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.

AFIT Designator


DTIC Accession Number

AD1078181 (pending DTIC)