IEEE Transactions on Applied Superconductivity最新文献

{"title":"Characteristic Timescales for the Operation of HTS CICCs in Compact Fusion Reactors","authors":"Marco Breschi;Laura Savoldi;Lorenzo Cavallucci;Luca Bottura","doi":"10.1109/TASC.2025.3554466","DOIUrl":"https://doi.org/10.1109/TASC.2025.3554466","url":null,"abstract":"In this work we address the shift from Low Temperature Superconductor (LTS) to High Temperature Superconductor (HTS) magnets presently occurring in the development of machines for controlled thermonuclear fusion with magnetic confinement. This shift implies several new challenges, which cannot be ignored in the design and modelling of the future HTS magnets. In this work, we identify the modelling needs driven by the adoption of HTS cables and coils technology for fusion machines. In particular, the characteristic times characterizing the development of the main physical phenomena occurring in HTS tapes, stacks and conductors are derived. These characteristics times in turn have a significant impact on the requirements of strong or weak coupling between different physics in the modelling of HTS magnets.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865268","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":"Optimization Design of Superconducting Shielding Layer in Double-Stator HTS Electrical Machine","authors":"Qidong Zhan;Xianglin Li;Mingzhe Sang;Shaorui Wang;Zhiheng Zhang;Haoyu Wang;Xinkai Zhu;Wei Hua","doi":"10.1109/TASC.2025.3553833","DOIUrl":"https://doi.org/10.1109/TASC.2025.3553833","url":null,"abstract":"High-temperature superconducting (HTS) electrical machines can offer high efficiency and power density, but the HTS magnets in these machines commonly suffer performance degradation caused by external alternating magnetic fields. Hence, superconducting shielding layers (SSLs) are used to enhance the critical current and reduce the AC loss of HTS magnets. Therefore, optimizing the design of SSLs is crucial to achieving the optimal performance of HTS magnets. In this paper, focusing on a double-stator HTS machine (DS-HTSM), a layered multi-objective optimization design based on parameter sensitivity analysis is conducted for SSLs, in which both the structural parameters and positions of SSLs are optimized simultaneously. A quantitative performance comparison of HTS magnets between initial and optimal design is conducted by using the finite element analysis (FEA), and the results demonstrate an improvement in the critical current safety margin, a significant reduction in AC loss, and effective space utilization, thus providing valuable insights for the design of high-performance HTS electrical machines.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817994","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":"Design and Implementation of a Mechanical Semipersistent Switch for HTS Magnets","authors":"Timon Käser;Snædís Björgvinsdóttir;Chukun Gao;Pin-Hui Chen;Michael Urban;Ronny Gunzenhauser;Alexander Däpp;Nicholas Alaniva","doi":"10.1109/TASC.2025.3553635","DOIUrl":"https://doi.org/10.1109/TASC.2025.3553635","url":null,"abstract":"Persistent-mode operation of superconducting magnets requires a persistent switch, usually a heater, to close their superconducting circuits. Here, we describe a mechanical copper switch that utilizes pressure to vary resistance. This switch is designed to provide a low-resistance short between two high-temperature superconducting (HTS) charging electrodes in an all-HTS pancake-coil magnet. The switch is able to achieve a contact resistance as low as 460 nΩ by pressing gold-coated copper surfaces together at 3.0 kN. At 77 K, with an HTS pancake coil charged to 0.45 T, the magnetic field decayed slowly with the switch closed. The decay fits to a 3.6-µΩ resistance, most of which arises from unrelated insufficient connections within the HTS magnet itself. The design shows the potential of building a persistent-mode superconducting magnet with a mechanical switch, where, as an example, a 30-T magnet with an inductance of 5.9 H has a field drift of −6 ppm/h.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10936986","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808935","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":"Compact Superconducting Kinetic Inductance Traveling Wave Parametric Amplifiers With On-Chip rf Components","authors":"L. Howe;A. Giachero;M. Vissers;J. Wheeler;J. Austermann;J. Hubmayr;J. Ullom","doi":"10.1109/TASC.2025.3553466","DOIUrl":"https://doi.org/10.1109/TASC.2025.3553466","url":null,"abstract":"Quantum computing systems and fundamental physics experiments using superconducting technologies frequently require signal amplification chains operating near the quantum limit of added noise. Both Josephson parametric amplifiers (JPAs) and traveling wave parametric amplifiers (TWPAs) have been used as first-stage amplifiers to enable readout chains operating within a few quanta or less of the quantum limit. These devices are also presently entering the commercial industry. However, nearly all demonstrations and existing products require bulky external microwave components for interconnection and application of requisite biases. These components – cabling interconnects, bias tees, directional couplers, and diplexers – increase the overall amplifier footprint, installation complexity, and reduce already limited available cryogenic volumes. Additionally, these components introduce loss and reflections which impact the measurement efficiency and readout system noise performance; thus making it more difficult to operate near the quantum limit. Here we present the design and validation of microfabricated bias tees and directional couplers for operating three-wave mixing kinetic inductance TWPAs (KITs). We report the performance of KITs integrated with the microfabricated rf components. Using these devices we demonstrate reduction in the amplifier installation footprint by a factor of nearly five and elimination of all external, lossy microwave components previously required to operate a KIT. Our device displays a 2.8 GHz 3 dB bandwidth with a median true gain of 17.5 dB and median system noise of 3.4 quanta. These efforts represent the first full integration of all rf components mandatory for TWPA operation on-chip. Our results mark significant progress towards the miniaturization and simplification of parametric amplifier setups and will aid in their more widespread applicability.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143777882","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":"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":"Research on End AC Loss and Electromagnetic Vibration of Superconducting Machine Based on 3-D H-Formulation","authors":"Chao Luo;Jiabo Shou;Jien Ma;Jie Chao;Youtong Fang","doi":"10.1109/TASC.2025.3552398","DOIUrl":"https://doi.org/10.1109/TASC.2025.3552398","url":null,"abstract":"In electrified drive systems, machine vibration has become as critical performance as power density. However, limited research has focused on the vibration characteristics of superconducting rotary machines. Most studies rely on 2-D numerical models that overlook the complex stacked racetrack superconducting coil end in the machine. The ac loss at the end in the complex and strong magnetic field needs precise calculation, as it subjects the stator end to significantly larger electromagnetic forces than those in conventional machines. It is crucial to analyze the magnetic field and coil vibrations caused by these forces and to investigate various end-fixation strategies. This article presents a comprehensive 3-D model of superconducting machines using the H-formulation, enabling accurate determination of electromagnetic performance under varying current conditions. The critical current density and ac losses in the superconducting coil ends are analyzed. This study further investigates the 3-D magnetic field distribution and the resulting electromagnetic vibrations, particularly in the stator armature windings. Significant electromagnetic forces are observed at the stator winding ends, leading to excessive vibration and deformation under rated conditions. The research also explores various end-fixation methods to mitigate these effects, ultimately enhancing the stability and performance of superconducting machines in next-generation low-carbon transportation systems.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 4","pages":"1-10"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792901","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":"Modeling Flux Tunability in Josephson Traveling Wave Parameteric Amplifiers With an Open-Source Frequency-Domain Simulator","authors":"Anna Levochkina;Isita Chatterjee;Pegah Darvehi;Halima Giovanna Ahmad;Pasquale Mastrovito;Davide Massarotti;Domenico Montemurro;Francesco Tafuri;Giovanni Piero Pepe;Kevin P. O'Brien;Martina Esposito","doi":"10.1109/TASC.2025.3552432","DOIUrl":"https://doi.org/10.1109/TASC.2025.3552432","url":null,"abstract":"Josephson traveling wave parameteric amplifiers (JTWPAs) are integral parts of many experiments carried out in quantum technologies. Being composed of hundreds of Josephson junction-based unit cells, such devices exhibit complex nonlinear behavior that typically cannot be fully explained with simple analytical models, thus necessitating the use of numerical simulators. A very useful characteristic of JTWPAs is the possibility of being biased by an external magnetic flux, allowing in-situ control of the nonlinearity. It is, therefore, very desirable for numerical simulators to support this feature. Open-source numerical tools that allow to model JTWPA flux biasing, such as <italic>WRSPICE</i> or <italic>PSCAN2</i>, are based on time-domain approaches, which typically require long simulation times to get accurate results. In this work, we model the gain performance in a prototypical flux-tunable JTWPA by using <italic>JosephsonCircuits.jl</i>, a recently developed frequency-domain open-source numerical simulator, which has the benefit of simulation times about 10 000 faster than time-domain methods. By comparing the numerical and experimental results, we validate this approach for modeling the flux dependent behavior of JTWPAs.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 3","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792933","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}