Investigation of Polymer Composites Developed for Radiation Shielding

Abstract

This thesis is concerned with the investigation of the properties of shields consisting of silicone rubber loaded with different concentrations of bismuth carbonate and boric acid for neutrons and gamma radiations.

Any material used for shielding purposes should fulfill some design criteria which includes mechanical and physical proficiency beside their main role as nuclear radiations attenuator. Therefore, some mechanical and physical properties were investigated to monitor the composited usefulness as radiation shields.

Silicone rubber shields of higher densities can be obtained by loading heavy elements. In this study, a silicone rubber loaded with different percentages of bismuth carbonate, (BiO)2CO3, of density  = 6.86 gm / cm3 is investigated for gamma ray attenuation. The emitted gamma – rays have been detected by Hyper Pure Germanium detector (HPGe). The total mass attenuation coefficient (µm), the half value layer (HVL), and the mean free path (MFP) values have been experimentally determined for the photon energies at 0.238, 0.583, 0.727, 0.911, 1.173, 1.332, and 2.614 MeV. The theoretical values were calculated using the WinXCom program. Then the obtained data were compared with the experimental data. A good agreement between the calculated and corresponding experimental results is obtained which supports the proposed method. Also, the effective atomic number, Zeff , for silicone rubber composites have been calculated using ZCom program.