IEEE Transactions on Applied Superconductivity最新文献

{"title":"Design of Hopfield Networks Based on Superconducting Coupled Oscillators","authors":"Ran Cheng;Christoph Kirst;Dilip Vasudevan","doi":"10.1109/TASC.2025.3545409","DOIUrl":"https://doi.org/10.1109/TASC.2025.3545409","url":null,"abstract":"The global energy shortage has driven the development of many energy-efficient computational platforms beyond Moore's law, among which brain-inspired neuromorphic computing is one of the promising solutions. Associative memory and pattern recognition are important computations solved by brain-inspired Hopfield networks. Classical Hopfield networks store memories via fixed point attractors of their dynamics. In oscillatory Hopfield networks, these attractors are replaced by periodic orbits. Here, we design an oscillatory Hopfield network based on coupled superconducting oscillators. We first employ a mathematical phase reduction approach to map networks of coupled superconducting rapid single flux quantum (RSFQ) ring oscillators to coupled Kuramoto phase-oscillator networks. We use this theory to numerically optimize the hardware's mutual inductances in order to directly match the phase-reduced superconducting oscillators to a model of phase-oscillator-based Hopfield networks. The resulting network can store multiple oscillatory phase-locked memory patterns and recover the patterns based on the initial phase conditions. As different pattern recognition tasks, or learning, require tunable connectivity strengths between the oscillatory nodes, we further employ a coupler circuit that enables tuning the coupling strength between two oscillators by applying an external flux. We demonstrate the functionality of our design through numerical simulations of a small example network with oscillators operating at 86 GHz and recognizing patterns within 10 ns. Our approach enables the learning and retrieval of dynamical memory patterns with a wide range of applications where rhythmic dynamic output is beneficial.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-9"},"PeriodicalIF":1.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Realization of a Monolithic, Planar SLUG Amplifier for the Quantum Electronics Toolbox","authors":"Gemma Chapman;Tom Godfrey;Jamie Potter;Laith Meti;Parth Bhandari;Ed Romans;John Gallop;Ling Hao","doi":"10.1109/TASC.2025.3549394","DOIUrl":"https://doi.org/10.1109/TASC.2025.3549394","url":null,"abstract":"The Superconducting Low-inductance Undulatory Galvanometer (SLUG) amplifier is an ultra-low noise rf amplifier that is simple to operate and can be designed for a wide range of microwave frequencies. A variant of the dc SQUID rf amplifier, the SLUG differs in that the rf signal is directly injected in the SQUID loop, allowing high frequency operation. Here, we realize a planar SLUG amplifier constructed with nanobridge weak-link junctions that is fabricated from a single layer of niobium. Impedance models for the SLUG gain element are presented in conjunction with a discussion of appropriate impedance matching techniques. Experimental characterization of a proof-of-concept SLUG amplifier designed with a single-stub tuning circuit show modulation of the SLUG operation frequency in line with biasing of the SLUG, a well-matched input network and forward gain of 8 dB.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10938301","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Improvement of LTS Undulators for Synchrotron Light Sources","authors":"Emanuela Barzi;Masaki Takeuchi;Daniele Turrioni;Akihiro Kikuchi","doi":"10.1109/TASC.2025.3540817","DOIUrl":"https://doi.org/10.1109/TASC.2025.3540817","url":null,"abstract":"The joint expertise of ANL and FNAL has led to the production of <inline-formula><tex-math>$text{Nb}_{3}text{Sn}$</tex-math></inline-formula> undulator magnets in operation in the ANL Advanced Photon Source (APS). These magnets showed performance reproducibility close to the short sample limit, and a design field increase of 20% at 820 A. However, the long training did not allow obtaining the expected 50% increase of the on-axis magnetic field with respect to the ∼1 T produced at 450 A current in the ANL NbTi undulator. To address this, 10-pole long undulator prototypes were fabricated, and CTD-101K was replaced as impregnation material with TELENE, an organic olefin-based thermosetting dicyclopentadiene resin produced by RIMTEC Corporation, Japan. Training and magnet retraining after a thermal cycle were nearly eliminated, with only a couple of quenches needed before reaching short sample limit at over 1,100 A. TELENE will enable operation of <inline-formula><tex-math>$text{Nb}_{3}text{Sn}$</tex-math></inline-formula> undulators much closer to their short sample limit, expanding the energy range and brightness intensity of light sources. TELENE is Co-60 gamma radiation resistant up to 7–8 MGy, and therefore already applicable to impregnate planar, helical and universal devices operating in lower radiation environments than high energy colliders.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Current Leads Test for FECR Cryostat","authors":"Xudong Wang;Zian Zhu;Shijun Zheng;Dongsheng Ni;Li Zhu;Lishi Wang;Yue Cheng;Xiangqi Qin;Qinggao Yao;Liangting Sun","doi":"10.1109/TASC.2025.3551635","DOIUrl":"https://doi.org/10.1109/TASC.2025.3551635","url":null,"abstract":"To fulfill the normal operational requirements of the fourth generation electron cyclotron resonance ion source (FECR) superconducting magnet, a cryostat in the form of liquid helium immersion was designed based on several Giffod McMahon cryocoolers. Considering the substantial number of current leads (a total of 9) and the high current value (with the maximum current of 709 A) of the superconducting magnet, a dedicated current lead test platform was designed and constructed to ensure operational stability and thermal management of the cryostat. This platform was utilized to conduct comprehensive tests on the high temperature superconductivity (HTS) leads and room temperature copper leads intended for use in the cryostat, including quantitative evaluation of conductive heating load and Joule heating load under operational conditions. The test results demonstrate that the designed leads can meet the normal working requirements of the FECR cryostat, achieving a maximum current capacity of 720 A with heat load of 28.88 W per copper lead and 0.12 W per HTS lead, respectively.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 3","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Axial Tensile/Transverse Compressive Stress Characteristics of Advanced Cu-Nb Reinforced Nb3Sn Wires for 33 T Cryogen-Free Superconducting Magnet","authors":"R. Taniguchi;M. Sugimoto;H. Fukushima;K. Nakao;K. Hirose;S. Awaji;H. Oguro","doi":"10.1109/TASC.2025.3551277","DOIUrl":"https://doi.org/10.1109/TASC.2025.3551277","url":null,"abstract":"Nb-rod method Cu-Nb reinforced Nb₃Sn wires (Cu-Nb/Nb₃Sn wires) have been applied in various applications as one of high strength Nb₃Sn wires and 25 T cryogen-free superconducting magnet (25 T-CSM) at Tohoku University is one of the successful examples. To further strengthen the Cu-Nb/Nb₃Sn strands for a 33 T cryogen-free superconducting magnet (33 T-CSM), currently under construction at Tohoku university, we implemented the following modifications: increasing Cu-Nb fraction, niobium content in Cu-Nb and tin content in the bronze material. The strands were cabled into 16- or 18-strands Rutherford cables and pre-bent with -0.30% to +0.31% strain after heat treatment for Nb₃Sn reaction. The heat treatment conditions were 670 °C × 96 h (HT-A) or 575 °C × 100 h +670 °C × 50 h (HT-B), depending on the critical current (<italic>I</i>_c) requirement of the magnets. To evaluate the performance of the Cu-Nb/Nb₃Sn wires, we measured the <italic>I</i>_c of both non-cabled strands and strands extracted from the cables under axial tensile stress and transverse compression stress at 14.5 T and 4.2 K, respectively. Under tensile stress, the <italic>I</i>_c of the 33 T-CSM wire with HT-A reached a peak at 251 MPa and became the same <italic>I</i>_c as zero applied stress/strain at 345 MPa. This is significantly higher than the previous Cu-Nb/Nb₃Sn wires for the 25 T-CSM, which had a peak <italic>I</i>_c at 215 MPa and the same <italic>I</i>_c as zero applied stress/strain at 300 MPa. An increase of residual strain by 0.049% was also observed. Regarding transverse compression characteristics, the 33 T-CSM strands maintained their initial <italic>I</i>_c value under higher compression stress compared to the 25 T-CSM wires and cabling process caused no degradation in compressive stress performance in 33 T-CSM strands.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistance of High-Temperature Superconducting Tapes Triggered by Alternating Magnetic Field","authors":"Quoc Hung Pham;Rainer Nast;Mathias Noe","doi":"10.1109/TASC.2025.3550837","DOIUrl":"https://doi.org/10.1109/TASC.2025.3550837","url":null,"abstract":"Dynamic resistance occurs in a superconducting tape carrying a dc transport current while being exposed to an alternating magnetic field. This effect is caused by flux movements interacting with the transport current. The dynamic resistance is already applied in many superconducting applications, for example, superconducting flux pumps or persistent current switches. The resistance is highly dependent on the magnetic field and the frequency the superconductor is subjected to and its properties. When the dynamic resistance exceeds a certain value and, thus, enters the magnitude of the resistances of the normal conducting layers of the high-temperature superconducting (HTS) tape, these normal conducting layers play a significant role in the total resistance of the tape. In this article, modifications were made to the silver stabilizer, and the total resistance of the HTS tape has been investigated. The experimental results with frequencies up to 1000 Hz and magnetic field up to 277 mT show significant increases in resistance. In addition, a multilayer model based on H-formulation is presented to calculate the losses of the superconductor. The results also show significant heating due to the losses and, therefore, a temperature rise, which affects the measured total resistance. These results can be further used for applications, where high switchable resistances are required with zero dc resistance when the magnet is turned <sc>off</small>.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 3","pages":"1-8"},"PeriodicalIF":1.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of Transport Critical Currents at 4.2 K – 20 K at Magnetic Fields Up to 31 T for MOCVD REBCO Conductors With Variable Zr and Growth Conditions","authors":"D. Abraimov;J. Gillman;C. Zha;Y. Oz;H. Pimentel;S. Mao;J. Kvitkovic;G. Bradford;J. Lee;J. Jaroszynski;N. Bishop;Y. Zhang","doi":"10.1109/TASC.2025.3549409","DOIUrl":"https://doi.org/10.1109/TASC.2025.3549409","url":null,"abstract":"The critical current, <inline-formula><tex-math>$I_{mathrm{c}}$</tex-math></inline-formula>, of REBCO full-width 4 mm short samples made by metal-organic chemical vapor deposition (MOCVD), optimized for high-field applications, were measured at magnetic fields perpendicular to sample plane up to 31.2 T in resistive magnets and temperature range <inline-formula><tex-math>${text{4.2}},{text{K}}$</tex-math></inline-formula>–55 K. Dependencies of <inline-formula><tex-math>$I_{mathrm{c}}$</tex-math></inline-formula>, critical current density (<inline-formula><tex-math>$J_{mathrm{c}}$</tex-math></inline-formula>), and pinning force density (<inline-formula><tex-math>$F_{mathrm{p}}$</tex-math></inline-formula>) on Zr doping and REBCO growth conditions were studied. SEM images of cross-section and top view of the REBCO layers for tapes with 15%, 20%, and 25% Zr doping show dense REBCO layers without secondary phases or porosity. REBCO tapes with 20% and 25% Zr doping perform better in transport <inline-formula><tex-math>$I_{mathrm{c}}$</tex-math></inline-formula>(<italic>T,</i><inline-formula><tex-math>$mu _{o}H$</tex-math></inline-formula>) tests at 20 K and 20 T conditions than tapes with lower Zr doping and can be promising candidates for applications focusing on magnetic plasma confinement.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resistance and Voltage–Current Characteristics of REBCO Superconducting Joint","authors":"Yasuaki Takeda;Gen Nishijima;Hitoshi Kitaguchi","doi":"10.1109/TASC.2025.3550140","DOIUrl":"https://doi.org/10.1109/TASC.2025.3550140","url":null,"abstract":"We discuss resistance and voltage–current characteristics of a REBa₂Cu₃O<italic>_y</i> (REBCO, RE = rare earth) intermediate grown superconducting (iGS) joint. These characteristics are evaluated based on the current decay measurements for a REBCO closed loop. The temperature and magnetic field dependencies of the <italic>n</i> value for the iGS joint, assessed using an empirical power-law model, are similar to those observed for REBCO tapes. The percolation model describes the voltage–current characteristics of the iGS joint more accurately. Using the critical current and <italic>n</i> values at 10⁻⁸ V, we can approximately estimate the upper limit of the current for a low target resistance.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143726576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of Fast Transients in Nb3Sn Magnets by Using a Static Harmonic-Coil","authors":"Piotr Rogacki;Lucio Fiscarelli;Arnaud Devred;Stephan Russenschuck","doi":"10.1109/TASC.2025.3550313","DOIUrl":"https://doi.org/10.1109/TASC.2025.3550313","url":null,"abstract":"An induction-coil magnetometer has been produced at CERN to determine the location of an incipient quench in the HL-LHC Nb<inline-formula><tex-math>$_{text{3}}$</tex-math></inline-formula>Sn inner-triplet quadrupoles. The instrument, known as a quench-antenna, allows the measurement of the position and propagation of quenches with a reduced number of acquisition channels. This is possible because four layers of nested coils are designed to be sensitive only to the normal and skew sextupole and octupole components. Moreover, the magnetometer allows the study of fast magnetic transients due to flux jumps observed during the ramping of Nb<inline-formula><tex-math>$_{text{3}}$</tex-math></inline-formula>Sn superconducting accelerator magnets. This paper presents the observation and characterization of flux jumps during powering ramps similar to machine operations. Spatial and temporal distributions of flux jumps are derived from the induced voltages in the quench-antenna as a function of the transport current. Modeling flux jumps as traveling magnetic moments allows the reconstruction of the effect in terms of position and magnitude and, thus, an estimation of the impact on the magnetic field quality.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10921665","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the Behavior of Superconducting Nanostructured Switching Device by the Numerical Calculation","authors":"Masumi Inoue;Ikumi Miyazaki","doi":"10.1109/TASC.2025.3549384","DOIUrl":"https://doi.org/10.1109/TASC.2025.3549384","url":null,"abstract":"We investigated the properties and switching behavior of superconducting nanostructured device such as nanocryotron using numerical calculation methods. Superconducting nanostructured switching devices such as nanocryotron (nTron) are promising candidates for the interface between the single-flux-quantum (SFQ) circuit and the CMOS memory in building highly integrated superconducting circuits. Although some simulations have been performed, the detailed physics of its operation is not clear. Therefore, we are studying the behavior of superconducting nanostructured devices through numerical simulations using the thermal diffusion equation and the time-dependent Ginzburg-Landau (TDGL) equation. We previously reported on the simulation of a simple T-shaped line with a current confluence of a constant bias current and a short-time gate current. As the next step, we report the simulation on a T-shaped device with a constriction in the channel. We observed the variation in current, temperature, voltage generated in the channel, etc. during switching. Although the simulations in this report are ongoing, they will help analyze and understand the experimental results and are also expected to provide guidelines for device design.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}