The Estimation of the Minimum Detectable Activity from Measured Passive Neutron Coincidence Counter Data

We describe the method applied within Canberra’s waste assay software, NDA2000, for estimating the Minimum Detectable Activity (MDA) following a Passive Neutron Coincidence Counter Assay. In order to clarify the approach and aid the explanation we illustrate its use by giving numerical examples. The MDA algorithm shows explicitly how design and operational parameters can be used to influence the detection limit. This enables the key factors to be identified and balanced in a structured way, when establishing the compromises between often conflicting requirements at the start of instrument design or measurement programs that target a given performance. We extend the discussion beyond the usual confines of ideal statistical counting distributions. Finally, we briefly comment on the role of Advanced Waste Analysis (AWA) algorithms available within NDA2000 involving statistical filtering and multiplicity truncation in relation to stabilizing the MDA estimates and overall system performance in real-life measurement situations.