Point light detection with UO2

UO2's electrical properties and U's inherently high fission energy release make a UO2-based direct conversion neutron detector a tantalizing possibility, but the evolution of even rudimentary devices is inhibited by the absence of large, high quality single crystals of UO2. Hydrothermally grown UO2 is incorporated into a prototype device here, and laser light is used as a surrogate for neutron-induced fission events. Excitation sources with wavelengths of 325, 488, 532, and 633 nm are incident on the device for a variety of timescales to test the detection responses, resolution, and saturation behaviors. The non-amplified changes in the current are presented, including when the illumination's diameter, power, and location are altered. Photocurrent changes follow a positively correlated linear trend with power and device efficiency is inversely correlated with illumination wavelength. The impact of illumination time on the detection efficiency is discussed. Illumination event detection is independent of illumination surface area size and largely independent of the illumination location. The ramifications of these results with regard to the development of UO2 as a neutron detector are considered.