Radiation resistance of organic materials in superconducting magnets at 77K; Gas evolution

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

Radiation resistance of polymeric materials used in the superconducting magnets installed for the J-PARC neutrino beam line was studied with respect to gas evolution. The polymeric materials were irradiated by rays at 77K. It was found that hydrogen gas evolved mainly from the polymeric materials, and the amount of hydrogen from whole superconducting magnet system per 1 year was estimated to be 0.37mol. This amount of hydrogen is low enough to be removed by a hydrogen absorbing apparatus. Therefore, the influence of hydrogen evolved from the magnet system on the operation of the helium purifying system can be negligible.