Comparative study of Monte Carlo particle transport code PHITS and nuclear data processing code NJOY for recoil cross section spectra under neutron irradiation

Iwamoto, Yosuke   ; Ogawa, Tatsuhiko   

It is important to validate the calculations of PKA spectra that are used to estimate radiation damage in materials. Here, the PKA spectra of fission-relevant materials were calculated using the Particle and Heavy Ion Transport code System (PHITS) and also using the data processing code NJOY with the nuclear data libraries. The heating number, which is the integral of the PKA spectrum, was also calculated using PHITS and compared with data extracted from the data libralies. From analyzing the PKA spectra, we found that the energy and angular recoil distributions were incorrect for Ge, As, Y, and Ag in the ENDF/B-VII.1 library. From analyzing the heating number, we found that the data extracted from the ACE file of TENDL2015 for all elements were problematic in the neutron capture region. However, PHITS+TENDL2015 can calculate PKA spectra and heating numbers correctly.