Total versus effective total efficiency in the computation of coincidence summing corrections in gamma-ray spectrometry of volume sources

For the evaluation of coincidence summing effects for volume sources an eff ective total efficiency (ETE) is used instead of the common total efficienc y (TE). In this paper ETE is computed by the Monte Carlo method. The differ ences between ETE and TE are analyzed and their origin is discussed. Measur ed values for the coincidence summing correction factors for a standard sol ution containing (EU)-E-152 in a one liter Marinelli beaker are compared wi th computed values obtained from appropriate values of ETE. It is shown tha t the procedure for the evaluation of the coincidence effects is reliable. As a consequence it can be concluded that (EU)-E-152 volume sources can be successfully used for efficiency calibration even in the case of high-effic iency detectors and close source-to-detector distances.