Comparison of radiation shielding ratios of nano-sized bismuth trioxide and molybdenum

In this study, radiation shielding fibers using non-hazardous nano-sized bismuth trioxide and molybdenum instead of lead were developed and evaluated. Among the elements with high densities and atomic numbers, non-hazardous elements such as bismuth trioxide and molybdenum were chosen as a shielding element. Then, bismuth trioxide (Bi2O3) with average particle size 1-500 mu m was ball milled for 10min to produce a powdered form of nanoparticles with average particle size of 10-100nm. Bismuth trioxide nanoparticles were dispersed to make a colloidal suspension, followed by spreading and hardening onto one or two sides of fabric, to create the radiation shielding fabric. The thicknesses of the shielding sheets using nano-sized bismuth and molybdenum were 0.4 and 0.7mm. According to the lead equivalent test of X-ray shielding products suggested by KS, the equivalent dose was measured, followed by calculation of the shielding rate. The shielding rate of bismuth with 0.4mm thickness and at 50kVp was 90.5%, which is comparable to lead of 0.082mm thickness. The shielding rate of molybdenum was 51.89%%, which is comparable to lead of 0.034mm. At a thickness of 0.7mm, the shielding rate of bismuth was 98.73%, equivalent to 0.101mm Pb, whereas the shielding rate of molybdenum was 74.68%, equivalent to 0.045mmPb. In conclusion, the radiation shielding fibers using nano-sized bismuth developed in this study are capable of reducing radiation exposure by X-ray and its low-dose scatter ray.