Benchmark study of PHITS for various projectiles and observables using SINBAD

Ogawa, Tatsuhiko   ; Labonnote, N.*

The general-purpose particle and heavy ion transport code system, PHITS, developed by the Japan Atomic Energy Agency, was validated against the SINBAD, an internationally recognized benchmark experiment archive for radiation shielding. Unlike the previous PHITS benchmark against SINBAD, which primarily focused on shielding experiments for proton accelerators, this study conducted benchmarking for double-differential neutron yields, activation, residual dose, and microdosimetric quantities induced by protons, electrons, ions, and pions. This allowed for the use of models and databases not previously employed in validation studies, leading to the discovery of previously overlooked issues. While PHITS calculations generally agreed with experimental data within a factor of two, a detailed comparison revealed the need for improvements in several areas. These include: the inability of the high-energy hadron cascade model to calculate the angular momentum of residual nuclei, the underestimation of neutrons below 100 MeV in pion-induced reactions by the same model, the underestimation of proton-rich nuclei by the evaporation model, and the underestimation of high-energy secondary neutrons by the heavy-ion reaction model. These findings will be used as guidelines for future improvements to PHITS.