Gamma radiation shielding performance of liquid silicone rubber based tungsten-tin and tungsten-bismuth polymer composites: Experimental and simulation study

Lightweight and flexible materials have emerged as promising alternatives to conventional lead-based gamma radiation shielding materials. In this study, two sets of flexible composites were fabricated using Liquid Silicone Rubber (LSR) reinforced with tungsten-tin (W-Sn) and tungsten-bismuth (W-Bi) fillers through an open-mold casting technique. The shielding performance was experimentally evaluated at 80, 356, 662, 1173 and 1132 keV gamma ray energies and validated using Geant4, Phy-X, and XMuDat. The experimental mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) showed excellent agreement with theoretical and simulated results, with average MAC deviations of 4.01%, 2.92%, and 3.05% for W-Sn composites and 1.26%, 5.56%, and 6.09% for W-Bi composites using Geant4, XMuDat, and Phy-X, respectively. The 30 phr W-110 phr Sn composite exhibited superior low-energy shielding, with a MAC of 2.628 cm²/g and HVL of 0.118 cm at 80 keV, whereas the 30 ph W-110 phr Bi composite demonstrated enhanced attenuation at 356 and 662 keV, achieving MAC values of 0.197 and 0.099 cm²/g with corresponding HVL values of 1.517 and 3.022 cm, respectively. These results demonstrate that the developed LSR composites are promising lightweight (13-20% of lead), flexible, and lead-free materials for effective gamma radiation shielding over a broad energy range.