On the categorization of uranium materials using low resolution gamma ray spectrometry

In order to characterize uranium materials during e.g. nuclear safeguards inspections and in initial stages of nuclear forensic investigations, hand-held low resolution gamma ray detection instruments with automatic uranium categorization capabilities may be used. In this paper, simulated response curves for a number of matrices applied on NaI(Tl) scintillation detector spectra show that the result of the categorization is strongly dependent on the physical properties of the uranium material. Recommendations on how to minimize the possibility of misclassification are discussed.

► Categorization of U using Na(Tl) detectors is dependent on matrix and shielding.
► Detector response curves were simulated.
► Errors in 235U abundance due to inadequate detector responses were quantified.