Triples Production by Cosmic Ray Interactions

I n low - activity neutron correlation/ multiplicity measurements, uncertainty and background are dominated by time - correlated neutrons originating from cosmic ray (CR) events in the materials close to and being measured. This work focuses on characterizing the multiplicity distribution from CR interactions and the manner in which it scales with presence of high Z materials likely to be in the vicinity of multiplicity measurements. Emphasis is placed on the triples production rate in such measurements. An active well coincidence counter was used for experimental data, and MCNP simulations were created to verify results. Singles and doubles rate production as a function of Z is known and present in the literature. However, no comparable information exists for triples production. This work furthers the capacity to perform low - activity assay where cosmic ray interactions dominate the multiplicity distribution.