Pub Date : 2026-05-01Epub Date: 2025-09-26DOI: 10.1109/tasc.2025.3614571
Jintao Hu, Junseong Kim, Liangjun Shao, Juan Bascuñán, Yukikazu Iwasa, Jerome L Ackerman, Dongkeun Park
In this paper, we present the design and test results of a low-AC-loss Nb3Sn model coil developed to validate key enabling technologies for a fast-switching-field magnetic resonance imaging (MRI) magnet concept that can change the magnetic field very quickly in time, within 1 second, between significantly different field strengths: a high field (3 T) for relaxometry and prepolarization and a low field (0.5 T) for spectroscopy and imaging. While conventional MRI magnets require a static magnetic field, we expect that our proposed superconducting magnet with rapidly changing fields can provide opportunities for novel contrast mechanisms, which include level-crossing between spin-1/2 and quadrupolar nuclei, accelerated spin-lattice relaxation, and adiabatic demagnetization/remagnetization, by permitting differential relaxometry enabled by a large field strength difference, and ratiometric molecular/superthermal imaging. We have developed and demonstrated an innovative magnet design that uses a very low-AC-loss Nb3Sn coil and a novel cooling technology featuring highly heat-conductive thermal links between the coil and solid nitrogen surrounding the coil. These thermal links in solid nitrogen are anchored at one end to the cryocooler cold head. This design enables rapid switching between two magnetic fields in the superconducting magnet without inducing quench. The paper provides details on the construction, test results, and an analysis of the maximum temperature rise in the coil of the small-scale fast-switching-field magnet system.
{"title":"Low-AC-Loss Nb3Sn Validation Model Coil in Solid Nitrogen for a Fast-Switching-Field MRI Magnet Prototype.","authors":"Jintao Hu, Junseong Kim, Liangjun Shao, Juan Bascuñán, Yukikazu Iwasa, Jerome L Ackerman, Dongkeun Park","doi":"10.1109/tasc.2025.3614571","DOIUrl":"10.1109/tasc.2025.3614571","url":null,"abstract":"<p><p>In this paper, we present the design and test results of a low-AC-loss Nb3Sn model coil developed to validate key enabling technologies for a fast-switching-field magnetic resonance imaging (MRI) magnet concept that can change the magnetic field very quickly in time, within 1 second, between significantly different field strengths: a high field (3 T) for relaxometry and prepolarization and a low field (0.5 T) for spectroscopy and imaging. While conventional MRI magnets require a static magnetic field, we expect that our proposed superconducting magnet with rapidly changing fields can provide opportunities for novel contrast mechanisms, which include level-crossing between spin-1/2 and quadrupolar nuclei, accelerated spin-lattice relaxation, and adiabatic demagnetization/remagnetization, by permitting differential relaxometry enabled by a large field strength difference, and ratiometric molecular/superthermal imaging. We have developed and demonstrated an innovative magnet design that uses a very low-AC-loss Nb3Sn coil and a novel cooling technology featuring highly heat-conductive thermal links between the coil and solid nitrogen surrounding the coil. These thermal links in solid nitrogen are anchored at one end to the cryocooler cold head. This design enables rapid switching between two magnetic fields in the superconducting magnet without inducing quench. The paper provides details on the construction, test results, and an analysis of the maximum temperature rise in the coil of the small-scale fast-switching-field magnet system.</p>","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12577748/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145431246","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 : 2025-12-17DOI: 10.1109/TASC.2025.3644708
{"title":"2025 Index IEEE Transactions on Applied Superconductivity","authors":"","doi":"10.1109/TASC.2025.3644708","DOIUrl":"https://doi.org/10.1109/TASC.2025.3644708","url":null,"abstract":"","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"1-174"},"PeriodicalIF":1.8,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11303079","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778355","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 : 2025-12-05DOI: 10.1109/TASC.2025.3639528
Jason Walter;Adam C. Weis;Kan-Ting Tsai;Meng-Ju Yu;Naveen Katam;Alex F. Kirichenko;Oleg A. Mukhanov;Shu-Jen Han;Igor V. Vernik
As quantum computing processors increase in size, there is growing interest in developing cryogenic electronics to overcome significant challenges to system scaling. Single flux-quantum (SFQ) circuits offer a promising alternative to remote, bulky, and power-hungry room temperature electronics. To meet the need for digital qubit control, readout, and co-processing, SFQ circuits must be adapted to operate at millikelvin temperatures near quantum processors. SEEQC's SFQuClass digital quantum management approach proximally places energy-efficient SFQ (ERSFQ) circuits and qubits in a multi-chip module. This enables extremely low power dissipation, compatible with a typical dilution cryostat's limited cooling power, while maintaining high processing speed and low error rates. We report on systematic testing from 4 K to 10 mK of a comprehensive set of ERSFQ cells, as well as more complex circuits such as programmable counters and demultiplexers used in digital qubit control. We compare the operating margins and error rates of these circuits and find that, at millikelvin, bias margins decrease and the center of the margins (i.e., the optimal bias current value) increases by ∼15%, compared to 4.2 K. The margins can be restored by thermal annealing by reducing Josephson junction (JJ) critical current Ic. To provide guidance for how circuit parameters vary from 4.2 K to millikelvin, relevant analog process control monitors (PCMs) were tested in the temperature range of interest. The measured JJ critical current (of the PCM JJ arrays) increases by ∼15% when decreasing temperature from 4.2 K to millikelvin, in good agreement with both theory and the empirically measured change in the center of bias margins for the tested digital circuits.
{"title":"Single Flux Quantum Circuit Operation at Millikelvin Temperatures","authors":"Jason Walter;Adam C. Weis;Kan-Ting Tsai;Meng-Ju Yu;Naveen Katam;Alex F. Kirichenko;Oleg A. Mukhanov;Shu-Jen Han;Igor V. Vernik","doi":"10.1109/TASC.2025.3639528","DOIUrl":"https://doi.org/10.1109/TASC.2025.3639528","url":null,"abstract":"As quantum computing processors increase in size, there is growing interest in developing cryogenic electronics to overcome significant challenges to system scaling. Single flux-quantum (SFQ) circuits offer a promising alternative to remote, bulky, and power-hungry room temperature electronics. To meet the need for digital qubit control, readout, and co-processing, SFQ circuits must be adapted to operate at millikelvin temperatures near quantum processors. SEEQC's SFQuClass digital quantum management approach proximally places energy-efficient SFQ (ERSFQ) circuits and qubits in a multi-chip module. This enables extremely low power dissipation, compatible with a typical dilution cryostat's limited cooling power, while maintaining high processing speed and low error rates. We report on systematic testing from 4 K to 10 mK of a comprehensive set of ERSFQ cells, as well as more complex circuits such as programmable counters and demultiplexers used in digital qubit control. We compare the operating margins and error rates of these circuits and find that, at millikelvin, bias margins decrease and the center of the margins (i.e., the optimal bias current value) increases by ∼15%, compared to 4.2 K. The margins can be restored by thermal annealing by reducing Josephson junction (JJ) critical current <italic>I<sub>c</sub></i>. To provide guidance for how circuit parameters vary from 4.2 K to millikelvin, relevant analog process control monitors (PCMs) were tested in the temperature range of interest. The measured JJ critical current (of the PCM JJ arrays) increases by ∼15% when decreasing temperature from 4.2 K to millikelvin, in good agreement with both theory and the empirically measured change in the center of bias margins for the tested digital circuits.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 5","pages":"1-6"},"PeriodicalIF":1.8,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766207","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 ITER superconducting magnet system comprises 18 Toroidal Field (TF) coils, one Central Solenoid (CS), 6 Poloidal Field (PF) coils, and 18 Correction Coils (CC). These superconducting coils are integrated using robust, flexible structures and over 4700 high-grade large studs ranging from M24 to M160. During assembly, these studs are preloaded from hundreds to thousands of kN with Hydraulic Tensioners or Multi-jack bolt Tensioners (MJT or Superbolts). Since preload losses are inevitable under current methods with hydraulic tensioners, and the maximum allowable loads are constrained by the material's yield strength as per ITER Magnet Structure Design Criteria, these constraints create a narrow operational window for successful assembly to the expected preload. Precise preload control is critical to ensuring proper integration of the superconducting magnets. Ultrasonic bolt load measurement emerges as a promising solution, especially in scenarios where one end of the stud is inaccessible after installation. Calibration tests at ITER are underway to validate the use of this method for preload measurement during machine assembly. This article presents calibration test results, including velocity, stress factor, load factor, preload loss, and field calibration measurements. It concludes with insights from the design and manufacturing of high-grade studs, highlighting their impact on achieving accurate preload control via ultrasonic inspection.
{"title":"Calibration Test for Preload Control With Ultrasonic Checking for Magnet Studs During ITER Machine Assembly","authors":"Shiqiang Han;Ignacio Aviles Santillana;Thierry Schild;Gonzalo Arnau Izquierdo;Shihang Wang;Gilles Rinaudo;Maciej Burkowski;Lionel Poncet;Fabrice Simon;Yury Ilin;Yasuyuki Miyoshi;Igor Rodin;Stefano Sgobba;Patrick Petit;Sebastien Koczorowski;Jens Reich","doi":"10.1109/TASC.2025.3634066","DOIUrl":"https://doi.org/10.1109/TASC.2025.3634066","url":null,"abstract":"The ITER superconducting magnet system comprises 18 Toroidal Field (TF) coils, one Central Solenoid (CS), 6 Poloidal Field (PF) coils, and 18 Correction Coils (CC). These superconducting coils are integrated using robust, flexible structures and over 4700 high-grade large studs ranging from M24 to M160. During assembly, these studs are preloaded from hundreds to thousands of kN with Hydraulic Tensioners or Multi-jack bolt Tensioners (MJT or Superbolts). Since preload losses are inevitable under current methods with hydraulic tensioners, and the maximum allowable loads are constrained by the material's yield strength as per ITER Magnet Structure Design Criteria, these constraints create a narrow operational window for successful assembly to the expected preload. Precise preload control is critical to ensuring proper integration of the superconducting magnets. Ultrasonic bolt load measurement emerges as a promising solution, especially in scenarios where one end of the stud is inaccessible after installation. Calibration tests at ITER are underway to validate the use of this method for preload measurement during machine assembly. This article presents calibration test results, including velocity, stress factor, load factor, preload loss, and field calibration measurements. It concludes with insights from the design and manufacturing of high-grade studs, highlighting their impact on achieving accurate preload control via ultrasonic inspection.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 3","pages":"1-5"},"PeriodicalIF":1.8,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778227","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 : 2025-12-04DOI: 10.1109/TASC.2025.3640122
Yi Ge;Hui Yu;Guanqiu Yuan;Bohan Tang;Bowen Xie;Shili Jiang;Donghui Jiang;Guangli Kuang
This work investigates a hybrid passive screen integrating superconductors and ferromagnets. The screening structure consists of multiple superconducting bulks, stacked closed-loop eye-shaped coated conductors, and a ferromagnetic (FM) sheet. The stacked coated conductors are concentrically arranged around the bulks, with the FM sheet positioned on the upper surface of the bulks. The screening effects are examined through experimental measurements and finite element calculations. We investigate superconducting screens of various structures, firstly, revealing that the combination of superconductors provides superior screening performance compared to using bulks alone. Furthermore, partial reversal of the tapes’ directions was applied to optimize geometrical asymmetry. The superconducting-FM hybrid screen was then tested, achieving a substantial reduction in residual magnetic flux density (up to 38%) in the gap region while simultaneously improving field uniformity. Importantly, the established numerical model enables further exploration and optimization of the screen, allowing for expanded screening volume and operation at higher magnetic field levels.
{"title":"Investigation of Magnetic Screening Performance Enhancement Using Various Superconductors and Ferromagnets","authors":"Yi Ge;Hui Yu;Guanqiu Yuan;Bohan Tang;Bowen Xie;Shili Jiang;Donghui Jiang;Guangli Kuang","doi":"10.1109/TASC.2025.3640122","DOIUrl":"https://doi.org/10.1109/TASC.2025.3640122","url":null,"abstract":"This work investigates a hybrid passive screen integrating superconductors and ferromagnets. The screening structure consists of multiple superconducting bulks, stacked closed-loop eye-shaped coated conductors, and a ferromagnetic (FM) sheet. The stacked coated conductors are concentrically arranged around the bulks, with the FM sheet positioned on the upper surface of the bulks. The screening effects are examined through experimental measurements and finite element calculations. We investigate superconducting screens of various structures, firstly, revealing that the combination of superconductors provides superior screening performance compared to using bulks alone. Furthermore, partial reversal of the tapes’ directions was applied to optimize geometrical asymmetry. The superconducting-FM hybrid screen was then tested, achieving a substantial reduction in residual magnetic flux density (up to 38%) in the gap region while simultaneously improving field uniformity. Importantly, the established numerical model enables further exploration and optimization of the screen, allowing for expanded screening volume and operation at higher magnetic field levels.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 1","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778474","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 : 2025-11-28DOI: 10.1109/TASC.2025.3638446
Jinzhao Zhao;Guangtong Ma;Cheng Luo;Zhenhua Su;Libin Cui;Menglong Guo;Jun Luo
Electrodynamic suspension (EDS) has a broad application prospect in high-speed magnetic levitation transportation due to its advantages, such as strong self-stabilization ability and simple control. However, in high-speed application scenarios, flat-plate permanent magnet electric suspension has a high magnetic drag force and requires a large amount of weight of the installed permanent magnets. To ameliorate these problems, this article addresses the plate-type superconducting EDS system with a higher lift-to-drag ratio. First, the structure and principles of the superconducting EDS system are presented. Second, a 3-D analytical model of the electromagnetic force considering the transverse end effect is established by the magnetic vector potential equation and the boundary conditions at the end of the conductor plate. Among them, the source magnetic field of the superconducting magnet array required by the boundary conditions is solved by the coil discretization idea. Then, the reliability of the proposed analytical model is verified by comparing the computational results of the analytical model with the finite element simulation results. Finally, based on the 3-D analytical model, the suspension stiffness characteristics of the superconducting EDS system and the influence of specific parameters on the system's suspension performance are analyzed.
{"title":"Three-Dimensional Analytical Modeling of Plate-Type Superconducting Electrodynamic Suspension for Electromagnetic Launch Application","authors":"Jinzhao Zhao;Guangtong Ma;Cheng Luo;Zhenhua Su;Libin Cui;Menglong Guo;Jun Luo","doi":"10.1109/TASC.2025.3638446","DOIUrl":"https://doi.org/10.1109/TASC.2025.3638446","url":null,"abstract":"Electrodynamic suspension (EDS) has a broad application prospect in high-speed magnetic levitation transportation due to its advantages, such as strong self-stabilization ability and simple control. However, in high-speed application scenarios, flat-plate permanent magnet electric suspension has a high magnetic drag force and requires a large amount of weight of the installed permanent magnets. To ameliorate these problems, this article addresses the plate-type superconducting EDS system with a higher lift-to-drag ratio. First, the structure and principles of the superconducting EDS system are presented. Second, a 3-D analytical model of the electromagnetic force considering the transverse end effect is established by the magnetic vector potential equation and the boundary conditions at the end of the conductor plate. Among them, the source magnetic field of the superconducting magnet array required by the boundary conditions is solved by the coil discretization idea. Then, the reliability of the proposed analytical model is verified by comparing the computational results of the analytical model with the finite element simulation results. Finally, based on the 3-D analytical model, the suspension stiffness characteristics of the superconducting EDS system and the influence of specific parameters on the system's suspension performance are analyzed.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 1","pages":"1-11"},"PeriodicalIF":1.8,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145729376","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 direct grid-connected high-temperature superconducting synchronous condenser (HTSSC) has high application potential in the new energy grid, based on its advantages of strong inertia support, high short-circuit capacity, high power density, and fast response speed. Therefore, this article explores the feasible technical solutions for direct grid-connected HTSSCs. By comparing the advantages and disadvantages of stators with different air-core armature structures in high-voltage applications, the stator with ring-type air-core armature is selected as the design basis. The insulation system and cooling system of the 35 kV high-voltage stator are comprehensively designed. The insulation reliability and anticorona ability of the high-voltage stator are verified through electric field simulation. At the same time, the cooling effect of the air-cooling system on the armature winding and the stator core is verified through temperature field simulation. The results show that the special insulation system of the stator with ring-type air-core armature can achieve an armature current density of 3.5 A/mm$^{2}$, which is higher than that of the traditional synchronous condenser of the same power level. Therefore, the stator with ring-type air-core armature has the potential for high-voltage applications and can support the direct grid-connected operation of the HTSSC.
{"title":"Design of High-Voltage Stator With Ring-Type Air-Core Armature for Direct Grid-Connected HTS Synchronous Condenser","authors":"Jiabo Shou;Chao Luo;Jien Ma;Pengcheng Huang;Yuang Zheng;Jie Chao;Youtong Fang","doi":"10.1109/TASC.2025.3638852","DOIUrl":"https://doi.org/10.1109/TASC.2025.3638852","url":null,"abstract":"The direct grid-connected high-temperature superconducting synchronous condenser (HTSSC) has high application potential in the new energy grid, based on its advantages of strong inertia support, high short-circuit capacity, high power density, and fast response speed. Therefore, this article explores the feasible technical solutions for direct grid-connected HTSSCs. By comparing the advantages and disadvantages of stators with different air-core armature structures in high-voltage applications, the stator with ring-type air-core armature is selected as the design basis. The insulation system and cooling system of the 35 kV high-voltage stator are comprehensively designed. The insulation reliability and anticorona ability of the high-voltage stator are verified through electric field simulation. At the same time, the cooling effect of the air-cooling system on the armature winding and the stator core is verified through temperature field simulation. The results show that the special insulation system of the stator with ring-type air-core armature can achieve an armature current density of 3.5 A/mm<inline-formula><tex-math>$^{2}$</tex-math></inline-formula>, which is higher than that of the traditional synchronous condenser of the same power level. Therefore, the stator with ring-type air-core armature has the potential for high-voltage applications and can support the direct grid-connected operation of the HTSSC.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 1","pages":"1-12"},"PeriodicalIF":1.8,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145729283","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}
Rapid changes in gradient magnetic fields induce eddy currents, posing a considerable challenge to the accuracy and stability of magnetic resonance imaging (MRI) systems. Accurate measurement of eddy currents is crucial for the rapid and efficient design of eddy current compensation parameters. The “six-point sample method” provides a systematic way to measure and quantify gradient eddy currents while its coils have inherent limitations in channel isolation. The device proposed in this study leverages the shielding effect of coaxial cables to reduce mutual interference between coils. It utilizes coaxial cables to construct coil units and compares the channels crosstalk with traditional copper-strip coils. Following system calibration, eddy current compensation was implemented on the 1.5-T MRI scanner using the dedicated eddy current measurement device. Results revealed that −15 dB coupling was achieved at a distance of 72 mm for the coaxial-cable coils, which was more than half shorter than the 120 mm required for the copper-strip coils. In addition, the coaxial-cable coils exhibited better transmission characteristics. With a power crosstalk ratio above 30 dB between any two units, the channel isolation is remarkably higher than that of copper-strip coils, exceeding it by approximately 50%. The device was employed to measure the eddy currents and subsequently, based on the results, compensation parameters were rapidly iterated to achieve good eddy current correction.
梯度磁场的快速变化会产生涡流，这对磁共振成像系统的准确性和稳定性提出了相当大的挑战。准确的涡流测量对于快速有效地设计涡流补偿参数至关重要。“六点采样法”提供了一种系统的方法来测量和量化梯度涡流，但其线圈在通道隔离方面存在固有的局限性。本研究提出的装置利用同轴电缆的屏蔽效应来减少线圈之间的相互干扰。它利用同轴电缆构建线圈单元，并将通道串扰与传统的铜带线圈进行比较。系统校准后，使用专用涡流测量装置对1.5 t MRI扫描仪进行涡流补偿。结果表明，同轴电缆线圈在72 mm的距离上实现了−15 dB的耦合，比铜带线圈所需的120 mm缩短了一半以上。此外，同轴电缆线圈具有更好的传输特性。当任意两个单元之间的功率串扰比大于30 dB时，通道隔离度显著高于铜带线圈，高出约50%。利用该装置对涡流进行测量，并根据测量结果快速迭代补偿参数，获得良好的涡流校正效果。
{"title":"Eddy Current Measuring Device for 1.5–T MRI Gradient Correction With Shielded-Coaxial-Cable Coils","authors":"Qingyun Liu;Xueyan Song;Yunyu Gao;Chuangjia Liu;Lin Chen;Kecheng Yuan;Bensheng Qiu","doi":"10.1109/TASC.2025.3637847","DOIUrl":"https://doi.org/10.1109/TASC.2025.3637847","url":null,"abstract":"Rapid changes in gradient magnetic fields induce eddy currents, posing a considerable challenge to the accuracy and stability of magnetic resonance imaging (MRI) systems. Accurate measurement of eddy currents is crucial for the rapid and efficient design of eddy current compensation parameters. The “six-point sample method” provides a systematic way to measure and quantify gradient eddy currents while its coils have inherent limitations in channel isolation. The device proposed in this study leverages the shielding effect of coaxial cables to reduce mutual interference between coils. It utilizes coaxial cables to construct coil units and compares the channels crosstalk with traditional copper-strip coils. Following system calibration, eddy current compensation was implemented on the 1.5-T MRI scanner using the dedicated eddy current measurement device. Results revealed that −15 dB coupling was achieved at a distance of 72 mm for the coaxial-cable coils, which was more than half shorter than the 120 mm required for the copper-strip coils. In addition, the coaxial-cable coils exhibited better transmission characteristics. With a power crosstalk ratio above 30 dB between any two units, the channel isolation is remarkably higher than that of copper-strip coils, exceeding it by approximately 50%. The device was employed to measure the eddy currents and subsequently, based on the results, compensation parameters were rapidly iterated to achieve good eddy current correction.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"36 1","pages":"1-8"},"PeriodicalIF":1.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145729435","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 : 2025-11-27DOI: 10.1109/TASC.2025.3633527
{"title":"IEEE Transactions on Applied Superconductivity Information for Authors","authors":"","doi":"10.1109/TASC.2025.3633527","DOIUrl":"https://doi.org/10.1109/TASC.2025.3633527","url":null,"abstract":"","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 9","pages":"C4-C4"},"PeriodicalIF":1.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11271053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145612176","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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