AbstractExperiments have been carried out to determine the difference between gammaray absorption in an inhomogeneous layer of material, composed of spherical heavy metal particles (tungsten) in a nonabsorbing matrix, and absorption in a uniform heavy metal sheet of the same average thickness. The results can be used to evaluate a function describing the distribution of absorber thickness at different points on the layer. The gamma rays used ranged in energy from 35 to 122 keV.