HPGe detector true-coincidence correction for extended cylinder and Marinelli-beaker sources

A semi-empirical method is developed to estimate the γ-γ true-coincidence correction factor (COI) for extended cylinder and Marinelli-beaker sources. Compared with point sources, the true-coincidence effects for extended sources are more complicated, since not only the source-volume averaged peak and total efficiencies but also the differential-efficiency distributions within the source itself are involved. A volume-effect factor (Fv), which can be calculated by the aid of our previously developed ESOLAN program, is introduced in this work to handle these complexities. The validity of using this method was successfully demonstrated by comparing the predicted COI values with the experimentally determined values for several radionuclides.