Neutron energy spectra and dose equivalent rates from heavy-ion reactions below 20 MeV/u using the PHITS code

Iwamoto, Yosuke   ; Ronningen, R. M.*; Niita, Koji*

The reliability of PHITS at low energies has not been investigated. In this work, neutron energy spectra from 10 MeV/u C and O ions incidence have been calculated using the QMD model coupled to the GEM model in PHITS. In particular, the influence of the "switching time", defined as the time when the QMD calculation is stopped and the calculation switches to the GEM model, was studied. The calculated neutron energy spectra obtained using a value of 100 fm/c for the switching time agree well with the experimental data. We have also used PHITS to simulate an experimental study by Ohnesorge et al., by calculating neutron dose equivalent rates, for 3-16 MeV/u C, O and Ne beams incident on Fe, Ni and Cu targets. The calculated neutron dose equivalent rates agree well with the data.