Characterization of Large Volume CLYC Scintillators for Nuclear Security Applications

We report on our development of large volume Cs
₂
LiYCl
₆
(CLYC) detectors for nuclear security applications. Three-inch diameter boules have been grown and 3-in right cylinders have been fabricated. Crystals containing either >95%
⁶
Li or >99%
⁷
Li have been grown for applications specific to thermal or fast neutron detection, respectively. We evaluated their gamma and neutron detection properties and the performance is as good as small size crystals. Gamma and neutron efficiencies were measured for large crystals and compared with smaller size crystals. With their excellent performance characteristics, and the ability to detect fast neutrons, CLYC detectors are excellent triple-mode scintillators for use in handheld and backpack instruments for nuclear security applications.