Design strategy for devices under high radiation field in J-PARC muon facility

The intensity of proton accelerator has attained the order of mega-watt, and several MW-class proton accelerators have started operating in the world. In comparison with the other MW-class accelerators, Japan Proton Accelerator Research Complex (J-PARC) is unique due to the muon facility. Materials and Life Science Facility, J-PARC, has not only the mercury target but also the graphite target to provide spallation neutrons and muons, respectively. The muon target is inserted upstream of the neutron target in the proton beam line. Full use of several mutually linking Monte-Carlo codes enables the design work of devices in the muon facility, which has to be operated under high radiation field from the muon target.