Experimental and Monte Carlo investigations of gamma ray transmission and buildup factors for inorganic nanoparticle/epoxy composites

The integration of inorganic nanoparticles into a polymer matrix presents a category of advanced materials, known as polymer inorganic nanocomposites (PINCs). In present work, the gamma-ray shielding parameters of epoxy resin loaded with two different proportions (5 and 25 wt%) of Pb, Zn, ZnO, Ti and TiO2 inorganic nanoparticles have been investigated. The prepared samples were characterized through structural investigations including SEM, EDS, XRD and FT-IR analyses. Furthermore, mechanical properties of the nanocomposites were evaluated on the basis of compressive strength. To evaluate the gamma-ray attenuation performance of the nanocomposites, the transmission and flux buildup factors have been measured experimentally. The 59.54 and 662 keV gamma-rays emitted from Am-241 and Cs-137 point sources were counted by a 2 '' x 2 '' NaI(Tl) detector. In addition, experimental results has been confirmed by a theoretical study using MCNPX code. The results showed that gamma-ray shielding effectiveness was enhanced by the increment of the filler loading. The experimental and theoretical calculations of transmission and buildup factors were found to be in a good agreement. As expected, 25 wt% Pb/epoxy nanocomposites indicated better shielding properties than their counterparts. However, it has to be notices that the mechanical strength of Pb/epoxy nanocomposites were determined significantly lower than those of Zn, ZnO, Ti and TiO2/epoxy nanocomposites. To design and choose an appropriate shielding material, therefore, a number of factors have to be considered.