bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Comparative Study of the Internal Tin Nb3Sn Wires with Different Layouts
Authors: Lukyanov P A , Pantsyrny V I , Polikarpova M V , Guryev V V , Novosilova D S , Bazaleeva K O , Tsapleva A S , Alekseev M V , Silaev A G , Abdyukhanov I M , Sergeev V V 
Published: June 2020

Abstract
The required combination of performance properties for internal tin Nb3Sn wires for high energy physics includes high critical current density (J
c) and RRR values as well as low magnetization and effective diameters (Deff
) value. It is quite a challenge to achieve them all at once. A comprehensive study has been carried out on two internal tin Nb3Sn wires with essentially different layouts and 37 sub-elements each. The first type of wires has distributed diffusion barriers. The second one has common diffusion barrier with sub-elements internally divided by resistive separators. Two sets of data for two types of wires have been obtained, which include transport measurements of J
c(B), magnetization loops M(B), superconducting transition temperature (Tc), RRR values, Sn-concentration by EDAX measurements and XRD analysis. XRD analysis of the superconducting layers has shown that the compressive macrostress is larger for the wire with overall barrier than for the wire with distributed diffusion barriers. This observation correlates with a shift of the stress-dependent curves of the superconducting transition. The difference in the volume fractions and the homogeneities of the Nb3Sn phase leads to a significant difference of the J
c(B) dependences and the values of the Kramer critical field (BKr) for these types of wires. In summary, the high critical current density for the first type of wires and the low hysteresis losses for the second type of wires have achieved with high RRR values in both cases.
The magnetic field, temperature, strain and angular dependence of the critical current density for Nb-Ti
Authors: Chislett-Mcdonald S B L , Tsui Y , Surrey E , Kovari M , Hampshire D P 
Published: June 2020

Abstract
A scaling law for J
c in commercial Nb-Ti wire is proposed that describes its magnetic field, temperature and strain dependence. The scaling law is used to fit extensive measurements of the total strand critical current density, J
c,TS(B, T, ε), with the applied field orthogonal to the axis of the wire. We present critical current density, heat capacity and resistivity measurements to obtain

B

c
2

*

(
θ
)

, which shows clear angular anisotropy. At 4.2 K, the resistivity data show

B

c
2

*

(
B
∥
J
)
−

B

c
2

*

(
B
⊥
J
)
≈
1

T

. We also discuss whether the fusion community should consider re-optimising standard commercial Nb-Ti wires that were developed for MRI applications at ~ 5 T, to produce higher J
c at say 10T, and higher upper critical fields, perhaps using quaternary Nb-Ti alloys with artificial pinning centres.
Joining condition dependency of joint resistance in ultrasonic welding of high-temperature superconducting tapes with indium
Authors: Ito S , Hayasaka R , Yuki K , Sato Y S , Hashizume H 
Published: June 2020

Abstract
Ultrasonic welding (UW) is a candidate for easy and simple fabrication of lap joints of high-temperature superconducting (HTS) tapes. Our previous study applied UW to both silver-sheathed BSCCO tapes and copper-stabilized REBCO tapes with indium foil inserted in-between. However, the fabrication was performed with limited joining conditions and critical current, I
C, degradation was confirmed in some of the BSCCO tape joints. In this study, we evaluated the joining-condition dependence of joint resistance and I
C to improve UW-joined HTS tape performance. Various UW samples using BSCCO and REBCO tapes were prepared with different thicknesses of indium foil, ultrasonic vibration amplitude, joining pressure, joining time, and metal plate arrangement. The results showed that HTS tapes layered between metal plates on the top and bottom can avoid I
C degradation even with higher joining energy, however thinner indium foil induced degradation in the BSCCO samples. Through this study, we found the value of joint resistivity only depended on the joining energy per unit joint area. The achieved joint resistivities were 14.0 nΩcm2 for the silver-sheathed BSCCO tapes and 36.1 nΩcm2 for the copper-stabilized REBCO tapes though it was strongly influenced by interface resistivity of the REBCO tape itself.
An electromagnetic method for measuring AC losses in HTS tapes without lock-in amplifier
Authors: Breschi Marco , Filicori Fabio , Musso Andrea , Pasini Gaetano 
Published: June 2020

Abstract
The measurement of AC losses in high temperature superconducting tapes is a complex task due to the small magnitude of the quantities to detect, and to the difficulty to separate the inductive and resistive parts of the measured voltage. This work describes a different approach to the electrical measurement of AC losses, not requiring lock-in amplifiers for the signal processing. The system is based on the acquisition of the voltage and current signals from the sample and their projection on a reference signal, performing a Hilbert transform based treatment procedure. This method allows one to retrieve the harmonic components of the signals with a significant noise reduction, thus improving the quality of the results. The experimental set-up is applied to measure AC losses in different HTS tapes, using sinusoidal currents of different amplitude and frequency. The results are compared with those obtained on the same tapes at other laboratories.
Facility for the Characterization of Planar Multilayer Thin Film Superconductors
Authors: Turner D. , Malyshev O. B. , Burt G. , Junginger T. , Gurran L. , Dumbell K. D. , May A. J. , Pattalwar N. , Pattalwar S. M. 
Published: June 2020

Abstract
The maximum accelerating gradient of SRF cavities can be increased by raising the field of full flux penetration, H
vp
. One method which can potentially increase H
vp
is to use structures consisting of alternating layers of superconductors and insulators (SIS). Magnetometry is commercially available but consists of limitations, such as SQUID measurements which apply a field over both superconducting layers, so H
vp
cannot be measured. If H
vp
is to be measured for SIS coatings, a parallel, local magnetic field must be applied from one plane of the sample, with no field on the opposing plane. A field penetration experiment has been developed at Daresbury laboratory allowing H
vp
to be measured using a local, parallel DC magnetic field. Using a field much smaller than the sample allows limitations such as edge effects to be significantly reduced. By increasing the field, H
vp
can be found by using 2 hall probes, one either side of the sample. The experiment was designed to use a variable temperature insert (VTI) to run in a cryogen free environment, but has been running in a LHe bath for thermal stability.
Developments of NDE method of jacket welds for ITER In-Vessel coil joints
Authors: Liu Xiao-chuan , Qin Jing-gang , Zhou Chao , Chen Wen-hui , Tang Jian-bang , Jomdecha cherdpong , Wu Yu , Chen Zhen-mao , Chen Hong-en 
Published: June 2020

Abstract
The ITER facility currently incorporates two types of In Vessel Coils (IVC) as a method of stabilizing “Edge Localized Modes” (ELM) and providing “Vertical Stabilization” (VS). To withstand the severe conditions, the IVCs are made of stainless steel mineral insulated conductor (SSMIC). The jacket of the SSMIC is modified stainless steel 316LN. The diameter is 59mm and thickness is only 2.5mm. In order to join the IVC coils, it is necessary to develop the joints manufacturing. Jacket welding is an important process of the joints manufacturing. Based on the structural analysis, the maximum acceptable defect sizes inside the jacket weld were defined. This paper presents the non-destructive examination (NDE) development of the jacket weld NDE is the thin thickness which will cause the scattering of sound waves and lead the difficulty of effective identification of defects. Phased Array Ultrasonic Test (PAUT) and eddy current test (ECT) were developed for the jacket welds inspection. The results indicated the feasibility of the PAUT and ECT method could solve the problem of the thin thickness tube weld inspection.
Assembly and Test of the HL-LHC Twin Aperture Orbit Corrector Based on Canted Cos-Theta Design
Authors: Kirby G. , Van Nugteren J. , Mentink M. , Canale M. , Gentini L. , Mazet J. , Pincot F-O. , Mangiarotti F.J. , Fiscarelli L. , Steckert J. , Coelingh G. J. , de Rijk G. , Perez J.C. , Verweij A. , Todesco E. , Rossi L. 
Published: June 2020

Abstract
In the frame of the high-luminosity upgrade project (HL-LHC) at CERN, a double aperture, independently powered, family of beam orbit corrector magnets will be installed close to the two main LHC experiments Atlas and CMS. These 2.6 T magnets, built using a canted cos-theta design. This paper describes the development of the prototype, full size 2-m-long magnets. We first focus on design and assembly techniques: from coil winding using a CNC machined aluminium former to impregnation, layer-jump, quench protection, and yoke assembly. We then present the power test results at 1.9 K: training, field quality and protection.
Design of the consolidated LHC dipole diode busbar insulation system
Authors: Meuter F. , Sahner T. , Scheuerlein C. , Tock J.Ph. 
Published: June 2020

Abstract
During the second long shutdown of the LHC in 2019 and 2020, the electrical insulation of the 1232 dipole diodes and diode busbars is presently consolidated. The newly designed insulation system, mainly consisting of polyimide laminated fiber reinforced epoxy sheets and injection molded pure resin inserts, can be installed in the very constricted space of the LHC tunnel, without removing the presently installed insulation. The consolidated insulation will prevent shorts to ground caused by metal debris in the LHC cold masses and allow preparing the LHC for operation at 7 TeV.
Electro-thermal analysis of the superconducting dipole circuit of SIS100
Authors: Raginel V. , Szwangruber P. , Freisleben W. , Roux C. 
Published: June 2020

Abstract
The heavy ion synchrotron SIS100, the core machine of the new international Facility for Antiproton and Ion Research (FAIR) in Darmstadt, is currently under construction. The 108 superconducting dipole magnets of SIS100 will be powered in series with a cycling rate up to 30kAs−1 which corresponds to 4Ts−1. The dipole magnet protection system considers 12 energy extraction resistors and two crowbars at the outputs of two power converters. As a part of the Failure Mode and Effects Analysis, the most critical failures of the magnet protection system are simulated. In this contribution, initial studies of the electrical and thermal behaviour of the SIS100 main dipole circuit during a quench are presented. The dipole magnet design and topology of the powering circuit (including the protection system) are described. The electro-thermal model in use is detailed. Finally, simulation of a failure mode of the magnet protection system is presented and results are discussed.
Busbar technology development for the HL-LHC inner triplet magnets
Authors: Tsolakis E. , Favier L. , Principe R. , Prin H. , Meuter F. , Scheuerlein C. 
Published: June 2020

Abstract
The busbars for the HL-LHC magnets are made of Nb-Ti/Cu conductor, the insulation system, and the auxiliary equipment to align the busbars with respect to the magnet coldmasses. This paper presents design options concerning the integration of the busbars inside the coldmass with a fixed point, and a reinforced insulation system for the flexible busbar part using thin PEEK tubes. Prototype splices for interconnecting Nb3Sn and Nb-Ti Rutherford cables, and round and flat 18 kA Nb-Ti cable have been produced and first test results are presented.
Distribution Feedbox for the Superconducting Link (SCLink) and Magnets of HL-LHC
Authors: Bailey W , Pelegrin J , Falorio I , Leclercq Y , Betemps R , Parma V , Ballarino A , Yang Y 
Published: June 2020

Abstract
The High Luminosity LHC (HL-LHC) project aims at upgrading the LHC collider to increase its luminosity by about a factor of five. The electrical connection between the magnets in the LHC tunnel and the power converters in a new transverse tunnel will be supplied by a superconducting line (SCLink), consisting of ten MgB2 cables housed into a 140 metre long flexible cryostat. This paper presents the detailed design for one of two types of distribution feedbox, (DFX) located between the magnet and the distribution feedbox. The vacuum barrier required to separate the vacuums of the upper SCLink and lower DFX sections; is to be integrated in the middle of the vertical section of DFX. A detailed study was performed, given the complexity of installing a vacuum barrier with a large diameter within a restricted height. Eccentric loading on the barrier is created by the “L-shape” vessel, necessary to accommodate the transition of the cable from vertical-to-horizontal. The solution considers a vacuum barrier assembly consisting of a flexible corrugated membrane (bellows) and deploys a lightweight “supporting cage” around the barrier and restraining rods in the horizontal section to ensure the barrier bares no substantial load or torque, and suffers no lateral or column type instability during operating and accidental conditions. The current design satisfies the mechanical and thermal design criteria outlined in the DFX specification.
Analysis of short-circuit transients in the LHC main dipole circuit
Authors: Liakopoulou A , Annema A J , Bortot L , Charifoulline Z , Maciejewski M , Prioli M , Ravaioli E , Salm C , Schmitz J , Verweij A P 
Published: June 2020

Abstract
After the occurrence and detection of a short circuit to ground in the LHC main dipole circuit, a fast power abort is triggered and the current in the circuit starts decaying semi-exponentially from a maximum value of 11.85 kA to zero, with a time constant of 103 s. If a short to ground occurs, the current flows through the fuse that is present in the grounding subcircuit. Depending on the value of the thermal load, the fuse first enters a pre-arcing region where it starts intermittently blowing up, until the blow-up threshold is reached, after which it definitively blows up. A simulation scheme utilising a common interface between PSpice and Matlab is proposed in order to simulate the blow-up behaviour of the fuse and hence increase the accuracy of the circuit model for short circuits to ground. A parametric analysis of the short circuit to ground parameters is performed and a better understanding of the behaviour of the circuit under different conditions is obtained. The worst-case values of the voltage to ground in the LHC main dipole circuit are identified for both the case where the intermittent behaviour of the fuse is included in the model as well as for the case where the fuse is not modelled and a comparison between the two is given.
Realisation of Hybrid Trapped Field Magnetic Lens (HTFML) consisting of REBCO bulk lens and REBCO bulk cylinder at 77 K
Authors: Namba S , Fujishiro H , Naito T , Ainslie M D , Zhou D 
Published: June 2020

Abstract
A hybrid trapped field magnet lens (HTFML) can reliably generate a concentrated magnetic field, B
c, in the centre of the magnetic lens higher than the trapped field of the trapped field magnet (TFM) and the applied magnetic field, B
app, even after the external magnetizing field decreased to zero. In this paper, the performance of HTFMLs consisting of EuBaCuO bulk TFM with various heights and a GdBaCuO bulk magnetic lens was investigated at 77 K using liquid nitrogen. A concentrated magnetic field of B
c = 0.80 T was achieved at the centre of the HTFML for the tallest TFM after removing an applied magnetic field of B
app = 0.50 T. The influence of the height of the outer TFM cylinder on the final concentrated field was studied experimentally and discussed using numerical simulation.
Investigation of flux jumps during pulsed field magnetization in graphene-added MgB2 bulks
Authors: Yokoyama K , Oka T , Berger K , Dorget R , Koblischka M , Grigoroscuta M , Burdusel M , Batalu D , Aldica G , Badica P , Sakai N , Muralidhar M , Murakami M 
Published: June 2020

Abstract
MgB2 bulk superconductors are expected to be utilized as rare-earth-free and lightweight trapped field magnets. However, the flux jumps frequently happen during the magnetizing processes, and heavily degrade the field-trapping performances. We have investigated the effect of additives to the MgB2 bulk samples prepared by spark plasma sintering process, and observed various flux jumps during the pulsed field magnetizing processes, which were carried out at 14 K which was obtained by the 2-stage GM cryocooler. The authors classified the flux motions as three categories as “no flux flow”, “fast flux flow”, and “flux jump” regions, and investigated the conditions where the flux jumps happen. We observed some drastic flux jumps in the pristine and clarified the effect of graphene addition to the flux jumps. The experimental results showed us a possible expansion of no flux jump region, and suggested us the improvement of field trapping capability.
Compact 2G HTS power cable: new cold tests results
Authors: Fetisov S S , Zubko V V , Zanegin S Yu , Nosov A A , Vysotsky V S 
Published: June 2020

Abstract
In Russian Scientific R&D Cable Institute we continue studies to develop as compact as possible 2G HTS power cables for electric power systems. Compact cables should have minimized diameter compared to other co-axial HTS cables developed before. Recently we developed the cable prototype with four HTS layers in the core and two layers in the shield. Numerical optimization of compact cables has been used together with manufacturing technology to produce small diameter cables with uniform current distribution. The first cold test of the compact cable demonstrated that we were able to control the homogeneous current distributions in a compact cable with the inner diameter of the core ~10 mm and the outer diameter of the shield ~20 mm. In this work we present more test results of this cable, including, mechanical test and high voltage tests. New test results demonstrated very high parameters of the compact cable developed. The compact cables perspectives for electric systems are discussed.
Development and test of a 35 kA - HTS CroCo cable demonstrator
Authors: Weiss K-P , Fietz W H , Heiduk M , Lange C , Preuß A , Wolf M J 
Published: June 2020

Abstract
The answer to energy-efficient electric power transfer of high currents in the range of several tens of kA can be given by high temperature superconducting (HTS) cables. BSCCO and MgB2 have been used widely for such cables, reaching maximum currents of about 20 kA. REBCO coated conductors are promising for future HTS cables beyond 20 kA and allow the operation based on subcooled liquid nitrogen. Several cabling concepts based on REBCO tapes were developed world-wide to realize such cables. Using the stacked-tape concept, a scalable semi-industrial process was developed by KIT, called HTS CrossConductor (HTS CroCo). Key aspects of the conceptual design of high-current HTS cables are discussed and the design of a 35 kA DC cable demonstrator made from HTS CroCo strands is presented. Aspects regarding joints, current redistribution between individual strands and electrical stabilization are highlighted. The performance of this demonstrator cable was tested, reaching the envisaged current.
The 2nd in-grid operation of superconducting cable in Yokohama project
Authors: Masuda Takato , Watanabe Michihiko , Mimura Tomoo , Tanazawa Masayuki , Yamaguchi Hirohito 
Published: June 2020

Abstract
The superconducting cable system was installed and operated in the real grid of Tokyo Electric Company (TEPCO) Holdings from 2012 to 2013, successfully. At this operation, the system had no degradation of its electrical and mechanical performances. After then, its cooling system was replaced to new turbo-Brayton refrigerator and the cable was re-connected to the grid in 2017. The cable system was successfully operated for another one year. In this operation, stable cooling system controlling, heat loads and vacuum rates of the cryostats etc. were observed continuously. After the operation, No Ic degradation of whole length was measured. In addition, the short sample cables cut from the system after the dismantlement, were applied with AC 90 kV and Imp 385 kV, successfully as the same condition of the shipping test in 2011. These results are one of the credibility confirmations for long time superconducting cable system operation.
Feasibility Assessment of the New Configuration of an Electric Power Grid with 23 kV Tri-axial HTS Power Cables for an Urban Power Supply
Authors: Lee C , Yang H , Choi J , Park M , Iwakuma M 
Published: June 2020

Abstract
The advantage of high temperature superconducting (HTS) power cables is that they can transmit large amounts of power at relatively low voltages, which can be used to reduce the number of lines in transmission cables or to configure a power grid at lower voltages. Because the commercial operation of 23 kV HTS power cables has begun, the optimal configuration between the 154 kV transformer substations and the 23 kV switching stations connected by the 23 kV HTS cables must be reviewed. In this paper, the new power supply model using 23 kV tri-axial HTS cables is presented for an urban power supply, and the economic feasibility is reviewed to present the appropriate cable capacity selection that matches the 23 kV switching stations.
Electrical and cryogenic tests of the 1200 m HTS DC cable system
Authors: Sytnikov V E , Kashcheev A V , Dubinin M V , Ryabin T V 
Published: June 2020

Abstract
Comprehensive tests of all the components of the HTS DC line were carried out as a part of the project to create a superconducting cable line with a capacity of 50 MW for the power system of St. Petersburg. HTS DC cable line will connect two substations of different voltage in the center of the city. The experimental stand included several cable lengths with joints and current leads, a reverse cryostat, a two-circuit cryogenic system with a capacity of 12 kW at 77K, a converter station and a control and monitoring system. The total length of the cryogenic line exceeded 1200 meters. The report presents the results of vacuum, cryogenic and electrical tests carried out over several months. The electrical and hydraulic characteristics of the HTS cable line were determined. Some emergency modes of the cryogenic system were studied. The possible time of cable operation in various accidents in the cryogenic system was estimated.
Heat extraction from HTS tape stacks applied in a superconducting motor in different cooling conditions
Authors: Tomkow Lukasz , Mineev Nikolay , Smara Anis , Climente-Alarcon Vicente , Glowacki Bartek A. 
Published: June 2020

Abstract
The heat is generated inside the stack of superconducting tapes mounted on the surface of the electrical machine rotor during its operation and magnetization. Cooling of such stack presents challenges because of the layered structure of both tape, and stack. Moreover, the tapes should be electrically isolated to minimize the AC losses, that assumes gluing them, rather than soldering. The calculations consider a conductive heat dissipation also through the rotor iron.
Results show that: liquid nitrogen provides an effective cooling; the temperature of the stack shows complex distribution patterns with the gaseous coolant. Additional preventive measures were analyzed to keep the stack operational in vacuum conditions.