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Polymer matrix composite (PMCs) materials developed by room temperature vulcanization having various compositions i.e. 0, 30.1, 47.8, 59.8, 68.1 and 88.1 wt. % of tungsten incorporated in silicon rubber matrix were investigated using EGS5 Monte Carlo Code. Narrow beam geometry similar to experimental setup was modeled and validated for Monte Carlo simulation by making a comparison with standard XCOM (NIST) results. Gamma-ray shielding features of all composite materials were studied for several photon energies (122, 511, 662, 837, 1173, 1332 and 1811 keV) and compared with the XCOM and previously reported experimental results. Monte Carlo simulation results were in high accordance with the previous experimental study at gamma ray energy of 662 keV and maximum deviation was observed to be around 10 %. Thus, it can be concluded that this method is suitable for predicting the shielding characteristics of different materials. Additionally, mass attenuation coefficients (μ/ρ), mean free path (MFP), half-value layer (HVL), tenth value layer (TVL) were determined and effective atomic numbers (Zeff) is calculated using Power law for all PMCs. PMCs with tungsten loading above 68% showed mass attenuation coefficients greater than lead with additional feature of flexibility which makes them promising candidate in radiation shielding. In addition, these silicon/tungsten composites having 68 and 88 % of tungsten are 3.6 and 1.7 times lighter than lead respectively.
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