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 power-law method, the energy-dependent Zeff for photon interaction (ZPI-eff) and photon energy absorption (ZPEA-eff ) 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.