Characterisation of light output in a deuterated stilbene crystal for use in fast neutron detection*

Neutron spectroscopy without time-of-flight is important to numerous applications, including nuclear security and accelerator-based measurements using DC beams. Deuterated organic scintillators with PSD-based n/g discrimination address this problem, allowing spectrum unfolding on a clean fast-neutron signal down to a PSD threshold. Solid detectors have practical advantages over liquids, PSD-plastics typically exhibit poorer PSD. A promising alternative is crystalline deuterated stilbene, which can provide excellent PSD and spectroscopy through spectrum unfolding. However, deuterated stilbene crystals may exhibit anisotropy in light production due to channelling in the lattice structure, which may complicate spectrum unfolding. To quantify this, the light output a deuterated stilbene crystal was studied as a function of electron direction using Compton scattering of gamma rays incident at various angles to the crystal lattice. Preliminary results will be presented.