Neutron detection is relevant to the fields of nuclear physics, nuclear power generation, homeland security, oil well logging, and medical imaging. Gas tubes filled with 3He are widely used to detect neutrons in the presence of gamma-ray background but due to the shortage of this material, many efforts have been made to develop replacement technologies for neutron detection.
Among these technologies, plastic scintillators are relevant candidates due to their low cost, fast decay times, wide range of environmental stability, low toxicity, ease of handling, and ease of scaling to large volumes. Fast neutrons produce signals in plastic scintillators by elastic scattering from hydrogen atoms which generate recoil protons with kinetic energy sufficient to ionize and excite the surrounding matrix.
These ionizations and excitations produce a flash of light which is detectable by a photomultiplier tube (PMT). Unambiguous detection of the presence of neutrons is often complicated by gamma-ray background which produces Compton-scattered electrons in the scintillator. These Compton-scattered electrons generate signals inside the scintillator which overlap with signals generated by neutrons.