Date of Award

3-24-2016

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

James C. Petrosky, PhD.

Abstract

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 (τ) 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 τ can be made to be uniquely distributed for a certain set of conditions allowing to discern alpha, back- ground and gamma irradiation, but it cannot be consistently reproduced. The overall Δτ itself was uniform for all radiation sources measured and the decay distributions were statistically different. This suggests that with well controlled environments, τ 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.

AFIT Designator

AFIT-ENP-MS-16-M-084

DTIC Accession Number

Pending

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