Upgraded cryogen-free 20 T superconducting magnet

Satoshi Hanai, Takahiro Tsuchihashi, Yuji Minemoto, Shigeru Ioka, Kazuo Watanabe, Satoshi Awaji, Hidetoshi Oguro

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


We have constructed an 18 T superconducting magnet conductively cooled by a GM/JT (Gifford-McMahon/Joule-Thomson) cryocooler. A double-pancake stacked insert coil using Ag-sheathed Bi2Sr2Ca2Cu3O10 (Bi2223) tape with stainless steel reinforcement has generated 2.5 T in a 15.5 T outer LTS coil. After we constructed the cryogen-free 18 T superconducting magnet (18 T-CSM), Bi2223 tape conductors have been improved in both critical current and strength. The critical current of the conductor doubled and a tape conductor with copper alloy reinforcement which has a strength of 250 MPa at 77 K was developed. So we developed a new Bi2223 insert coil for the cryogen-free superconducting magnet which can generate 4.5 T in a 15.5 T outer LTS coil by exchanging the insert coil. The new 20 T cryogen-free superconducting magnet (20 T-CSM) can generate constant magnetic fields up to 20 T in a 52-mm room-temperature bore.

Original languageEnglish
Article number6655923
JournalIEEE Transactions on Applied Superconductivity
Issue number3
Publication statusPublished - 2014 Jun


  • Bi2223 tape conductor
  • Cryogen-free magnet
  • High magnetic field
  • Hoop stress
  • Hysteresis loss
  • Upgrade


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