Experimental assessment of the coincidence summing corrections in gamma-ray spectrometry of bulk samples

•TCS-dependence on the source-to-detector distance d is linearized for point source.•A representative distance dV is evaluated in the case of volume-source TCS-effect.•TCS-correction for volume source is evaluated on the basis of TCS-linear dependence.•The representative distance dV is like the volume-source effective thickness deff.•Parameters dV and deff are related to average solid angle subtended by the detector.

This work presents an experimental approach for estimation of the true coincidence-summing (TCS) correction for volume sources on the basis of TCS dependence on the source-to-detector distance. Firstly, it is shown that the TCS dependence on the source-to-detector distance can be linearized for point source geometry. If this linear dependence is established then TCS correction for an arbitrary source-to-detector distance can be obtained. In the case of a volume source a representative parameter dV can be formulated as the distance at which the point-source summing effect is the same as the one for the volume-source. Then if the TCS dependence on the source-to-detector distance is established for the point-source case and the volume-source dV-value is known, the TCS correction corresponding to the volume-source measuring geometry can be estimated. Experimental method and results are presented in the work too.