Author: Nakamoto, T.
Paper Title Page
THYA01 High Field Magnet Developments 3185
  • T. Nakamoto
    KEK, Ibaraki, Japan
  Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.  
slides icon Slides THYA01 [7.578 MB]  
THPPD024 Irradiation Effects in Superconducting Magnet Materials at Low Temperature 3551
  • M.Y. Yoshida, M.I. Iio, S. Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, M. Sugano, K. Yoshimura
    KEK, Ibaraki, Japan
  • M. Aoki, T. Itahashi, Y. Kuno, A. Sato
    Osaka University, Osaka, Japan
  • Y. Kuriyama, Y. Mori, B. Qin, K. Sato, Q. Xu, T. Yoshiie
    Kyoto University, Research Reactor Institute, Osaka, Japan
  Superconducting magnets for high intensity accelerators and particle sources are exposed to severe radiation from beam collisions and other beam losses. Neutron fluence on the superconducting magnets for the next generation projects of high energy particle physics, such as LHC upgrades and the COMET experiment at J-PARC, is expected to exceed 1021 n/m2, which is close to the requirements on the fusion reactor magnets. Irradiation effects at low temperature in superconducting magnet materials should be reviewed to estimate the stability of the superconducting magnet system in operation and its life. The pion capture superconducting solenoids for the COMET experiment are designed with aluminum stabilized superconducting cable to reduce the nuclear heating by neutrons. Also, the heat is designed to be transferred in pure aluminum strips. Irradiation effects on the electrical conductance of aluminum stabilizer and other materials are tested at cryogenic temperature using the reactor neutrons. This paper describes the study on the irradiation effects for the magnet developments.