Investigations into the Effect Detector Thickness has on CLYC Performance

Abstract

Research into the use of detectors which have the ability to simultaneously detect neutron and gamma radiation has become more common place. One such detector is the inorganic scintillator Cs2LiYCl6 (CLYC) which has the ability to detect thermal neutrons, fast neutrons and gamma radiation. One significant disadvantage of CLYC is the in-ability to grow large crystals in addition to a high detector cost. As a result a series of measurements and simulations were undertaken to assess the effect CLYC detector thickness has on detector performance with respect to spectroscopy, pulse shape discrimination and thermal neutron detection efficiency. An improvement in the pulse shape discrimination performance of CLYC was observed for more symmetric crystal sizes. No plateauing in the number of detected neutrons with crystal thickness was observed when scatter corrected thermal neutron efficiency measurements were undertaken. MCNP6 simulations of a 252Cf source positioned within a high density polyethylene sphere found that for an increase in crystal thickness from 1 to 2 inches a 20 the observed number of detected thermal neutrons was observed despite a 54% increase in cost.