Speaker
Description
Radiation shielding and calculation are essential for the construction and operation of accelerator facilities. High energy gamma-rays in accelerators can produce secondary neutrons, which can penetrate through shielding materials and produce additional dose rate by activating accelerator components; thus, the double differential cross sections (DDXs) of photoneutron are very essential. Calculation of radiation and shielding in accelerators can be carried out by Monte Carlo simulation tools using nuclear data library (NDL). The DDXs of ($\gamma$,xn) reactions of a polarized photon beam with the mono energy of 16.6 MeV and different materials (including Pb, Au, Sn, Fe, Cu, and Ti) are reported in Reference [1]. In this study, we will show the comparisons in the DDXs between the experimental data measured in Reference [1] and the DDXs from NDL for medium-heavy atomic mass targets. Our python-based software extracted the DDXs from NDL to construct the neutron energy spectra, which were later analyzed considering the abundances of each target's isotopes, energy resolution of photon beam, and energy resolution of neutron detectors. For Pb, Au, Sn and Cu targets, the experimental DDX data at neutron energy higher 4 MeV are larger than the DDX values obtained from NDL. For Fe and Ti targets, the experimental DDX data are quite consistent with that of the NDL. The inconsistency between the neutron spectra of experimental data and NDL implies a need to improve physical models in generating the spectrum of photoneutron.
Keywords: differential double cross-section, photoneutron, polarized monoenergetic photon.
[1] T.K. Tuyet, T. Sanami, H. Yamazaki et al., “Energy and angular distribution of photo-neutrons for 16.6 MeV polarized photon on medium-heavy targets”, Nuclear Inst. and Methods in Physics, A 989 (2021)164965.