Evaluation of Gamma Rays Shielding Competence for Bentonite Clay /PVA Polymer Matrix Using MCNPX Code

This Radiation shielding capability in terms of mass and linear attenuation coefficients, half value layer, tenth value layer, and mean free path haven been evaluated for natural bentonite coated with polyvinyl alcohol polymer (PVA) using Monte Carlo simulation (MCNPX) and XCOM program. All data were determined at gamma photons energies 662, 1173 and 1332 keV emitted from point sources of ¹³⁷Cs and ⁶⁰Co, respectively, and compared with calculated experimental data. XCOM results of mass attenuation coefficients showed better agreement with experimental data in comparison with MCNPX code. The relative deviations between experimental and theoretical mass attenuation coefficients are 4.3, 2.5 and 1.25 % at 662, 1173 and 1332 (keV) while deviation between simulated and experimental mass attenuation coefficients are -3.1, -10.96 and -10.35 % at the same energies, respectively. The relative deviation between simulated shielding factors HVL, TVL and MFP with experimental data exhibit the same behavior as mass attenuation coefficient and having average relative deviations percentage equal to 2.5, 13.4 and 13.8 % at the studied energies, respectively