Title: High density polyethylene-bismuth oxide nanocomposite: A dental shield applied in radiography centers

Abstract

Due to the importance and approach of lead-free radiation shields, which has received serious attention in recent years, in this research, radiation shielding characteristics of High Density Polyethylene/Bismuth Oxide (Bi2O3/HDPE) nanocomposite against the gamma rays of 241Am source with 59 keV photon energy was investigated by MCNP, XCOM simulations and experimental methods. First, the quantities of linear attenuation coefficient (µ), mass attenuation coefficient (µ/ρ), Half-Value Layer (HVL) and Tenth-Value Layer (TVL) related to different weight percentages of the composite were simulated using the MCNP code. Then, the simulation results were validated with XCOM software data, which indicated the high accuracy of the simulation. The simulation results showed that by increasing the energy of the incident photons, the attenuation coefficient of the photons was decreased. At the end of the simulation phase, 60 wt% Bi2O3/HDPE composite with density of 2.01 g/cm3, µ=5.9193 cm-1, µ/ρ=2.945 cm2/g, HVL=1.2 mm, TVL=3.9 mm was selected to fabricate a jaw shielding material at 59 keV. With increasing the Bi2O3 weight percentage in the polymer matrix, the effective atomic number and density of the composite will be increased accordingly, thus the amount of attenuation coefficient will be increased and the HVL and TVL values in the mentioned energy will be decreased. In the experimental phase, 60 wt% Bi2O3/HDPE nanocomposite was fabricated via soloution method. Then, various tests such as FESEM and XRD were performed on the samples, which indicated good dispersion states of bismuth oxide nanoparticles in the polyethylene substrate. After fabrication of the samples, the quantities of µ, µ/ρ, HVL and TVL were measured. Results showed an acceptable correlation with simulated values with MCNP code and XCOM software.