First-principles simulation of radiation shielding performance in TaS₂-HDPE composites using Geant4

High atomic number (Z) fillers in polymer matrices provide lightweight alternatives to conventional radiation shielding. Previous studies have examined fillers such as CdO, [Formula: see text], and [Formula: see text]. However, no prior work has investigated tantalum disulfide ([Formula: see text]) in polymer composites for gamma-ray shielding, leaving a clear gap in the literature. Here, we report the photon attenuation performance of high-density polyethylene (HDPE) composites containing 10-50 wt% [Formula: see text] over 0.06-2.0 MeV, evaluated by Geant4 Monte Carlo simulations and validated with XCOM data. At 80 keV, where enhancement is most pronounced, the 50 wt% composite achieved a mass attenuation coefficient of 2.88 ± 0.04 [Formula: see text]/g, corresponding to a 15.9 ± 0.21 improvement over pure HDPE. Composites with 35, 20, and 10 wt% [Formula: see text] showed enhancements of 11.55 ± 0.05, 7.07 ± 0.03, and 4.04 ± 0.02 times, respectively. Benchmarking against micro-CdO-HDPE confirmed competitive or superior attenuation across the photon spectrum. These results establish TaS₂-HDPE as a tunable, non-toxic, and effective candidate for next-generation radiation shielding applications.