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}
Pub Date : 2025-12-26DOI: 10.1109/TASC.2025.3648679
Joshua D. Fuhrman;Fred M. Finkbeiner;Joseph S. Adams;Simon R. Bandler;Rachel B. Borrelli;James A. Chervenak;Tannaz Farrahi;Felipe A. Colazo Petit;Renata S. Cumbee;Samuel V. Hull;Richard L. Kelley;Caroline A. Kilbourne;Haruka Muramatsu;Frederick Scott Porter;Asha Rani;Kazuhiro Sakai;Stephen J. Smith;Ambarish C. Venkatasubraman;Nicholas A. Wakeham;Edward J. Wassell;Michael C. Witthoeft;Sang H. Yoon
The X-IFU instrument for ESA’s upcoming flagship mission Athena will use Mo/Au bilayer transition-edge sensors (TES) with Au/Bi X-ray absorbers to form a kilopixel microcalorimeter array. Such detectors require careful calibration to maintain their best possible performance, but such calibrations can change over long periods of time when exposed to certain environmental conditions. We have previously reported the effects of humidity and elevated temperature on prototype array characteristics. In that study, storage of a prototype array at 60 $^{circ }$C for ten days under vacuum produced an unexpected shift in the TES critical temperature T$_{c}$ (+13% to +19%) and normal resistance R$_{n}$ (+4%). In this work, we continue investigating shifts in array characteristics after long-duration temperature exposures so that safe storage and handling conditions for X-IFU flight arrays can be set. A prototype array exposed to 35 $^{circ }$C under vacuum for 26 days gradually increased in TES normal resistance. The energy scale of a second prototype array was measured before aging and then recovered to within 0.5 eV following a similar aging induced R$_{n}$ increase. Aging of the TES was studied directly by applying the same thermal conditions exclusively to Mo/Au bilayers on Si substrate. These measurements allow a better understanding of the cause of the observed shift by decoupling the TES bilayer from the remaining device structures, such as the SiNx membrane and the absorber. Four-point resistance measurements were used to readout the bilayer samples at 4.2 K. Bilayers aged in a vacuum generally saw no change or a slight increase in resistance, while bilayers aged in nitrogen gas decreased in resistance. Finally, we conclude with a comparative overview of all test results on prototype arrays and TES bilayers, elaborate on possible mechanisms for the observed shifts in characteristics, and make recommendations for maintaining the long-term stability of our devices.
{"title":"Accelerating Storage Lifetime Testing of Microcalorimeter Arrays for NewAthena X-IFU","authors":"Joshua D. Fuhrman;Fred M. Finkbeiner;Joseph S. Adams;Simon R. Bandler;Rachel B. Borrelli;James A. Chervenak;Tannaz Farrahi;Felipe A. Colazo Petit;Renata S. Cumbee;Samuel V. Hull;Richard L. Kelley;Caroline A. Kilbourne;Haruka Muramatsu;Frederick Scott Porter;Asha Rani;Kazuhiro Sakai;Stephen J. Smith;Ambarish C. Venkatasubraman;Nicholas A. Wakeham;Edward J. Wassell;Michael C. Witthoeft;Sang H. Yoon","doi":"10.1109/TASC.2025.3648679","DOIUrl":"https://doi.org/10.1109/TASC.2025.3648679","url":null,"abstract":"The X-IFU instrument for ESA’s upcoming flagship mission Athena will use Mo/Au bilayer transition-edge sensors (TES) with Au/Bi X-ray absorbers to form a kilopixel microcalorimeter array. Such detectors require careful calibration to maintain their best possible performance, but such calibrations can change over long periods of time when exposed to certain environmental conditions. We have previously reported the effects of humidity and elevated temperature on prototype array characteristics. In that study, storage of a prototype array at 60 <inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>C for ten days under vacuum produced an unexpected shift in the TES critical temperature T<inline-formula><tex-math>$_{c}$</tex-math></inline-formula> (+13% to +19%) and normal resistance R<inline-formula><tex-math>$_{n}$</tex-math></inline-formula> (+4%). In this work, we continue investigating shifts in array characteristics after long-duration temperature exposures so that safe storage and handling conditions for X-IFU flight arrays can be set. A prototype array exposed to 35 <inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>C under vacuum for 26 days gradually increased in TES normal resistance. The energy scale of a second prototype array was measured before aging and then recovered to within 0.5 eV following a similar aging induced R<inline-formula><tex-math>$_{n}$</tex-math></inline-formula> increase. Aging of the TES was studied directly by applying the same thermal conditions exclusively to Mo/Au bilayers on Si substrate. These measurements allow a better understanding of the cause of the observed shift by decoupling the TES bilayer from the remaining device structures, such as the SiNx membrane and the absorber. Four-point resistance measurements were used to readout the bilayer samples at 4.2 K. Bilayers aged in a vacuum generally saw no change or a slight increase in resistance, while bilayers aged in nitrogen gas decreased in resistance. Finally, we conclude with a comparative overview of all test results on prototype arrays and TES bilayers, elaborate on possible mechanisms for the observed shifts in characteristics, and make recommendations for maintaining the long-term stability of our devices.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 6","pages":"1-7"},"PeriodicalIF":1.8,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057653","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}
High temperature superconducting (HTS) conductor on round core (CORC) cable has been considered as an outstanding choice for power applications due to its advantages of high current-carrying density and robust mechanical properties. However, heat generation resulting from the AC loss of CORC cable will increase the cooling burden and in turn affect the operation and maintenance safety of the system. In this paper, both rigid-core CORC cables and flexible-core CORC cables are fabricated. Equivalent modeling for the flexible former of corrugated tube is proposed and the simulation validity is verified through transport loss experiment. Transport AC loss characteristics of flexible-core cables are evaluated and compared with traditional rigid-core cables. Result shows that for single-layer cable, the former selection of corrugated tube with low electrical conductivity could also significantly reduce eddy current losses; while for double-layer cables, hysteresis loss in HTS tapes always dominates total loss despite changes in the central former. Conclusions obtained from this paper will provide valuable guidance for the preparation and optimization of CORC cables.
{"title":"Effect of Flexible Core Former on the AC Loss Characteristics of Conductor on Round Core Cable","authors":"Yuxuan Chen;Zhixing Yang;Qingyuan Gou;Xiangde Zhang;Zhijian Jin;Jie Sheng","doi":"10.1109/TASC.2025.3645714","DOIUrl":"https://doi.org/10.1109/TASC.2025.3645714","url":null,"abstract":"High temperature superconducting (HTS) conductor on round core (CORC) cable has been considered as an outstanding choice for power applications due to its advantages of high current-carrying density and robust mechanical properties. However, heat generation resulting from the AC loss of CORC cable will increase the cooling burden and in turn affect the operation and maintenance safety of the system. In this paper, both rigid-core CORC cables and flexible-core CORC cables are fabricated. Equivalent modeling for the flexible former of corrugated tube is proposed and the simulation validity is verified through transport loss experiment. Transport AC loss characteristics of flexible-core cables are evaluated and compared with traditional rigid-core cables. Result shows that for single-layer cable, the former selection of corrugated tube with low electrical conductivity could also significantly reduce eddy current losses; while for double-layer cables, hysteresis loss in HTS tapes always dominates total loss despite changes in the central former. Conclusions obtained from this paper will provide valuable guidance for the preparation and optimization of CORC cables.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886570","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 : 2025-12-24DOI: 10.1109/TASC.2025.3648278
Magnus Bøgh Borregaard Christensen;Peter Koch;Tomasz Podzorny;Jan Østergaard
Superconducting magnet impedance measurements are vital for assessing magnet health and electrical integrity. To further enhance monitoring capabilities beyond contemporary methods that largely rely on manual intervention, recent efforts have focused on enabling in situ and continuous measurements during magnet operation. This evolution is becoming increasingly relevant due to the growing complexity and aging of modern particle accelerator facilities. However, implementing such measurements presents challenges, particularly due to operational constraints and interference from the power converter. This article focuses on noise reduction techniques aimed at reducing the variance of impedance estimates derived from samples collected by a differential probing measurement system. A key contribution is the analysis of a unique, high-resolution dataset comprising uninterrupted impedance measurements across both steady-state magnet current plateaus and current ramping stages. This dataset enables inspection of the interaction between injected stimuli and power converter noise throughout key stages of a magnet's powering cycle, an aspect not previously explored and reported in the literature. Using a differential measurement configuration, we extract a reference of the power converter noise and apply Wiener filtering to reduce the variance of impedance estimates. We evaluate two denoising strategies, a static approach with fixed filter coefficients and an adaptive method with periodically updated coefficients. For long estimation windows (1 s), neither approach yields significant improvements. However, for short windows (10 ms), both methods achieve substantial variance reduction of up to two orders of magnitude. Under certain operating conditions, the adaptive method provides a further improvement of approximately one order of magnitude over the static approach, highlighting the potential advantage of adaptivity for real-time impedance monitoring.
{"title":"Noise Analysis and Variance Reduction of Continuous Impedance Measurements of Energized Superconducting Magnets","authors":"Magnus Bøgh Borregaard Christensen;Peter Koch;Tomasz Podzorny;Jan Østergaard","doi":"10.1109/TASC.2025.3648278","DOIUrl":"https://doi.org/10.1109/TASC.2025.3648278","url":null,"abstract":"Superconducting magnet impedance measurements are vital for assessing magnet health and electrical integrity. To further enhance monitoring capabilities beyond contemporary methods that largely rely on manual intervention, recent efforts have focused on enabling in situ and continuous measurements during magnet operation. This evolution is becoming increasingly relevant due to the growing complexity and aging of modern particle accelerator facilities. However, implementing such measurements presents challenges, particularly due to operational constraints and interference from the power converter. This article focuses on noise reduction techniques aimed at reducing the variance of impedance estimates derived from samples collected by a differential probing measurement system. A key contribution is the analysis of a unique, high-resolution dataset comprising uninterrupted impedance measurements across both steady-state magnet current plateaus and current ramping stages. This dataset enables inspection of the interaction between injected stimuli and power converter noise throughout key stages of a magnet's powering cycle, an aspect not previously explored and reported in the literature. Using a differential measurement configuration, we extract a reference of the power converter noise and apply Wiener filtering to reduce the variance of impedance estimates. We evaluate two denoising strategies, a static approach with fixed filter coefficients and an adaptive method with periodically updated coefficients. For long estimation windows (1 s), neither approach yields significant improvements. However, for short windows (10 ms), both methods achieve substantial variance reduction of up to two orders of magnitude. Under certain operating conditions, the adaptive method provides a further improvement of approximately one order of magnitude over the static approach, highlighting the potential advantage of adaptivity for real-time impedance monitoring.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 2","pages":"1-20"},"PeriodicalIF":1.8,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11314731","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982296","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}
We propose an optimization method for a superconductor-insulator-superconductor (SIS) mixer-based amplifier circuit that employs SIS up- and down-converters. Such a novel amplifier configuration could enable superior low-noise performance for future broadband amplifier systems, such as those for large arrays of superconducting sensors or qubits. Optimization was achieved by identifying a solution in which the mutually dependent impedances of the SIS mixers converge under given conditions. A circuit design using this method predicted an amplifier gain of approximately 20 dB and a noise temperature of approximately 2 K at 4 K operation when practical current-voltage characteristics of Nb SIS junctions are used in the simulation. To verify the validity of this method, an amplifier circuit was prepared using waveguide Nb/AlOx/Nb mixer modules. By varying the phase delay between the two SIS mixers, changes in gain were observed, resulting from different convergence conditions of their mutually dependent impedances, which closely matched the predictions made using this method. These results are promising for the development of an integrated circuit including SIS amplifiers and superconducting detector arrays, with bandwidths of 10 GHz or above. This may also enable novel nonreciprocal microwave circuits such as gyrators, isolators, and circulators.
{"title":"Optimization and Validation of the Design of Superconductor-Insulator-Superconductor Mixer-Based Amplifier Circuits","authors":"Yoshinori Uzawa;Wenlei Shan;Akira Kawakami;Yosuke Murayama;Sho Masui;Takafumi Kojima;Kazumasa Makise;Takatomi Kumagai","doi":"10.1109/TASC.2025.3646187","DOIUrl":"https://doi.org/10.1109/TASC.2025.3646187","url":null,"abstract":"We propose an optimization method for a superconductor-insulator-superconductor (SIS) mixer-based amplifier circuit that employs SIS up- and down-converters. Such a novel amplifier configuration could enable superior low-noise performance for future broadband amplifier systems, such as those for large arrays of superconducting sensors or qubits. Optimization was achieved by identifying a solution in which the mutually dependent impedances of the SIS mixers converge under given conditions. A circuit design using this method predicted an amplifier gain of approximately 20 dB and a noise temperature of approximately 2 K at 4 K operation when practical current-voltage characteristics of Nb SIS junctions are used in the simulation. To verify the validity of this method, an amplifier circuit was prepared using waveguide Nb/AlOx/Nb mixer modules. By varying the phase delay between the two SIS mixers, changes in gain were observed, resulting from different convergence conditions of their mutually dependent impedances, which closely matched the predictions made using this method. These results are promising for the development of an integrated circuit including SIS amplifiers and superconducting detector arrays, with bandwidths of 10 GHz or above. This may also enable novel nonreciprocal microwave circuits such as gyrators, isolators, and circulators.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929429","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 : 2025-12-23DOI: 10.1109/TASC.2025.3646171
Yahao Wu;Wenjuan Song;Mohammad Yazdani-Asrami
Fast and reliable quench detection is critical for protecting high temperature superconducting coils, magnets, and devices, yet experimental datasets remain limited due to cryogenic constraints and risk of conductor damage. This limitation is one of the key challenges in developing machine learning (ML) techniques for predicting quench through regression-based forecasting of voltage signals. To address this, we propose a framework that combines Time-series Generative Adversarial Networks (TimeGAN) for artificial sequence generation with Long Short-Term Memory (LSTM) predictors. From 36 measured voltage sequences, TimeGAN generated 90 artificial sequences to expand the dataset and mitigate overfitting. Augmenting the LSTM improved quench prediction accuracy to ∼3% mean relative error. This study demonstrates the first application of TimeGAN to superconducting quench signals and highlights the benefit of ML-driven augmentation for improving quench prediction robustness.
{"title":"Machine Learning Prediction for Experimental Quench Voltage of HTS Coils Using a Combined Framework With Time-Series Generative Adversarial Network and Long Short-Term Memory Techniques","authors":"Yahao Wu;Wenjuan Song;Mohammad Yazdani-Asrami","doi":"10.1109/TASC.2025.3646171","DOIUrl":"https://doi.org/10.1109/TASC.2025.3646171","url":null,"abstract":"Fast and reliable quench detection is critical for protecting high temperature superconducting coils, magnets, and devices, yet experimental datasets remain limited due to cryogenic constraints and risk of conductor damage. This limitation is one of the key challenges in developing machine learning (ML) techniques for predicting quench through regression-based forecasting of voltage signals. To address this, we propose a framework that combines Time-series Generative Adversarial Networks (TimeGAN) for artificial sequence generation with Long Short-Term Memory (LSTM) predictors. From 36 measured voltage sequences, TimeGAN generated 90 artificial sequences to expand the dataset and mitigate overfitting. Augmenting the LSTM improved quench prediction accuracy to ∼3% mean relative error. This study demonstrates the first application of TimeGAN to superconducting quench signals and highlights the benefit of ML-driven augmentation for improving quench prediction robustness.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886665","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 : 2025-12-23DOI: 10.1109/TASC.2025.3647434
Yasuhiro H. Matsuda;Yuto Ishii;Xu-Guang Zhou;Hiroaki Hayashi;Hironobu Sawabe
An ultrahigh magnetic field in the multi-megagauss field (mMGF) range (100–1000 T) is a potential tool to explore undeveloped science disciplines. The recent development of measurement techniques in material science in the mMGF is considerable. It implies that the development of ultrahigh magnetic field science can expand not only for materials but also for other subjects, such as chemical reactions or biological systems. Destruction of the coil during the mMGF production makes the measurement a single-shot measurement. Reproducibility of the magnetic field waveform on the microsecond time scale is the key technology that ensures the high reliability of the experimental results. The current status of the waveform reproducibility of the mMGF generated by the single-turn coil and the electromagnetic flux compression is reported. The current status of the available measurements for material science in the mMGF is also introduced.
{"title":"Production of Multi-Megagauss Ultrahigh Magnetic Fields Using Destructive Magnets for Material Science","authors":"Yasuhiro H. Matsuda;Yuto Ishii;Xu-Guang Zhou;Hiroaki Hayashi;Hironobu Sawabe","doi":"10.1109/TASC.2025.3647434","DOIUrl":"https://doi.org/10.1109/TASC.2025.3647434","url":null,"abstract":"An ultrahigh magnetic field in the multi-megagauss field (<italic>m</i>MGF) range (100–1000 T) is a potential tool to explore undeveloped science disciplines. The recent development of measurement techniques in material science in the <italic>m</i>MGF is considerable. It implies that the development of ultrahigh magnetic field science can expand not only for materials but also for other subjects, such as chemical reactions or biological systems. Destruction of the coil during the <italic>m</i>MGF production makes the measurement a single-shot measurement. Reproducibility of the magnetic field waveform on the microsecond time scale is the key technology that ensures the high reliability of the experimental results. The current status of the waveform reproducibility of the <italic>m</i>MGF generated by the single-turn coil and the electromagnetic flux compression is reported. The current status of the available measurements for material science in the <italic>m</i>MGF is also introduced.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11313525","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145929362","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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