C$^{7}$LYC: A New Scintillator for Fast Neutron Spectroscopy
The scintillator Cs 2 LiYCl 6 (CLYC) has emerged as a versatile detector for both gammas and neutrons, with excellent pulse shape discrimination. Originally developed as a thermal neutron counter, the discovery of its unexpected and unprecedented ~10% pulse height resolution for fast neutrons in the few MeV range has prompted studies to benchmark its use in low-energy nuclear science and applications. Since the typical long time-of-flight arms are not needed for achieving good energy resolution, geometrical efficiency can be enhanced by positioning the detectors much closer to the target. We have constructed a 16-element array of 1” × 1”7Li-enriched C 7 LYC, to eliminate the dominant peak in the spectrum from thermal neutron capture on 6Li, leaving the energy region above 3 MeV with a clean baseline for fast neutron spectroscopy. We have also procured the first ever 3” × 3” C 7 LYC crystal. Test experiments under way with C 7 LYC include elastic and inelastic neutron scattering cross sections at Los Alamos with a pulsed white neutron source, efficiency measurements using mono-energetic neutron beams up to a few MeV at UMass Lowell, and fission neutron measurements with GRETINA and CHICO detector arrays at Argonne. Beta-delayed neutron spectroscopy experiments have also been initiated at the CARIBU and NSCL facilities, to evaluate C 7 LYC as a possible candidate for auxiliary scintillator arrays for stopped beam physics at the next generation rare isotope accelerators.