Superconducting magnet system for the J-PARC neutrino experiment, 13; -ray irradiation effects on organic materials at 77 K

Nakamoto, Tatsushi*; Ohata, Hirokatsu*; Ogitsu, Toru*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Yamamoto, Akira*; Idesaki, Akira; Ito, Hisayoshi; Morishita, Norio

A Superconducting magnet system will be adopted for the J-PARC neutrino beam line. GFRPs whose matrices are phenol resin and epoxy resin, and polyimides are used as structural materials and electrical insulation. Radiation resistance of these polymeric materials is very important, because they are exposed to high radiation field. In this work, specimens were irradiated by rays with the maximum dose beyond 10MGy at liquid nitrogen temperature (77K), and the properties of gas evolution and mechanical strength were investigated. It was verified experimentally that the polymeric materials have sufficient radiation resistance for the using in the J-PARC neutrino beam line.