The effect of cerium oxide nanoparticles on gamma-ray shielding capacity of vinyl ester resin: experimental, MCNP6 and WinXCOM results

The present study investigates the gamma-ray shielding effectiveness of nano-sized CeO2 doped vinyl ester composites (VE/nCeO2) produced via the direct pouring method, with nCeO2 concentrations ranging from 2.5 to 20% by weight. The structural properties of the nCeO2 particles were characterized using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The gamma-ray shielding performance of the resulting composites was evaluated experimentally, through simulation with MCNP6, and theoretically via WinXCOM calculations, focusing on primary shielding parameters such as mass attenuation coefficient, half value layer, tenth value layer, mean free path and effective atomic number. Experimental data were obtained using a NaI(Tl) scintillation detector for gamma-ray energies emitted from Ba-133, Cs-137, and Co-60 radioactive point sources in narrow beam geometry. The experimental data were contrasted with the Monte Carlo N-Particle Transport (MCNP6) simulation results and theoretical predictions computed through WinXCOM calculations. Among all the composites, the VE/20% nCeO2 composite, with the highest nCeO2 concentration, demonstrated the best gamma-ray shielding performance across all studied energies. The addition of nCeO2 was found to significantly enhance the radiation attenuation properties of vinyl ester, with the mass attenuation coefficients of the composites increasing from 0.15 to 0.79 cm²/g at 81 keV. The gamma-ray attenuation capabilities of the composites were compared with those of traditional shielding materials and previously studied composites, showing them to be promising lightweight, non-toxic alternatives for low-energy gamma-ray shielding applications.