Soil mass attenuation coefficient: Analysis and evaluation

The mass attenuation coefficient (mu) is an important parameter to characterize the penetration and interaction of gamma-rays in the soil. Accurate determinations of mu are important to obtain representative values of soil physical properties by gamma-ray attenuation technique. In this study, the effect of collimator size (2-4 mm diameters) and absorber thickness (2-15 cm) on the experimental mu values of water and soils with different textures were investigated for 59.54 key (Am-241) and 661.1 keV (Cs-137) gamma-ray sources. Theoretical results were calculated using the program XCOM. Experimental results were compared with theoretical ones showing a good correlation between methods. It was observed that for the Cs-137 the best agreements between theoretical and experimental mu were obtained for sample thickness >= 10 cm while for the Am-241 were those obtained for thickness <5 cm for small collimators. (C) 2013 Elsevier Ltd. All rights reserved.