**CALCULATION OF THE ACTIVITIES OF GAMMA-RAY EMITTERS PRESENT IN HOMOGENEOUS
CYLINDRICAL SAMPLES **

*M. Korun
J. Stefan Institute, Jamova 39, Ljubljana, Slovenia *

ABSTRACT

When the activities of gamma-ray emitters present in samples are calculated from gamma-ray spectra by automated spectral analysis procedures, data describing realistic counting conditions must be used in the procedures in order to obtain reliable results. Therefore parameters such as sample dimensions, composition and density must enter into the calculations as well as the probabilities for coincident detection of photons. To carry out the calculations, two basic approximations are made: the self-attenuation function is calculated supposing a simple detector model and the spatial dependence of the efficiencies for point sources is approximated by exponential functions. The approaches leading to these approximations are briefly described.