Multi-energy neutron detector for counting thermal neutrons, high-energy neutrons, and gamma photons separately

This scintillation detector is composed of two scintillators optically coupled and mounted on a single photomultiplier tube. The first scintillator is a 6Li-loaded glass that has high efficiency for thermal neutrons, and the second is a liquid scintillator (BC 501) that has fairly high efficiency for higher energy neutrons. The 6Li glass scintillator emits light with a characteristic time constant of ∼ 60 ns, whereas light emitted in the liquid scintillator by proton recoil from energetic neutrons has a time constant of ∼ 30 ns and the time constant for scintillations occurring from gamma-scattered Compton electrons in the liquid scintillator is ∼ 3.7 ns. These differences in light decay time constants make this detector conducive to electronic separation of pulses generated by the three different radiations. The thermal neutrons, high-energy neutrons, and gamma radiation can be counted separately by operating this detector with a pulse-shape discriminator recently developed. Experimental data demonstrates the proof of principle of this dual scintillator detector for many applications