The dependence of the counting efficiency of Marinelli beakers for environmental samples on the density of the samples

The effect of the density of the radioactive material packed in a Marinelli beaker on the counting efficiency was studied. It was found that for all densities (0.4–1.7 g/cm3) studied the counting efficiency (ε) fits the linear log–log dependence on the photon energy (E) above 200 keV, i.e. obeying the equation ε=αEβ (α, β—parameters). It was found that for each photon energy the counting efficiency is linearly dependent on the density (ρ) of the matrix. ε=a-bρ (a, b—parameters). The parameters of the linear dependence are energy dependent (linear log–log dependence), leading to a final equation for the counting efficiency of Marinelli beaker involving both density of the matrix and the photon energy: ε=α1•Eβ1-α2Eβ2ρ.