Neutron and gamma radiation shielding block from natural rubber

Abstract

A neutron and gamma radiation shielding block was developed based on natural rubber mixed with boron compounds and lead oxide. In this study, two types of boron compounds, including borax and boric acid, were considered. This shielding block was exposed to the radiation from an 241Am/Be radiation source. It was found that both types of the rubber shielding blocks can efficiently reduce thermal neutrons, where its efficiency increases with the thickness and boron concentration. Although the amount of boron per weight of boric acid was higher than that of borax, the radiation shield efficiency of the rubber shielding block mixed with borax was higher. In addition, lead was mixed into the rubber shielding block to absorb the gamma ray radiated from the neutron absorption. It was found that the rubber shielding block with boron compound and lead can efficiently absorb both neutron and gamma radiation. However, the decrease of physical properties of those rubber shielding blocks, including hardness, tensile strength, and elongation at break, were also found.