On the determination of the effective volume of a gamma ray density gauge in backscatter mode

Measurement of density of soil, asphalt and concrete by a γ-ray gauge in backscatter mode requires some notion of the volume of measurement. The weight of each volume element in the 90% response volume for homogeneous media has been calculated using correlated Monte Carlo techniques. To verify the program an experiment has been performed based on an effective volume which is the sum of the weighted volume elements in the 90% response volume. This calculated volume is compared to the requirements of the ASTM 1556 «Sand Cone Method for Density Measurement»