INVESTIGATING THE DIRECTIONAL DEPENDENCE IN ORGANIC CRYSTAL SCINTILLATORS THROUGH NEUTRON MEASUREMENTS

Organic crystal scintillators have long been used as radiation detectors, but their performance as neutron detectors is limited by a directional dependence that exists in heavy charged particle interactions. A system has been constructed to characterize the dependence of the light output and pulse shape on the proton recoil direction in organic crystal scintillator detectors. The effect has been measured in anthracene and stilbene and it has been shown that the magnitude of the effect varies with energy and material, and the variation in light output and pulse shape are not coupled. For 2.5 MeV proton recoils in anthracene, it was found that the light output varies by a factor of 1.396 ± 0.036 and the tail-to-total value used to quantify the pulse shape varies by a factor of 1.317 ± 0.007. This effect degrades the energy resolution of these materials, but may provide a modality for these materials to serve as directional neutron detectors.