H. Yamasaki, K. Arai, M. Furuse, Y. Nakagawa, K. Kaiho, T. Kumagai, M. Shibuya, T. Nitta
We recently proposed a new design for a high-temperature superconducting thin-film fault-current limiter (FCL), which uses high-resistivity Au-Ag alloy shunt layers instead of the pure gold (or silver) shunt layers conventionally used. Due to the much larger resistance of the Au-Ag alloy layers, the FCL elements withstood very high electric fields (> 40 Vpeak/cm), and realized a very high switching power density, ∼2.0 kVA/cm2. The composition of our FCL element is very simple, and the achieved power density is more than five times higher than conventional devices, which leads to a dramatic reduction in the amount of expensive superconducting thin films required. Similarly, Kinder et al. recently proposed a new coated-conductor-based FCL element, which achieved a relatively high electric field of 2.7 Vpeak/cm. We estimated the cost of our thin-film FCL elements used in a typical 6.6 kV FCL that is introduced in a distributed power supply site. We also estimated the cost of coated conductors used to produce the FCL, and compared the two.
{"title":"Comparison of Estimated Conductor Costs between a Superconducting Thin-film Fault-current Limiter (FCL) and a Coated-conductor-based Superconducting FCL","authors":"H. Yamasaki, K. Arai, M. Furuse, Y. Nakagawa, K. Kaiho, T. Kumagai, M. Shibuya, T. Nitta","doi":"10.2221/JCSJ.41.397","DOIUrl":"https://doi.org/10.2221/JCSJ.41.397","url":null,"abstract":"We recently proposed a new design for a high-temperature superconducting thin-film fault-current limiter (FCL), which uses high-resistivity Au-Ag alloy shunt layers instead of the pure gold (or silver) shunt layers conventionally used. Due to the much larger resistance of the Au-Ag alloy layers, the FCL elements withstood very high electric fields (> 40 Vpeak/cm), and realized a very high switching power density, ∼2.0 kVA/cm2. The composition of our FCL element is very simple, and the achieved power density is more than five times higher than conventional devices, which leads to a dramatic reduction in the amount of expensive superconducting thin films required. Similarly, Kinder et al. recently proposed a new coated-conductor-based FCL element, which achieved a relatively high electric field of 2.7 Vpeak/cm. We estimated the cost of our thin-film FCL elements used in a typical 6.6 kV FCL that is introduced in a distributed power supply site. We also estimated the cost of coated conductors used to produce the FCL, and compared the two.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116112841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"特集「金属材料研究所における小型冷凍機冷却超伝導マグネットの強磁場化」によせて","authors":"和雄 渡辺","doi":"10.2221/JCSJ.41.301","DOIUrl":"https://doi.org/10.2221/JCSJ.41.301","url":null,"abstract":"","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122420499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Takahashi, S. Awaji, Y. Sasaki, K. Koyama, Kazuo Watanabe
{"title":"小型冷凍機冷却34 T-8 MWハイブリッドマグネットへの発展と磁気科学応用","authors":"K. Takahashi, S. Awaji, Y. Sasaki, K. Koyama, Kazuo Watanabe","doi":"10.2221/JCSJ.41.316","DOIUrl":"https://doi.org/10.2221/JCSJ.41.316","url":null,"abstract":"","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114214904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We employed Ba-Cu-O substrates for the fabrication of bulk Nd-Ba-Cu-O superconductors using the top-seeded melt-growth method. There were several advantages for the use of Ba-Cu-O substrate compared to conventional substrate materials such as MgO, ZrO2, Al2O3, RE123 and RE211 (RE: rare earth). The Ba-Cu-O did not react with the precursor and minimized the loss of liquid. Accordingly, the introduction of large-sized cracks was suppressed. We also found that Tc values were high at the bottom regions, which was ascribed to the beneficial effect of Ba-Cu-O in suppressing Nd/Ba substitution. As a result, we could obtain bulk Nd-Ba-Cu-O superconductors that exhibit fairly good field-trapping capabilities even at the bottom surfaces.
我们采用Ba-Cu-O衬底，采用顶种熔体生长方法制备了大块Nd-Ba-Cu-O超导体。与MgO、ZrO2、Al2O3、RE123和RE211 (RE:稀土)等传统衬底材料相比，Ba-Cu-O衬底具有许多优点。Ba-Cu-O不与前驱体发生反应，减少了液体损失。因此，大裂缝的出现受到了抑制。我们还发现Tc值在底部区域较高，这归因于Ba- cu - o抑制Nd/Ba取代的有益作用。因此，我们可以获得大块的Nd-Ba-Cu-O超导体，即使在底部表面也表现出相当好的场捕获能力。
{"title":"Ba-Cu-O系酸化物支持材を用いた超電導バルク体の品質向上に関する研究","authors":"元英 松井, 紳也 成木, 浩志 藤本, 直道 坂井, 研吾 岩渕, 雅人 村上","doi":"10.2221/JCSJ.41.170","DOIUrl":"https://doi.org/10.2221/JCSJ.41.170","url":null,"abstract":"We employed Ba-Cu-O substrates for the fabrication of bulk Nd-Ba-Cu-O superconductors using the top-seeded melt-growth method. There were several advantages for the use of Ba-Cu-O substrate compared to conventional substrate materials such as MgO, ZrO2, Al2O3, RE123 and RE211 (RE: rare earth). The Ba-Cu-O did not react with the precursor and minimized the loss of liquid. Accordingly, the introduction of large-sized cracks was suppressed. We also found that Tc values were high at the bottom regions, which was ascribed to the beneficial effect of Ba-Cu-O in suppressing Nd/Ba substitution. As a result, we could obtain bulk Nd-Ba-Cu-O superconductors that exhibit fairly good field-trapping capabilities even at the bottom surfaces.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130694797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Japanese intense spallation neutron source (JSNS) driven by 3 GeV protons with power of 1 MW is constructed under the joint project of Japan Atomic Energy Agency and High Energy Accelerator Research Organization. Supercritical hydrogen of around 20K with 2 MPa is selected as a neutron moderator material and cryogenic hydrogen transfer lines are constructed from the moderators to the refrigerator. Then, a super insulator (SI) is adopted to reduce heat load in the hydrogen transfer lines. We performed irradiation test of SI using 60Co gamma ray to evaluate the irradiation effect. Two kinds of super insulator (polyimide and polyester) coated both sides by aluminum with thickness of 5 x 10-8 m were irradiated. After gamma ray irradiation, tensile test and gas yield measurement of super insulator were performed. Polyester based SI became brittle at about 10 MGy, on the other hand, polyimide based SI did not loss ductility so much even 80 MGy. Polyester based SI generated gas yield higher than that of polyimide based SI about one order of magnitude. We developed the gas analysis method by using a Q-mass and a mass-flow, providing to identify the unknown gas (i.e. H2O) effectively compared to a gas chromatography method.
{"title":"スーパーインシュレータ（ポリイミド及びポリエステル）のγ線照射後のガス生成量と機械的特性","authors":"誠司 勅使河原, 譲一 草野, 憲雄 森下, 藤夫 前川, 崇英 加藤, 謙二 細山, 和文 原, 裕二 小島","doi":"10.2221/JCSJ.41.99","DOIUrl":"https://doi.org/10.2221/JCSJ.41.99","url":null,"abstract":"Japanese intense spallation neutron source (JSNS) driven by 3 GeV protons with power of 1 MW is constructed under the joint project of Japan Atomic Energy Agency and High Energy Accelerator Research Organization. Supercritical hydrogen of around 20K with 2 MPa is selected as a neutron moderator material and cryogenic hydrogen transfer lines are constructed from the moderators to the refrigerator. Then, a super insulator (SI) is adopted to reduce heat load in the hydrogen transfer lines. We performed irradiation test of SI using 60Co gamma ray to evaluate the irradiation effect. Two kinds of super insulator (polyimide and polyester) coated both sides by aluminum with thickness of 5 x 10-8 m were irradiated. After gamma ray irradiation, tensile test and gas yield measurement of super insulator were performed. Polyester based SI became brittle at about 10 MGy, on the other hand, polyimide based SI did not loss ductility so much even 80 MGy. Polyester based SI generated gas yield higher than that of polyimide based SI about one order of magnitude. We developed the gas analysis method by using a Q-mass and a mass-flow, providing to identify the unknown gas (i.e. H2O) effectively compared to a gas chromatography method.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114596454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the temperature dependence of the trapped magnetic field and levitation force for c-axis-oriented single-grain Gd-Ba-Cu-O bulk superconductors 48 mm in diameter. The trapped magnetic fields of the samples were 2.1-2.2 T at 77 K and increased with decreasing temperature, reaching 4.1 T at 70 K. However, the samples fractured during the measurements at lower temperatures due to a large electromagnetic force. Reinforcement using a metal ring was effective in improving the mechanical strength. The sample encapsulated in an Al ring could trap a very high magnetic field of 9.0 T at 50 K. In liquid O2(90.2 K), the Gd-Ba-Cu-O bulk superconductor exhibited a trapped magnetic field of 0.4 T and a levitation force about half the value of that in liquid N2.
{"title":"Gd-Ba-Cu-O系大型バルク超電導材料の捕捉磁場，磁気浮上力の温度依存性","authors":"紳也 成木, 正敬 藤倉, 直道 坂井, 泉 平林, 雅人 村上","doi":"10.2221/JCSJ.40.292","DOIUrl":"https://doi.org/10.2221/JCSJ.40.292","url":null,"abstract":"We investigated the temperature dependence of the trapped magnetic field and levitation force for c-axis-oriented single-grain Gd-Ba-Cu-O bulk superconductors 48 mm in diameter. The trapped magnetic fields of the samples were 2.1-2.2 T at 77 K and increased with decreasing temperature, reaching 4.1 T at 70 K. However, the samples fractured during the measurements at lower temperatures due to a large electromagnetic force. Reinforcement using a metal ring was effective in improving the mechanical strength. The sample encapsulated in an Al ring could trap a very high magnetic field of 9.0 T at 50 K. In liquid O2(90.2 K), the Gd-Ba-Cu-O bulk superconductor exhibited a trapped magnetic field of 0.4 T and a levitation force about half the value of that in liquid N2.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126958930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pulse-field magnetization (PFM) has been investigated for a bulk Sm-Ba-Cu-O superconductor cryo-cooled at 20 - 40 K using pulse magnetic fields Bex of 3.83 - 6.07 T. The temperature rise ΔT after applying the pulse fields increases as the bulk superconductor's initial temperature Ts decreases and as the applied field Bex increases. The generated heat Q, estimated using ΔT and the specific heat C of the bulk superconductor, decreases with decreasing Ts for lower Bex (=3.83 T), but increases with decreasing Ts for higher Bex (≥5.53 T). There is a slight increase in the pinning loss Qp determined from the magnetization M vs the applied field μ0Ha hysteresis curve at a lower Ts. These results can be explained by the increase in pinning force Fp at lower temperatures. The lowering of Ts is one of the promising approaches for enhancing trapped field BTP using PFM.
{"title":"20-40 KにおけるSm-Ba-Cu-Oバルクに対するパルス着磁による捕捉磁場と発熱解析","authors":"雅彦 金山, 博之 藤代, 和哉 横山, 徹雄 岡, 宏七 能登","doi":"10.2221/JCSJ.40.231","DOIUrl":"https://doi.org/10.2221/JCSJ.40.231","url":null,"abstract":"Pulse-field magnetization (PFM) has been investigated for a bulk Sm-Ba-Cu-O superconductor cryo-cooled at 20 - 40 K using pulse magnetic fields Bex of 3.83 - 6.07 T. The temperature rise ΔT after applying the pulse fields increases as the bulk superconductor's initial temperature Ts decreases and as the applied field Bex increases. The generated heat Q, estimated using ΔT and the specific heat C of the bulk superconductor, decreases with decreasing Ts for lower Bex (=3.83 T), but increases with decreasing Ts for higher Bex (≥5.53 T). There is a slight increase in the pinning loss Qp determined from the magnetization M vs the applied field μ0Ha hysteresis curve at a lower Ts. These results can be explained by the increase in pinning force Fp at lower temperatures. The lowering of Ts is one of the promising approaches for enhancing trapped field BTP using PFM.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"99 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134580766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Ichinose, S. Akita, A. Ishiyama, S. Koso, Y. Tatsuta
High-Tc superconducting technology is thought to provide many merits for SMES systems. For example, a cryo-cooled system can be used as a cooling system for high-Tc superconducting coils, indicating that a wide range of operation temperatures can be selected. As a result, the heat capacity of the coil system becomes much larger than that at 4.2 K. If we could absorb transient heat generation with the heat capacity of the coil, SMES systems can be designed under the over-current state of critical current for a short duration. As the cooling capacity for an average heat load will be enough to cool the High-Tc superconducting coil system for an SMES, it is expected that refrigeration system cost can be reduced. Moreover, we are developing a high critical-current superconducting wire for the SMES system. The Bi2212 Rutherford conductors can carry 4 kA at 26 K under cryo-cooling. We also estimate the superconducting wire cost of the whole coil system, which is designed to minimize the superconductor volume. The conclusion is that the cost of a high-Tc SMES system can be reduced remarkably by using low-cost YBCO superconducting wires in the future.
{"title":"Feasibility Study on High-T_c SMES","authors":"A. Ichinose, S. Akita, A. Ishiyama, S. Koso, Y. Tatsuta","doi":"10.2221/JCSJ.40.150","DOIUrl":"https://doi.org/10.2221/JCSJ.40.150","url":null,"abstract":"High-Tc superconducting technology is thought to provide many merits for SMES systems. For example, a cryo-cooled system can be used as a cooling system for high-Tc superconducting coils, indicating that a wide range of operation temperatures can be selected. As a result, the heat capacity of the coil system becomes much larger than that at 4.2 K. If we could absorb transient heat generation with the heat capacity of the coil, SMES systems can be designed under the over-current state of critical current for a short duration. As the cooling capacity for an average heat load will be enough to cool the High-Tc superconducting coil system for an SMES, it is expected that refrigeration system cost can be reduced. Moreover, we are developing a high critical-current superconducting wire for the SMES system. The Bi2212 Rutherford conductors can carry 4 kA at 26 K under cryo-cooling. We also estimate the superconducting wire cost of the whole coil system, which is designed to minimize the superconductor volume. The conclusion is that the cost of a high-Tc SMES system can be reduced remarkably by using low-cost YBCO superconducting wires in the future.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126367135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yosuke Fukumoto, M. Kiuchi, E. Otabe, T. Matsushita, T. Kiss, Tomonori Watanabe, S. Miyata, A. Ibi, T. Muroga, Y. Yamada, Y. Shiohara
A significant overestimation of the critical current density Jc was discovered in a measuring method that utilizes induced third harmonic voltage for thin superconductors with a thickness less than 1 μm. This is speculated to be caused by the reversible motion of flux lines in the pinning potential, which reduces nonlinear properties such as hysteresis loss or third harmonic voltage. It is known that the effect of reversible flux motion is prominent for superconductors comparable to or smaller than the pinning correlation length at the sub-micrometer order called Campbell's AC penetration depth. In this paper, the effect of reversible flux motion on the estimation of Jc utilizing this method is investigated using a simplified Campbell's model for the force-displacement characteristics of flux lines, and the factor of overestimation of Jc is discussed.
{"title":"Effect of Reversible Flux Motion on the Estimation of Critical Current Density in Thin Superconductors Using the Third Harmonic Voltage Method","authors":"Yosuke Fukumoto, M. Kiuchi, E. Otabe, T. Matsushita, T. Kiss, Tomonori Watanabe, S. Miyata, A. Ibi, T. Muroga, Y. Yamada, Y. Shiohara","doi":"10.2221/JCSJ.40.116","DOIUrl":"https://doi.org/10.2221/JCSJ.40.116","url":null,"abstract":"A significant overestimation of the critical current density Jc was discovered in a measuring method that utilizes induced third harmonic voltage for thin superconductors with a thickness less than 1 μm. This is speculated to be caused by the reversible motion of flux lines in the pinning potential, which reduces nonlinear properties such as hysteresis loss or third harmonic voltage. It is known that the effect of reversible flux motion is prominent for superconductors comparable to or smaller than the pinning correlation length at the sub-micrometer order called Campbell's AC penetration depth. In this paper, the effect of reversible flux motion on the estimation of Jc utilizing this method is investigated using a simplified Campbell's model for the force-displacement characteristics of flux lines, and the factor of overestimation of Jc is discussed.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124601381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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