The optimal relationship between differential die away counting gate settings and minimal detectable activities of fissile materials

A recent development on the calculation method of Minimal Detectable Activities (MDA) of fissile material for Differential Die Away (DDA) assays has shown the relevance of precisely characterizing the active background that arises from the interrogating pulse of neutrons [1]. This contribution to the background noise is dependent on the type of matrix material being assayed. It also depends on the time limits of the counting gates set in the Multi Channel Scaler (MCS) used for DDA data acquisition. The present research investigates the relationship between MDA and gate settings leading to the definition of an optimal setting for which the signal to noise ratio in the early gate of the MCS is maximized.