The Badlands of Neutron Multiplicity Counting

Previous work on the Correlated Neutron Dead Time Model (CNDTM) and subsequent high-fidelity simulations revealed that the dead time of neutron multiplicity counters leads to resonant behaviour in measured multiplicity rates should the neutron source be of sufficient strength. The onset of resonant behaviour seems to be determined by the magnitude, type, and structure of the system’s dead time. Moreover, currently-fielded dead time correction algorithms fail for such strong neutron sources to recover the multiplicity rates impacted by the dead time with sufficient accuracy, hence effectively imposing a practical limit on neutron multiplicity counting that is detector dependent. Using high fidelity simulations of neutron pulse trains including realistic effective dead times and the advanced dead time algorithm CNDTM, we demonstrate and quantify the limits of neutron multiplicity counting for several standard counters, such as the Active Well Coincidence Counter.