Benchmark calculations of target heat deposition and bulk shielding

As a first step of a design study of the neutron science research center using an intense proton accelerator of 1.5 GeV with a current of 1 mA, a benchmark calculation was carried out with the NMTC/JAERI-MCNP-4A code system for the heat deposition in thick targets of Cu, Pb and U bombarded with 1.2 GeV protons. The thickness of bulk shielding around a spallation target was also estimated with the Moyer model and Sn calculation. It was found from these calculations that the code system reproduced well the experimental heat distribution around the beam axis. However, the code gave rather lower heat deposition at peripheral region of the target. As for the bulk shielding, it was estimated that the shielding made of iron having the thickness of 4 m surrounded by ordinary concrete with the thickness of 1 m was required for the 1.5 GeV proton incidence on a stopping-length Ta target with the diameter of 15 cm. (author)