Assessment of Cosmogenically Produced Neutrons at the Sudbury Neutrino Observatory

Neutrons produced via nuclear interactions by cosmic muons present an irreducible background to many rare event searches, even in detectors located deep underground. We report the observation of collections of neutrons following throughgoing muons at the Sudbury Neutrino Observatory, as well as a set of Monte Carlo simulations using the GEANT4 package which accurately reproduce characteristic observables of the follower neutrons in relation to the leading muon. Also presented is an estimate of the cosmogenic neutron yield per unit muon track length in heavy water at a depth water-equivalent of 6 km.