Phy-X/PSD and NGCAL Models of Several Metal Sulphides: Theoretical Prediction of Gamma Shielding Efficiency

Abstract

Various metal sulphides were selected for gamma and neutron shielding prediction by (Phy-X and NGCAL). The gamma parameters calculated by both software programs in the studied energy range were found to be identical, with differences (Δ% less than 1%) between both models. The Mass Attenuation Coefficient (MAC), Mean Free Path (MFP), Half Value Layer (HVL), Tenth Value Layer (TVL), and Effective Atomic Number (Z_eff) were calculated. Ag₂S was a superior neutron and photon attenuator because it contains two silver ions with the highest density, mean atomic number, and metal composition in addition to the lowest (S%) among all sulphides under evaluation. Additionally, the Ag₂S monoclinic network is fabricated from (2Ag⁺) linked to one (S^2-). Therefore, the presence of heavy packed ions in the unit cell resulted in more gamma attenuation. The Z_eff variation with the energy range of 0.015–15 MeV may be associated with the density, mean atomic number, composition (%) or weight fraction, total atomic cross-section, crystal geometry and elemental packing of each molecule. It can be concluded that Ag₂S was the superior attenuator between the sulphides under prediction, especially at higher energies. The Gamma Protection Efficiency (GPE, %) was also calculated for the gamma shielding subject based on the Linear Attenuation Coefficient (LAC) data presented in the Beer–Lamberts law: GPE% = (1-e^(-µx)) * 100, where the thickness was assumed. The GPE% increased with increasing thickness and decreased with increasing energy. Also, silver sulphide showed the highest GPE among the other tested materials. The GPE% of the thermal or fast neutrons was also calculated, where the increasing order was SnS, SnS₂, ZnS, MoS₂, As₂S₃, CuFeS₂, FeS, CoS, and Ag₂S for thermal neutrons and SnS₂, SnS, MoS₂, As₂S₃, ZnS, CuFeS₂, FeS, Ag₂S, and CoS for fast neutrons.