J-PARC ニュートリノビームライン超伝導磁石冷却システム

―運転制御系と6 年間の運転経過―

抄録

A helium cryogenic system, which a circulates supercritical helium (SHE) flow of 300 g/s at 4.5 K through a string of superconducting magnets for a J-PARC neutrino beam, was constructed in 2008. Subsequently, the cryogenic system has been operated for approximately 24,000 hours over a six-year period without any serious problems, and has contributed to the T2K neutrino experiment. A control system, which is an essential for reliable operation of the cryogenic system, is described in this report. The experiences and problems that occurred in the six years of operation are also summarized.