Field Stability of a 600 MHz NMR Magnet in the Driven-Mode
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- OTSUKA Akihiro
- National Institute for Materials Science
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- KIYOSHI Tsukasa
- National Institute for Materials Science
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- MATSUMOTO Shinji
- National Institute for Materials Science
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- NOGUCHI Takashi
- Ikegami Technology
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- KOMINATO Kentaro
- Japan Superconductor Technology, Inc.
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- TAKEDA Masaaki
- Japan Superconductor Technology, Inc.
Bibliographic Information
- Other Title
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- 600MHz NMRマグネットの電源駆動モードにおける磁場安定度
- 600 MHz NMR マグネット ノ デンゲン クドウ モード ニ オケル ジバ アンテイド
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Abstract
Although high-Tc superconductors (HTS) are very promising for high-field generation over 25 T, it is difficult to apply them to NMR magnets because of their low index values and the difficulty caused by superconducting joints. Therefore, high-field NMR magnets including HTS coils will be operated in the driven-mode. In order to evaluate magnetic filed stability in the driven-mode, we remodeled a 14 T (600 MHz) NMR magnet. Regarding the magnet, persistent switches for axial shim coils (z0, z1, z2) as well as for the main coil were removed for constant operation with a power supply. In addition, a 1 W GM cryocooler at 4 K and HTS current leads were installed in the cryostat to re-condense the boiled helium gas. As a result, there was a long-term change of about 6 ppm in the magnetic field stability, but in the short-term (a few hours), a change of about 2 ppm was observed. In order to reduce the field fluctuation, we tested the damper coil by making a closed-loop circuit using Bi2223 tapes. The damper coil was cooled to about 23 K lower than Tc by a single-stage GM cryocooler in the magnetic field. The magnetic field fluctuation was reduced to less than 0.07 ppm by the damper coil.
Journal
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- TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)
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TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 43 (7), 287-295, 2008
CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN
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Details 詳細情報について
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- CRID
- 1390282679589492736
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- NII Article ID
- 10021018287
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- NII Book ID
- AN00333419
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- COI
- 1:CAS:528:DC%2BD1cXhtVGmurfE
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- ISSN
- 18800408
- 03892441
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- NDL BIB ID
- 9606039
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- Text Lang
- ja
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed