Neutron efficiency and gamma rejection performance of CLYC and He alternative technologies

A great deal of scientific research in recent years has focused on alternative neutron detection technologies to the more commonly used 3 He proportional counter. One such example is a novel thermal neutron detector developed by Los Alamos National Laboratory consisting of multiple thin film 10 B layers combined with a double helix electrode configuration. The detector promises low manufacturing costs and is designed to fit into an existing high density polyethylene moderator housing used by two standard 2 bar 3 He proportional counters, making this a potential direct replacement for many current portal scanning modules. Also of interest is the dual neutron-gamma detector Cs 2 LiYCl 6 (CLYC), which has the ability to discriminate between thermal neutron, fast neutron and gamma interactions and has a gamma spectroscopic performance surpassing common alkali-halide scintillators such as NaI(Tl). In this work a calibrated neutron facility was used to measure the intrinsic neutron detection efficiency of the detectors when exposed to 252 Cf and the gamma rejection performance when the detectors were exposed to two 137 Cs sources. The subsequent results were compared to a commercially available 3 He detector module measured in the same experimental setup.