Gamma-rays attenuation by mineralized siltstone and dolostone rocks: Monte Carlo simulation, theoretical and experimental evaluations

Radiation shielding performance against gamma rays for four mineralized natural rock samples collected from Um Bogma area, Southwestern Sinai, Egypt was determined by Monte-Carlo simulation, theoretical calculations and confirmed by experimental evaluations. The Monte Carlo simulation was utilized to investigate the shielding capacity of the investigated rock samples in the energy range between 0.015 and 15 MeV. According to the Monte Carlo simulation the best shielding properties were achieved for sample siltstone S22 which contains (Fe-Mn) mineralization and density of 3.85 (g/cm(3)), where the simulated linear attenuation coefficient decreased from 71.30 cm(-1) to 0.09 cm(-1), increasing the incident gamma photon energy between 0.015 and 15 MeV. On the other hand, the lowest gamma ray shielding capacity achieved for sample siltstone S24 which rich in iron sulfate, with linear attenuation coefficient decreased from 37.50 cm(-1) to 0.05 cm(-1), increasing the incident gamma ray energy between 0.015 and 15 MeV, respectively. The gamma ray shielding properties for sample siltstone S22 were examined experimentally to confirm the simulated results. Both of experimental and simulated results are close together, with a difference of +/- 0.5%. Moreover, the siltstone S22 sample shows a thin half-value layer, high effective and equivalent atomic numbers as well as low EBF and EABF values.