Design of a Novel Capture-Gated Neutron Spectrometer With a CLYC Scintillator

A novel capture-gate neutron spectrometer with a Cs2LiYCl6:Ce (CLYC) scintillator and a liquid scintillator (LS) has been developed for measuring fast neutrons and studying cosmic neutron spectrum detection. The detector consists of an LS surrounding a central CLYC scintillator, designed for neutron capture after moderation. The CLYC scintillator can be easily replaced, allowing flexibility in its application. Two CLYC scintillators are compared: one enriched with 6Li, which has a relatively high thermal neutron cross section, and one enriched with 7Li, which has significantly reduced thermal neutron capture. The spectrometer was tested in a monoenergetic neutron field from 3.2 to 14.8 MeV. Pulse shape discrimination (PSD) was employed to separate neutron and gamma-ray events, and neutron identification relied on coincidence signals from both scintillators. The 6Li-enriched CLYC scintillator demonstrated high neutron event efficiency below 3.2 MeV, while the 7Li-enriched CLYC scintillator showed higher efficiency at 14.8 MeV. This approach enhances the efficiency of fast neutron spectroscopy for cosmic neutron spectrum measurements.