Pub Date : 2025-02-10DOI: 10.1109/TASC.2025.3540046
M. C. Lin;C. T. Huang;F. Y. Chang;C. H. Lo;Z. K. Liu;Ch. Wang;M. S. Yeh;M. H. Chang;F. T. Chung;L. J. Chen;Y. T. Li;S. W. Chang
Higher order modes of a superconducting radio-frequency (SRF) cavity are typically conducted through the beam pipes to the microwave absorbers on both sides of the cavity to eliminate disturbances to the beam behavior. The cutoff frequency of the beam pipe is designed to be lower than the higher-order modes to reduce the trapped modes as much as possible. However, some modes are trapped inside the cavity even though their resonance frequencies are much higher than the cutoff frequencies of the beam pipes. In this study, we develop a numerical process to efficiently determine the trapped modes. Illustrated with a two-cell 1.5 GHz SRF cavity, the numerical results show there are eight trapped modes below 3.5 GHz. To prove the computation accuracy, the resonance frequencies of a two-cell niobium cavity with both ends of the beam pipes covered with metal plates were measured, showing great agreement with the numerical computation results. The electromagnetic fields of the trapped modes along the cavity's central axis were also examined to understand how the particle beam would be affected.
{"title":"Determination of Trapped Modes on a Two-Cell 1.5-GHz Superconducting Radio-Frequency Cavity","authors":"M. C. Lin;C. T. Huang;F. Y. Chang;C. H. Lo;Z. K. Liu;Ch. Wang;M. S. Yeh;M. H. Chang;F. T. Chung;L. J. Chen;Y. T. Li;S. W. Chang","doi":"10.1109/TASC.2025.3540046","DOIUrl":"https://doi.org/10.1109/TASC.2025.3540046","url":null,"abstract":"Higher order modes of a superconducting radio-frequency (SRF) cavity are typically conducted through the beam pipes to the microwave absorbers on both sides of the cavity to eliminate disturbances to the beam behavior. The cutoff frequency of the beam pipe is designed to be lower than the higher-order modes to reduce the trapped modes as much as possible. However, some modes are trapped inside the cavity even though their resonance frequencies are much higher than the cutoff frequencies of the beam pipes. In this study, we develop a numerical process to efficiently determine the trapped modes. Illustrated with a two-cell 1.5 GHz SRF cavity, the numerical results show there are eight trapped modes below 3.5 GHz. To prove the computation accuracy, the resonance frequencies of a two-cell niobium cavity with both ends of the beam pipes covered with metal plates were measured, showing great agreement with the numerical computation results. The electromagnetic fields of the trapped modes along the cavity's central axis were also examined to understand how the particle beam would be affected.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489266","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 : 2025-02-10DOI: 10.1109/TASC.2025.3540025
Jing Chen;Rongtie Huang;Xinghang Zhou;Wenjing Wu;Yuan Du;Zhiyong Liu;Minjuan Li;Gang Wang;Chuanbing Cai
The flux pinning of metal-organic deposition-REBa2Cu3O7-δ (MOD-REBCO) coated conductors can be effectively enhanced through a BaHfO3 (BHO) nanocrystal addition strategy. The present research explores the performance enhancement achieved by BHO additions with different concentrations and the BHO sizes. BHO nanocrystals with size of 5.5 nm and 6.5 nm were respectively added to REBCO at concentrations ranging from 0 to 15 mol%, resulting in significant increase in the in-field critical current density ($J_{mathrm{c}}$) of the BHO-REBCO films at low temperatures. At 30 K and 3 T, the 15 mol% BHO-REBCO film exhibited a 2.94-fold enhancement in $J_{mathrm{c}}$ compared to the pristine film. For the two different sizes of BHO addition, the REBCO films with 5.5 nm-BHO exhibited lower in-field performance than those with 6.5 nm-BHO. This is attributed to instability-induced coarsening of smaller BHO nanocrystals in 5.5 nm case, leading to reduced flux pinning efficiency. The results demonstrate that optimizing the size of BHO nanocrystals can significantly enhance the in-field performance of REBCO films.
{"title":"Optimizing BaHfO3 Nanocrystal Size and Concentration to Enhance MOD-YBCO Film Performance","authors":"Jing Chen;Rongtie Huang;Xinghang Zhou;Wenjing Wu;Yuan Du;Zhiyong Liu;Minjuan Li;Gang Wang;Chuanbing Cai","doi":"10.1109/TASC.2025.3540025","DOIUrl":"https://doi.org/10.1109/TASC.2025.3540025","url":null,"abstract":"The flux pinning of metal-organic deposition-REBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> (MOD-REBCO) coated conductors can be effectively enhanced through a BaHfO<sub>3</sub> (BHO) nanocrystal addition strategy. The present research explores the performance enhancement achieved by BHO additions with different concentrations and the BHO sizes. BHO nanocrystals with size of 5.5 nm and 6.5 nm were respectively added to REBCO at concentrations ranging from 0 to 15 mol%, resulting in significant increase in the in-field critical current density (<inline-formula><tex-math>$J_{mathrm{c}}$</tex-math></inline-formula>) of the BHO-REBCO films at low temperatures. At 30 K and 3 T, the 15 mol% BHO-REBCO film exhibited a 2.94-fold enhancement in <inline-formula><tex-math>$J_{mathrm{c}}$</tex-math></inline-formula> compared to the pristine film. For the two different sizes of BHO addition, the REBCO films with 5.5 nm-BHO exhibited lower in-field performance than those with 6.5 nm-BHO. This is attributed to instability-induced coarsening of smaller BHO nanocrystals in 5.5 nm case, leading to reduced flux pinning efficiency. The results demonstrate that optimizing the size of BHO nanocrystals can significantly enhance the in-field performance of REBCO films.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489146","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}
This article presents the superconducting machine demonstrator realized within the frame of project FROST (Flux-barrier Rotating Superconducting Topology) which started in 2020. This demonstrator is a 250 kW partially superconducting machine adopting the so-called flux modulation topology which employs a superconducting static coil fed with DC current to produce a magnetic field which is modulated by a rotor composed of superconducting bulks. Both these components are the machine inductor which generate a torque by interacting with a three-phase conventional copper wound armature. This article presents the machine expected performances as well as an overview of the demonstrator assembly.
{"title":"Design and Assembly of a 250 kW Partially Superconducting Flux Modulation Machine","authors":"R. Dorget;A. Cipriani;J. Lévêque;W. Dirahoui;S. Ayat;T. Lubin;P. Gning;J. Labbé;J. Tanchon;J. Lacapère","doi":"10.1109/TASC.2025.3539621","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539621","url":null,"abstract":"This article presents the superconducting machine demonstrator realized within the frame of project FROST (Flux-barrier Rotating Superconducting Topology) which started in 2020. This demonstrator is a 250 kW partially superconducting machine adopting the so-called flux modulation topology which employs a superconducting static coil fed with DC current to produce a magnetic field which is modulated by a rotor composed of superconducting bulks. Both these components are the machine inductor which generate a torque by interacting with a three-phase conventional copper wound armature. This article presents the machine expected performances as well as an overview of the demonstrator assembly.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465678","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 : 2025-02-07DOI: 10.1109/TASC.2025.3538638
Aixia Xu;Yan Xin;Dmytro Abraimov;Jin Gyu Park;Jan Jaroszynski;Fumitake Kametani;David C. Larbalestier
Comprehensive understanding is needed in order for the commercial pulsed laser deposited REBa2Cu3O7-δ (RE: rare earth) coated conductors to be effectively used in the magnet and cable designs. Here we demonstrate the superconducting property characterization and microstructural analysis to show how different or similar the 3 commercial REBCO coated conductors are at present. Our work shows that the ab-plane of REBCO tilts from the coated conductor tape plane, leading to the offset of critical current density peak from the tape plane. In particular, the offset angle varies from less than 0.5° for one coated conductor to close to 5° for another. RE2O3 nanoparticles are dominant pins at 20 K and 15 T. The weak pinning introduced by RE2O3 particles and cation disorders contribute to critical current density at 20 K as well.
{"title":"A Comprehensive Characterization of Commercial Pulsed Laser Deposited Coated Conductors","authors":"Aixia Xu;Yan Xin;Dmytro Abraimov;Jin Gyu Park;Jan Jaroszynski;Fumitake Kametani;David C. Larbalestier","doi":"10.1109/TASC.2025.3538638","DOIUrl":"https://doi.org/10.1109/TASC.2025.3538638","url":null,"abstract":"Comprehensive understanding is needed in order for the commercial pulsed laser deposited REBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> (RE: rare earth) coated conductors to be effectively used in the magnet and cable designs. Here we demonstrate the superconducting property characterization and microstructural analysis to show how different or similar the 3 commercial REBCO coated conductors are at present. Our work shows that the <italic>ab</i>-plane of REBCO tilts from the coated conductor tape plane, leading to the offset of critical current density peak from the tape plane. In particular, the offset angle varies from less than 0.5° for one coated conductor to close to 5° for another. RE<sub>2</sub>O<sub>3</sub> nanoparticles are dominant pins at 20 K and 15 T. The weak pinning introduced by RE<sub>2</sub>O<sub>3</sub> particles and cation disorders contribute to critical current density at 20 K as well.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465615","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 : 2025-02-07DOI: 10.1109/TASC.2025.3539773
Yuan Wang;James G. Storey;Yueming Sun;Jin Fang;Timothy J. Haugan;Zhenan Jiang
Large superconducting windings can be considered as assemblies of many arrays consisting of high-temperature superconductor (HTS) tapes. In HTS applications, they will be exposed to external fields with various orientations, resulting in magnetization loss (Qm). Understanding the magnetization loss behaviors of HTS arrays is crucial for those HTS applications. In this work, we measure Qm of single- and four-row arrays with one, two, and four columns at 72.23 and 145.51 Hz. We refer an array as a/b, where “a” and “b” represent the number of columns and rows, respectively. Qm of the 4/1 and 4/4 arrays with various magnetic field angles is also measured. All measured Qm results are compared with corresponding finite-element method simulations. Notably, the measured Qm per tape in the single-column arrays is smaller than that of the two-column arrays, while the four-column arrays exhibit the highest loss at low field (e.g., below 60 mT for the four-row array). On the other hand, simulation results on the arrays with up to eight rows and columns show that as the column count increases, the magnetization loss values become saturated due to the dominance of magnetization loss in the inner columns.
{"title":"Measurement and Simulation of Magnetization Loss in HTS Arrays","authors":"Yuan Wang;James G. Storey;Yueming Sun;Jin Fang;Timothy J. Haugan;Zhenan Jiang","doi":"10.1109/TASC.2025.3539773","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539773","url":null,"abstract":"Large superconducting windings can be considered as assemblies of many arrays consisting of high-temperature superconductor (HTS) tapes. In HTS applications, they will be exposed to external fields with various orientations, resulting in magnetization loss (<italic>Q</i><sub>m</sub>). Understanding the magnetization loss behaviors of HTS arrays is crucial for those HTS applications. In this work, we measure <italic>Q</i><sub>m</sub> of single- and four-row arrays with one, two, and four columns at 72.23 and 145.51 Hz. We refer an array as <italic>a</i>/<italic>b</i>, where “<italic>a</i>” and “<italic>b</i>” represent the number of columns and rows, respectively. <italic>Q</i><sub>m</sub> of the 4/1 and 4/4 arrays with various magnetic field angles is also measured. All measured <italic>Q</i><sub>m</sub> results are compared with corresponding finite-element method simulations. Notably, the measured <italic>Q</i><sub>m</sub> per tape in the single-column arrays is smaller than that of the two-column arrays, while the four-column arrays exhibit the highest loss at low field (e.g., below 60 mT for the four-row array). On the other hand, simulation results on the arrays with up to eight rows and columns show that as the column count increases, the magnetization loss values become saturated due to the dominance of magnetization loss in the inner columns.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 3","pages":"1-7"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463295","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}
In this work, we propose a novel methodology for on-chip control and readout circuits for the Lechner-Hauke-Zoller (LHZ) based superconductor Ising machines (IMs). By enabling the precise mapping of weight values on each spin realized by the Josephson parametric oscillator (JPO), we solve combinatorial optimization problems (COPs) efficiently. Our approach overcomes key challenges in mapping weighted Non-deterministic Polynomial Complete (NPC) problems. We demonstrate 3-bit weight resolution by dynamically modulating the phase of the pump current, $I_{pump}$, in JPOs using integrated control circuits. For the readout, we designed a Quasi One Junction SQUID (QOS) circuit capable of detecting 0 and $pi$ phase differences at the output of the JPOs. Finally, we validate our methodology by solving two weighted NPC problems by simulation.
{"title":"An On-Chip Control and Readout Circuit Design for an Ising Annealer","authors":"Beyza Zeynep Ucpinar;Mustafa Altay Karamuftuoglu;Sasan Razmkhah;Mehdi Kamal;Massoud Pedram","doi":"10.1109/TASC.2025.3540049","DOIUrl":"https://doi.org/10.1109/TASC.2025.3540049","url":null,"abstract":"In this work, we propose a novel methodology for on-chip control and readout circuits for the Lechner-Hauke-Zoller (LHZ) based superconductor Ising machines (IMs). By enabling the precise mapping of weight values on each spin realized by the Josephson parametric oscillator (JPO), we solve combinatorial optimization problems (COPs) efficiently. Our approach overcomes key challenges in mapping weighted Non-deterministic Polynomial Complete (NPC) problems. We demonstrate 3-bit weight resolution by dynamically modulating the phase of the pump current, <inline-formula><tex-math>$I_{pump}$</tex-math></inline-formula>, in JPOs using integrated control circuits. For the readout, we designed a Quasi One Junction SQUID (QOS) circuit capable of detecting 0 and <inline-formula><tex-math>$pi$</tex-math></inline-formula> phase differences at the output of the JPOs. Finally, we validate our methodology by solving two weighted NPC problems by simulation.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553021","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}
Dipole magnets with higher magnetic fields can contribute to further improving the performance of future accelerators. Using high-temperature superconducting (HTS) materials and no-insulation (NI) winding techniques is a potential approach for increasing the magnetic field of dipole magnets. The screening current effect in REBCO coated conductors and the characteristics of NI coils may influence the field magnitude and field quality of dipole magnets. To address these challenges, we developed a block-type REBCO dipole magnet consisting of six NI coils. The magnet was tested at 4.2 K in liquid helium, with multipole components measured using rotating Printed Circuit Board (PCB) coils. During the test, the maximum magnetic field was 2.90 T. The measured central magnetic field showed good agreement with calculations considering the screening current effect. The measured multipole components at 140 A, 210 A, and 250 A indicate that the asymmetry of the magnet increased during the test. The current source was turned off automatically at 251.1 A, resulting in the sudden discharge of the magnet. The measured voltages and magnetic fields after the sudden discharge are discussed.
{"title":"Test Results and Analysis of a 2.9 T No-Insulation REBCO Dipole Magnet at 4.2 K","authors":"Yulong Liu;Peng Song;Mianjun Xiao;Liangjun Shao;Yongjie Zhang;Canjie Xin;Mingzhi Guan;Timing Qu","doi":"10.1109/TASC.2025.3539617","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539617","url":null,"abstract":"Dipole magnets with higher magnetic fields can contribute to further improving the performance of future accelerators. Using high-temperature superconducting (HTS) materials and no-insulation (NI) winding techniques is a potential approach for increasing the magnetic field of dipole magnets. The screening current effect in REBCO coated conductors and the characteristics of NI coils may influence the field magnitude and field quality of dipole magnets. To address these challenges, we developed a block-type REBCO dipole magnet consisting of six NI coils. The magnet was tested at 4.2 K in liquid helium, with multipole components measured using rotating Printed Circuit Board (PCB) coils. During the test, the maximum magnetic field was 2.90 T. The measured central magnetic field showed good agreement with calculations considering the screening current effect. The measured multipole components at 140 A, 210 A, and 250 A indicate that the asymmetry of the magnet increased during the test. The current source was turned off automatically at 251.1 A, resulting in the sudden discharge of the magnet. The measured voltages and magnetic fields after the sudden discharge are discussed.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553479","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}
We develop X-ray transition-edge sensors (TESs) based on Ti/Au bilayers with Au absorber deposited on the center of TES. The thermal conductance after etching the silicon substrate underneath the TES sensor is reduced to 530 pW/K, only ∼10% that before etching, which agrees well with thermal simulation using COMSOL software. Principal component analysis is adopted to simultaneously discriminate the true pulse traces from the false ones and improve the signal-to-noise ratio by ∼20 dB. The obtained energy resolution is 102 eV at 5.9 keV for etched TES device. In addition, we perform complex impedance measurement to extract the parameters of thermal capacity, temperature and current sensitivity, which is very useful to understand the dynamics of TESs.
{"title":"Pulse Discrimination and Filtering of X-Ray Ti/Au TESs Using Principal Component Analysis","authors":"Qing-Xiao Ma;Wen Zhang;Zheng Wang;Pei-Zhan Li;Zhi-Fa Feng;Jia-Qiang Zhong;Wei Miao;Yuan Ren;Jing Li;Sheng-Cai Shi","doi":"10.1109/TASC.2025.3539603","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539603","url":null,"abstract":"We develop X-ray transition-edge sensors (TESs) based on Ti/Au bilayers with Au absorber deposited on the center of TES. The thermal conductance after etching the silicon substrate underneath the TES sensor is reduced to 530 pW/K, only ∼10% that before etching, which agrees well with thermal simulation using COMSOL software. Principal component analysis is adopted to simultaneously discriminate the true pulse traces from the false ones and improve the signal-to-noise ratio by ∼20 dB. The obtained energy resolution is 102 eV at 5.9 keV for etched TES device. In addition, we perform complex impedance measurement to extract the parameters of thermal capacity, temperature and current sensitivity, which is very useful to understand the dynamics of TESs.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-6"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465677","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 : 2025-02-07DOI: 10.1109/TASC.2025.3539266
Nobuya Banno;Koki Asai;Tsuyoshi Yagai
Large-scale devices, such as the next generation high energy particle accelerator project, demand the enhancement of the Jc and cost performance of Nb3Sn wires. The cost performance is closely related to the design and drawability of the wires. This study aims to increase the hardness of the soft Sn core of the wires through the precipitation of fine compound particles, improve the hardness balance between the constituent materials (Nb, Cu, and Sn), and investigate the feasibility of this method for practical wire drawing. First, we investigated the variations in microstructure and hardness when Cu and Zn were co-added to Sn. A total addition of 50% Cu–Zn to the Sn alloy can triple the hardness, leaving the alloy ductile enough to sustain the entire deformation process. Subsequently, we manufactured tube-type multifilamentary wires using subelements containing different types of Sn alloys, with and without an intermediate layer of Cu between Sn and Nb. In the absence of Cu, we observed the formation of a large area of Nb6 Sn5, which is responsible for the formation of a large coarse Nb3Sn grain area. The presence of Cu suppresses the formation of the Nb6Sn5, demonstrating that controlling the Cu/Sn ratio at the subelement level is critical to suppressing the formation of coarse Nb3Sn areas.
{"title":"Nb3Sn Wire Fabrication Using Rod-in-Tube Method With a Diffusion Couple of Nb and Sn Alloy With Co-Addition of Cu and Zn","authors":"Nobuya Banno;Koki Asai;Tsuyoshi Yagai","doi":"10.1109/TASC.2025.3539266","DOIUrl":"https://doi.org/10.1109/TASC.2025.3539266","url":null,"abstract":"Large-scale devices, such as the next generation high energy particle accelerator project, demand the enhancement of the <italic>J</i><sub>c</sub> and cost performance of Nb<sub>3</sub>Sn wires. The cost performance is closely related to the design and drawability of the wires. This study aims to increase the hardness of the soft Sn core of the wires through the precipitation of fine compound particles, improve the hardness balance between the constituent materials (Nb, Cu, and Sn), and investigate the feasibility of this method for practical wire drawing. First, we investigated the variations in microstructure and hardness when Cu and Zn were co-added to Sn. A total addition of 50% Cu–Zn to the Sn alloy can triple the hardness, leaving the alloy ductile enough to sustain the entire deformation process. Subsequently, we manufactured tube-type multifilamentary wires using subelements containing different types of Sn alloys, with and without an intermediate layer of Cu between Sn and Nb. In the absence of Cu, we observed the formation of a large area of Nb<sub>6</sub> Sn<sub>5</sub>, which is responsible for the formation of a large coarse Nb<sub>3</sub>Sn grain area. The presence of Cu suppresses the formation of the Nb<sub>6</sub>Sn<sub>5</sub>, demonstrating that controlling the Cu/Sn ratio at the subelement level is critical to suppressing the formation of coarse Nb<sub>3</sub>Sn areas.","PeriodicalId":13104,"journal":{"name":"IEEE Transactions on Applied Superconductivity","volume":"35 5","pages":"1-5"},"PeriodicalIF":1.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471820","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 : 2025-02-07DOI: 10.1109/TASC.2025.3539601
M. Wozniak;A. Devred;R. Ferriere;C. Geuzaine;A. Haziot;G. Kirby;E. Ravaioli;A. Verweij
A quench protection study was performed on the Fusillo Demonstrator Curved Canted Cosine Theta (CCCT) dipole magnet developed at CERN. This magnet features an aperture of 236 mm and a bending radius and angle of 1 m and 90 degrees, respectively. It has an inductance of 9.14 H, a peak winding field of 3.6 T and multi-harmonic aperture field correction. Ten turns of a rope cable made of Nb-Ti strands are placed in each channel of aluminium formers, which are surrounded by an aluminium shell. The aluminium structures not only support mechanical forces but also affect the quench behavior of the magnet. A discharge of the stored energy over an external resistor results in significant eddy current heating of the aluminium structures, which quickly brings a large part of the superconducting winding to the resistive state. A three-dimensional (3D) simulation of the eddy currents and heat propagation in the formers with heat propagation in the magnet windings was performed. It uses a cooperative simulation approach involving two software tools developed at CERN as part of the STEAM framework: a finite-element-based tool called FiQuS and a finite-difference-based tool called LEDET. FiQuS calculates the eddy currents and the temperature distribution of the formers, whereas LEDET calculates the current, voltage, and temperature of the windings. This approach enables a 3D quench simulation with great geometrical detail while maintaining reasonable computational cost. Energy extraction with a fixed resistor is studied, and key parameters of the discharge are calculated. The voltage of the magnet remains below the target specification of 1.5 kV, and the adiabatic hot spot temperature of the windings reaches 185 K. It is shown that the magnet differential inductance and winding resistance dominate the protection transient. The simulations provide great insights into the transient behaviour of the magnet, including the metal structures' temperature and the eddy currents' temporal and spatial distribution.
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