) and textured ceramics. However, these materials are very brittle because of their porosity and this makes it impossible to measure their Jc. Press-forging (or creep sintering) is the second technique who has allowed us to prepare highly textured ceramics materials which are also dense. We have studied the influence of various conditions of thermomechanical treatment (sintering time and temperature, applied load, rate of deformation, density of the material at the beginning) on the texture quality. We have shown that at 900 deg, the eutectic liquid formed by BaCuO 2 , CuO and YBa 2 Cu 3 0 7-Y various mechanisms that help explain the formation of observed texture. After the oxidation stage which requires heat treatment under controlled atmospheres, we obtain superconducting ceramics (Tc=85 K). Moreover, this study also shows that the texture can improve the Jc by 400%, to 750 A/cm 2 at 77 K in the best specimens. This low value is explained by the presence of non-superconducting secondary phases and amorphous phases at the grain boundaries. (Author). 120 refs., figs., tabs

  13. Lanthanum gallate substrates for epitaxial high-temperature superconducting thin films

    International Nuclear Information System (INIS)

    Sandstrom, R.L.; Giess, E.A.; Gallagher, W.J.; Segmueller, A.; Cooper, E.I.; Chisholm, M.F.; Gupta, A.; Shinde, S.; Laibowitz, R.B.

    1988-01-01

    We demonstrate that lanthanum gallate (LaGaO 3 ) has considerable potential as an electronic substrate material for high-temperature superconducting films. It provides a good lattice and thermal expansion match to YBa 2 Cu 3 O/sub 7-//sub x/, can be grown in large crystal sizes, is compatible with high-temperature film processing, and has a reasonably low dielectric constant (ε≅25) and low dielectric losses. Epitaxial YBa 2 Cu 3 O/sub 7-//sub x/ films grown on LaGaO 3 single-crystal substrates by three techniques have zero resistance between 87 and 91 K

  14. Lanthanum gallate substrates for epitaxial high-temperature superconducting thin films

    Science.gov (United States)

    Sandstrom, R. L.; Giess, E. A.; Gallagher, W. J.; Segmuller, A.; Cooper, E. I.

    1988-11-01

    It is demonstrated that lanthanum gallate (LaGaO3) has considerable potential as an electronic substrate material for high-temperature superconducting films. It provides a good lattice and thermal expansion match to YBa2Cu3O(7-x), can be grown in large crystal sizes, is compatible with high-temperature film processing, and has a reasonably low dielectric constant and low dielectric losses. Epitaxial YBa2Cu3O(7-x) films grown on LaGaO3 single-crystal substrates by three techniques have zero resistance between 87 and 91 K.

  15. Magnetic field and temperature dependence of the critical vortex velocity in type-II superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, G; Leo, A; Cirillo, C; Attanasio, C; Nigro, A; Pace, S [CNR-INFM Laboratorio Regionale SuperMat, Via Salvador Allende, I-84081 Baronissi (Italy)], E-mail: grimaldi@sa.infn.it

    2009-06-24

    We study the vortex dynamics in the instability regime induced by high dissipative states well above the critical current in Nb superconducting strips. The magnetic field and temperature behavior of the critical vortex velocity corresponding to the observed dynamic instability is ascribed to intrinsic non-equilibrium phenomena. The Larkin-Ovchinnikov (LO) theory of electronic instability in high velocity vortex motion has been applied to interpret the temperature dependence of the critical vortex velocity. The magnetic field dependence of the vortex critical velocity shows new features in the low-field regime not predicted by LO.

  16. Size, Shape and Impurity Effects on Superconducting critical temperature.

    Science.gov (United States)

    Umeda, Masaki; Kato, Masaru; Sato, Osamu

    Bulk superconductors have their own critical temperatures Tc. However, for a nano-structured superconductor, Tc depends on size and shape of the superconductor. Nishizaki showed that the high pressure torsion on bulks of Nb makes Tc higher, because the torsion makes many nano-sized fine grains in the bulks. However the high pressure torsion on bulks of V makes Tc lower, and Nishizaki discussed that the decrease of Tc is caused by impurities in the bulks of V. We studied size, shape, and impurity effects on Tc, by solving the Gor'kov equations, using the finite element method. We found that smaller and narrower superconductors show higher Tc. We found how size and shape affects Tc by studying spacial order parameter distributions and quasi-particle eigen-energies. Also we studied the impurity effects on Tc, and found that Tc decreases with increase of scattering rate by impurities. This work was supported in part of KAKENHI Grant Number JP26400367 and JP16K05460, and program for leading graduate schools of ministry of education, culture, sports, science and technology-Japan.

  17. Theory of superconductivity

    International Nuclear Information System (INIS)

    Crisan, M.

    1988-01-01

    This book discusses the most important aspects of the theory. The phenomenological model is followed by the microscopic theory of superconductivity, in which modern formalism of the many-body theory is used to treat most important problems such as superconducting alloys, coexistence of superconductivity with the magnetic order, and superconductivity in quasi-one-dimensional systems. It concludes with a discussion on models for exotic and high temperature superconductivity. Its main aim is to review, as complete as possible, the theory of superconductivity from classical models and methods up to the 1987 results on high temperature superconductivity. Contents: Phenomenological Theory of Superconductivity; Microscopic Theory of Superconductivity; Theory of Superconducting Alloys; Superconductors in a Magnetic Field; Superconductivity and Magnetic Order; Superconductivity in Quasi-One-Dimensional Systems; and Non-Conventional Superconductivity

  18. Feasibility study of electric motors constructed with high temperature superconducting materials

    International Nuclear Information System (INIS)

    Jordan, H.E.

    1989-01-01

    The potential application of high temperature superconducting (HTSC) materials to electric motors is discussed. The specific application area of motors in electric power generating stations has been selected and a feasible study has been initiated on the use of HTSC materials in the design of motors for this application. A progress report on this feasibility study is presented. Technical challenges in both the development of HTSC wire and the design of a motor to utilize this wire are discussed. Finally, the results of design calculations comparing a superconducting motor with one of conventional design are presented assuming that success can be achieved in overcoming the technical problems which must be resolved to produce a high performance HTSC wire

  19. High-temperature superconductivity: Perseverance and cooperation on the road to commercialization

    International Nuclear Information System (INIS)

    1988-01-01

    Early in 1986 two European researchers working in the Swiss laboratory of a U.S. firm made a remarkable and unexpected discovery. After years of dedicated materials research they had in fact found a class of materials which exhibited the remarkable phenomenon of superconductivity at a new and higher range of temperatures. Scientifically, the result was completely unexpected. Technologically, the result immediately brought out of mothballs the many applications of superconductivity that had generally seemed out of reach with the earlier materials. The recommendations are in two parts, the first aimed at strengthening the purely scientific effort, and the second aimed at providing strength and stability in the long term race for applications

  20. High-temperature superconducting phase of HBr under pressure predicted by first-principles calculations

    Science.gov (United States)

    Gu, Qinyan; Lu, Pengchao; Xia, Kang; Sun, Jian; Xing, Dingyu

    2017-08-01

    The high pressure phases of HBr are explored with an ab initio crystal structure search. By taking into account the contribution of zero-point energy (ZPE), we find that the P 4 /n m m phase of HBr is thermodynamically stable in the pressure range from 150 to 200 GPa. The superconducting critical temperature (Tc) of P 4 /n m m HBr is evaluated to be around 73 K at 170 GPa, which is the highest record so far among binary halogen hydrides. Its Tc can be further raised to around 95K under 170 GPa if half of the bromine atoms in the P 4 /n m m HBr are substituted by the lighter chlorine atoms. Our study shows that, in addition to lower mass, higher coordination number, shorter bonds, and more highly symmetric environment for the hydrogen atoms are important factors to enhance the superconductivity in hydrides.

  1. Gauge models of planar high-temperature superconductivity without parity violation

    International Nuclear Information System (INIS)

    Mavromatos, N.E.; Grenoble-1 Univ., 74 - Annecy

    1993-02-01

    A status report is given of a parity-invariant model of two-dimensional superconductivity. The model consists of two-species of fermions coupled with opposite sign to an Abelian gauge field and is closely related to QED 3 . The dynamical generation of a parity-conserving fermion mass and the finite temperature symmetry restoration transition is studied, and it is shown, how the parity-invariant model arises as an effective long-wavelength theory of the dynamics of holes in a two-dimensional quantum antiferromagnetic system on a bi-partite lattice. The model exhibits type-II superconductivity without parity or time-reversal symmetry violation, a high value of 2 Δ /k B T c , flux quantization with quantum hc/2e and a two-dimensional Meissner effect. (author) 82 refs.; 15 figs.; 4 tabs

  2. Calibration of tip and sample temperature of a scanning tunneling microscope using a superconductive sample

    Energy Technology Data Exchange (ETDEWEB)

    Stocker, Matthias; Pfeifer, Holger; Koslowski, Berndt, E-mail: berndt.koslowski@uni-ulm.de [Institute of Solid State Physics, University of Ulm, D-89069 Ulm (Germany)

    2014-05-15

    The temperature of the electrodes is a crucial parameter in virtually all tunneling experiments. The temperature not only controls the thermodynamic state of the electrodes but also causes thermal broadening, which limits the energy resolution. Unfortunately, the construction of many scanning tunneling microscopes inherits a weak thermal link between tip and sample in order to make one side movable. Such, the temperature of that electrode is badly defined. Here, the authors present a procedure to calibrate the tip temperature by very simple means. The authors use a superconducting sample (Nb) and a standard tip made from W. Due to the asymmetry in the density of states of the superconductor (SC)—normal metal (NM) tunneling junction, the SC temperature controls predominantly the density of states while the NM controls the thermal smearing. By numerically simulating the I-V curves and numerically optimizing the tip temperature and the SC gap width, the tip temperature can be accurately deduced if the sample temperature is known or measureable. In our case, the temperature dependence of the SC gap may serve as a temperature sensor, leading to an accurate NM temperature even if the SC temperature is unknown.

  3. Calibration of tip and sample temperature of a scanning tunneling microscope using a superconductive sample

    International Nuclear Information System (INIS)

    Stocker, Matthias; Pfeifer, Holger; Koslowski, Berndt

    2014-01-01

    The temperature of the electrodes is a crucial parameter in virtually all tunneling experiments. The temperature not only controls the thermodynamic state of the electrodes but also causes thermal broadening, which limits the energy resolution. Unfortunately, the construction of many scanning tunneling microscopes inherits a weak thermal link between tip and sample in order to make one side movable. Such, the temperature of that electrode is badly defined. Here, the authors present a procedure to calibrate the tip temperature by very simple means. The authors use a superconducting sample (Nb) and a standard tip made from W. Due to the asymmetry in the density of states of the superconductor (SC)—normal metal (NM) tunneling junction, the SC temperature controls predominantly the density of states while the NM controls the thermal smearing. By numerically simulating the I-V curves and numerically optimizing the tip temperature and the SC gap width, the tip temperature can be accurately deduced if the sample temperature is known or measureable. In our case, the temperature dependence of the SC gap may serve as a temperature sensor, leading to an accurate NM temperature even if the SC temperature is unknown

  4. Overview of Superconductivity and Challenges in Applications

    CERN Document Server

    Flükiger, Rene

    2012-01-01

    Considerable progress has been achieved during the last few decades in the various fields of applied superconductivity, while the related low temperature technology has reached a high level. Magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) are so far the most successful applications, with tens of thousands of units worldwide, but high potential can also be recognized in the energy sector, with high energy cables, transformers, motors, generators for wind turbines, fault current limiters and devices for magnetic energy storage. A large number of magnet and cable prototypes have been constructed, showing in all cases high reliability. Large projects involving the construction of magnets, solenoids as well as dipoles and quadrupoles are described in the present book. A very large project, the LHC, is currently in operation, demonstrating that superconductivity is a reliable technology, even in a device of unprecedented high complexity. A project of similar complexity is ITER, a fusion device...

  5. Status and prospects on development of yttrium-based high-temperature superconducting coated conductor

    International Nuclear Information System (INIS)

    Izumi, Teruo; Yanagi, Nagato

    2017-01-01

    Development of a large-sized large-current conductor using a high-temperature superconducting wire rod based on copper oxide has been started worldwide for the purpose of applying it as an option of a magnet for a nuclear fusion prototype reactor. There is yttrium-based thin film wire rod as a promising candidate. Japan is leading the development of this wire rod for many years, aiming to apply it to power equipment and the like. This paper explained the history of wire rod development, basic superconducting properties and manufacturing method, and latest achievements, and overviewed the feasibility of application to nuclear fusion reactor magnets. At present, the use of niobium-based low-temperature superconducting wire rod that is used in ITER is the basic idea. On the other hand, the development of wire rod using a copper oxide type high-temperature superconductor (HTS) has also been started. HTS wire rod is evaluated as suitable for application to nuclear fusion magnets due to its superior critical current characteristics and high mechanical rigidity up to high magnetic fields at high temperatures of yttrium. As current development progress, there are development of high-quality wire rod in the magnetic field and development of low AC loss wire rod. As future prospects, cost reduction due to mass production and improvement of yield, and investigation of low-resistance connection technology are being studied. The remaining future challenges of yttrium-based HTS are improvement of the anisotropy, influence on neutron irradiation, and problem of activation. (A.O.)

  6. Overview of Superconductivity and Challenges in Applications

    Science.gov (United States)

    Flükiger, Rene

    2012-01-01

    Considerable progress has been achieved during the last few decades in the various fields of applied superconductivity, while the related low temperature technology has reached a high level. Magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) are so far the most successful applications, with tens of thousands of units worldwide, but high potential can also be recognized in the energy sector, with high energy cables, transformers, motors, generators for wind turbines, fault current limiters and devices for magnetic energy storage. A large number of magnet and cable prototypes have been constructed, showing in all cases high reliability. Large projects involving the construction of magnets, solenoids as well as dipoles and quadrupoles are described in the present book. A very large project, the LHC, is currently in operation, demonstrating that superconductivity is a reliable technology, even in a device of unprecedented high complexity. A project of similar complexity is ITER, a fusion device that is presently under construction. This article starts with a brief historical introduction to superconductivity as a phenomenon, and some fundamental properties necessary for the understanding of the technical behavior of superconductors are described. The introduction of superconductivity in the industrial cycle faces many challenges, first for the properties of the base elements, e.g. the wires, tapes and thin films, then for the various applied devices, where a number of new difficulties had to be resolved. A variety of industrial applications in energy, medicine and communications are briefly presented, showing how superconductivity is now entering the market.

  7. Transition temperature to the superconducting phase of QCD at high baryon density

    International Nuclear Information System (INIS)

    Brown, William E.; Liu, James T.; Ren, Hai-cang

    2000-01-01

    Recent interest in the study of color superconductivity has focused on the regime of high baryon density where perturbative QCD may be employed. Based on the dominant one-gluon-exchange interaction, both the transition temperature and zero temperature gap have been determined to leading order in the coupling g. While the leading non-BCS behavior T C ∼μg -5 e -κ/g is easily obtained, the pre-exponential factor has proved more difficult to evaluate. Focusing on the transition temperature, we present a perturbative derivation of this factor, exact to leading order in g. This approach is first motivated by the study of a toy model and involves working to second order in the perturbative expansion. We compare this result to the zero temperature gap. Additionally, we extend the analysis to the case of higher angular momentum for longitudinal and transverse quark pairing. (c) 2000 The American Physical Society

  8. Measurement of stability of cabled conductors cooled by He I at reduced temperature, or He II

    International Nuclear Information System (INIS)

    Hsu, Y.H.; Purcell, J.R.; Chen, W.Y.; Alcorn, J.S.

    1980-09-01

    Stability tests of cabled NbTi alloy conductor are underway at the General Atomic High Field Test Facility, in support of the Team One effort of the DOE 12 Tesla Coil Development Program. A background field of up to 10 tesla within a 20 cm bore is provided by a nested pair of 4.2 0 K bath cooled NbTi coils. An insulated bore insert tube (coldfinger) is provided in order to perform heat pulse/recovery tests of coiled samples in cooling regimes anticipated for the 1 m O.D. coil to be tested at the LLNL 12 tesla facility during FY 82. Specifically, tests are being performed in the 2.5 to 3 0 K He I, and saturated superfluid (He II) regimes. The testing apparatus, procedures, and initial results are presented

  9. High-temperature superconductivity from fine-tuning of Fermi-surface singularities in iron oxypnictides

    Science.gov (United States)

    Charnukha, A.; Evtushinsky, D. V.; Matt, C. E.; Xu, N.; Shi, M.; Büchner, B.; Zhigadlo, N. D.; Batlogg, B.; Borisenko, S. V.

    2015-12-01

    In the family of the iron-based superconductors, the REFeAsO-type compounds (with RE being a rare-earth metal) exhibit the highest bulk superconducting transition temperatures (Tc) up to 55 K and thus hold the key to the elusive pairing mechanism. Recently, it has been demonstrated that the intrinsic electronic structure of SmFe0.92Co0.08AsO (Tc = 18 K) is highly nontrivial and consists of multiple band-edge singularities in close proximity to the Fermi level. However, it remains unclear whether these singularities are generic to the REFeAsO-type materials and if so, whether their exact topology is responsible for the aforementioned record Tc. In this work, we use angle-resolved photoemission spectroscopy (ARPES) to investigate the inherent electronic structure of the NdFeAsO0.6F0.4 compound with a twice higher Tc = 38 K. We find a similarly singular Fermi surface and further demonstrate that the dramatic enhancement of superconductivity in this compound correlates closely with the fine-tuning of one of the band-edge singularities to within a fraction of the superconducting energy gap Δ below the Fermi level. Our results provide compelling evidence that the band-structure singularities near the Fermi level in the iron-based superconductors must be explicitly accounted for in any attempt to understand the mechanism of superconducting pairing in these materials.

  10. Cryogenics Vision Workshop for High-Temperature Superconducting Electric Power Systems Proceedings

    International Nuclear Information System (INIS)

    Energetics, Inc.

    2000-01-01

    The US Department of Energy's Superconductivity Program for Electric Systems sponsored the Cryogenics Vision Workshop, which was held on July 27, 1999 in Washington, D.C. This workshop was held in conjunction with the Program's Annual Peer Review meeting. Of the 175 people attending the peer review meeting, 31 were selected in advance to participate in the Cryogenics Vision Workshops discussions. The participants represented cryogenic equipment manufactures, industrial gas manufacturers and distributors, component suppliers, electric power equipment manufacturers (Superconductivity Partnership Initiative participants), electric utilities, federal agencies, national laboratories, and consulting firms. Critical factors were discussed that need to be considered in describing the successful future commercialization of cryogenic systems. Such systems will enable the widespread deployment of high-temperature superconducting (HTS) electric power equipment. Potential research, development, and demonstration (RD and D) activities and partnership opportunities for advancing suitable cryogenic systems were also discussed. The workshop agenda can be found in the following section of this report. Facilitated sessions were held to discuss the following specific focus topics: identifying Critical Factors that need to be included in a Cryogenics Vision for HTS Electric Power Systems (From the HTS equipment end-user perspective) identifying R and D Needs and Partnership Roles (From the cryogenic industry perspective) The findings of the facilitated Cryogenics Vision Workshop were then presented in a plenary session of the Annual Peer Review Meeting. Approximately 120 attendees participated in the afternoon plenary session. This large group heard summary reports from the workshop session leaders and then held a wrap-up session to discuss the findings, cross-cutting themes, and next steps. These summary reports are presented in this document. The ideas and suggestions raised during

  11. Cable Diagnostic Focused Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Hartlein, R.A.; Hampton, R.N.

    2010-12-30

    This report summarizes an extensive effort made to understand how to effectively use the various diagnostic technologies to establish the condition of medium voltage underground cable circuits. These circuits make up an extensive portion of the electric delivery infrastructure in the United States. Much of this infrastructure is old and experiencing unacceptable failure rates. By deploying efficient diagnostic testing programs, electric utilities can replace or repair circuits that are about to fail, providing an optimal approach to improving electric system reliability. This is an intrinsically complex topic. Underground cable systems are not homogeneous. Cable circuits often contain multiple branches with different cable designs and a range of insulation materials. In addition, each insulation material ages differently as a function of time, temperature and operating environment. To complicate matters further, there are a wide variety of diagnostic technologies available for assessing the condition of cable circuits with a diversity of claims about the effectiveness of each approach. As a result, the benefits of deploying cable diagnostic testing programs have been difficult to establish, leading many utilities to avoid the their use altogether. This project was designed to help address these issues. The information provided is the result of a collaborative effort between Georgia Tech NEETRAC staff, Georgia Tech academic faculty, electric utility industry participants, as well as cable system diagnostic testing service providers and test equipment providers. Report topics include: •How cable systems age and fail, •The various technologies available for detecting potential failure sites, •The advantages and disadvantages of different diagnostic technologies, •Different approaches for utilities to employ cable system diagnostics. The primary deliverables of this project are this report, a Cable Diagnostic Handbook (a subset of this report) and an online

  12. The insulation coordination and surge arrester design for HTS cable system in Icheon substation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hansang, E-mail: Hansang80@korea.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yoon, Dong-Hee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Lee, Seung-Ryul [Korea Electrotechnology Research Institute, Naeson-dong, Uiwang-si, Gyeonggi-do 437-080 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-01-15

    Highlights: ► It is necessary to study lightning response of the HTS cable. ► The analytic model has been developed for the HTS cable in the Icheon substation. ► Well-designed surge arrester has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.

  13. Discussion of superconducting and room-temperature high-intensity ion linacs

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1996-01-01

    The point of view taken in this discussion is that the basic technology base exists in all essential respects for both superconducting or room-temperature rf linac accelerators and associated power and control systems, and thus a project can make a choice between these technologies on overall system considerations. These include performance, cost, availability, flexibility, and upgradability. Large high-intensity neutron source proposals involving light-ion rf linacs in three categories are reviewed in this context. The categories arc cw linacs to high (∼1 GeV) and low (∼40 MeV) output energy, and pulsed linacs to energy ∼1 GeV

  14. High temperature superconducting Josephson transmission lines for pulse and step sharpening

    International Nuclear Information System (INIS)

    Martens, J.S.; Wendt, J.R.; Hietala, V.M.; Ginley, D.S.; Ashby, C.I.H.; Plut, T.A.; Vawter, G.A.; Tigges, C.P.; Siegal, M.P.; Hou, S.Y.; Phillips, J.M.; Hohenwarter, G.K.G.

    1992-01-01

    An increasing number of high speed digital and other circuit applications require very narrow impulses or rapid pulse edge transitions. Shock wave transmission lines using series or shunt Josephson junctions are one way to generate these signals. Using two different high temperature superconducting Josephson junction processes (step-edge and electron beam defined nanobridges), such transmission lines have been constructed and tested at 77 K. Shock wave lines with approximately 60 YBaCuO nanobridges, have generated steps with fall times of about 10 ps. With step-edge junctions (with higher figures of merit but lower uniformity), step transition times have been reduced to an estimated 1 ps

  15. Temperature dependence of the experimental penetration depth of superconducting thin films

    International Nuclear Information System (INIS)

    Fink, H.J.; Gruenfeld, V.; Pastawski, H.

    1982-01-01

    Experimental magnetic field penetration depths delta(t,d,H) of the stable and superheated Meissner state were calculated as a function of temperature for various applied magnetic fields and various film thicknesses for two cases: (1) lambda(t)/d<< kappa→infinity and (2) kappa< or approx. =2lambda(t)/d (lambda is the Ginzburg-Landau penetration depth, d is the film thickness, kappa is the GL parameter). The results of the first case should be a useful tool for obtaining lambda(0) of amorphous superconducting thin films

  16. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    OpenAIRE

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-01-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about one order of magnitude better than with earlier methods and surface resistance resolution of ~ 1 micro-Ohm at 3.3 GHz. A signal-to-noise ratio of about 10 dB was...

  17. A Pole Pair Segment of a 2-MW High-Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2017-01-01

    A 2-MW high-temperature superconducting (HTS) generator with 24 pole pairs has been designed for the wind turbine application. In order to identify potential challenges and obtain practical knowledge prior to production, a full-size stationary experimental setup, which is one pole pair segment...... and the setup in terms of the flux density, the operating condition of the HTS winding, and the force-generation capability. Finite element (FE) software MagNet is used to carry out numerical simulations. The findings show that the HTS winding in the setup is a good surrogate for these that would be used...

  18. A Pole Pair Segment of a 2 MW High Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2016-01-01

    A 2 MW high temperature superconducting (HTS) generator with 24 pole pairs has been designed for the wind turbine application. In order to identify potential challenges and obtain practical knowledge prior to production, a fullsize stationary experimental set-up, which is one pole pair segment...... generator and the set-up in terms of the flux density, the operating condition of the HTS winding, and the force-generation capability. Finite element (FE) software MagNet is used to carry out numerical simulations. The findings show that the HTS winding in the set-up is a good surrogate...

  19. Vertical Vibration Characteristics of a High-Temperature Superconducting Maglev Vehicle System

    Science.gov (United States)

    Jiang, Jing; Li, Ke Cai; Zhao, Li Feng; Ma, Jia Qing; Zhang, Yong; Zhao, Yong

    2013-06-01

    The vertical vibration characteristics of a high-temperature superconducting maglev vehicle system are investigated experimentally. The displacement variations of the maglev vehicle system are measured with different external excitation frequency, in the case of a certain levitation gap. When the external vibration frequency is low, the amplitude variations of the response curve are small. With the increase of the vibration frequency, chaos status can be found. The resonance frequencies with difference levitation gap are also investigated, while the external excitation frequency range is 0-100 Hz. Along with the different levitation gap, resonance frequency is also different. There almost is a linear relationship between the levitation gap and the resonance frequency.

  20. Transient characteristics of current lead losses for the large scale high-temperature superconducting rotating machine

    International Nuclear Information System (INIS)

    Le, T. D.; Kim, J. H.; Park, S. I.; Kim, D. J.; Kim, H. M.; Lee, H. G.; Yoon, Y. S.; Jo, Y. S.; Yoon, K. Y.

    2014-01-01

    To minimize most heat loss of current lead for high-temperature superconducting (HTS) rotating machine, the choice of conductor properties and lead geometry - such as length, cross section, and cooling surface area - are one of the various significant factors must be selected. Therefore, an optimal lead for large scale of HTS rotating machine has presented before. Not let up with these trends, this paper continues to improve of diminishing heat loss for HTS part according to different model. It also determines the simplification conditions for an evaluation of the main flux flow loss and eddy current loss transient characteristics during charging and discharging period.

  1. Influence of anisotropy effect and internal stresses upon the superconductive critical temperature of plastically deformed tin

    International Nuclear Information System (INIS)

    Wagner, D.; Stangler, F.

    1976-01-01

    The influence of plastic deformation on the superconductive critical temperature of tin single crystals has been investigated experimentally. It was shown by measurements that the lattice defects produced by plastic deformation lead to an anisotropy effect (according to the theory of Markowitz and Kadanoff), as do impurities in alloyed material. The decrease in T/sub c/ due to this effect can be measured, however, only with samples of certain special orientations. Samples with other orientations show an increase in T/sub c/, which can be explained by the assumption of internal stresses from dislocation pileups. A model is discussed which accounts for the measured rise in T/sub c/

  2. Experimental results of current distribution in Rutherford-type LHC cables

    CERN Document Server

    Verweij, A P

    2000-01-01

    Current distribution among the wires of multi-strand superconducting cables is an important item for accelerator magnets. A non-uniform distribution could cause additional field distortions in the magnet bore and can as well be one of the reasons of premature quenching. Since two years electrical measurements on superconducting Rutherford-type cables are performed at CERN as part of the reception tests for the Large Hadron Collider (LHC). Cable samples of 2.4 m length are tested at currents up to 32 kA, temperatures around 1.9 and 4.3 K, and fields up to 10 T, applied perpendicularly as well as parallel to the broad face of the cable. Last year, an array of 24 Hall probes was installed in the test set-up in order to measure the self-field of the cable samples along one cable pitch. Each of the probes measures the local field generated by the current in the strands close by, and the results of the all probes reflect therefore the distribution of the strand currents. Experiments are done varying the applied fie...

  3. Improving superconducting properties of YBCO high temperature superconductor by Graphene Oxide doping

    Energy Technology Data Exchange (ETDEWEB)

    Dadras, S., E-mail: dadras@alzahra.ac.ir; Dehghani, S.; Davoudiniya, M.; Falahati, S.

    2017-06-01

    In this research, we report the synthesis and characterization of YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) high temperature superconductor prepared by sol-gel method and doped with Graphene Oxide (GO) in different weight percentages, 0, 0.1, 0.7 and 1 % wt. The x-ray diffraction (XRD) analysis confirms the formation of orthorhombic phase of superconductivity for all the prepared samples. We found that GO doping reduces the crystalline size of the samples. We evaluated the effects of GO doping on the normal state resistivity (ρ), superconducting transition temperature (T{sub c}) and critical current density (J{sub c}). The results show that the GO doping has a positive effect on these properties. Also, the highest J{sub c} is obtained for the 0.7 %wt GO doped YBCO compound that its critical current density is about 15 times more than the J{sub c} of pure one in 0.4 T magnetic field. The scanning electron microscope (SEM) analysis shows that there are better connections between the grains of GO doped samples. - Highlights: • Graphene Oxide doping increased the YBCO critical current density. • Graphene Oxide creates a better connection between the YBCO grains. • The normal resistivity of samples were decreased by GO doping to YBCO compounds. • Graphene Oxide doping has a positive effect on the critical transition temperature.

  4. Calorimeters for Precision Power Dissipation Measurements on Controlled-Temperature Superconducting Radiofrequency Samples

    International Nuclear Information System (INIS)

    Xiao, Binping P.; Kelley, Michael J.; Reece, Charles E.; Phillips, H. L.

    2012-01-01

    Two calorimeters, with stainless steel and Cu as the thermal path material for high precision and high power versions, respectively, have been designed and commissioned for the surface impedance characterization (SIC) system at Jefferson Lab to provide low temperature control and measurement for CW power up to 22 W on a 5 cm dia. disk sample which is thermally isolated from the RF portion of the system. A power compensation method has been developed to measure the RF induced power on the sample. Simulation and experimental results show that with these two calorimeters, the whole thermal range of interest for superconducting radiofrequency (SRF) materials has been covered. The power measurement error in the interested power range is within 1.2% and 2.7% for the high precision and high power versions, respectively. Temperature distributions on the sample surface for both versions have been simulated and the accuracy of sample temperature measurements have been analysed. Both versions have the ability to accept bulk superconductors and thin film superconducting samples with a variety of substrate materials such as Al, Al 2 O 3 , Cu, MgO, Nb and Si

  5. Effect of low temperature reactor irradiation on organic insulators in superconducting magnets, (4)

    International Nuclear Information System (INIS)

    Kato, Teruo; Takamura, Saburo

    1983-01-01

    In order to study effects of irradiation at low temperature on insulating materials of superconducting magnets, flexural and impact tests are carried out at 4.2K without warmup after low temperature irradiation for several fiber reinforced plastics. The used materials are glass fiber reinforced epoxies and polyimide, and carbon fiber reinforced epoxies. After irradiation of 1.1 X 10 9 rad, the reduction in flexural strength of G-10 CR is about 70% and that of G-11 CR about 25%. No change are observed in strength of glass fiber reinforced polyimide by low temperature irradiation. Other kinds of glass fiber reinforced epoxies show a reduction in strength but the flexural strength of carbon fiber reinforced epoxies increases a small by irradiation. Irradiation effect of these materials on impact value is similar to that on flexural strength. (author)

  6. Development of a novel method for the exploration of the thermal response of superfluid helium cooled superconducting cables to pulse heat loads

    NARCIS (Netherlands)

    Winkler, Tiemo; Koettig, T.; van Weelderen, R.; Bremer, J.; ter Brake, Hermanus J.M.

    2015-01-01

    Management of transient heat deposition in superconducting magnets and its extraction from the aforementioned is becoming increasingly important to bring high energy particle accelerator performance to higher beam energies and intensities. Precise knowledge of transient heat deposition phenomena in

  7. Interplay between magnetism and superconductivity in iron based high temperature superconductors

    International Nuclear Information System (INIS)

    Price, Stephen

    2013-01-01

    In this thesis, magnetic properties of a series of different Fe-based superconducting materials have been studied by means of neutron scattering techniques. Magnetic correlations in underdoped Ba(Fe 0.95 Co 0.05 ) 2 As 2 have been investigated for three phases of the phase diagram. It was possible to detect the spin gap and spin resonance signal, two features of the particle hole excitation spectrum at Q=(0.5,0.5,0), characteristic for the superconducting phase. The spin wave excitations present in the ordered phase have been analyzed quantitatively in terms of a linear spin wave model, whereas a spin diffusion model was applied to the collective excitations of the paramagnetic phase. However, it was found that both models can be applied to excitations in all three phases. In optimally doped CaFe 0.88 Co 0.12 AsF, a spin resonance signal was detected as part of the spin excitation spectrum at Q=(0.5,0.5,0). The observation of the spin resonance signal supports the s ± symmetry of the superconducting gap function. In the undoped CaFeAsF compound three dimensional spin wave like excitations of the static Fe-SDW order have been observed at Q AFM =(0.5,0.5,0.5), for temperatures below T N . Above T N and for energies below 20 meV, the spin wave like excitations are replaced by short range two dimensional paramagnetic excitations, which persist up to 270 K. In superconducting FeSe 0.5 Te 0.5 polarized neutron scattering investigations revealed the magnetic nature of the spin resonance signal and the excitation spectrum at Q=(0.5,0.5,0) up to 30 meV. The whole excitation spectrum including the spin resonance signal consists of an isotropic distribution of spin excitations with magnetic moments fluctuating in the ab-plane and perpendicular to the ab-plane, χ ab ''(Q,ω)∼χ c ''(Q,ω). In Eu(Fe 1-x Co x ) 2 As 2 and EuFe 2 (As 1-x P x ) 2 the effect of impurity doping on the static order of the magnetic lattice of the Eu 2+ -moments has been studied by means of

  8. Electronic properties of rocksalt copper monoxide: a proxy structure for high temperature superconductivity

    International Nuclear Information System (INIS)

    Grant, Paul M

    2008-01-01

    Cubic rocksalt copper monoxide, in contrast to its lighter transition metal neighbours, does not exist in nature nor has it yet been successfully synthesized. Nonetheless, its numerical study as a structurally much simpler proxy for the layered cuprate perovskites may prove useful in probing the source of high temperature superconductivity in the latter family of compounds. Here we report such a study employing density functional theory (DFT) abetted by the local density approximation including cation on-site Hubbard interactions (LDA+U). Rather surprisingly, we find that unlike oxides of the light transition metals, cubic CuO remains metallic for all physically reasonable values of U and does not result in a Mott- Hubbard induced charge transfer insulator as might be expected, and, in fact, displays a Fermi surface with clearly nesting tendencies. Preliminary calculations of the net dimensionless electron-phonon coupling constant, λ, yield values in the range 0.6 - 0.7 similar to those found for the superconducting fullerenes and magnesium diboride. On the other hand, we do find as we gradually introduce a tetragonal distortion away from pure cubic symmetry that a charge- transfer insulator emerges for values of U ∼ 5 eV and c/a ∼ 1.3 in agreement with recent experimental data on forced-epitaxial growth of 2-4 ML thick films of tetragonal rocksalt CuO. We preliminarily conclude from these computational studies that high temperature superconductivity in the copper oxide compounds is at least initially mediated by Jahn-Teller driven electron-phonon coupling as originally suggested by Bednorz and Mueller.

  9. The tests at Saclay of the stellarator W7X superconducting magnets

    International Nuclear Information System (INIS)

    Jacquemet, M.

    2000-05-01

    The tests on the superconducting magnets should allow to check at ambient or cryogenic temperature, the mechanical behaviour and the lack of leak from the conductor, the correct configuration of the cable in the pipe, the electric insulation, the magnet behaviour during a transition, the buckling and mechanical constraints on the whole. (N.C.)

  10. Nexan receives two CMS Awards of the Year 2002 for its work in superconductivity

    CERN Multimedia

    2002-01-01

    Nexans has received one Crystal and one Gold CMS award for its contribution to the Compact Muon Solenoid Detector project. The CMS detector is designed to study the fundamental constituents of matter. The prizes recompense the excellent quality of Nexans' service in the supply of the necessary low-temperature superconducting cables sheathed in extruded aluminium.

  11. Power supply system for the superconducting outsert of the CHMFL hybrid magnet

    Science.gov (United States)

    Fang, Z.; Zhu, J.; Chen, W.; Jiang, D.; Huang, P.; Chen, Z.; Tan, Y.; Kuang, G.

    2017-12-01

    The construction of a new hybrid magnet, consisting of a 11 T superconducting outsert and a 34 T resistive insert magnet, has been finished at the Chinese High Magnetic Field Laboratory (CHMFL) in Hefei. With a room temperature bore of 800 mm in diameter, the hybrid magnet superconducting outsert is composed of four separate Nb3Sn-based Cable-in-Conduit Conductor (CICC) coils electrically connected in series and powered by a single power supply system. The power supply system for the superconducting outsert consists of a 16 kA DC power supply, a quench protection system, a pair of 16 kA High Temperature Superconducting (HTS) current leads, and two Low Temperature Superconducting bus-lines. The design and manufacturing of the power supply system have been completed at the CHMFL. This paper describes the design features of the power supply system as well as the current fabrication condition of its main components.

  12. Elucidation of the origins of transport behaviour and quantum oscillations in high temperature superconducting cuprates

    International Nuclear Information System (INIS)

    Wilson, John A

    2009-01-01

    A detailed exposition is given of recent transport and 'quantum oscillation' results from high temperature superconducting (HTSC) systems covering the full carrier range from overdoped to underdoped material. This now very extensive and high quality data set is here interpreted within the framework developed by the author of local pairs and boson-fermion resonance, arising in the context of negative- U behaviour within an inhomogeneous electronic environment. The strong inhomogeneity comes with the mixed-valence condition of these materials, which when underdoped lie in close proximity to the Mott-Anderson transition. The observed intense scattering is presented as resulting from pair formation and from electron-boson collisions in the resonant crossover circumstance. The high level of scattering carries the systems to incoherence in the pseudogapped state, p c (= 0.183). In a high magnetic field the striped partition of the inhomogeneous charge distribution becomes much strengthened and regularized. Magnetization and resistance oscillations, of period dictated by the favoured positioning of the fluxon array within the real space environment of the diagonal 2D charge striping array, are demonstrated to be responsible for the recently reported behaviour hitherto widely attributed to the quantum oscillation response of a much more standard Fermi liquid condition. A detailed analysis embracing all the experimental data serves to reveal that in the given conditions of very high field, low temperature, 2D-striped, underdoped, d-wave superconducting, HTSC material the flux quantum becomes doubled to h/e.

  13. Superconductivity revisited

    CERN Document Server

    Dougherty, Ralph

    2013-01-01

    While the macroscopic phenomenon of superconductivity is well known and in practical use worldwide in many industries, including MRIs in medical diagnostics, the current theoretical paradigm for superconductivity (BCS theory) suffers from a number of limitations, not the least of which is an adequate explanation of high temperature superconductivity. This book reviews the current theory and its limitations and suggests new ideas and approaches in addressing these issues. The central objective of the book is to develop a new, coherent, understandable theory of superconductivity directly based on molecular quantum mechanics.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bhunia, Uttam, E-mail: ubhunia@vecc.gov.in; Saha, Subimal; Chakrabarti, Alok

    2014-10-15

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

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

    International Nuclear Information System (INIS)

    Bhunia, Uttam; Saha, Subimal; Chakrabarti, Alok

    2014-01-01

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

  16. High-field superconducting nested coil magnet

    Science.gov (United States)

    Laverick, C.; Lobell, G. M.

    1970-01-01

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

  17. Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Milos Nesladek, Jiri J. Mares, Dominique Tromson, Christine Mer, Philippe Bergonzo, Pavel Hubik and Jozef Kristofik

    2006-01-01

    Full Text Available In this work, we report on superconductivity (SC found in thin B-doped nanocrystalline diamond films, prepared by the PE-CVD technique. The thickness of the films varies from about 100 to 400 nm, the films are grown on low-alkaline glass at substrate temperatures of about 500–700 °C. The SIMS measurements show that films can be heavily doped with boron in concentrations in the range of 3×1021 cm−3. The Raman spectra show Fano resonances, confirming the substitutional B-incorporation. The low temperature magnetotransport measurements reveal a positive magnetoresistance. The SC transition is observed at about Tc=1.66 K. A simple theory exploiting the concept of weak localization accounting for this transition is proposed.

  18. Superconductors with low critical temperature for electro-magnets

    International Nuclear Information System (INIS)

    Devred, A.

    2002-07-01

    Among the superconductors with low critical temperature that are used to build magnets, NbTi has reached a development state that allows a massive production for big equipment of physics and an industrial production in the domain of medicine imaging. The material that might challenge the supremacy of NbTi is Nb 3 Sn but some technical difficulties have yet to be overcome. This report begins with a review of the different industrial processes used to produce superconducting wires based on the NbTi and Nb 3 Sn materials. The transition from the superconducting state to the resistive normal state is described for both materials, the magnetizing of multi-wire superconducting cables is also presented. The author details the different patterns of wires in cables and proposes a formulary that allows the determination, in some simple cases,of energy losses that are generated in a superconducting cable by a variable magnetic field. (A.C.)

  19. Nonempirical Calculation of Superconducting Transition Temperatures in Light-Element Superconductors.

    Science.gov (United States)

    Arita, Ryotaro; Koretsune, Takashi; Sakai, Shiro; Akashi, Ryosuke; Nomura, Yusuke; Sano, Wataru

    2017-07-01

    Recent progress in the fully nonempirical calculation of the superconducting transition temperature (T c ) is reviewed. Especially, this study focuses on three representative light-element high-T c superconductors, i.e., elemental Li, sulfur hydrides, and alkali-doped fullerides. Here, it is discussed how crucial it is to develop the beyond Migdal-Eliashberg (ME) methods. For Li, a scheme of superconducting density functional theory for the plasmon mechanism is formulated and it is found that T c is dramatically enhanced by considering the frequency dependence of the screened Coulomb interaction. For sulfur hydrides, it is essential to go beyond not only the static approximation for the screened Coulomb interaction, but also the constant density-of-states approximation for electrons, the harmonic approximation for phonons, and the Migdal approximation for the electron-phonon vertex, all of which have been employed in the standard ME calculation. It is also shown that the feedback effect in the self-consistent calculation of the self-energy and the zero point motion considerably affect the calculation of T c . For alkali-doped fullerides, the interplay between electron-phonon coupling and electron correlations becomes more nontrivial. It has been demonstrated that the combination of density functional theory and dynamical mean field theory with the ab initio downfolding scheme for electron-phonon coupled systems works successfully. This study not only reproduces the experimental phase diagram but also obtains a unified view of the high-T c superconductivity and the Mott-Hubbard transition in the fullerides. The results for these high-T c superconductors will provide a firm ground for future materials design of new superconductors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. On the mechanism of high-temperature superconductivity in hydrogen sulfide at 200 GPa: Transition into superconducting anti-adiabatic state in coupling to H-vibrations

    Directory of Open Access Journals (Sweden)

    Pavol Baňacký

    Full Text Available It has been shown that the adiabatic electronic structure of the superconducting phase of sulfur hydride at 200 GPa is unstable toward the vibration motion of H-atoms. A theoretical study indicates that in coupling to H-vibrations, the system undergoes a transition from adiabatic into a stabilized anti-adiabatic multi-gap superconducting state at a temperature that can reach 203 K. Keywords: Superconductivity of sulfur hydride, Electron–phonon coupling in superconductors, Anti-adiabatic theory of superconductivity

  1. Space charge build-up in XLPE-cable with temperature gradient

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Hjerrild, Jesper

    2000-01-01

    and temperatures were applied in the 20 - 80°C range with gradients across the insulation of up to 15°C. In this paper, the observed charge phenomena in the bulk and at the interfaces are related to the external conditions, in particular to the temperature gradient. The measured space charge distributions...

  2. Critical Current and Stability of MgB$_2$ Twisted-Pair DC Cable Assembly Cooled by Helium Gas

    CERN Document Server

    AUTHOR|(CDS)2069632; Ballarino, Amalia; Yang, Yifeng; Young, Edward Andrew; Bailey, Wendell; Beduz, Carlo

    2013-01-01

    Long length superconducting cables/bus-bars cooled by cryogenic gases such as helium operating over a wider temperature range are a challenging but exciting technical development prospects, with applications ranging from super-grid transmission to future accelerator systems. With limited existing knowledge and previous experiences, the cryogenic stability and quench protection of such cables are crucial research areas because the heat transfer is reduced and temperature gradient increased compared to liquid cryogen cooled cables. V-I measurements on gas-cooled cables over a significant length are an essential step towards a fully cryogenic stabilized cable with adequate quench protection. Prototype twisted-pair cables using high-temperature superconductor and MgB2 tapes have been under development at CERN within the FP7 EuCARD project. Experimental studies have been carried out on a 5-m-long multiple MgB$_2$ cable assembly at different temperatures between 20 and 30 K. The subcables of the assembly showed sim...

  3. Uniaxial strain orientation dependence of superconducting transition temperature (Tc) and critical superconducting pressure (Pc) in β-(BDA-TTP)2I3.

    Science.gov (United States)

    Kikuchi, Koichi; Isono, Takayuki; Kojima, Masayuki; Yoshimoto, Haruo; Kodama, Takeshi; Fujita, Wataru; Yokogawa, Keiichi; Yoshino, Harukazu; Murata, Keizo; Kaihatsu, Takayuki; Akutsu, Hiroki; Yamada, Jun-ichi

    2011-12-14

    Dependence of the superconducting transition temperature (T(c)) and critial superconducting pressure (P(c)) of the pressure-induced superconductor β-(BDA-TTP)(2)I(3) [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] on the orientation of uniaxial strain has been investigated. On the basis of the overlap between the upper and lower bands in the energy dispersion curve, the pressure orientation is thought to change the half-filled band to the quarter-filled one. The observed variations in T(c) and P(c) are explained by considering the degree of application of the pressure and the degree of contribution of the effective electronic correlation at uniaxial strains with different orientations parallel to the conducting donor layer. © 2011 American Chemical Society

  4. Dynamic temperature estimation and real time emergency rating of transmission cables

    DEFF Research Database (Denmark)

    Olsen, R. S.; Holboll, J.; Gudmundsdottir, Unnur Stella

    2012-01-01

    enables real time emergency ratings, such that the transmission system operator can make well-founded decisions during faults. Hereunder is included the capability of producing high resolution loadability vs. time schedules within few minutes, such that the TSO can safely control the system.......). It is found that the calculated temperature estimations are fairly accurate — within 1.5oC of the finite element method (FEM) simulation to which it is compared — both when looking at the temperature profile (time dependent) and the temperature distribution (geometric dependent). The methodology moreover...

  5. Composite conductor containing superconductive wires

    Energy Technology Data Exchange (ETDEWEB)

    Larson, W.L.; Wong, J.

    1974-03-26

    A superconductor cable substitute made by coworking multiple rods of superconductive niobium--titanium or niobium--zirconium alloy with a common copper matrix to extend the copper and rods to form a final elongated product which has superconductive wires distributed in a reduced cross-section copper conductor with a complete metallurgical bond between the normal-conductive copper and the superconductor wires contained therein is described. The superconductor cable can be in the form of a tube.

  6. Aspects of the SO(5) symmetry and the problem of high temperature superconductivity

    Science.gov (United States)

    Demler, Eugene A.

    This dissertation reviews several aspects of the SO(5) theory, that unifies superconductivity and antiferromagnetism and that has recently been suggested in connection with the problem of high temperature superconductivity. Microscopic analysis of the pi operators (generators of the SO(5) symmetry) is given for the t-J and Hubbard models and it is argued that pseudo-Goldstone bosons that correspond to these operators produce resonant peaks observed in neutron scattering experiments on YBCO. Microscopic models with exact SO(5) symmetry are considered and the nature of the AF/SC transition in these systems is discussed. Analysis of a non-Abelian SU(2) holonomy of the SO (5) spinor states is presented, the SO(5) Berry's phase is shown to be related to the second Hopf map and described by a Yang monopole at the degeneracy point. These results are used to show that fermionic excitations in models with exact SO(5) symmetry may be described as four component Dirac fermions coupled to SU(2) gauge fields in 2 + 1 dimensions. Finally some experimental tests of the SO(5) model are suggested.

  7. Contrasting dynamic spin susceptibility models and their relation to high-temperature superconductivity

    International Nuclear Information System (INIS)

    Schuettler, H.; Norman, M.R.

    1996-01-01

    We compare the normal-state resistivities ρ and the critical temperatures T c for superconducting d x 2 -y 2 pairing due to antiferromagnetic (AF) spin fluctuation exchange in the context of two phenomenological dynamical spin susceptibility models for the cuprate high-T c materials, one based on fits to NMR data on Y-Ba-Cu-O (YBCO) proposed by Millis, Monien, and Pines (MMP) and Monthoux and Pines (MP), and the other based on fits to neutron scattering data on YBCO proposed by Radtke, Ullah, Levin, and Norman (RULN). Assuming comparable electronic bandwidths and resistivities in both models, we show that the RULN model gives a much lower d-wave T c (approx-lt 20 K) than the MMP model (with T c ∼100 K). We demonstrate that these profound differences in the T c close-quote s arise from fundamental differences in the spectral weight distributions of the two model susceptibilities at high (>100 meV) frequencies and are not primarily caused by differences in the calculational techniques employed by MP and RULN. Further neutron scattering experiments, to explore the spectral weight distribution at all wave vectors over a sufficiently large excitation energy range, will thus be of crucial importance to resolve the question whether AF spin fluctuation exchange can provide a viable mechanism to account for high-T c superconductivity. Limitations of the Migdal-Eliashberg approach in such models will be discussed. copyright 1996 The American Physical Society

  8. High pressure driven superconducting critical temperature tuning in Sb{sub 2}Se{sub 3} topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Anversa, Jonas [Departamento de Física, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Escola de Engenharia Civil, Faculdade Meridional, 99070-220, Passo Fundo, RS (Brazil); Chakraborty, Sudip, E-mail: sudiphys@gmail.com [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala (Sweden); Piquini, Paulo [Departamento de Física, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS (Brazil); Ahuja, Rajeev [Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala (Sweden); Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), S-100 44 Stockholm (Sweden)

    2016-05-23

    In this letter, we are reporting the change of superconducting critical temperature in Sb{sub 2}Se{sub 3} topological insulator under the influence of an external hydrostatic pressure based on first principles electronic structure calculations coupled with Migdal–Eliashberg model. Experimentally, it was shown previously that Sb{sub 2}Se{sub 3} was undergoing through a transition to a superconducting phase when subjected to a compressive pressure. Our results show that the critical temperature increases up to 6.15 K under the pressure unto 40 GPa and, subsequently, drops down until 70 GPa. Throughout this pressure range, the system is preserving the initial Pnma symmetry without any structural transformation. Our results suggest that the possible relevant mechanism behind the superconductivity in Sb{sub 2}Se{sub 3} is primarily the electron–phonon coupling.

  9. Superconducting materials

    International Nuclear Information System (INIS)

    Kormann, R.; Loiseau, R.; Marcilhac, B.

    1989-01-01

    The invention concerns superconducting ceramics containing essentially barium, calcium and copper fluorinated oxides with close offset and onset temperatures around 97 K and 100 K and containing neither Y nor rare earth [fr

  10. Static and Dynamic Mechanical Properties of Long-Span Cable-Stayed Bridges Using CFRP Cables

    Directory of Open Access Journals (Sweden)

    Mei Kuihua

    2017-01-01

    Full Text Available The elastic modulus and deadweight of carbon fiber-reinforced polymer (CFRP cables are different from those of steel cables. Thus, the static and dynamic behaviors of cable-stayed bridges using CFRP cables are different from those of cable-stayed bridges using steel cables. The static and dynamic performances of the two kinds of bridges with a span of 1000 m were studied using the numerical method. The effects of geometric nonlinear factors on static performance of the two kinds of cable-stayed bridges were analyzed. The live load effects and temperature effects of the two cable-stayed bridges were also analyzed. The influences of design parameters, including different structural systems, the numbers of auxiliary piers, and the space arrangement types of cable, on the dynamic performance of the cable-stayed bridge using CFRP cables were also studied. Results demonstrate that sag effect of the CFRP cable is much smaller than that of steel cable. The temperature effects of CFRP cable-stayed bridge are less than those of steel cable-stayed bridge. The vertical bending natural vibration frequency of the CFRP cable-stayed bridge is generally lower than that of steel cable-stayed bridge, whereas the torsional natural vibration frequency of the former is higher than that of the latter.

  11. The present status of the high temperature superconducting Maglev vehicle in China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J S; Wang, S Y; Zeng, Y W; Deng, C Y; Ren, Z Y; Wang, X R; Song, H H; Wang, X Z; Zheng, J; Zhao, Y [Superconductivity R and D Center, Mail Stop: 152, Southwest Jiaotong University, Chengdu 610031, Sichuan (China)

    2005-02-01

    Since the first successful running of the people-carrying high temperature superconducting (HTS) Maglev test vehicle on 31 December 2000, about 27,000 people have taken it, and the accumulated running distance is about 400 km. The levitation force of the onboard HTS equipment is measured periodically, and new experimental results measured on 5 March 2003 show that the performance of the onboard HTS Maglev equipment is almost the same as that of two years ago. Experimental results indicate that the long-term stability of the HTS Maglev vehicle is good. This further proves the feasibility of the HTS Maglev vehicle for practical transportation. It is worth mentioning that all the results are measured at a low speed; however, investigations of the dynamic performance of the HTS Maglev vehicle at high speed are necessary for practical application. Research on the dynamic performance of the HTS Maglev vehicle is ongoing.

  12. The present status of the high temperature superconducting Maglev vehicle in China

    International Nuclear Information System (INIS)

    Wang, J S; Wang, S Y; Zeng, Y W; Deng, C Y; Ren, Z Y; Wang, X R; Song, H H; Wang, X Z; Zheng, J; Zhao, Y

    2005-01-01

    Since the first successful running of the people-carrying high temperature superconducting (HTS) Maglev test vehicle on 31 December 2000, about 27,000 people have taken it, and the accumulated running distance is about 400 km. The levitation force of the onboard HTS equipment is measured periodically, and new experimental results measured on 5 March 2003 show that the performance of the onboard HTS Maglev equipment is almost the same as that of two years ago. Experimental results indicate that the long-term stability of the HTS Maglev vehicle is good. This further proves the feasibility of the HTS Maglev vehicle for practical transportation. It is worth mentioning that all the results are measured at a low speed; however, investigations of the dynamic performance of the HTS Maglev vehicle at high speed are necessary for practical application. Research on the dynamic performance of the HTS Maglev vehicle is ongoing

  13. Studies on the levitation height decay of the high temperature superconducting Maglev vehicle

    International Nuclear Information System (INIS)

    Deng, Z.G.; Zheng, J.; Zhang, J.; Wang, J.S.; Wang, S.Y.; Zhang, Y.; Liu, L.

    2007-01-01

    The levitation height decay was found in the high temperature superconducting (HTS) Maglev test vehicle system during man-loading running. Experimental results show that the no-load levitating system would drift to a new equilibrium position by the external loaded history, but the new equilibrium position will almost not drift by the second-round same loaded history. A new method is proposed to improve the stability of the HTS Maglev vehicle, that is, a pre-load was applied to the HTS Maglev vehicle before running. The impulse responses are performed on the HTS Maglev vehicle before the pre-load and after the pre-load. The results show that the pre-load method is considerably effective to improve the stiffness and damping coefficient of the HTS Maglev vehicle. Moreover, it helps to suppress the levitation height decay and enhance the stability of the HTS Maglev vehicle in practical operation

  14. Dynamic motion modes of high temperature superconducting maglev on a 45-m long ring test line

    Science.gov (United States)

    Lei, W. Y.; Qian, N.; Zheng, J.; Jin, L. W.; Zhang, Y.; Deng, Z. G.

    2017-10-01

    With the development of high temperature superconducting (HTS) maglev, studies on the running stability have become more and more significant to ensure the operation safety. An experimental HTS maglev vehicle was tested on a 45-m long ring test line under the speed from 4 km/h to 20 km/h. The lateral and vertical acceleration signals of each cryostat were collected by tri-axis accelerometers in real time. By analyzing the phase relationship of acceleration signals on the four cryostats, several typical motion modes of the HTS maglev vehicle, including lateral, yaw, pitch and heave motions were observed. This experimental finding is important for the next improvement of the HTS maglev system.

  15. Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Liu, Dong; Polinder, Henk

    2016-01-01

    Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen...... at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator’s equivalent circuits is developed to simulate short circuit faults. Afterwards, the model is used to study the transient performance of a 10 MW HTS wind turbine generator under four different short...... that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The results presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator....

  16. Short Circuits of a 10-MW High-Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Liu, Dong; Polinder, Henk

    2017-01-01

    Direct Drive high-temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits take...... place at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator's equivalent circuits is developed to simulate short-circuit faults. Afterward, the model is used to study the transient performance of a 10-MW HTS wind turbine generator under four...... show that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The findings presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator....

  17. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

    Science.gov (United States)

    Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ˜1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  18. Application of high-temperature superconducting permanent magnets to synchrotron radiation sources

    Directory of Open Access Journals (Sweden)

    Takashi Tanaka

    2004-09-01

    Full Text Available A simple scheme for field enhancement in synchrotron radiation sources such as undulators and wigglers is proposed, which is based on the fundamental nature of the superconducting loop where the magnetic flux is preserved. A superconductor ring placed to enclose the magnetic pole works as a kind of permanent magnet. The magnetization is performed by electromagnetic induction brought by the opening movement of the magnetic gap. Since neither additional external power supplies nor current leads are necessary, high-temperature bulk superconductors can easily be implemented in this scheme. Calculations to check the effectiveness of the new concept show that the critical current density of the superconductor is crucial to the performance of the synchrotron radiation sources based on this concept. Experiments were performed to verify the principle of the proposed scheme, which gave promising results to strongly support it.

  19. The design of high-Tc superconductors - Room-temperature superconductivity?

    International Nuclear Information System (INIS)

    Tallon, J.L.; Storey, J.G.; Mallett, B.

    2012-01-01

    This year is the centennial of the discovery of superconductivity and the 25th anniversary of the discovery of high-T c superconductors (HTS). Though we still do not fully understand how HTS work, the basic rules of design can be determined from studying their systematics. We know what to do to increase T c and, more importantly, what to do to increase critical current density J c . This in turn lays down a challenge for the chemist. Can the ideal design be synthesized? More importantly, what are the limits? Can one make a room-temperature superconductor? In fact fluctuations place strict constraints on this objective and provide important guidelines for the design of the ideal superconductor.

  20. Design study of high-temperature superconducting generators for wind power systems

    Energy Technology Data Exchange (ETDEWEB)

    Maki, N [Technova Inc. 13th Fl. Imperial Hotel Tower, 1-chome, Chiyoda-ku, Tokyo 100-0011 (Japan)], E-mail: naokmaki@technova.co.jp

    2008-02-15

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown.

  1. Low temperature laser scanning microscopy of a superconducting radio-frequency cavity.

    Science.gov (United States)

    Ciovati, G; Anlage, Steven M; Baldwin, C; Cheng, G; Flood, R; Jordan, K; Kneisel, P; Morrone, M; Nemes, G; Turlington, L; Wang, H; Wilson, K; Zhang, S

    2012-03-01

    An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ~1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

  2. Novel method to improve power handling capability for coplanar waveguide high-temperature superconducting filter

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, K; Koizumi, D; Narahashi, S [NTT DoCoMo, Inc., 3-5 Hikari-no-oka, 239-8536 Yokosuka (Japan)

    2006-06-01

    This paper proposes a novel method to improve the power handling capability of a coplanar waveguide (CPW) high-temperature superconducting (HTS) filter. The noteworthy point of the proposed method is that it is based on the concept that the power handling capability is improved by reducing the maximum current density of the filter. Numerical investigations confirm that a CPW HTS filter using 66-{omega} characteristic impedance resonators (66-{omega} CPW HTSF) reduces the maximum current density compared to that using conventional 50-{omega} resonators (50-{omega} CPW HTSF). We fabricated 5-GHz band four-pole Chevyshev CPW HTSFs based on the proposed and conventional methods. The fabricated 66-{omega} CPW HTSF exhibited the third-order intercept point (TOI) of + 61 dBm while the 50-{omega} CPW HTSF exhibited the TOI of + 54 dBm, both at 60 K. These results indicate the effectiveness of the proposed method.

  3. Conceptual design of current lead for large scale high temperature superconducting rotating machine

    International Nuclear Information System (INIS)

    Le, T. D.; Kim, J. H.; Park, S. I.; Kim, H. M.

    2014-01-01

    High-temperature superconducting (HTS) rotating machines always require an electric current of from several hundreds to several thousand amperes to be led from outside into cold region of the field coil. Heat losses through the current leads then assume tremendous importance. Consequently, it is necessary to acquire optimal design for the leads which would achieve minimum heat loss during operation of machines for a given electrical current. In this paper, conduction cooled current lead type of 10 MW-Class HTS rotating machine will be chosen, a conceptual design will be discussed and performed relied on the least heat lost estimation between conventional metal lead and partially HTS lead. In addition, steady-state thermal characteristic of each one also is considered and illustrated.

  4. Design study of high-temperature superconducting generators for wind power systems

    International Nuclear Information System (INIS)

    Maki, N

    2008-01-01

    Design study on high-temperature superconducting machines (HTSM) for wind power systems was carried out using specially developed design program. Outline of the design program was shown and the influence of machine parameters such as pole number, rotor outer diameter and synchronous reactance on the machine performance was clarified. Three kinds of generator structure are considered for wind power systems and the HTSM operated under highly magnetic saturated conditions with conventional rotor and stator has better performance than the other types of HTSM. Furthermore, conceptual structure of 8 MW, 20 pole HTSM adopting salient-pole rotor as in the case of water turbine generators and race-truck shaped HTS field windings like Japanese Maglev was shown

  5. Analogue demonstration of a high temperature superconducting sigma-delta modulator with 27 GHz sampling

    Energy Technology Data Exchange (ETDEWEB)

    Forrester, M.G.; Hunt, B.D.; Miller, D.L.; Talvacchio, J.; Young, R.M. [Northrop Grumman Science and Technology Center, Pittsburgh, PA 15235-5098 (United States)

    1999-11-01

    We have successfully fabricated and tested a high temperature superconducting (HTS) sigma-delta modulator for analogue-to-digital conversion. This is the first demonstration of a GHz sampling A-to-D in HTS. The 15-junction single-flux-quantum (SFQ) circuit, fabricated using an epitaxial multilayer HTS process with YBCO/Co-YBCO/YBCO edge junctions, was internally clocked at 27 GHz and used to convert a 5.01 MHz signal. The modulator demonstrated a spur-free dynamic range of more than 75 dB. Two-tone measurements with 5.01 MHz and 5.51 MHz signals demonstrated third-order intermodulation products to be lower than -59 dBc. Demonstration of a functional HTS modulator represents a significant milestone in the development of high dynamic range ADCs suitable for such applications as surveillance radar. (author)

  6. Study on AC loss measurements of HTS power cable for standardizing

    Science.gov (United States)

    Mukoyama, Shinichi; Amemiya, Naoyuki; Watanabe, Kazuo; Iijima, Yasuhiro; Mido, Nobuhiro; Masuda, Takao; Morimura, Toshiya; Oya, Masayoshi; Nakano, Tetsutaro; Yamamoto, Kiyoshi

    2017-09-01

    High-temperature superconducting power cables (HTS cables) have been developed for more than 20 years. In addition of the cable developments, the test methods of the HTS cables have been discussed and proposed in many laboratories and companies. Recently the test methods of the HTS cables is required to standardize and to common in the world. CIGRE made the working group (B1-31) for the discussion of the test methods of the HTS cables as a power cable, and published the recommendation of the test method. Additionally, IEC TC20 submitted the New Work Item Proposal (NP) based on the recommendation of CIGRE this year, IEC TC20 and IEC TC90 started the standardization work on Testing of HTS AC cables. However, the individual test method that used to measure a performance of HTS cables hasn’t been established as world’s common methods. The AC loss is one of the most important properties to disseminate low loss and economical efficient HTS cables in the world. We regard to establish the method of the AC loss measurements in rational and in high accuracy. Japan is at a leading position in the AC loss study, because Japanese researchers have studied on the AC loss technically and scientifically, and also developed the effective technologies for the AC loss reduction. The JP domestic commission of TC90 made a working team to discussion the methods of the AC loss measurements for aiming an international standard finally. This paper reports about the AC loss measurement of two type of the HTS conductors, such as a HTS conductor without a HTS shield and a HTS conductor with a HTS shield. The AC loss measurement method is suggested by the electrical method..

  7. Superconductive crossbar system for communication applications

    International Nuclear Information System (INIS)

    Murdock, B.; Kwong, Y.K.; Gimlett, J.

    1994-01-01

    This paper reviews current efforts toward the integration of a high-speed crossbar switch for digital communication applications. This system is an intelligent switching matrix for 128 inputs and 128 outputs, each capable of 2 Gbs (10 9 bits per second). An array of Josephson junction integrated circuits are interconnected with the use of a superconductive multichip module maintained at 4.2 K. This module is connected to room-temperature electronics by means of flexible cables, each containing impedance-matched microstrip transmission lines. Room-temperature interface electronics will permit interconversion between standard level input/output signals and Josephson junction logic levels. (orig.)

  8. Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor: La-214

    International Nuclear Information System (INIS)

    Yung Moo Huh

    2001-01-01

    Thermodynamics has been studied systematically for the high temperature cuprate superconductor La 2-x Sr x CuO 4-δ , La-214, in the entire superconductive region from strongly underdoped to strongly overdoped regimes. Magnetization studies with H(parallel)c have been made in order to investigate the changes in free energy of the system as the number of carriers is reduced. Above the superconducting transition temperature, the normal-state magnetization exhibits a two-dimensional Heisenberg antiferromagnetic behavior. Below T c , magnetization data are thermodynamically reversible over large portions of the H-T plane, so the free energy is well defined in these regions. As the Sr concentration is varied over the wide range from 0.060 (strongly underdoped) to 0.234 (strongly overdoped), the free energy change goes through a maximum at the optimum doped in a manner similar to the T c0 vs. x curve. The density of states, N(0), remains nearly constant in the overdoped and optimum doped regimes, taking a broad maximum around x = 0.188, and then drops abruptly towards zero in the underdoped regime. The La 2-x Sr x CuO 4 (La-214) system displays the fluctuating vortex behavior with the characteristic of either 2D or 3D fluctuations as indicated by clearly identifiable crossing points T* close to T c . The dimensional character of the fluctuations depends on both applied magnetic fields and the density of charge carriers. The dimensional crossover from 2D to 3D occurs in the strongly underdoped regime when the c-axis coherence distance ζ c becomes comparable to the spacing between adjacent CuO 2 layers s at sufficiently high magnetic fields near H c2

  9. Thermodynamic Critical Field and Superconducting Fluctuation of Vortices for High Temperature Cuprate Superconductor: La-214

    International Nuclear Information System (INIS)

    Finnemore, Douglas K.

    2001-01-01

    Thermodynamics has been studied systematically for the high temperature cuprate superconductor La 2-x Sr x CuO 4-δ , La-214, in the entire superconductive region from strongly underdoped to strongly overdoped regimes. Magnetization studies with H (parallel) c have been made in order to investigate the changes in free energy of the system as the number of carriers is reduced. Above the superconducting transition temperature, the normal-state magnetization exhibits a two-dimensional Heisenberg antiferromagnetic behavior. Below T c , magnetization data are thermodynamically reversible over large portions of the H-T plane, so the free energy is well defined in these regions. As the Sr concentration is varied over the wide range from 0.060 (strongly underdoped) to 0.234 (strongly overdoped), the free energy change goes through a maximum at the optimum doped in a manner similar to the T c0 vs. x curve. The density of states, N(0), remains nearly constant in the overdoped and optimum doped regimes, taking a broad maximum around x = 0.188, and then drops abruptly towards zero in the underdoped regime. The La 2-x Sr x CuO 4 (La-214) system displays the fluctuating vortex behavior with the characteristic of either 2D or 3D fluctuations as indicated by clearly identifiable crossing points T* close to T c . The dimensional character of the fluctuations depends on both applied magnetic fields and the density of charge carriers. The dimensional crossover from 2D to 3D occurs in the strongly underdoped regime when the c-axis coherence distance ξ c becomes comparable to the spacing between adjacent CuO 2 layers s at sufficiently high magnetic field near H c2

  10. Superconductivity: materials and applications

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Kircher, F.; Leveque, J.; Tixador, P.

    2008-01-01

    This digest paper presents the different types of superconducting materials: 1 - the low-TC superconductors: the multi-filament composite as elementary constituent, the world production of NbTi, the superconducting cables of the LHC collider and of the ITER tokamak; 2 - the high-TC superconductors: BiSrCaCuO (PIT 1G) ribbons and wires, deposited coatings; 3 - application to particle physics: the the LHC collider of the CERN, the LHC detectors; 4 - applications to thermonuclear fusion: Tore Supra and ITER tokamaks; 5 - NMR imaging: properties of superconducting magnets; 6 - applications in electrotechnics: cables, motors and alternators, current limiters, transformers, superconducting energy storage systems (SMES). (J.S.)

  11. Journal of Superconductivity. Volume 8, Number 4. Special Issue: Miami University Workshop on High-Temperature Superconductivity. Part 1,

    Science.gov (United States)

    1995-08-01

    in HgBa2Can- 1CUnO 2n+2 +6 507 Massimo Marezio, Edgar T. Alexandre , Pierre Bordet, Jean-Jacques Capponi, Catherine Chaillout, Evgueni M. Kopnin...polarization configurations normal- the A.-von- Humboldt Foundation for support. ized to the absolute scattering efficiency. Note that for the sake of...1994). Journal of Superconductivity, Vol. 8, No. 4, 1995 Cation and Anion Disorder in HgBa2Can-1CunO2n+2+8 Massimo Marezio, 1 ,2 Edgar T. Alexandre

  12. 2008 LHC Open Days: Super(-conducting) events and activities

    CERN Multimedia

    2008-01-01

    Superconductivity will be one of the central themes of the programme of events and discovery activities of the forthcoming LHC Open Days on 5 and 6 April. Visitors will be invited to take part in a range of activities, experiments and exchanges all about this amazing aspect of the LHC project. Why superconductivity? Simply because it’s the principle on which the very operation of the LHC is based. At the heart of the LHC magnets lie 7000 kilometres of superconducting cables, each strand containing between 6000 and 9000 filaments of the superconducting alloy niobium-titanium in a copper coating. These cables, cooled to a temperature close to absolute zero, are able to conduct electricity without resistance. 12000 amp currents - an intensity some 30000 times greater than that of a 100 watt light bulb - pass through the cables of the LHC magnets.   Programme:   BLDG 163 (Saturday 5 and Sunday 6 April): See weird and wonderful experiments with your own eyes In the workshop where the 2...

  13. Interplay between magnetism and superconductivity in iron based high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Price, Stephen

    2013-07-01

    In this thesis, magnetic properties of a series of different Fe-based superconducting materials have been studied by means of neutron scattering techniques. Magnetic correlations in underdoped Ba(Fe{sub 0.95}Co{sub 0.05}){sub 2}As{sub 2} have been investigated for three phases of the phase diagram. It was possible to detect the spin gap and spin resonance signal, two features of the particle hole excitation spectrum at Q=(0.5,0.5,0), characteristic for the superconducting phase. The spin wave excitations present in the ordered phase have been analyzed quantitatively in terms of a linear spin wave model, whereas a spin diffusion model was applied to the collective excitations of the paramagnetic phase. However, it was found that both models can be applied to excitations in all three phases. In optimally doped CaFe{sub 0.88}Co{sub 0.12}AsF, a spin resonance signal was detected as part of the spin excitation spectrum at Q=(0.5,0.5,0). The observation of the spin resonance signal supports the s{sub ±} symmetry of the superconducting gap function. In the undoped CaFeAsF compound three dimensional spin wave like excitations of the static Fe-SDW order have been observed at Q{sub AFM}=(0.5,0.5,0.5), for temperatures below T{sub N}. Above T{sub N} and for energies below 20 meV, the spin wave like excitations are replaced by short range two dimensional paramagnetic excitations, which persist up to 270 K. In superconducting FeSe{sub 0.5}Te{sub 0.5} polarized neutron scattering investigations revealed the magnetic nature of the spin resonance signal and the excitation spectrum at Q=(0.5,0.5,0) up to 30 meV. The whole excitation spectrum including the spin resonance signal consists of an isotropic distribution of spin excitations with magnetic moments fluctuating in the ab-plane and perpendicular to the ab-plane, χ{sub ab}''(Q,ω)∼χ{sub c}''(Q,ω). In Eu(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} and EuFe{sub 2}(As{sub 1-x}P{sub x}){sub 2} the effect of

  14. The influence of the s-d(f) Coulomb interaction on the transition element compound superconductive critical temperature

    International Nuclear Information System (INIS)

    Kravtsov, V.E.; Mal'shukov, A.G.

    1978-01-01

    The influence of s-d Coulomb interaction on the superconductive critical temperature Tsub(c) of transition element compounds and their dilute alloys was investigated in the frame of Anderson model. Coulomb interaction of electrons with opposite spins on the same atom was considered in a ladder approximation valid when hybridization is sufficiently small while s-d Coulomb interaction has led to the 'parquet' summation. It is shown that s-d Coulomb interaction results in the decrease of Tsub(c) and hence the electron mechanism of superconductivity seems to be non-effective in systems under consideration. (author)

  15. The effect of low temperature cryocoolers on the development of low temperature superconducting magnets

    International Nuclear Information System (INIS)

    Green, Michael A.

    2000-01-01

    The commercial development of reliable 4 K cryocoolers improves the future prospects for magnets made from low temperature superconductors (LTS). The hope of the developers of high temperature superconductors (HTS) has been to replace liquid helium cooled LTS magnets with HTS magnets that operate at or near liquid nitrogen temperature. There has been limited success in this endeavor, but continued problems with HTS conductors have greatly slowed progress toward this goal. The development of cryocoolers that reliably operate below 4 K will allow magnets made from LTS conductor to remain very competitive for many years to come. A key enabling technology for the use of low temperature cryocoolers on LTS magnets has been the development of HTS leads. This report describes the characteristics of LTS magnets that can be successfully melded to low-temperature cryocoolers. This report will also show when it is not appropriate to consider the use of low-temperature cryocoolers to cool magnets made with LTS conductor. A couple of specific examples of LTS magnets where cryocoolers can be used are given

  16. Coherent Anti-Stokes and Coherent Stokes in Raman Scattering by Superconducting Nanowire Single-Photon Detector for Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Annepu Venkata Naga Vamsi

    2016-01-01

    Full Text Available We have reported the measurement of temperature by using coherent anti-Stroke and coherent Stroke Raman scattering using superconducting nano wire single-photon detector. The measured temperatures by both methods (Coherent Anti-Raman scattering & Coherent Stroke Raman scattering and TC 340 are in good accuracy of ± 5 K temperature range. The length of the pipe line under test can be increased by increasing the power of the pump laser. This methodology can be widely used to measure temperatures at instantaneous positions in test pipe line or the entire temperature of the pipe line under test.

  17. Contribution of ion beam analysis methods to the development of 2nd generation high temperature superconducting (HTS) wires

    Energy Technology Data Exchange (ETDEWEB)

    Usov, Igor O [Los Alamos National Laboratory; Arendt, Paul N [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; Holesinger, Terry G [Los Alamos National Laboratory; Foltyn, Steven R [Los Alamos National Laboratory; Depaula, Raymond F [Los Alamos National Laboratory

    2009-01-01

    One of the crucial steps in the second generation high temperature superconducting wire program was development of the buffer layer architecture. The architecture designed at the Superconductivity Technology Center at Los Alamos National Laboratory consists of several oxide layers wherein each layer plays a specific role, namely: nucleation layer, diffusion barrier, biaxially textured template, and an intermediate layer with a good match to the lattice parameter of superconducting Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} (YBCO) compound. This report demonstrates how a wide range of ion beam analysis techniques (SIMS, RBS, channeling, PIXE, PIGE, NRA, ERD) was employed for analysis of each buffer layer and the YBCO films. These results assisted in understanding of a variety of physical processes occurring during the buffet layer fabrication and helped to optimize the buffer layer architecture as a whole.

  18. Epitaxial YBa2Cu3O7 films on rolled-textured metals for high temperature superconducting applications

    International Nuclear Information System (INIS)

    Norton, D.P.; Park, C.; Prouteau, C.

    1998-04-01

    The epitaxial growth of high temperature superconducting (HTS) films on rolled-textured metal represents a viable approach for long-length superconducting tapes. Epitaxial, 0.5 microm thick YBa 2 Cu 3 O 7 (YBCO) films with critical current densities, J c , greater than 1 MA/cm 2 have been realized on rolled-textured (001) Ni tapes with yttria-stabilized zirconia (YSZ)/CeO 2 oxide buffer layers. This paper describes the synthesis using pulsed-laser deposition (PLD) of epitaxial oxide buffer layers on biaxially-textured metal that comprise the so-called rolling-assisted biaxially-textured substrates (RABiTs trademark). The properties of the buffer and YBa 2 Cu 3 O 7 films on rolled-textured Ni are discussed, with emphasis given to the crystallographic and microstructural properties that determine the superconducting properties of these multilayer structures

  19. Influence of dump voltage and allowable temperature rise on stabilizer requirements in superconducting coils

    International Nuclear Information System (INIS)

    Schwenterly, S.W.

    1988-01-01

    A superconducting winding must have enough stabilizer to satisfy two sets of criteria. During normal operation, the amount of stabilizer must be large enough either to make the coil unconditionally stable or to give a certain desired stability margin. Once a dump occurs, the amount of stabilizer must be large enough to carry the current without generating excessive dump voltages or allowing the winding to exceed a certain maximum temperature (and maximum pressure, in the case of force-cooled coils). The voltage criterion often dominates for very large coil systems, but it is frequently ignored in initial design studies. This paper gives some simple relations between the dump voltage and the stored energy, temperature rise, and coil geometry that are useful in scooping the required amount of stabilizer. Comparison with some recently proposed fusion magnet system designs indicates that excessive dump voltages could result in some cases. High-temperature superconductors may require more stabilizer than the conventional alloys. Calculations with simple model coil systems indicate how trade-offs between various coil parameters affect the dump voltage. 12 refs., 1 fig., 1 tab

  20. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Science.gov (United States)

    Byun, Thak Sang; Kim, Sang-Ho; Mammosser, John

    2009-08-01

    Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  1. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang [ORNL; Kim, Sang-Ho [ORNL; Mammosser, John [ORNL

    2009-01-01

    Low temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30 40 MPa m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 K and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  2. Low temperature preparation and superconductivity of F-doped SmFeAsO

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.L.; Cui, Y.J. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Yang, Y.; Wang, L.; Li, Y.C.; Zhang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y., E-mail: yzhao@swjtu.edu.c [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia)

    2010-11-01

    A low temperature (1100 deg. C) process of preparing F-doped SmFeAsO samples has been developed using SmF{sub 3} with nanometer scale as the source of fluorine. A series of the SmFeAsO{sub 1-x}F{sub x} (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) samples have been prepared using the present method. Compared with previous reports, the present SmF{sub 3} is more effective to introduce F into SmFeAsO system in which a transition temperature of 39 K can be observed when x = 0.05. The superconductivity is definitely enhanced with the increasing F-doping level. All the samples presented to be layered structure and the crystal particle size is about three times larger with sintering time increasing from 36 h to 48 h. Except for the nanometer scale of SmF{sub 3}, the flux effect of SmF{sub 3} is recognized to be another reason for the decrease of the sintering temperature. Further more, a relatively large amount of SmF{sub 3} was also employed in the raw materials to introduce excessive F and this has induced higher T{sub c} (55 K) in SmFeAsO{sub 0.8}F{sub 0.2+{delta}}system.

  3. Influence of radiant heating treatments on fusion of high-temperature superconducting yttrium ceramics

    International Nuclear Information System (INIS)

    Bitenbaev, M.I.; Polyakov, A.I.

    1999-01-01

    Regardless of the fact that the materials made of HTSC-ceramics are promising, there is no any information about their successful practical application in publications. To our opinion, it is explained by the fact, first of all, that the conservative technologies of the powder metallurgy do not allow producing HTSC systems with excellent operating performance (structure homogeneity, long-term stability of Sc properties and etc.). This report presents outcomes of experiments on fusion of yttrium ceramics containing raw components irradiated by g-rays 60 Co under the temperature exceeding 500 degrees C. HTSC properties of ceramics were studied according to their differential spectra of radio-frequency (RF) field absorption. The RF absorption spectrum of yttrium ceramics samples produced according to conservative technology is sufficiently permitted triplet with the Sc transition temperatures range of 80 K, 90 K, 95 K. Irradiation under the increased temperatures and mechanical limitation allow producing samples of yttrium HTSC-ceramics with sufficient homogeneous structure and superconducting properties that are stable to air conditions for not less than one year

  4. Nanostructures of Boron, Carbon and Magnesium Diboride for High Temperature Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferle, Lisa [Yale Univ., New Haven, CT (United States); Fang, Fang [Yale Univ., New Haven, CT (United States); Iyyamperumal, Eswarmoorthi [Yale Univ., New Haven, CT (United States); Keskar, Gayatri [Yale Univ., New Haven, CT (United States)

    2013-12-23

    Direct fabrication of MgxBy nanostructures is achieved by employing metal (Ni,Mg) incorporated MCM-41 in the Hybrid Physical-Chemical Vapor Deposition (HPCVD) reaction. Different reaction conditions are tested to optimize the fabrication process. TEM analysis shows the fabrication of MgxBy nanostructures starting at the reaction temperature of 600oC, with the yield of the nanostructures increasing with increasing reaction temperature. The as-synthesized MgxBy nanostructures have the diameters in the range of 3-5nm, which do not increase with the reaction temperature consistent with templated synthesis. EELS analysis of the template removed nanostructures confirms the existence of B and Mg with possible contamination of Si and O. NEXAFS and Raman spectroscopy analysis suggested a concentric layer-by-layer MgxBy nanowire/nanotube growth model for our as-synthesized nanostructures. Ni k-edge XAS indicates that the formation of MgNi alloy particles is important for the Vapor-Liquid-Solid (VLS) growth of MgxBy nanostructures with fine diameters, and the presence of Mg vapor not just Mg in the catalyst is crucial for the formation of Ni-Mg clusters. Physical templating by the MCM-41 pores was shown to confine the diameter of the nanostructures. DC magnetization measurements indicate possible superconductive behaviors in the as-synthesized samples.

  5. Superconducting devices at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Dahl, P.F.

    1978-04-01

    The various ongoing programs in applied superconductivity supported by BNL are summarized, including the development of high field ac and dc superconducting magnets for accelerators and other applications, of microwave deflecting cavities for high energy particle beam separators, and of cables for underground power transmission, and materials research on methods of fabricating new superconductors and on metallurgical properties affecting the performance of superconducting devices

  6. Influence of oxygen stoichiometry on the structure and superconducting transition temperature of YBa 2Cu 3O x

    Science.gov (United States)

    Farneth, W. E.; Bordia, R. K.; McCarron, E. M.; Crawford, M. K.; Flippen, R. B.

    1988-06-01

    A detailed study of the superconducting properties and the crystal symmetry of YBa 2Cu 3O x as a function of oxygen content (x) is presented. We correlate the oxygen content, structure and superconducting transition temperature for YBa 2Cu 3O x (6topotactic intercalation/deintercalation of oxygen. It is shown that the orthorhombic to tetragonal phase transition coincides with a loss in superconductivity for samples prepared both by quenching from high temperature and samples prepared by deoxygenation at low temperature. For the orthorhombic phase, T c monotonically decreases as x goes from 7.0 to 6.4 along with a complementary decrease in the extent of orthorhombic distortion. The decrease in T c, however, is not uniform. For quenched samples it shows a plateau for x ˜ 6.75 to 6.55 and then a rather abrupt drop around x ˜ 6.5. Comparison of our data with the literature indicates that the dependence of superconducting properties and crystal structure on the oxygen content can be a complex function of sample processing history. Samples with the same oxygen content but prepared in different ways may have x-ray powder patterns that are indistinguishable, but significantly different electrical properties.

  7. Simulation of the cabling process for Rutherford cables: An advanced finite element model

    Science.gov (United States)

    Cabanes, J.; Garlasche, M.; Bordini, B.; Dallocchio, A.

    2016-12-01

    In all existing large particle accelerators (Tevatron, HERA, RHIC, LHC) the main superconducting magnets are based on Rutherford cables, which are characterized by having: strands fully transposed with respect to the magnetic field, a significant compaction that assures a large engineering critical current density and a geometry that allows efficient winding of the coils. The Nb3Sn magnets developed in the framework of the HL-LHC project for improving the luminosity of the Large Hadron Collider (LHC) are also based on Rutherford cables. Due to the characteristics of Nb3Sn wires, the cabling process has become a crucial step in the magnet manufacturing. During cabling the wires experience large plastic deformations that strongly modify the geometrical dimensions of the sub-elements constituting the superconducting strand. These deformations are particularly severe on the cable edges and can result in a significant reduction of the cable critical current as well as of the Residual Resistivity Ratio (RRR) of the stabilizing copper. In order to understand the main parameters that rule the cabling process and their impact on the cable performance, CERN has developed a 3D Finite Element (FE) model based on the LS-Dyna® software that simulates the whole cabling process. In the paper the model is presented together with a comparison between experimental and numerical results for a copper cable produced at CERN.

  8. An industrial cabling machine for the SSC

    International Nuclear Information System (INIS)

    Royet, J.; Armer, R.; Hannaford, R.; Scanlan, R.

    1989-02-01

    The SSC project will need the manufacturing of some 25,000 kilometers of keystoned flat cable. The technical specifications of the various cables to be produced are the result of five years of research and development work at LBL. An experimental cable machine was built and run in the laboratory; many improvements were implemented and tested. Semi-industrial production of the various cables was performed, and the resulting cables were used and tested in the one-meter model magnets and 17.5 meter dipole prototypes. From these experiments an industrial cabler specification was generated and used for an international RFQ. The winner of the contract is Dour Metal, a Belgium company that built the first industrial prototype which is now in a production line at New England Electric Wire Company. In this paper we describe the main characteristics of the machine and give the first industrial production results of superconducting keystoned cable for the SSC project. 4 refs

  9. Effect of low temperature baking on the RF properties of niobium superconducting cavities for particle accelerators

    International Nuclear Information System (INIS)

    Gianluigi Ciovati

    2004-01-01

    Radio-frequency superconducting (SRF) cavities are widely used to accelerate a charged particle beam in particle accelerators. The performance of SRF cavities made of bulk niobium has significantly improved over the last ten years and is approaching the theoretical limit for niobium. Nevertheless, RF tests of niobium cavities are still showing some ''anomalous'' losses that require a better understanding in order to reliably obtain better performance. These losses are characterized by a marked dependence of the surface resistance on the surface electromagnetic field and can be detected by measuring the quality factor of the resonator as a function of the peak surface field. A low temperature (100 C-150 C) ''in situ'' bake under ultra-high vacuum has been successfully applied as final preparation of niobium RF cavities by several laboratories over the last few years. The benefits reported consist mainly of an improvement of the cavity quality factor at low field and a recovery from ''anomalous'' losses (so-called ''Q-drop'') without field emission at higher field. A series of experiments with a CEBAF single-cell cavity have been carried out at Jefferson Lab to carefully investigate the effect of baking at progressively higher temperatures for a fixed time on all the relevant material parameters. Measurements of the cavity quality factor in the temperature range 1.37 K-280 K and resonant frequency shift between 6 K-9.3 K provide information about the surface resistance, energy gap, penetration depth and mean free path. The experimental data have been analyzed with the complete BCS theory of superconductivity. The hydrogen content of small niobium samples inserted in the cavity during its surface preparation was analyzed with Nuclear Reaction Analysis (NRA). The single-cell cavity has been tested at three different temperatures before and after baking to gain some insight on thermal conductivity and Kapitza resistance and the data are compared with different models

  10. Superconductivity in technology

    International Nuclear Information System (INIS)

    Komarek, P.

    1976-01-01

    Physics, especially high energy physics and solid state physics was the first area in which superconducting magnets were used but in the long run, the most extensive application of superconductivity will probably be in energy technology. Superconducting power transmission cables, magnets for energy conversion in superconducting electrical machines, MHD-generators and fusion reactors and magnets for energy storage are being investigated. Magnets for fusion reactors will have particularly large physical dimensions, which means that much development effort is still needed, for there is no economic alternative. Superconducting surfaces in radio frequency cavities can give Q-values up to a factor of 10 6 higher than those of conventional resonators. Particle accelerators are the important application. And for telecommunication, simple coaxial superconducting radio frequency cables seem promising. The tunnel effect in superconducting junctions is now being developed commercially for sensitive magnetometers and may soon possibly feature in the memory cells of computer devices. Hence superconductivity can play an important role in the technological world, solving physical and technological problems and showing economic advantages as compared with possible conventional techniques, bearing also in mind the importance of reliability and safety. (author)

  11. Code Development and Validation Towards Modeling and Diagnosing Current Redistribution in an ITER-Type Superconducting Cable Subject to Current Imbalance

    International Nuclear Information System (INIS)

    Zani, L.; Gille, P.E.; Gonzales, C.; Kuppel, S.; Torre, A.

    2009-01-01

    In the framework of ITER magnet R and D activities, a significant number of conductor short-samples or inserts were tested throughout the past decades, either for development on cable layouts or for industrial qualifications. On a certain number of them critical properties degradations were encountered, some of which were identified to be caused by current imbalance between the different strands bundles twisted inside the cable. In order to address the analyses of those samples as reliably as possible, CEA developed a dedicated home code named Coupled Algorithm Resistive Modelling Electrical Network (CARMEN) having basically two specific functionalities: -a first routine which is devoted to compute strand bundles trajectories, with bundles down to the individual strand scale. This point allows to obtain a realistic E(J) law over the full conductor length -a second routine which is devoted to model inter-bundle currents redistribution, taking into account the magnetic field map. It basically makes use of a relevant discrete electrical network with defined sections including E(J) law obtained from the above-mentioned subroutine As a result, the E-J or E-T curves can be calculated and compared to the experimental data, provided adapted inputs on sample features are considered, such as strand contact resistances in joints, inter-bundles resistances or cable geometry. In a first part, the paper describes the different hypotheses that built the code structure, and in a second part, the application to the ITER TFCl insert coil is presented, focusing particularly on the validation of the potential use of the code to stand as a diagnostic tool for currents imbalance probing

  12. Lattice parameters guide superconductivity in iron-arsenides

    Science.gov (United States)

    Konzen, Lance M. N.; Sefat, Athena S.

    2017-03-01

    The discovery of superconducting materials has led to their use in technological marvels such as magnetic-field sensors in MRI machines, powerful research magnets, short transmission cables, and high-speed trains. Despite such applications, the uses of superconductors are not widespread because they function much below room-temperature, hence the costly cooling. Since the discovery of Cu- and Fe-based high-temperature superconductors (HTS), much intense effort has tried to explain and understand the superconducting phenomenon. While no exact explanations are given, several trends are reported in relation to the materials basis in magnetism and spin excitations. In fact, most HTS have antiferromagnetic undoped ‘parent’ materials that undergo a superconducting transition upon small chemical substitutions in them. As it is currently unclear which ‘dopants’ can favor superconductivity, this manuscript investigates crystal structure changes upon chemical substitutions, to find clues in lattice parameters for the superconducting occurrence. We review the chemical substitution effects on the crystal lattice of iron-arsenide-based crystals (2008 to present). We note that (a) HTS compounds have nearly tetragonal structures with a-lattice parameter close to 4 Å, and (b) superconductivity can depend strongly on the c-lattice parameter changes with chemical substitution. For example, a decrease in c-lattice parameter is required to induce ‘in-plane’ superconductivity. The review of lattice parameter trends in iron-arsenides presented here should guide synthesis of new materials and provoke theoretical input, giving clues for HTS.

  13. Influence of ion beam mixing on the growth of high temperature oxide superconducting thin film

    International Nuclear Information System (INIS)

    Bordes, N.; Rollett, A.D.; Cohen, M.R.; Nastasi, M.

    1989-01-01

    The superconducting properties of high temperature superconductor thin films are dependent on the quality of the substrate used to grow these films. In order to maximize the lattice matching between the superconducting film and the substrate, we have used a YBa 2 Cu 3 O 7 thin film deposited on left-angle 100 right-angle SrTiO 3 as a template. The first film was prepared by coevaporation of Y, BaF 2 and Cu on left-angle 100 right-angle SrTiO 3 , followed by an anneal in ''wet'' oxygen at 850 degree C. This film showed a sharp transition at about 90 K. A thicker layer of about 5000 A was then deposited on top of this first 2000 angstrom film, using the same procedure. After the post anneal at 850 degree C, the transition took place at 80 K and no epitaxy of the second film was observed. Ion beam mixing at 400 degree C, using 400 keV O ions was done at the interface of the two films (the second one being not annealed). After the post anneal, the film displayed an improved Tc at 90K. Moreover, epitaxy was shown to take place from the interface SrTiO 3 -123 film towards the surface and was dependent of the dose. These results will be discussed from the data obtained from Rutherford backscattering spectroscopy (RBS) combined with channeling experiments, x-ray diffraction (XRD) and scanning electron microscopy (SEM) observations. 8 refs., 2 figs., 2 tabs

  14. Superconducting materials

    International Nuclear Information System (INIS)

    Ruvalds, J.

    1990-01-01

    This report discusses the following topics: Fermi liquid nesting in high temperature superconductors; optical properties of high temperature superconductors; Hall effect in superconducting La 2-x Sr x CuO 4 ; source of high transition temperatures; and prospects for new superconductors

  15. Evaluation of high temperature superconductive thermal bridges for space borne cryogenic detectors

    Science.gov (United States)

    Scott, Elaine P.

    1996-01-01

    Infrared sensor satellites are used to monitor the conditions in the earth's upper atmosphere. In these systems, the electronic links connecting the cryogenically cooled infrared detectors to the significantly warmer amplification electronics act as thermal bridges and, consequently, the mission lifetimes of the satellites are limited due to cryogenic evaporation. High-temperature superconductor (HTS) materials have been proposed by researchers at the National Aeronautics and Space Administration Langley's Research Center (NASA-LaRC) as an alternative to the currently used manganin wires for electrical connection. The potential for using HTS films as thermal bridges has provided the motivation for the design and the analysis of a spaceflight experiment to evaluate the performance of this superconductive technology in the space environment. The initial efforts were focused on the preliminary design of the experimental system which allows for the quantitative comparison of superconductive leads with manganin leads, and on the thermal conduction modeling of the proposed system. Most of the HTS materials were indicated to be potential replacements for the manganin wires. In the continuation of this multi-year research, the objectives of this study were to evaluate the sources of heat transfer on the thermal bridges that have been neglected in the preliminary conductive model and then to develop a methodology for the estimation of the thermal conductivities of the HTS thermal bridges in space. The Joule heating created by the electrical current through the manganin wires was incorporated as a volumetric heat source into the manganin conductive model. The radiative heat source on the HTS thermal bridges was determined by performing a separate radiant interchange analysis within a high-T(sub c) superconductor housing area. Both heat sources indicated no significant contribution on the cryogenic heat load, which validates the results obtained in the preliminary conduction

  16. Cable handling

    International Nuclear Information System (INIS)

    1980-01-01

    In computerized axial tomography scanning, problems arise in exchanging electrical signals between fixed and rotating assemblies. A novel method of overcoming this problem is described in detail for both signal and high voltage cables. Apparatus using a sequence of drums and pulleys is used to maintain the interconnecting cables in a neat arrangement and free from mechanical strain. The apparatus is simple and relatively easy and inexpensive to assemble and maintain. (UK)

  17. Status and future perspective of applications of high temperature superconductors

    Science.gov (United States)

    Tanaka, Shoji

    The material research on the high temperature superconductivity for the past ten years gave us sufficient information on the new phenomena of these new materials. It seems that new applications in a very wide range of industries are increasing rapidly. In this report three main topics of the applications are given ; [a] progress of the superconducting bulk materials and their applications to the flywheel electricity storage system and others, [b] progress in the development of superconducting tapes and their applications to power cables, the high field superconducting magnet for the SMES and for the pulling system of large silicon single crystal, and [c] development of new superconducting electronic devices (SFQ) and the possiblity of the application to next generation supercomputers. These examples show the great capability of the superconductivity technology and it is expected that the real superconductivity industry will take off around the year of 2005.

  18. Enhancing the superconducting temperature of MgB2 by SWCNT dilution

    Science.gov (United States)

    Ma, Danhao; Jayasingha, Ruwantha; Hess, Dustin T.; Adu, Kofi W.; Sumanasekera, Gamini U.; Terrones, Mauricio

    2014-02-01

    We report, for the first time, an increase in the superconducting critical temperature, TC of commercial “dirty” MgB2 by a nonsubstitutional hole-doping of the MgB2 structure using minute, single-wall carbon nanotube (SWCNT) inclusions. We varied the SWCNTs concentration from 0.05 wt% to 5 wt% and investigated the temperature-dependent resistivity from 10 K to 300 K. We used micro-Raman spectroscopy, field-emission scanning electron microscopy, and X-ray diffraction to analyze the interfacial interactions between the SWCNTs and the MgB2 grains. We obtained an increase in TC from 33.0 to 37.8 K (ΔTC+=4.8 K), which is attributed to charge transfer from the MgB2 structure to the SWCNT structure. The charge transfer phenomenon is confirmed by micro-Raman analysis of the phonon states of the SWCNT tangential band frequency in the composites. We determined the charge transfer per carbon atom to be 0.0023/C, 0.0018/C and 0.0008/C for 0.05 wt%, 0.5 wt% and 5 wt% SWCNT inclusions, respectively, taking into account the contributions from the softening of the lattice constant and the nonadiabatic (dynamic) effects at the Fermi level. This report provides an experimental, alternative pathway to hole-doping of MgB2 without appealing to chemical substitution.

  19. Towards room-temperature superconductivity in low-dimensional C60 nanoarrays: An ab initio study

    Science.gov (United States)

    Erbahar, Dogan; Liu, Dan; Berber, Savas; Tománek, David

    2018-04-01

    We propose to raise the critical temperature Tc for superconductivity in doped C60 molecular crystals by increasing the electronic density of states at the Fermi level N (EF) and thus the electron-phonon coupling constant in low-dimensional C60 nanoarrays. We consider both electron and hole dopings and present numerical results for N (EF) , which increases with the decreasing bandwidth of the partly filled hu- and t1 u-derived frontier bands with the decreasing coordination number of C60. Whereas a significant increase in N (EF) occurs in two-dimensional (2D) arrays of doped C60 intercalated in-between graphene layers, we propose that the highest-Tc values approaching room temperature may occur in bundles of nanotubes filled by one-dimensional (1D) arrays of externally doped C60 or La @C60 or in diluted three-dimensional (3D) crystals where quasi-1D arrangements of C60 form percolation paths.

  20. Characterization of the microwave properties of superconducting films with high transition temperature

    International Nuclear Information System (INIS)

    Richter, W.; Klinger, M.; Daginnus, M.

    1989-01-01

    In the meantime high quality Y-Ba-Cu-O thin films were produced. The latest results show, that its surface resistances are clearly lower than the values of copper, measured at a temperature of 77 K and up to frequencies of 86 GHz. This examination had the aim to produce high-T c films with a simple and low cost method, to use them as transmission lines at frequencies up to 30 GHz and above. A screen printing process was investigated, and high-T c thick films were fabricated on several substrates. Superconducting transition temperatures up to 80 K (dc zero resistance) were obtained. The films showed no complete magnetic shielding, and its microwave surface resistances were clearly higher than that ones for copper. The a. c. Josephson effect was proved with granular structures of bulk Y-Ba-Cu-O material and with screen printed thick films. Because of its high surface resistances, these thick films are unsuitable for the use as transmission lines at high frequencies. However, the a.c. Josephson effect can be used to manufacture microwave sensors in bulk Y-Ba-Cu-O and screen printed films of Y-Ba-Cu-O, which have a favourable geometric structure. (orig.) With 16 refs., 2 tabs., 24 figs [de