Variation in tungsten(<sc>vi</sc>) oxide particle size for enhancing the radiation shielding ability of silicone rubber composites

In this work, the attenuation properties of silicon rubber (SR) composites reinforced by both micro- and nano-sized Tungsten trioxide (WO3) particles are studied. Different SR composites with different combinations of micro-WO3 and nano-WO3 have been prepared. The main composite, SR-(WO3)(60m) (40% SR containing 60% micro-WO3), and other compositions were prepared by replacing percentages of microparticles with nanoparticles of WO3. The linear attenuation coefficient for these composites was measured in the range of 0.06-1.333 MeV. The existence of micro and nanoparticles together may result in enhanced interactions with incoming photons, leading to greater shielding. In other words, micro-WO3 and nano-WO3 have various sizes and surface areas. At 0.06 MeV, we notice a distinguished decrease in the half value layer (HVL) from SR-W60m to SR-W60n. The sequence of reducing HVL values (SR-(WO3)(60m) > SR-(WO3)(60n) > SR-(WO3)(40m20n) > SR-(WO3)(20m40n) > SR-(WO3)(30m30n)) suggest that the inclusion of both micro- and nano-WO3 contributes to more efficient radiation shielding compared to the reference material. The radiation shielding efficiency (RSE) for SR-(WO3)(30m30n) at 0.662 MeV is 38.40%. This means that if a beam of photons with energy of 0.662 MeV interacts with SR-W40m20n sample, only 38.12% of the photons are successfully absorbed or stopped, whereas the remaining 61.88% can pass through this sample. At 1.333 MeV, the lowest RSE is observed, which means that the prepared composites have weak attenuation ability at higher energy levels.