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}
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.2026.3653437
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}
Equivalent contact resistivity is a key parameter that affects the dynamic process and overcurrent characteristic of the non-insulation (NI) high-temperature superconducting coil. Adding stainless steel material between turns of a parallel-wound NI coil results in the formation of various types of internal contact interfaces. Therefore, describing the shunt behavior of the coil, i.e., the parallel-wound metal-insulation (PWMI) coil, requires more than one equivalent contact resistivity, which makes it difficult to determine their specific values only through coil inductance and time constant. To handle this problem, we propose a method to acquire distinct equivalent contact resistivities of the PWMI coil. In this method, the equivalent contact resistivities are inverted based on the measured coil voltage or magnetic field. The bridge to connect the experimental data and equivalent contact resistivities is the streamlined field–circuit coupling model based on the T–A formulation, which can reflect the complex electromagnetic topology and the distribution of equivalent contact resistivities of the PWMI coil. After obtaining the measurement results, the least-squares method is used to optimize the equivalent contact resistivities until the simulation curve is sufficiently consistent with the experimental curve. In order to improve the efficiency of the optimization, we construct the lumped circuit model of the PWMI coil. Before the optimization process begins, the initial values of equivalent contact resistivities can be obtained based on this model, which can reduce the search scope of the optimization. The results of multiprocess testing indicate that using the equivalent contact resistivities obtained by the proposed method can effectively predict the transient behavior of the coil.
{"title":"Inversion of Equivalent Contact Resistivities of Parallel-Wound Metal-Insulation HTS Coil Based on Experimental Data and Multilevel Simulation","authors":"Hongzhuo Zeng;Qiuliang Wang;Yong Chen;Kangshuai Wang;Benzhe Zhou;Xiaoyu Ji;Fangliang Dong;Shunzhong Chen;Yinming Dai;Zili Zhang;Lei Wang;Jianhua Liu;Lei Qi","doi":"10.1109/TASC.2025.3650502","DOIUrl":"https://doi.org/10.1109/TASC.2025.3650502","url":null,"abstract":"Equivalent contact resistivity is a key parameter that affects the dynamic process and overcurrent characteristic of the non-insulation (NI) high-temperature superconducting coil. Adding stainless steel material between turns of a parallel-wound NI coil results in the formation of various types of internal contact interfaces. Therefore, describing the shunt behavior of the coil, i.e., the parallel-wound metal-insulation (PWMI) coil, requires more than one equivalent contact resistivity, which makes it difficult to determine their specific values only through coil inductance and time constant. To handle this problem, we propose a method to acquire distinct equivalent contact resistivities of the PWMI coil. In this method, the equivalent contact resistivities are inverted based on the measured coil voltage or magnetic field. The bridge to connect the experimental data and equivalent contact resistivities is the streamlined field–circuit coupling model based on the <italic>T</i>–<italic>A</i> formulation, which can reflect the complex electromagnetic topology and the distribution of equivalent contact resistivities of the PWMI coil. After obtaining the measurement results, the least-squares method is used to optimize the equivalent contact resistivities until the simulation curve is sufficiently consistent with the experimental curve. In order to improve the efficiency of the optimization, we construct the lumped circuit model of the PWMI coil. Before the optimization process begins, the initial values of equivalent contact resistivities can be obtained based on this model, which can reduce the search scope of the optimization. The results of multiprocess testing indicate that using the equivalent contact resistivities obtained by the proposed method can effectively predict the transient behavior of the coil.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 2","pages":"1-12"},"PeriodicalIF":1.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026575","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 : 2025-12-31DOI: 10.1109/TASC.2025.3649784
Yiming Ma;Yusuke Shimada;Hongye Gao;Yuta Hasegawa;Shinnosuke Tokuta;Akiyasu Yamamoto;Akinori Yamanaka;Satoshi Hata
For polycrystalline cobalt-doped BaFe2As2 (Ba122:Co) superconductors, controlling their microstructure, such as grain size, crystallographic texture, is crucial for achieving high critical current densities (Jc). A prevailing academic view holds that heat treatment is a key step in forming a desired crystallographic texture. This study performed in-situ heating and four-dimensional scanning transmission electron microscopy (4D-STEM) observation to characterize microstructural evolution in precursor Ba122:Co powders prepared by high-energy ball milling and subsequent spark plasma sintering. A formation path for the Ba122 phase was revealed: a crystallographic orientation relationship was recognized between fine Ba122 grains and adjacent larger FeAs grains in the precursor powders, which suggests epitaxial growth of the Ba122 phase from the FeAs phase. However, in the subsequent in-situ heating process, the microstructural changes in the thin foil specimens of the precursor powders exhibited a different trend from that of bulk specimens of the precursor powders: the fine Ba122 grains did not coarsen but exhibit grain refinement and amorphization. The observed results described above were discussed from the viewpoints of the microstructural control of polycrystalline Ba122:Co.
{"title":"Polycrystalline Phase Formation of Co-Doped BaFe2As2 Studied by In-Situ 4D-STEM","authors":"Yiming Ma;Yusuke Shimada;Hongye Gao;Yuta Hasegawa;Shinnosuke Tokuta;Akiyasu Yamamoto;Akinori Yamanaka;Satoshi Hata","doi":"10.1109/TASC.2025.3649784","DOIUrl":"https://doi.org/10.1109/TASC.2025.3649784","url":null,"abstract":"For polycrystalline cobalt-doped BaFe<sub>2</sub>As<sub>2</sub> (Ba122:Co) superconductors, controlling their microstructure, such as grain size, crystallographic texture, is crucial for achieving high critical current densities (<italic>J</i><sub>c</sub>). A prevailing academic view holds that heat treatment is a key step in forming a desired crystallographic texture. This study performed in-situ heating and four-dimensional scanning transmission electron microscopy (4D-STEM) observation to characterize microstructural evolution in precursor Ba122:Co powders prepared by high-energy ball milling and subsequent spark plasma sintering. A formation path for the Ba122 phase was revealed: a crystallographic orientation relationship was recognized between fine Ba122 grains and adjacent larger FeAs grains in the precursor powders, which suggests epitaxial growth of the Ba122 phase from the FeAs phase. However, in the subsequent in-situ heating process, the microstructural changes in the thin foil specimens of the precursor powders exhibited a different trend from that of bulk specimens of the precursor powders: the fine Ba122 grains did not coarsen but exhibit grain refinement and amorphization. The observed results described above were discussed from the viewpoints of the microstructural control of polycrystalline Ba122:Co.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026519","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 : 2025-12-31DOI: 10.1109/TASC.2025.3649790
Richard Pascua;Michael de Leon;Sang Heon Lee;Hyung-Seop Shin
Multilayer REBCO-coated conductor (CC) tapes undergo various stresses and strains when utilized in superconducting devices such as high-field magnets and coils. The stresses encountered by REBCO tapes include radial transverse tensile stresses from Lorenz forces and thermal stresses arising from differences in the thermal expansion coefficients of the constituent layers during quenching. These stresses can cause delamination at multiple interfaces within the REBCO CC tape’s multilayer architecture, compromising its integrity and leading to catastrophic failure of the superconducting device. Meanwhile, the Cu stabilizer surrounding the CC tape plays a key role in preventing delamination failure by binding multiple constituent layers with different mechanical properties and maintaining structural stability against transverse external forces. However, the effect of slit edges created during CC tape manufacturing on delamination resistance under transverse loading remains unclear. To address this critical research gap, we conducted comprehensive delamination tests using the anvil method. We compared the effects of the slit edge geometry and the Cu layer at the edges on the mechanical delamination strength of REBCO CC tapes. By conducting a comprehensive analysis, we aimed to examine the roles of edge geometry and interfacial properties in the delamination behavior of REBCO CC tapes. This will offer valuable insights for optimizing the design and fabrication of these high-field coils, contributing to the development of more robust and reliable superconducting devices.
{"title":"Effects of Edge Geometry and Interface Characteristics on Delamination Strength of REBCO Tapes Under Transverse Tension Using Anvil Method","authors":"Richard Pascua;Michael de Leon;Sang Heon Lee;Hyung-Seop Shin","doi":"10.1109/TASC.2025.3649790","DOIUrl":"https://doi.org/10.1109/TASC.2025.3649790","url":null,"abstract":"Multilayer REBCO-coated conductor (CC) tapes undergo various stresses and strains when utilized in superconducting devices such as high-field magnets and coils. The stresses encountered by REBCO tapes include radial transverse tensile stresses from Lorenz forces and thermal stresses arising from differences in the thermal expansion coefficients of the constituent layers during quenching. These stresses can cause delamination at multiple interfaces within the REBCO CC tape’s multilayer architecture, compromising its integrity and leading to catastrophic failure of the superconducting device. Meanwhile, the Cu stabilizer surrounding the CC tape plays a key role in preventing delamination failure by binding multiple constituent layers with different mechanical properties and maintaining structural stability against transverse external forces. However, the effect of slit edges created during CC tape manufacturing on delamination resistance under transverse loading remains unclear. To address this critical research gap, we conducted comprehensive delamination tests using the anvil method. We compared the effects of the slit edge geometry and the Cu layer at the edges on the mechanical delamination strength of REBCO CC tapes. By conducting a comprehensive analysis, we aimed to examine the roles of edge geometry and interfacial properties in the delamination behavior of REBCO CC tapes. This will offer valuable insights for optimizing the design and fabrication of these high-field coils, contributing to the development of more robust and reliable superconducting devices.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982242","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 : 2025-12-29DOI: 10.1109/TASC.2025.3644628
{"title":"IEEE Transactions on Applied Superconductivity Information for Authors","authors":"","doi":"10.1109/TASC.2025.3644628","DOIUrl":"https://doi.org/10.1109/TASC.2025.3644628","url":null,"abstract":"","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 1","pages":"C4-C4"},"PeriodicalIF":1.8,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11318111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879970","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}
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