Application and validation of event generator in the PHITS code for the low-energy neutron-induced reactions

Iwamoto, Yosuke   ; Niita, Koji*; Sato, Tatsuhiko   ; Matsuda, Norihiro  ; Iwase, Hiroshi*; Nakashima, Hiroshi; Sakamoto, Yukio

The "Event Generator Mode (E-mode)" has been introduced into the PHITS code in the treatment of transport phenomena of low energy neutrons below 20 MeV. In the E-mode, the evaluated nuclear data for neutron-induced reactions and a special evaporation model are combined so as to trace all correlations of ejectiles and residuals in a collision under the energy and the momentum conservation. For the validation of the E-mode below 20 MeV, we have calculated neutron-induced activation cross sections by the E-mode, and compared them with the experimental data and the evaluated nuclear data library of activation cross sections. All calculated results agreed well with the experimental data and the evaluated data of activation cross sections below 20 MeV. As an application of the E-mode, we indicate a new approach to the deposit energy distribution of the thermal neutron transport for the boron-neutron capture therapy.