Transmittance of γ-ray from Cs-137 and Co-60 for hydrogel containing metal oxides as soft radiation shielding materials

Hydrogels with 0.1 mol of three kinds of metal oxides are fabricated to improve shielding performance with ductility. Fe2O3, WO3, and PbO2 micropowders as a supplement are used to shield γ-ray radiation. Transmittance of γ-ray is measured for the hydrogels according to the energy level of γ-ray from Cs-137 (0.662 MeV) and Co-60 (1.173 and 1.332 MeV). Subsequently, tenth value layers (TVLs) as thickness to nearly shield radiation are calculated using the obtained attenuation coefficient from the transmittance. The shielding performance as the transmittance and attenuation coefficient is improved according to the atomic number of contained metal. Among Fe2O3, WO3, and PbO2 composite, the PbO2 composite has the lowest transmittance and highest attenuation coefficient for the all γ-ray energy range. The calculated TVLs of the PbO2 and WO3 composites are 12.65 and 13.62 cm for Co-60, respectively. The difference of TVLs between the PbO2 and WO3 composites is merely small as 1 cm, and the tungsten metal is not harmful to human and environment, unlike lead. As a result, it is suggested that the WO3 composite is suitable for the soft radiation shielding materials of the radioactive waste multiple containers with appropriate shielding and cushioning performance.