HPGE DETECTOR TRUE-COINCIDENCE CORRECTION FOR EXTENDED CYLINDER AND MARINELLI-BEAKER SOURCES

A semi-empirical method is developed to estimate the gamma-gamma true- coincidence correction factor (COI) for extended cylinder and Marinell i-beaker sources. Compared with point sources, the true-coincidence ef fects for extended sources are more complicated, since not only the so urce-volume averaged peak and total efficiencies but also the differen tial-efficiency distributions within the source itself are involved. A volume-effect factor (F-v). which can be calculated by the aid of our previously developed ESOLAN program, is introduced in this work to ha ndle these complexities. The validity of using this method was success fully demonstrated by comparing the predicted COI values with the expe rimentally determined values for several radionuclides.