Radiation Response from a Novel UO2 Crystal
AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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The radiation response of a novel, single-crystalline UO2 sample was analyzed using several types of radiation. The crystal was exposed to alpha, gamma, and neutron radiation under various environmental conditions and the electronic response of the crystal was measured using a pulse shape discrimination algorithm. The distributions of pulse amplitude Vmax and pulse decay times tau were used to compare the output. This research revealed that the crystal radiation response is exceptionally sensitive to surface conditions, specifically humidity, which tends to alter the time dependent currents resulting from the radiation interactions. The pulse tau can be made to be uniquely distributed for a certain set of conditions allowing to discern alpha, background and gamma irradiation, but it cannot be consistently reproduced. The overall delta tau itself was uniform for all radiation sources measured and the decay distributions were statistically different. This suggests that with well controlled environments,tau distributions may be sufficient to identifying a radiation interaction type. This preliminary research on novel uranium-based detectors indicates that further research into the crystal surface electronic structure is needed if it is possible to separate radiation types, especially neutron interactions. Furthermore, developing a better method for making crystal contacts to ensure bulk conductivity is a priority.