Calculation of photon shielding properties for some neutron shielding materials

The objective of the present study is to calculate photon shielding parameters for seven polyethylene-based neutron shielding materials.The parameters include the effective atomic number (Zeff),the effective electron density (Neff) for photon interaction and photon energy absorption,and gamma-ray kerma coefficient (kγ).The calculations of Zeff are presented as a single-valued and are energy dependent.While Zeff values were calculated via simplistic powerlaw method,the energy-dependent Zeff for photon interaction (ZPI-eff) and photon energy absorption (ZpEA-erf) are obtained via the direct method for energy ranges of 1 keV-100 GeV and 1 keV-20 MeV,respectively.The kγ coefficients are calculated by summing the contributions of the major partial photon interactions for energy range of 1 keV-100 MeV.In most cases,data are presented relative to pure polyethylene to allow direct comparison over a range of energy.The results show that combination of polyethylene with other elements such as lithium and aluminum leads to neutron shielding material with more ability to absorb neutron and γ-rays.Also,the kerma coefficient first increases with Z of the additive element at low photon energies and then converges with pure polyethylene at energies greater than 100 keV.