Date of Award


Document Type



Department of Engineering Physics

First Advisor

Larry W. Burggraf, PhD


Previous work demonstrated gamma-ray directional detection through the integration of a radiation detection system and an additively manufactured rotating scatter mask (RSM). This work advances the RSM directional detection system through improvements in the system's design, validation of a new scatter mask, and the novel ability to directionally detect both neutrons and gamma rays, a desirable feature for many nuclear safeguard and counterproliferation applications. The mixed-radiation RSM system developed for this research utilized the Spartan I mask design coupled with a 1" EJ-309 liquid scintillator. A GEome-try ANd Tracking (Geant4) model is developed and quantitatively compared to experimental measurements for both pulse-height energy spectra and detector response curves, validating the system's directional detection capabilities. Two sets of directional measurements are performed with an americium-beryllium source, varying the source's distance and direction for each set. The RSM correctly identified the direction of the source within 5° in both the azimuthal and polar directions for neutron induced events and within 10° for gamma rays. The results demonstrated the RSM is a compact, lightweight, and modular directional detection system useful for safeguard and counterproliferation missions that require rapid identification of the type and location of radioactive sources.

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