Simulation, Fabrication, and Characterization of Bismuth Oxide-Ethylene Vinyl Acetate (Bi2O3-EVA) Composite As a Cesium-137 Gamma Radiation Shield

Prolonged exposure to cesium-137 (Cs-137) gamma radiation, a high-energy source widely used in medicine, is known to cause cellular damage and increased rates of cancer. Wearable lead-lined radiation shields provide a direct protective barrier that attenuates ionizing radiation. Aside from being toxic, lead is heavy and rigid-this limits the dexterity of medical workers. Non-toxic polymer composites are promising solutions as they combine high attenuation rates of high-density materials with the lightness and flexibility of polymers. In this study, a composite consisting of bismuth oxide and ethylene vinyl acetate (Bi2O3-EVA) was simulated, fabricated, and characterized to determine its structural and radiation shielding performance. The simulation results determined that increasing Bi2O3 filler content enhances shielding performance. Bi2O3-EVA composites were then fabricated through melt-mixing methods and compression molding. Radiation shield testing showed that composites with higher Bi2O3 filler content displayed improved shielding efficiencies, with higher linear attenuation coefficients and lower half-value layer thicknesses. Samples consisting of 60% Bi2O3 by weight produced optimal shielding performance, achieving half-value layer values between 1.508 cm and 1.878 cm. Analysis of homogeneity levels through the ISO-based rapid comparative method and texture analysis yielded acceptable values, entailing that its consistent structure does not compromise radiation shielding performance. Moreover, the tensile strength is maintained even at a high 80% Bi2O3 by weight. The positive results obtained in this study present new opportunities for developing lighter and more flexible wearable medical gamma radiation shields that effectively attenuate gamma radiation.