Analyses of Neutron and Gamma Ray Measurements in a Target Room of Several Tens MeV Proton Facility

In order to estimate the accuracy of calculation methods such as an empirical formula and Monte Carlo codes for neutron and gamma ray flux in a room with a Cu target irradiated by 68-MeV-proton, experimental analyses are carried out. The analyses reveals that (1) the NMTC/JAERI code is applicable to source neutron calculation, (2) the Patterson’s equation with Ishikawa’s parameter is useful and estimates thermal neutron flux conservatively and (3) the MCNP calculation underestimates the fast neutron scattered back from the wall of the room, consequently the secondary gamma ray from the wall.