Abstract - The experimental attenuation coefficient of ten soil samples was measured for a 661.66 keV photon belonging to 137Cs. The chemical composition of the samples was determined by XRF method and according to the results; the mass attenuation coefficient was calculated using MCNP software. For each sample, a hypothetical elementary compound based on the experimental attenuation factor is presented. HPGe efficiency was calculated using MCNP software based on the elemental composition measured by XRF and hypothetical. The result was compared with the experimental value, which shows good agreement. In this study, self-absorption correction was determined in gamma-ray spectrometry of environmental samples.
