Radiation safety aspects in J-PARC facility

Shibata, Tokushi; Nakashima, Hiroshi; Nakane, Yoshihiro  ; Masukawa, Fumihiro  ; Matsuda, Norihiro  ; Miura, Taichi*; Numajiri, Masaharu*; Suzuki, Takenori*; Takeuchi, Yasunori*

J-PARC (Japan Proton Accelerator Research Complex) consists of a 400 MeV LINAC, a 3 GeV synchrotron, a 50 GeV synchrotron and three experimental halls for material and life science, hadron physics and neutrino physics. The radiation safety design for J-PARC is based on calculations on radiation outside the shielding, on the boundary of the controlled area and on the cite boundary. In order to study the accuracy of different methods and make clear the differences among different methods, some benchmark analyses on beam dump, bulk shielding, streaming and activation experiments were carried out. The activation of air, cooling water and the activation of soil and its effect to underground water have been also estimated. Since J-PARC is a complex accelerator facility, an interlock system is important for radiation safety. To prevent unintended radiation exposure, a carefully designed system was incorporated.