The investigation of gamma-ray and neutron shielding parameters of Na2O-CaO-P2O5-SiO2 bioactive glasses using MCNPX code

Bioactive glasses are silicate glasses with sodium, calcium and phosphorus in its composition used to fulfill or support the functions of living tissues in the human body. The superiority of physical and mechanical properties of the bioactive glasses leads to the opportunity to use for radiation protection. From this point of view, radiation absorption parameters of nine bioactive glasses were reported in the present research. The mass attenuation coefficient (mu/rho) for the selected bioactive glasses was calculated using MCNPX simulation code in the photon energy range 0.02-20 MeV and the results were compared with XCOM data. The values of mu/rho calculated in two methods were found to support each other. Other vital parameters like half and tenth value layer (HVL and TVL), mean free path (MFP) and effective atomic number (Z(eff)) for the selected bioactive glasses were also evaluated by utilizing the mu/rho. ICSW9 glass with more phosphate and sodium contents possess the lowest MFP, HVL and TVL values while has the highest Z(eff) values among the bioactive glasses under study. To evaluate the neutron protection performance of investigated bioactive glasses, effective removal cross-section values (Sigma R) have been determined. The results showed that ICSW9 has also superior neutron attenuation properties. Additionally, exposure buildup factor (EBF) values were found with G-P fitting approach depending on the energy and penetration depths. The bioactive glasses with further equivalent atomic number possesses the minimum value of EBF.