Evaluation of fission product isotopes for field or laboratory detection

An International Monitoring System (IMS) is being created to monitor the Co mprehensive Nuclear-Test-Ban Treaty (CTBT). Radionuclide aerosols will be m onitored to provide positive proof of an atmospheric explosion In addition, a group of laboratories will perform quality assurance and confirmatory an alyses of samples of interest. The field and laboratory systems will perfor m gamma-ray spectrometric analysis of air filters. While laboratories may u ndertake additional analysis such as chemical separation and beta counting, the scope of the work reported here is to make evaluations with respect on ly to gamma-ray spectrometry. Activation products have not been completely considered and are shaded with uncertainty, from the probability of escape from an underground test and the dependence on the sub-surface elemental co mposition.