Pulsed Laser Deposition (PLD) offers a powerful route for the fabrication of high-quality YBCO films with exceptional crystallographic alignment. In this study, the influence of film thickness on the corresponding electrical properties was investigated, with a particular emphasis on their correlation with microstructural features. Transport measurements indicate that the critical current density (Jc) shows a progressive decline as the film thickness increases, a phenomenon that can be directly related to the microstructural characteristics observed. These findings provide valuable insight into the inherent challenges associated with growing thick films and may guide future strategies for optimizing their properties in high-field applications. Furthermore, understanding these mechanisms is crucial for advancing the design and performance of high-temperature superconducting magnets and other electronic devices that require thick, high-performance films.
{"title":"Optimization of High-Quality YBCO Thin Films Deposited by PLD as a Function of Thickness","authors":"Violetta Poletto Dotsenko;Antonella Mancini;Achille Angrisani Armenio;Alessandro Rufoloni;Alessandra Fava;Giovanni Sotgiu;Francesco Rizzo","doi":"10.1109/TASC.2026.3652031","DOIUrl":"https://doi.org/10.1109/TASC.2026.3652031","url":null,"abstract":"Pulsed Laser Deposition (PLD) offers a powerful route for the fabrication of high-quality YBCO films with exceptional crystallographic alignment. In this study, the influence of film thickness on the corresponding electrical properties was investigated, with a particular emphasis on their correlation with microstructural features. Transport measurements indicate that the critical current density (<italic>J<sub>c</sub></i>) shows a progressive decline as the film thickness increases, a phenomenon that can be directly related to the microstructural characteristics observed. These findings provide valuable insight into the inherent challenges associated with growing thick films and may guide future strategies for optimizing their properties in high-field applications. Furthermore, understanding these mechanisms is crucial for advancing the design and performance of high-temperature superconducting magnets and other electronic devices that require thick, high-performance films.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082105","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3652116
Shunta Ito;Ataru Ichinose;Tomoya Horide;Yutaka Yoshida
To achieve both high in-field critical current density (Jc) and high deposition rates in REBa2C3Oγ (REBCO) coated conductors, we investigated liquid-phase-assisted crystal growth using a non-stoichiometric target composition. Conventional pulsed laser deposition (PLD) with a stoichiometric target suffers from degradation of BaHfO3 (BHO) nanorod alignment at high deposition rates, resulting in a significant reduction in Jc. In this study, a newly designed target with the composition Y:Ba:Cu = 1:2.3:3.7 was employed to induce liquid-phase formation during PLD growth. Structural and compositional analyses revealed the presence of Cu-rich precipitates and microstructural features characteristic of liquid-mediated growth. The use of a YBCO+BHO seed layer prevented the reaction between Ba species and the CeO2 surface of the substrate. Consequently, the formation of BaCeO3 was effectively suppressed at elevated substrate temperatures. Furthermore, YBCO+BHO films grown from the non-stoichiometric target maintained well-aligned nanorods even at high deposition frequencies (100 Hz), exhibiting Jc values comparable to those of films deposited at low rates. These findings demonstrate that liquid-phase-assisted growth enabled by non-stoichiometric target design is an effective strategy for achieving both high Jc and high-rate deposition in REBCO films. This approach provides new insights into the control of liquid-phase formation in PLD processes and offers a promising pathway for cost-effective fabrication of high-performance coated conductors.
{"title":"Liquid-Assisted Growth in Non-Stoichiometric YBa2Cu3Oy+BaHfO3 Films for High-Rate Deposition with Enhanced Jc","authors":"Shunta Ito;Ataru Ichinose;Tomoya Horide;Yutaka Yoshida","doi":"10.1109/TASC.2026.3652116","DOIUrl":"https://doi.org/10.1109/TASC.2026.3652116","url":null,"abstract":"To achieve both high in-field critical current density (<italic>J</i><sub>c</sub>) and high deposition rates in REBa<sub>2</sub>C<sub>3</sub>O<sub>γ</sub> (REBCO) coated conductors, we investigated liquid-phase-assisted crystal growth using a non-stoichiometric target composition. Conventional pulsed laser deposition (PLD) with a stoichiometric target suffers from degradation of BaHfO<sub>3</sub> (BHO) nanorod alignment at high deposition rates, resulting in a significant reduction in <italic>J</i><sub>c</sub>. In this study, a newly designed target with the composition Y:Ba:Cu = 1:2.3:3.7 was employed to induce liquid-phase formation during PLD growth. Structural and compositional analyses revealed the presence of Cu-rich precipitates and microstructural features characteristic of liquid-mediated growth. The use of a YBCO+BHO seed layer prevented the reaction between Ba species and the CeO<sub>2</sub> surface of the substrate. Consequently, the formation of BaCeO<sub>3</sub> was effectively suppressed at elevated substrate temperatures. Furthermore, YBCO+BHO films grown from the non-stoichiometric target maintained well-aligned nanorods even at high deposition frequencies (100 Hz), exhibiting <italic>J</i><sub>c</sub> values comparable to those of films deposited at low rates. These findings demonstrate that liquid-phase-assisted growth enabled by non-stoichiometric target design is an effective strategy for achieving both high <italic>J</i><sub>c</sub> and high-rate deposition in REBCO films. This approach provides new insights into the control of liquid-phase formation in PLD processes and offers a promising pathway for cost-effective fabrication of high-performance coated conductors.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026388","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3653349
Yusuke Sogabe;Sho Honda;Naoyuki Amemiya
Spiral Copper-plated Striated Coated-conductor (SCSC) cables are anticipated to be a game-changer for ac applications of high-temperature superconducting technology due to their low ac losses and high robustness. Experiments and numerical electromagnetic field analyses have confirmed that the structure of SCSC cables is effective in reducing dynamic losses and dynamic resistances, which is a problem in flux pumps and rotating machines. However, these results were confirmed for a single copper-plated multifilament coated conductor in a spiral configuration. It remains unclear whether they hold true for SCSC cables with the multilayer structure required for practical current-carrying capacity. Particularly, there is concern that the effect of reducing the dynamic resistance of SCSC cables may be lost due to tape-to-tape interactions caused by an increase in the number of layers or the number of tapes within a layer. We evaluated this using numerical electromagnetic field analyses.
{"title":"Numerical Electromagnetic Field Analyses of Dynamic Losses and Dynamic Resistances in Multilayered Spiral Copper-Plated Striated Coated-Conductor Cables","authors":"Yusuke Sogabe;Sho Honda;Naoyuki Amemiya","doi":"10.1109/TASC.2026.3653349","DOIUrl":"https://doi.org/10.1109/TASC.2026.3653349","url":null,"abstract":"Spiral Copper-plated Striated Coated-conductor (SCSC) cables are anticipated to be a game-changer for ac applications of high-temperature superconducting technology due to their low ac losses and high robustness. Experiments and numerical electromagnetic field analyses have confirmed that the structure of SCSC cables is effective in reducing dynamic losses and dynamic resistances, which is a problem in flux pumps and rotating machines. However, these results were confirmed for a single copper-plated multifilament coated conductor in a spiral configuration. It remains unclear whether they hold true for SCSC cables with the multilayer structure required for practical current-carrying capacity. Particularly, there is concern that the effect of reducing the dynamic resistance of SCSC cables may be lost due to tape-to-tape interactions caused by an increase in the number of layers or the number of tapes within a layer. We evaluated this using numerical electromagnetic field analyses.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026497","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3651414
Caida Fu;Chiheng Dong;Meng Han;He Huang;Dongliang Wang;Xianping Zhang;Yanwei Ma
The scalable manufacturing of high-performance iron-based superconducting (IBS) tapes is contingent upon solving two critical challenges in rolling processes: the lack of uniform core densification and the occurrence of cross-sectional distortion known as the saddle-core morphology. Both issues originate from the mechanical incompatibility between the silver sheath and the porous superconducting core, which leads to nonuniform compaction and degraded current transport. Here, we establish a multi-scale finite element model that explicitly couples the elastoplastic deformation of the silver sheath with the compaction behavior of the superconducting core governed by a modified Drucker-Prager Cap model. The simulations show that high interfacial friction between the silver sheath and the flat roller induces shear dilation and bulging, while low initial core density amplifies strain inhomogeneity. Guided by these mechanisms, we demonstrate that applying interfacial lubrication and optimizing initial packing density and rolling reduction can suppress dilation and enable homogeneous densification. This work delivers essential theoretical insights and practical guidance for the production of high-performance IBS tapes for high-field applications.
{"title":"Lubrication-Enabled Homogeneous Densification and Morphology Control in Iron-Based Superconducting Tapes","authors":"Caida Fu;Chiheng Dong;Meng Han;He Huang;Dongliang Wang;Xianping Zhang;Yanwei Ma","doi":"10.1109/TASC.2026.3651414","DOIUrl":"https://doi.org/10.1109/TASC.2026.3651414","url":null,"abstract":"The scalable manufacturing of high-performance iron-based superconducting (IBS) tapes is contingent upon solving two critical challenges in rolling processes: the lack of uniform core densification and the occurrence of cross-sectional distortion known as the saddle-core morphology. Both issues originate from the mechanical incompatibility between the silver sheath and the porous superconducting core, which leads to nonuniform compaction and degraded current transport. Here, we establish a multi-scale finite element model that explicitly couples the elastoplastic deformation of the silver sheath with the compaction behavior of the superconducting core governed by a modified Drucker-Prager Cap model. The simulations show that high interfacial friction between the silver sheath and the flat roller induces shear dilation and bulging, while low initial core density amplifies strain inhomogeneity. Guided by these mechanisms, we demonstrate that applying interfacial lubrication and optimizing initial packing density and rolling reduction can suppress dilation and enable homogeneous densification. This work delivers essential theoretical insights and practical guidance for the production of high-performance IBS tapes for high-field applications.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082055","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3651428
Caitlyn Stone-Whitehead;Israel Hernandez;Connor Bray;Allison Davenport;Spencer Fretwell;Abigail Gillespie;Joren Husic;Mingyu Li;Andrew Marino;Kyle Leach;Bismah Rizwan;Wouter Van De Pontseele;Grace Wagner
Superconducting detectors with sub-eV energy resolution have demonstrated success setting limits on Beyond the Standard Model (BSM) physics due to their unique sensitivity to low-energy events. G4CMP, a Geant4-based extension for condensed matter physics, provides a comprehensive toolkit for modeling phonon and charge dynamics in cryogenic materials. This paper introduces a technical formalism to support the superconducting qubit and low-threshold detector community in implementing phonon simulations in custom materials into the G4CMP. As a case study, we present the results of a detailed analysis of silica phonon transport properties relevant for simulating substrate backgrounds in Beryllium Electron capture in Superconducting Tunnel junctions (BeEST)-style experiments using G4CMP. Additionally, Python-based tools were developed to aid users in implementing their own materials and are available on the G4CMP repository.
具有亚ev能量分辨率的超导探测器由于其对低能事件的独特敏感性，已经成功地为超越标准模型（BSM）物理设定了限制。G4CMP是一个基于geant4的凝聚态物理扩展，为低温材料中的声子和电荷动力学建模提供了一个全面的工具包。本文介绍了一种技术形式，以支持超导量子比特和低阈值探测器社区在G4CMP中实现定制材料中的声子模拟。作为一个案例研究，我们介绍了使用G4CMP模拟超导隧道结（BeEST）中铍电子捕获（Electron capture in Superconducting Tunnel junction, BeEST）式实验中与衬底背景相关的硅声子输运特性的详细分析结果。此外，开发了基于python的工具来帮助用户实现他们自己的材料，这些工具可以在G4CMP存储库中获得。
{"title":"Integration of Silica in G4CMP for Phonon Simulations: Framework and Tools for Material Integration","authors":"Caitlyn Stone-Whitehead;Israel Hernandez;Connor Bray;Allison Davenport;Spencer Fretwell;Abigail Gillespie;Joren Husic;Mingyu Li;Andrew Marino;Kyle Leach;Bismah Rizwan;Wouter Van De Pontseele;Grace Wagner","doi":"10.1109/TASC.2026.3651428","DOIUrl":"https://doi.org/10.1109/TASC.2026.3651428","url":null,"abstract":"Superconducting detectors with sub-eV energy resolution have demonstrated success setting limits on Beyond the Standard Model (BSM) physics due to their unique sensitivity to low-energy events. G4CMP, a Geant4-based extension for condensed matter physics, provides a comprehensive toolkit for modeling phonon and charge dynamics in cryogenic materials. This paper introduces a technical formalism to support the superconducting qubit and low-threshold detector community in implementing phonon simulations in custom materials into the G4CMP. As a case study, we present the results of a detailed analysis of silica phonon transport properties relevant for simulating substrate backgrounds in Beryllium Electron capture in Superconducting Tunnel junctions (BeEST)-style experiments using G4CMP. Additionally, Python-based tools were developed to aid users in implementing their own materials and are available on the G4CMP repository.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057657","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3652485
K. Sakai;J. S. Adams;C. V. Ambarish;S. R. Bandler;J. A. Chervenak;T. Farrahi;F. M. Finkbeiner;J. D. Fuhrman;S. V. Hull;R. L. Kelley;C. A. Kilbourne;H. Muramatsu;F. S. Porter;S. J. Smith;N. A. Wakeham;E. J. Wassell
We present a novel noise modulation technique using superconducting quantum interference device (SQUID) gain switching for time division multiplexing (TDM) readout systems that reduces 1/f noise by a factor of 3.5 while preserving the architectural simplicity that makes TDM a widely used technique for transition edge sensor (TES) arrays. In contrast to frequency division multiplexing or microwave multiplexing, where signal modulation inherently provides immunity to low-frequency noise, conventional TDM systems can be susceptible to 1/f noise from downstream electronics as the TES signals remain in the low-frequency band. In our approach, the operating point of the SQUID amplifier alternates between positive and negative gain slopes at the frame frequency, combined with synchronized digital inversion of the error signals prior to flux-locked loop integration. This modulation scheme shifts the readout noise, including the 1/f components of low noise amplifiers, analog-to-digital converters and room temperature electronics, into the frame frequency range where it can be separated from the DC-TES signal by decimation filtering. Laboratory validation using an 8 column ×32 row TDM platform designed for Athena X-IFU applications shows a reduction in 1/f noise from 73 pA/√Hz@1 Hz (9.3 µΦ0/√Hz) to 21 pA/√Hz@1 Hz (2.7 µΦ0/√Hz) in channels with no TES connected, with the additional benefits of a 14-fold reduction in SQUID bias sensitivity through dynamic resistance matching and a 6.5-fold reduction in temperature-induced baseline drift. The technique avoids the disadvantage of doubling white noise, which occurs with conventional noise subtraction methods, and at the same time achieves a comparable suppression of 1/f noise. Implementation requires only minor firmware modifications to existing TDM systems, making it easily implementable for far-infrared bolometric and X-ray spectroscopy applications.
{"title":"1/f Noise Reduction With Noise Modulation in Time-Division Multiplexing","authors":"K. Sakai;J. S. Adams;C. V. Ambarish;S. R. Bandler;J. A. Chervenak;T. Farrahi;F. M. Finkbeiner;J. D. Fuhrman;S. V. Hull;R. L. Kelley;C. A. Kilbourne;H. Muramatsu;F. S. Porter;S. J. Smith;N. A. Wakeham;E. J. Wassell","doi":"10.1109/TASC.2026.3652485","DOIUrl":"https://doi.org/10.1109/TASC.2026.3652485","url":null,"abstract":"We present a novel noise modulation technique using superconducting quantum interference device (SQUID) gain switching for time division multiplexing (TDM) readout systems that reduces 1/f noise by a factor of 3.5 while preserving the architectural simplicity that makes TDM a widely used technique for transition edge sensor (TES) arrays. In contrast to frequency division multiplexing or microwave multiplexing, where signal modulation inherently provides immunity to low-frequency noise, conventional TDM systems can be susceptible to 1/f noise from downstream electronics as the TES signals remain in the low-frequency band. In our approach, the operating point of the SQUID amplifier alternates between positive and negative gain slopes at the frame frequency, combined with synchronized digital inversion of the error signals prior to flux-locked loop integration. This modulation scheme shifts the readout noise, including the 1/<italic>f</i> components of low noise amplifiers, analog-to-digital converters and room temperature electronics, into the frame frequency range where it can be separated from the DC-TES signal by decimation filtering. Laboratory validation using an 8 column ×32 row TDM platform designed for Athena X-IFU applications shows a reduction in 1/<italic>f</i> noise from 73 pA/√Hz@1 Hz (9.3 µΦ<sub>0</sub>/√Hz) to 21 pA/√Hz@1 Hz (2.7 µΦ<sub>0</sub>/√Hz) in channels with no TES connected, with the additional benefits of a 14-fold reduction in SQUID bias sensitivity through dynamic resistance matching and a 6.5-fold reduction in temperature-induced baseline drift. The technique avoids the disadvantage of doubling white noise, which occurs with conventional noise subtraction methods, and at the same time achieves a comparable suppression of 1/f noise. Implementation requires only minor firmware modifications to existing TDM systems, making it easily implementable for far-infrared bolometric and X-ray spectroscopy applications.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175912","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3652506
Giacomo Gorla;M. D’Andrea;C. Macculi;G. Torrioli;L. Piro;F. Gatti;L. Ferrari Barusso
The Cryogenic AntiCoincidence detector (CryoAC) is a transition-edge sensor (TES)-based auxiliary detector designed to reduce the particle background of the X-ray Integral Field Unit instrument onboard the Athena X-ray observatory. In preparation for integration with the Focal Plane Assembly, we characterized two nearly identical CryoAC Demonstration Models (DM143 and DM144, the latter being selected as DM1.1) to assess their performance and evaluate the replicability and robustness of the fabrication process. We present here the results of transition curve measurements, thermal conductance evaluation between the TES, the absorber, and the thermal bath, as well as current–voltage characterization. The performance was validated using both background particle events and shielded radioactive sources (${}^{55}$Fe and ${}^{241}$Am).
{"title":"Characterization of CryoAC Demonstration Model 1.1 Candidates for the Athena X-IFU Instrument","authors":"Giacomo Gorla;M. D’Andrea;C. Macculi;G. Torrioli;L. Piro;F. Gatti;L. Ferrari Barusso","doi":"10.1109/TASC.2026.3652506","DOIUrl":"https://doi.org/10.1109/TASC.2026.3652506","url":null,"abstract":"The Cryogenic AntiCoincidence detector (CryoAC) is a transition-edge sensor (TES)-based auxiliary detector designed to reduce the particle background of the X-ray Integral Field Unit instrument onboard the Athena X-ray observatory. In preparation for integration with the Focal Plane Assembly, we characterized two nearly identical CryoAC Demonstration Models (DM143 and DM144, the latter being selected as DM1.1) to assess their performance and evaluate the replicability and robustness of the fabrication process. We present here the results of transition curve measurements, thermal conductance evaluation between the TES, the absorber, and the thermal bath, as well as current–voltage characterization. The performance was validated using both background particle events and shielded radioactive sources (<inline-formula><tex-math>${}^{55}$</tex-math></inline-formula>Fe and <inline-formula><tex-math>${}^{241}$</tex-math></inline-formula>Am).","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175953","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}
The properties of superconducting joints for REBa2Cu3Oy (REBCO, RE = rare earth) superconducting tapes fabricated using a slurry process were investigated. Microstructural observation revealed that a joining layer fabricated using a slurry was well-connected to the REBCO layer of the joined tape. The resistance and critical current of closed-loop samples containing slurry-processed superconducting joint were evaluated using current decay measurements. The joint resistance was found to be lower than 10−12 and 10−11 Ω at 4 and 77 K, respectively, in the self-field. It is inferred that a persistent current can flow through a slurry-processed superconducting joint. Conversely, in-field critical current was low and exhibited hysteresis due to weak links in the joining layer.
研究了浆料法制备REBa2Cu3Oy （REBCO, RE =稀土）超导带的超导接头性能。显微结构观察表明，用浆料制备的连接层与连接带的REBCO层连接良好。采用电流衰减法对含浆料加工超导接头的闭环试样的电阻和临界电流进行了计算。在自场中，在4 K和77 K时，接头电阻分别小于10−12和10−11 Ω。由此推断，在浆料加工的超导接头中可以产生持续电流。相反，由于连接层中的薄弱环节，场内临界电流较低，并表现出迟滞。
{"title":"Evaluation of Microstructure, Resistance, and Critical Current of REBCO Superconducting Joints Fabricated by Slurry Process","authors":"Yasuaki Takeda;Tomoko Eguchi;Ariane Keiko Albessard;Gen Nishijima","doi":"10.1109/TASC.2025.3649135","DOIUrl":"https://doi.org/10.1109/TASC.2025.3649135","url":null,"abstract":"The properties of superconducting joints for REBa<sub>2</sub>Cu<sub>3</sub>O<italic><sub>y</sub></i> (REBCO, RE = rare earth) superconducting tapes fabricated using a slurry process were investigated. Microstructural observation revealed that a joining layer fabricated using a slurry was well-connected to the REBCO layer of the joined tape. The resistance and critical current of closed-loop samples containing slurry-processed superconducting joint were evaluated using current decay measurements. The joint resistance was found to be lower than 10<sup>−12</sup> and 10<sup>−11</sup> Ω at 4 and 77 K, respectively, in the self-field. It is inferred that a persistent current can flow through a slurry-processed superconducting joint. Conversely, in-field critical current was low and exhibited hysteresis due to weak links in the joining layer.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982294","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3652454
S. V. Hull;J. S. Adams;C. V. Ambarish;S. R. Bandler;R. B. Borrelli;J. A. Chervenak;F. A. Colazo Petit;N. DeNigris;T. Farrahi;F. M. Finkbeiner;J. D. Fuhrman;R. L. Kelley;C. A. Kilbourne;H. Muramatsu;F. S. Porter;A. Rani;K. Sakai;S. J. Smith;N. A. Wakeham;E. J. Wassell;S. H. Yoon
The X-ray Integral Field Unit (X-IFU) on the NewAthena X-ray Observatory will fly a 1504 pixel transition-edge sensor (TES) microcalorimeter array to study the Hot and Energetic X-ray Universe. For the first time, we have developed and measured a flight-like X-IFU detector that matches the pixel design and array configuration of the planned flight model, including the now baselined 50 $mathrm{mu }$m × 30 $mathrm{mu }$m TES pixels as well as flight-like electrical and mechanical wafer interfaces. This detector has undergone detailed characterization at NASA Goddard Space Flight Center in preparation to serve as the development model array for the X-IFU instrument. We measured roughly 150 pixels distributed across the $sim$1.5-cm diameter hexagonal detector array to verify target adherence and spatial uniformity of key TES pixel parameters and performance metrics, including transition temperature, transition shape, normal-state resistance, conductance to thermal bath, complex impedance, and spectral resolution. The average spectral resolution at 6.9 keV is 2.01 $pm$ 0.31 eV, or 1.93 $pm$ 0.11 eV when removing 16 pixels with degraded performance from fabrication defects. For a smaller subset of pixels, we also verified that the pixel crosstalk and gain sensitivities meet requirements.
NewAthena x射线天文台上的x射线积分场单元（X-IFU）将飞行一个1504像素的过渡边缘传感器（TES）微热量计阵列来研究热高能x射线宇宙。我们首次开发并测量了一个类似飞行的X-IFU探测器，它与计划飞行模型的像素设计和阵列配置相匹配，包括现在基线的50 $mathrm{mu }$ m × 30 $mathrm{mu }$ m TES像素以及类似飞行的电气和机械晶圆接口。该探测器在美国宇航局戈达德太空飞行中心进行了详细的表征，准备作为X-IFU仪器的开发模型阵列。我们测量了分布在直径为$sim$ 1.5 cm的六边形探测器阵列上的大约150个像素，以验证关键TES像素参数和性能指标的目标粘附性和空间均匀性，包括转变温度、转变形状、正常状态电阻、热浴电导、复杂阻抗和光谱分辨率。6.9 keV时的平均光谱分辨率为2.01 $pm$ 0.31 eV，去除16个因制造缺陷导致性能下降的像素时为1.93 $pm$ 0.11 eV。对于较小的像素子集，我们还验证了像素串扰和增益灵敏度满足要求。
{"title":"Measurement of a Flight-Like TES Microcalorimeter Array for the NewAthena X-IFU Development Model","authors":"S. V. Hull;J. S. Adams;C. V. Ambarish;S. R. Bandler;R. B. Borrelli;J. A. Chervenak;F. A. Colazo Petit;N. DeNigris;T. Farrahi;F. M. Finkbeiner;J. D. Fuhrman;R. L. Kelley;C. A. Kilbourne;H. Muramatsu;F. S. Porter;A. Rani;K. Sakai;S. J. Smith;N. A. Wakeham;E. J. Wassell;S. H. Yoon","doi":"10.1109/TASC.2026.3652454","DOIUrl":"https://doi.org/10.1109/TASC.2026.3652454","url":null,"abstract":"The X-ray Integral Field Unit (X-IFU) on the NewAthena X-ray Observatory will fly a 1504 pixel transition-edge sensor (TES) microcalorimeter array to study the Hot and Energetic X-ray Universe. For the first time, we have developed and measured a flight-like X-IFU detector that matches the pixel design and array configuration of the planned flight model, including the now baselined 50 <inline-formula><tex-math>$mathrm{mu }$</tex-math></inline-formula>m × 30 <inline-formula><tex-math>$mathrm{mu }$</tex-math></inline-formula>m TES pixels as well as flight-like electrical and mechanical wafer interfaces. This detector has undergone detailed characterization at NASA Goddard Space Flight Center in preparation to serve as the development model array for the X-IFU instrument. We measured roughly 150 pixels distributed across the <inline-formula><tex-math>$sim$</tex-math></inline-formula>1.5-cm diameter hexagonal detector array to verify target adherence and spatial uniformity of key TES pixel parameters and performance metrics, including transition temperature, transition shape, normal-state resistance, conductance to thermal bath, complex impedance, and spectral resolution. The average spectral resolution at 6.9 keV is 2.01 <inline-formula><tex-math>$pm$</tex-math></inline-formula> 0.31 eV, or 1.93 <inline-formula><tex-math>$pm$</tex-math></inline-formula> 0.11 eV when removing 16 pixels with degraded performance from fabrication defects. For a smaller subset of pixels, we also verified that the pixel crosstalk and gain sensitivities meet requirements.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175919","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}
Pub Date : 2026-01-12DOI: 10.1109/TASC.2026.3653437
Jianghong Wan;Mathias Noe;Magnus Dam;Tabea Arndt
High-temperature superconducting distributed windings in fully superconducting rotating machines offer lower ac losses, less higher harmonics, and higher power density but face challenges in nonplanar coil design due to the mechanical limitation of the REBCO tapes. This article presents a segmentation method for designing nonplanar REBCO coils that meet geometric and mechanical limitations. To generate the nonplanar coil shape, we selectively combine three types of segments: easy-way bending, twisting, and helix. To prevent critical current degradation of the tape, the constraints of the corresponding design parameters for each segment will be displayed. With this method, we report a design proposal of a nonplanar coil shape for distributed double-layer windings in superconducting rotating machines.
{"title":"Segmentation Method for the Design of Nonplanar Coils With REBCO Tapes for Superconducting Rotating Machines","authors":"Jianghong Wan;Mathias Noe;Magnus Dam;Tabea Arndt","doi":"10.1109/TASC.2026.3653437","DOIUrl":"https://doi.org/10.1109/TASC.2026.3653437","url":null,"abstract":"High-temperature superconducting distributed windings in fully superconducting rotating machines offer lower ac losses, less higher harmonics, and higher power density but face challenges in nonplanar coil design due to the mechanical limitation of the REBCO tapes. This article presents a segmentation method for designing nonplanar REBCO coils that meet geometric and mechanical limitations. To generate the nonplanar coil shape, we selectively combine three types of segments: easy-way bending, twisting, and helix. To prevent critical current degradation of the tape, the constraints of the corresponding design parameters for each segment will be displayed. With this method, we report a design proposal of a nonplanar coil shape for distributed double-layer windings in superconducting rotating machines.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 2","pages":"1-9"},"PeriodicalIF":1.8,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026574","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}
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