MISC

2015年6月

Design of a Cooling System for a REBCO Insert Coil in a Cryogen-Free 25 T Superconducting Magnet

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
  • S. Iwai
  • ,
  • M. Takahashi
  • ,
  • H. Miyazaki
  • ,
  • T. Tosaka
  • ,
  • K. Tasaki
  • ,
  • S. Hanai
  • ,
  • S. Ioka
  • ,
  • K. Watanabe
  • ,
  • S. Awaji
  • ,
  • H. Oguro

25
3
開始ページ
0500304
終了ページ
記述言語
英語
掲載種別
DOI
10.1109/TASC.2014.2368713
出版者・発行元
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

A cryogen-free 20 T superconducting magnet with a 52 mm room-temperature bore was developed and installed in Tohoku University in 2013. This magnet consists of a Bi2223 insert coil, which generates 4.5 T, and outer low-temperature superconducting (LTS) coils. Both coils were cooled by a GM/JT cryocooler with 4.2 W-class cooling capacity at 4.3 K. To generate a higher magnetic field, a new cryogen-free 25 T superconducting magnet using a REBCO insert coil, which generates 11.5 T, and new outer LTS coils is now under development. The magnetic field contribution of this REBCO insert coil is considerably higher than that of the previous Bi2223 insert coil, and the ac-loss of the insert coil during field ramping rises to approximately 9.7 W. The LTS coils have to operate at about 4 K, but the REBCO coil can operate at various temperatures above 4K. In addition, the cooling capacity of a GM cryocooler is greater than that of a GM/JT cryocooler around 10 K. Thus, the REBCO insert coil is cooled to about 10 K by using two GM cryocoolers, independently of the LTS coils, which are cooled by two GM/JT cryocoolers. To protect the cryocoolers from the leakage field of the magnet, the two GM cryocoolers cool circulating helium gas through heat exchangers, and the gas is transported over a long distance to another heat exchanger provided for the REBCO insert coil. The maximum temperature of the REBCO insert coil was calculated under the most severe condition where an insert coil ac-loss of 9.7 W was generated continuously. And it was confirmed to be less than the target maximum temperature of 12 K.

リンク情報
DOI
https://doi.org/10.1109/TASC.2014.2368713
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000216433300001&DestApp=WOS_CPL
ID情報
  • DOI : 10.1109/TASC.2014.2368713
  • ISSN : 1051-8223
  • eISSN : 1558-2515
  • Web of Science ID : WOS:000216433300001

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