Numerical Evaluation on Mechanical Behavior of No-Insulation REBCO Pancake Coils in Small-Scale Model of Skeleton Cyclotron

Yuta Miyake, Yuki Nakai, Ryota Inoue, Seok Beom Kim, Hiroshi Ueda, So Noguchi, Tomonori Watanabe, Shigeo Nagaya, Mitsuhiro Fukuda, Atsushi Ishiyama

Research output: Contribution to journalArticlepeer-review


We are developing a high-temperature superconducting (HTS) air-core compact cyclotron, named Skeleton Cyclotron (Ueda et al. 2013), (Ueda et al. 2019), that can accelerate various particles and variable energy for radioisotope (RI) production. The coil system of Skeleton Cyclotron consists of circular main coils and noncircular sector coils which are wound by REBa2Cu3O6+δ (REBCO) tape applied no-insulation (NI) winding technique for both high current densities and thermal stabilities. The electromagnetic and thermal behaviors in NI coil differs from those in conventional insulated coils during charging, discharging, and quenching. Therefore, it is necessary to investigate the mechanical behavior and reinforcement structure of multiple NI coils in Skeleton Cyclotron. In this study, we report on the numerical evaluation of mechanical properties of NI REBCO coils in Skeleton Cyclotron at charging and quenching considering the current distributions and electromagnetic stresses unique to NI coils. In the quenching process, the radial current in a quenching pancake of the sector coil became dominant, resulting in generating the rotating force and non-symmetric deformation. YOROI-coil (Y-based oxide superconductor and reinforcing outer integrated coil) structure is effective for the additional magnetic stress.

Original languageEnglish
Article number4603905
JournalIEEE Transactions on Applied Superconductivity
Issue number6
Publication statusPublished - Sept 1 2022


  • Cyclotrons
  • high-temperature
  • no-insulation
  • superconducting magnets

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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