A15 Nb3Al has gained much interests for high-field and large-scale applications due to its excellent critical current density Jc and strain tolerance. However, the shift of Nb3Al composition from stoichiometry at temperatures below 1800°C causes difficulties in the fabrication of conductors with inherent Nb3Al characteristics. In this study, Nb3Al powders prepared by arc melting in an Ar / H2 atmosphere were encased in a sheath and fabricated into tapes through the ex-situ PIT (Powder in Tube) process. The present study revealed that the oxygen content in the Nb3Al powder plays a crucial role in yielding large Jc in the tape. Furthermore, the addition of Ag powder to the Nb3Al powder was found to appreciably enhance the Jc of the tape in lower fields. The superconducting performance of the tapes is discussed in relating to their structures.
A15 Nb3Al由于其优异的临界电流密度Jc和应变容限，在高场和大规模应用中受到了广泛的关注。然而，在1800°C以下的温度下，Nb3Al成分从化学计量的转变导致了具有固有Nb3Al特性的导体的制造困难。本研究将在Ar / H2气氛中电弧熔化制备的Nb3Al粉末包裹在护套中，并通过非原位PIT (Powder In Tube)工艺制成带状。本研究表明，Nb3Al粉末中的氧含量对带中产生大的Jc起着至关重要的作用。此外，在Nb3Al粉末中添加Ag粉末可以明显提高带的低场Jc。从结构上讨论了超导带的性能。
{"title":"Ex-situ PIT法 Nb3Al線材の作製と特性","authors":"恭治 太刀川, 剛史 中陳, 祐哉 池田, 寛之 伊澤, 修 井戸原, 好明 井上","doi":"10.2221/JCSJ.39.645","DOIUrl":"https://doi.org/10.2221/JCSJ.39.645","url":null,"abstract":"A15 Nb3Al has gained much interests for high-field and large-scale applications due to its excellent critical current density Jc and strain tolerance. However, the shift of Nb3Al composition from stoichiometry at temperatures below 1800°C causes difficulties in the fabrication of conductors with inherent Nb3Al characteristics. In this study, Nb3Al powders prepared by arc melting in an Ar / H2 atmosphere were encased in a sheath and fabricated into tapes through the ex-situ PIT (Powder in Tube) process. The present study revealed that the oxygen content in the Nb3Al powder plays a crucial role in yielding large Jc in the tape. Furthermore, the addition of Ag powder to the Nb3Al powder was found to appreciably enhance the Jc of the tape in lower fields. The superconducting performance of the tapes is discussed in relating to their structures.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133816466","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}
The stress and strain dependence of the critical current (Ic) was examined for YBCO-coated conductors with IBAD-CeO2/YSZ or ISD-MgO buffer layers. For all samples, Ic increased as the stress was increased and reached a maximum. For larger tensile stress, Ic started to decrease. The reversibility of Ic showed a different behavior depending on the buffer layer. For the tape buffered with IBAD-CeO2/YSZ, Ic recovered to the initial value after the applied strain reached 0.30%. On the other hand, a smaller reversible strain was observed for the ISD-buffered tape. The difference of the reversible strain was discussed based on a microstructure observation. For all samples, quenching occurred at a strain of more than 0.30%. Compared to the stress-strain curve of composite tapes, it was confirmed that quenching strains were determined by the yield strain of the Hastelloy substrate. The strain scaling law for the present YBCO-coated conductors was found to be similar to that for A15-type superconductors.
{"title":"YBCO coated conductor の臨界電流の応力（ひずみ）効果に与えるバッファー層の影響","authors":"菅野 未知央, 光造 長村, Werner Prussuit, 司 木吉, 伊藤 喜久男","doi":"10.2221/JCSJ.39.547","DOIUrl":"https://doi.org/10.2221/JCSJ.39.547","url":null,"abstract":"The stress and strain dependence of the critical current (Ic) was examined for YBCO-coated conductors with IBAD-CeO2/YSZ or ISD-MgO buffer layers. For all samples, Ic increased as the stress was increased and reached a maximum. For larger tensile stress, Ic started to decrease. The reversibility of Ic showed a different behavior depending on the buffer layer. For the tape buffered with IBAD-CeO2/YSZ, Ic recovered to the initial value after the applied strain reached 0.30%. On the other hand, a smaller reversible strain was observed for the ISD-buffered tape. The difference of the reversible strain was discussed based on a microstructure observation. For all samples, quenching occurred at a strain of more than 0.30%. Compared to the stress-strain curve of composite tapes, it was confirmed that quenching strains were determined by the yield strain of the Hastelloy substrate. The strain scaling law for the present YBCO-coated conductors was found to be similar to that for A15-type superconductors.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131516034","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 have investigated the high-speed deposition of YBa2Cu3O7-x (YBCO) using PLD on a CeO2-capped IBAD buffer layer. In order to speed up the coated conductor process, we introduced a continuous PLD system mainly consisting of high-power laser equipment and a vacuum chamber with a reel-to-reel substrate transfer system. The laser system was designed so that the laser beam scans YBCO targets during deposition and raises plural and discrete plumes (multi-plume). The aim of this is to perform high-speed production of YBCO layers. Although high laser pulse frequency deposition makes high-speed deposition possible, it causes roughening of the surface morphology and lowers the Jc. The multi-plume gave us a high Jc during low laser pulse frequency deposition and high-speed deposition at a higher frequency. The substrates were turned three times to enlarge the deposition area (multi-turn). Within 15 degrees aslant to a plume center, we obtained a high Jc for all turns. Using this multi-plume and multi-turn PLD equipment, we have succeeded in deposition of a 21m-long YBCO layer with a high end-to-end critical current (Ic) of 85 A and high Jc exceeding 1 MA/cm2. Ic data measured in 1.4m intervals showed good uniformity, with a standard deviation of 3.43%. This layer also showed high in-plane alignment, attaining 5.2 degrees of full-width-at-half-maximum as observed by X-ray phi scans. These results indicate the availability of utilizing multi-plume and multi-turn PLD for YBCO-coated conductor preparation.
{"title":"YBCOのマルチ-プルーム・マルチ-ターンPLD成膜","authors":"智則 渡部, 礼二 栗木, 博幸 岩井, 成紀 宮田, 岳海 室賀, 顕 衣斐, 穣 山田, 融 塩原","doi":"10.2221/JCSJ.39.553","DOIUrl":"https://doi.org/10.2221/JCSJ.39.553","url":null,"abstract":"We have investigated the high-speed deposition of YBa2Cu3O7-x (YBCO) using PLD on a CeO2-capped IBAD buffer layer. In order to speed up the coated conductor process, we introduced a continuous PLD system mainly consisting of high-power laser equipment and a vacuum chamber with a reel-to-reel substrate transfer system. The laser system was designed so that the laser beam scans YBCO targets during deposition and raises plural and discrete plumes (multi-plume). The aim of this is to perform high-speed production of YBCO layers. Although high laser pulse frequency deposition makes high-speed deposition possible, it causes roughening of the surface morphology and lowers the Jc. The multi-plume gave us a high Jc during low laser pulse frequency deposition and high-speed deposition at a higher frequency. The substrates were turned three times to enlarge the deposition area (multi-turn). Within 15 degrees aslant to a plume center, we obtained a high Jc for all turns. Using this multi-plume and multi-turn PLD equipment, we have succeeded in deposition of a 21m-long YBCO layer with a high end-to-end critical current (Ic) of 85 A and high Jc exceeding 1 MA/cm2. Ic data measured in 1.4m intervals showed good uniformity, with a standard deviation of 3.43%. This layer also showed high in-plane alignment, attaining 5.2 degrees of full-width-at-half-maximum as observed by X-ray phi scans. These results indicate the availability of utilizing multi-plume and multi-turn PLD for YBCO-coated conductor preparation.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"330 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134300124","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}
H. Sasaki, T. Kato, Y. Sasaki, T. Hirayama, J. Matsuda, T. Izumi, Y. Shiohara, N. Kashima, S. Nagaya
Synopsis: We have developed a defect analysis procedure that combines a magneto-optical (MO) imaging system with scanning ion microscopy (SIM) and transmission electron microscopy (TEM). Low Ic areas of coated conductors were inspected using the MO imaging system. The defective area revealed in the MO image was prepared for cross-sectional SIM specimen using a focused Ga ion beam. The porous YBCO layers were found by SIM observation. Furthermore, defective areas were picked up using micro-sampling and then thinned using a focused Ga ion beam. TEM observation and energy dispersive X-ray spectroscopy indicated that the YBCO layers were composed of Y-rich phases and Ba-Cu-O.
{"title":"SIM and TEM Micro-structure Observation of Defective Areas Determined by MO Imaging of YBCO-coated Conductors","authors":"H. Sasaki, T. Kato, Y. Sasaki, T. Hirayama, J. Matsuda, T. Izumi, Y. Shiohara, N. Kashima, S. Nagaya","doi":"10.2221/JCSJ.39.541","DOIUrl":"https://doi.org/10.2221/JCSJ.39.541","url":null,"abstract":"Synopsis: We have developed a defect analysis procedure that combines a magneto-optical (MO) imaging system with scanning ion microscopy (SIM) and transmission electron microscopy (TEM). Low Ic areas of coated conductors were inspected using the MO imaging system. The defective area revealed in the MO image was prepared for cross-sectional SIM specimen using a focused Ga ion beam. The porous YBCO layers were found by SIM observation. Furthermore, defective areas were picked up using micro-sampling and then thinned using a focused Ga ion beam. TEM observation and energy dispersive X-ray spectroscopy indicated that the YBCO layers were composed of Y-rich phases and Ba-Cu-O.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"128 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124242554","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 found that a PLD-CeO2 cap layer on an IBAD-Gd2Zr2O7 (GZO) tape can make a high grain alignment without ion-beam assistance such as the IBAD process. We call this phenomenon “self-epitaxy in a PLD-CeO2 cap layer”. At present, we are developing long tapes by the Reel-to-Reel process for the self-epitaxial PLD-CeO2 cap layer on an IBAD-GZO tape. A 108 m-long tape with a PLD-CeO2 cap layer was obtained. The delta phi values of the buffer layer were improved to 4.3-4.8 degrees of PLD-CeO2 from 13.3-14.0 degrees of IBAD-GZO. Although the fabrication rate of the PLD-CeO2 cap layer was as fast as 5-6 m/h, that of the IBAD-GZO was 1 m/h. Then, we tried to improve the overall fabrication rate of the total buffer layers using a thin IBAD layer and the self-epitaxial PLD-CeO2 cap layer. A PLD-CeO2 cap layer was deposited at a tape transfer speed of 2.5 m/h on a 55 m-long IBAD-GZO tape with the delta phi values of 23.1-24.0 degrees fabricated at 2 m/h, which was two times faster than the conventional IBAD process. As a result, the delta phi values of the PLD-CeO2 cap layer were in the range of 8.6-10.4 degrees. The fabrication rate throughout all of the processes for buffer layers was achieved to be 2 m/h. It was found that PLD-CeO2 was effective for enhancing both the fabrication rate and grain alignment.
{"title":"IBAD-PLD法長尺YBCO線材の開発 —IBAD中間層上における自己配向PLD-CeO2キャップ層の長尺化—","authors":"岳海 室賀, 成紀 宮田, 智則 渡部, 顕 衣斐, 穣 山田, 輝郎 和泉, 融 塩原, 丈晴 加藤, 司 平山","doi":"10.2221/JCSJ.39.529","DOIUrl":"https://doi.org/10.2221/JCSJ.39.529","url":null,"abstract":"We found that a PLD-CeO2 cap layer on an IBAD-Gd2Zr2O7 (GZO) tape can make a high grain alignment without ion-beam assistance such as the IBAD process. We call this phenomenon “self-epitaxy in a PLD-CeO2 cap layer”. At present, we are developing long tapes by the Reel-to-Reel process for the self-epitaxial PLD-CeO2 cap layer on an IBAD-GZO tape. A 108 m-long tape with a PLD-CeO2 cap layer was obtained. The delta phi values of the buffer layer were improved to 4.3-4.8 degrees of PLD-CeO2 from 13.3-14.0 degrees of IBAD-GZO. Although the fabrication rate of the PLD-CeO2 cap layer was as fast as 5-6 m/h, that of the IBAD-GZO was 1 m/h. Then, we tried to improve the overall fabrication rate of the total buffer layers using a thin IBAD layer and the self-epitaxial PLD-CeO2 cap layer. A PLD-CeO2 cap layer was deposited at a tape transfer speed of 2.5 m/h on a 55 m-long IBAD-GZO tape with the delta phi values of 23.1-24.0 degrees fabricated at 2 m/h, which was two times faster than the conventional IBAD process. As a result, the delta phi values of the PLD-CeO2 cap layer were in the range of 8.6-10.4 degrees. The fabrication rate throughout all of the processes for buffer layers was achieved to be 2 m/h. It was found that PLD-CeO2 was effective for enhancing both the fabrication rate and grain alignment.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133385819","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. Ishiyama, M. Yanai, H. Ueda, Y. Iijima, T. Saitoh, Y. Shiohara
There are great expectations for YBCO tape as a “next-generation superconductor tape” because the Jc characteristic has better magnetic field dependence at high temperatures and/or in a high magnetic field. It is important to consider stability for superconducting applications; however, the stability criterion for YBCO has not yet been distinctly established. Thus, for the sake of establishing stability criterion for YBCO, we examined the normal-zone initiation and propagation characteristics of a YBCO tape sample experimentally and numerically, and the experimental results were compared with a simulation conducted utilizing a newly developed computer program based on the finite element method (FEM). We also investigated the influence of Ag stabilizer thickness and Hastelloy substrate on the transient thermal behavior of the YBCO tapes.
{"title":"Evaluation of the Normal-zone Initiation and Propagation Characteristics of YBCO Tape","authors":"A. Ishiyama, M. Yanai, H. Ueda, Y. Iijima, T. Saitoh, Y. Shiohara","doi":"10.2221/JCSJ.39.560","DOIUrl":"https://doi.org/10.2221/JCSJ.39.560","url":null,"abstract":"There are great expectations for YBCO tape as a “next-generation superconductor tape” because the Jc characteristic has better magnetic field dependence at high temperatures and/or in a high magnetic field. It is important to consider stability for superconducting applications; however, the stability criterion for YBCO has not yet been distinctly established. Thus, for the sake of establishing stability criterion for YBCO, we examined the normal-zone initiation and propagation characteristics of a YBCO tape sample experimentally and numerically, and the experimental results were compared with a simulation conducted utilizing a newly developed computer program based on the finite element method (FEM). We also investigated the influence of Ag stabilizer thickness and Hastelloy substrate on the transient thermal behavior of the YBCO tapes.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"517 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116239291","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":"「Nb3Sn線材の現状と将来展望—発見から50年を記念して—」特集によせて","authors":"浩明 熊倉","doi":"10.2221/JCSJ.39.376","DOIUrl":"https://doi.org/10.2221/JCSJ.39.376","url":null,"abstract":"","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117337545","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}
The development of new high-performance refrigerants has been highly desired from the viewpoints of energy efficiency and environmental safety. Recently, we developed promising magnetic refrigerant compounds La(Fe1-xSix)13 (0.86≤x≤0.90), that show the first-order of itinerant-electron metamagnetic transition from the paramagnetic state to the ferromagnetic state in applied magnetic fields. By adjusting the hydrogen concentration in La(Fe1-xSix)13Hy, the Curie temperature TC and the working temperature for cooling are controlled covering room temperature. Furthermore, the thermal conductivity of the present compounds is excellent. It should also be emphasized that the elements of the present compounds are very cheap economically and completely harmless to humans.
{"title":"Development of High-performance Magnetic Refrigerants and Recent Trend in Room-temperature Magnetic Cooling","authors":"K. Fukamichi, A. Fujita","doi":"10.2221/JCSJ.39.314","DOIUrl":"https://doi.org/10.2221/JCSJ.39.314","url":null,"abstract":"The development of new high-performance refrigerants has been highly desired from the viewpoints of energy efficiency and environmental safety. Recently, we developed promising magnetic refrigerant compounds La(Fe1-xSix)13 (0.86≤x≤0.90), that show the first-order of itinerant-electron metamagnetic transition from the paramagnetic state to the ferromagnetic state in applied magnetic fields. By adjusting the hydrogen concentration in La(Fe1-xSix)13Hy, the Curie temperature TC and the working temperature for cooling are controlled covering room temperature. Furthermore, the thermal conductivity of the present compounds is excellent. It should also be emphasized that the elements of the present compounds are very cheap economically and completely harmless to humans.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"278 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121034015","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}
The use of a non-neutral plasma confinement device with a floating internal coil has been planned for the purpose of high-beta plasma confinement research at the University of Tokyo. A device known as the Mini-RT (Miniature Ring Trap) has been constructed as a joint research project between the University of Tokyo, NIFS and Kyushu University. In the experiment, a magnetic-levitation coil (floating coil) operated in a persistent current mode is levitated for 8 hours in a plasma vacuum vessel. The high-temperature superconducting (HTS) floating coil is wound with Bi-2223 tape, and has a diameter of 300 mm and an electromotive force of 50 kA. Since refrigerant cannot be fed to the coil during the plasma experiment, the coil is designed so that the temperature rise after 8 hours of levitation is less than 40 K as the result of considering the specific heat of the coil and incorporating a radiation shield. At the end of the daily plasma experiment, the coil is drawn down to the maintenance location at the bottom of the plasma vacuum vessel, and is re-cooled to 20 K. The engineering design points of the Mini-RT, such as the HTS floating coil, HTS persistent current switch (PCS), cooling system and excitation scheme are summarized.
{"title":"Mini-RT装置の設計・製作","authors":"利行 三戸, 長門 柳, 雄一 小川, 惇二 森川, 大國 浩太郎, 成卓 岩熊, 俊夫 上出, 眞一 能瀬, 郁夫 伊藤, 滋夫 福居, 俊毅 長山, 純一 奥野","doi":"10.2221/JCSJ.39.182","DOIUrl":"https://doi.org/10.2221/JCSJ.39.182","url":null,"abstract":"The use of a non-neutral plasma confinement device with a floating internal coil has been planned for the purpose of high-beta plasma confinement research at the University of Tokyo. A device known as the Mini-RT (Miniature Ring Trap) has been constructed as a joint research project between the University of Tokyo, NIFS and Kyushu University. In the experiment, a magnetic-levitation coil (floating coil) operated in a persistent current mode is levitated for 8 hours in a plasma vacuum vessel. The high-temperature superconducting (HTS) floating coil is wound with Bi-2223 tape, and has a diameter of 300 mm and an electromotive force of 50 kA. Since refrigerant cannot be fed to the coil during the plasma experiment, the coil is designed so that the temperature rise after 8 hours of levitation is less than 40 K as the result of considering the specific heat of the coil and incorporating a radiation shield. At the end of the daily plasma experiment, the coil is drawn down to the maintenance location at the bottom of the plasma vacuum vessel, and is re-cooled to 20 K. The engineering design points of the Mini-RT, such as the HTS floating coil, HTS persistent current switch (PCS), cooling system and excitation scheme are summarized.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"46 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120918796","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 magnetically levitated superconducting coil device, Mini-RT, has been constructed using a high temperature superconductor (HTS) for the purpose of examining a new magnetic confinement scheme of high-beta non-neutral plasmas. The floating coil and persistent current switch (PCS) are wound with silver-sheathed Bi-2223 tapes, and they are operated in the temperature range of 20-40 K. After the basic properties of the main coil and HTS-PCS were examined in a liquid helium cryostat, the coil was installed into the vacuum chamber of the Mini-RT device. The HTS floating coil was then cooled by helium gas using GM cryo-coolers equipped with detachable transfer tubes. The excitation tests of the coil were carried out by supplying current from an external DC power supply through the detachable current feeder terminals as the HTS-PCS was turned off. The nominal operation condition was examined by overcoming many difficulties and the persistent current mode was tried by turning on the HTS-PCS. The decay time-constant was evaluated by maintaining the coil temperature for up to four days and the results were compared with calculations. The first magnetic levitation was also examined.
{"title":"Mini-RT装置用高温超伝導磁気浮上コイルの冷却・励磁試験","authors":"長門 柳, 惇二 森川, 利行 三戸, 雄一 小川, 大國 浩太郎, 茂雄 山越, 成卓 岩熊, 俊夫 上出","doi":"10.2221/JCSJ.39.201","DOIUrl":"https://doi.org/10.2221/JCSJ.39.201","url":null,"abstract":"A magnetically levitated superconducting coil device, Mini-RT, has been constructed using a high temperature superconductor (HTS) for the purpose of examining a new magnetic confinement scheme of high-beta non-neutral plasmas. The floating coil and persistent current switch (PCS) are wound with silver-sheathed Bi-2223 tapes, and they are operated in the temperature range of 20-40 K. After the basic properties of the main coil and HTS-PCS were examined in a liquid helium cryostat, the coil was installed into the vacuum chamber of the Mini-RT device. The HTS floating coil was then cooled by helium gas using GM cryo-coolers equipped with detachable transfer tubes. The excitation tests of the coil were carried out by supplying current from an external DC power supply through the detachable current feeder terminals as the HTS-PCS was turned off. The nominal operation condition was examined by overcoming many difficulties and the persistent current mode was tried by turning on the HTS-PCS. The decay time-constant was evaluated by maintaining the coil temperature for up to four days and the results were compared with calculations. The first magnetic levitation was also examined.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130820011","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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