Determining the efficiency of a detector for gamma spectrometry of large-volume samples

An experimental and calculational method for obtaining calibration curves for detectors used in the analysis of environment and rock large-diameter samples using the method of gamma spectrometry is suggested. The method permits to determine for samples of any density and unknown chemical composition the va-- lues of the coefficient ω(E)=epslon/epsilon0 (where epsilon is the efficiency of gamma detection for the studied sample placed in a standart container, epslon0 is the efficiency of gamma detection for a container filled with water of the known specific activity). Test of the method applicability is conducted at gamma spectrometer with the Li-drifted Ge detector for two contaners with 500 and 1000 cm3 volumes. The 0.8 g/cm3 density ethanol solution and salt solutions wth the densities of 1.2 and 1.5 g/cm3 were used as smulators of the samples with different attenuation coefficients when testing the method. RMS deviation for the efficiency calculated values from the experimental ones is 5%