Intercomparison of efficiency transfer software for gamma-ray spectrometry

The EUROMET project 428 examines efficiency transfer results for Ge gamma-r ay spectrometers when the efficiency is known for a reference point source geometry. For this, different methods are used, such as Monte Carlo simulat ion or semi-empirical computation. The exercise compares the application of these methods to the same selected experimental cases to determine the usa ge limitations versus the requested accuracy. For carefully examining these results and trying to derive information for improving the computation cod es, this study was limited to a few simple cases. The first part concerns t he simplest case of geometry transfer, i.e., using point sources for 3 sour ce-to-detect or distances: 2, 5 and 20 cm; the second part deals with trans fer from point source geometry to cylindrical geometry with three different matrices. The general conclusion is that the deviations between the comput ed results and the measured efficiencies are mostly within 10%, The quality of the results is rather inhomogeneous and shows that these codes cannot b e used directly for metrological purposes. However, most of them are operat ional for routine measurements when efficiency uncertainties of 5-10% can b e sufficient. (C) 2001 Elsevier Science Ltd. All rights reserved.