Neutron multiplicity moments with detector cross-talk

Passive neutron multiplicity counting (NMC) methods extract the intensity of a primary fission source from the measured moments of the count distribution. This extraction is typically derived using a stochastic point model, assuming neutrons are generated by the primary fission source, a secondary induced one, and an α,n source. Traditional NMC is based on neutron absorption in ³He tubes, embedded in a moderating medium. For such systems, the point models were adapted to the time scales of the moderation and absorption. Recent years have seen a growing interest in the development of NMC based on neutron scattering in scintillators, in part due to the increase in demand for ³He. This poses the need to adapt the models to scattering-based systems. This paper addresses a key feature evident only in scattering-based systems: the so-called detector cross-talk, created by neutron re-scattering in multiple detectors. We derive a novel model for the sampled NMC moments which takes into account the detector cross-talk. The model assumes that the typical time scale of cross-talk is significantly shorter than the average neutron lifetime, which allows considering multiple detections due to detector cross-talk as simultaneous events.