Development of a New Fast Neutron/Gamma Spectrometer Array Using CLYC

Neutron physics has long suffered from a lack of detectors that provide spectroscopic information without the need for inefficient time-of-flight techniques. Any headway made towards a spectrometer with good energy resolution and neutron/gamma pulse-shape discrimination represents an important step forward in the field. Recent investigations at the University of Massachusetts Lowell with Cs$_2$LiYCl$_6$ (CLYC) scintillators have demonstrated their potential for direct pulse-height measurements via the $^{35}$Cl(n,p) reaction. From this work, it was recognized that CLYC could be optimized for fast neutron detection by growing $^6$Li-depleted crystals to suppress the overwhelming thermal neutron response. A project is now underway to develop a versatile array of 16 1"x1" $^6$Li-depleted CLYC detectors for measurements in nuclear astrophysics, reactor data, homeland security, and nuclear structure. Initial measurements of interest include prompt fission neutrons, $\beta$-delayed neutrons, and scattering cross sections. Characterizations of the neutron and gamma-ray response for the first two detectors of the array are being carried out at various facilities with both mono-energetic and continuous fast neutron beams.