This paper describes the design and performance of a 50 liter, two-segment 6Li-loaded liquid scintillator detector that was designed and operated as prototype for the PROSPECT (Precision Reactor Oscillation and Spectrum) Experiment. The two-segment detector was constructed according to the design specifications of the experiment. It features low-mass optical separators, an integrated source and optical calibration system, and materials that are compatible with the Li- doped scintillator developed by PROSPECT. We demonstrate high light collection of 850±20 PE/MeV, an energy resolution of sigma/sqrt(E(MeV)) = 4.0±0.2%, and efficient pulse-shape discrimination of low dE=dX (gamma-like) and high dE=dx (neutron-like) energy depositions. An effective attenuation length of 853 cm is measured in each segment. The 0.1% by mass concentration of 6Li in the scintillator produces a measured neutron capture time of t = 42.80.2 ms. The long-term stability of the scintillator is also discussed. The detector response meets the criteria necessary for achieving the PROSPECT physics goals and demonstrates features that may find application in fast neutron detection.
Journal of Instrumentation
neutrino detectors, scintillators, neutron detectors, liquid detectors