Development of a Muon Rotating Target for J-PARC/MUSE
作者单位：Muon Science LaboratoryHigh Energy Accelerator Research Organization （KEK）
会议名称：《第18届国际真空大会》
会议日期：2010年
学科分类：07[理学] 070202[理学-粒子物理与原子核物理] 0702[理学-物理学]
关 键 词：J-PARC Muon Target Bearing
摘 要：At the J-PARC muon science facility （J-PARC/MUSE）, a graphite target with 20-mm thickness has been used in vacuum to obtain an intense pulsed muon beam from the RCS 3-GeV proton beam [1]. In the current design, the target frame is constructed using copper with a stainless steel tube embedded for water cooling. The energy deposited by the proton beam at 1MW is evaluated to be 3.3 kW on the graphite target and 600 W on the copper frame by a Monte-Carlo simulation code, PHITS [2]. Graphite materials are known to lose their crystal structure and can be shrunk by the intense proton beam irradiation. Consequently, the lifetime of the muon target is essentially determined by the radiation damage in graphite, and is evaluated to be half a year [3]. Hence, we are planning to distribute the radiation damage by rotating a graphite wheel. Although the lifetime of graphite in this case will be more than 10 years, the design of the bearing must be carefully considered. Because the bearing in J-PARC/MUSE is utilized in vacuum, under high radiation, and in high temperature, an inorganic and solid lubricant must be applied on the bearing. Simultaneously, the temperature at the bearing must be also decreased to extend the lifetime. In 2009, a mock-up of the Muon Rotating Target, which could heat up and rotate a graphite wheel, was fabricated and then several tests were started to select the lubricant, and to decide the structure of the Muon Rotating Target, the control system and so on. In this presentation, the present status of the Muon Rotating Target for J-PARC/MUSE, especially the development of a rotation system in vacuum, will be described.