Development of liquid helium-free superconducting magnet

Junji Sakuraba, Mamoru Ishihara, Seiji Yasuhara, Kazunori Jikihara, Keiichi Watazawa, Tsuginori Hasebe, Chin Kung Chong, Yutaka Yamada, Kazuo Watanabe

Research output: Contribution to journalArticlepeer-review


Cryocooler cooled superconducting magnets using Bismuth based high-Tc current leads have been successfully demonstrated. The magnets mainly consisted of a superconducting coil, current leads and a radiation shield which are cooled by a two stage Gifford-McMahon cryocooler without using liquid helium. Our first liquid helium-free 4.6 T (Nb, Ti)3Sn superconducting magnet with a room temperature bore of 38 mm operated at 11 K has recorded a continuous operation at 3.7 T for 1,200 hours and total cooling time over 10,000 hours without trouble. As a next step, we constructed a (Nb, Ti)3Sn liquid helium-free superconducting magnet with a wider room temperature bore of 60 mm. The coil temperature reached 8.3 K in 37 hours after starting the cryocooler. The magnet generated 5.0 T at the center of the 60 mm room temperature bore at an operating current of 140 A. An operation at a field of 5 T was confirmed to be stable even if the cryocooler has been stopped for 4 minutes. These results show that the liquid helium-free superconducting magnets can provide an excellent performance for a new application of the superconducting magnet.

Original languageEnglish
Pages (from-to)535-541
Number of pages7
JournalIEICE Transactions on Electronics
Issue number5
Publication statusPublished - 1995 May 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


Dive into the research topics of 'Development of liquid helium-free superconducting magnet'. Together they form a unique fingerprint.

Cite this