Evaluation of three software programs for calculating true-coincidence summing correction factors

True-coincidence summing correction is an essential element in k(0)-based N AA(1) and becomes important when samples are counted with a high efficiency detector. This may be the case where large detectors are used or where sam ples are counted in or in the vicinity of the detector in order to achieve low detection limits in conjunction with low-flux reactors. In some laborat ories coincidence correction is accomplished by calculating the coincidence correction factors. Since experimental validation of the calculations will reveal only the most significant errors and is a laborious task due to the high number of radionuclides involved, three laboratories decided to compa re their calculated coincidence factors. Each laboratory uses a different s oftware package. A comparative performance analysis was made of COINCALC de veloped at the INW of the University of Gent (implemented in SOLCOI by DSM Research), the software of the IRI, University of Delft the Netherlands, an d the software of the Ecole Polytechnique, Montreal, Canada. The overall ap proach, data and algorithms were chosen independently by each institute as the software was being developed and, so, the comparison has yielded a numb er of interesting conclusions. A follow-up investigation of the discrepanci es found will probably allow the performance of each program to be improved .