Radiation Detection and Classification of Heavy Oxide Inorganic Scintillator Crystals for Detection of Fast Neutrons
Naval Postgraduate School Monterey United States
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Improved detection of fast neutrons can help prevent illicit nuclear materials from being trafficked, and potentially used on American soil. To detect fast neutrons, most current systems use a multi-step process of thermalizing the neutrons, providing a medium or material for neutron capture or other interaction, and then detecting the resultant gamma radiation signal. Heavy inorganic oxide scintillators can detect fast neutrons without thermalization. Simplifying the complex, multi-step detection process into a single interaction and detection medium reduces the detection systems complexity while improving efficiency, compactness, and cost effectiveness. To understand how such scintillators respond to gamma and neutron radiation, we exposed selected scintillators to different gamma and neutron sources and measured the resulting emission responses with photomultiplier tubes and photonic devices. The resultant emission responses were found to depend on a variety of factors including temperature, crystal fabrication, and structure. In addition to considering these factors, the target materials relationship of response to the effective atomic number, Zeff, was characterized. Follow-on work is recommended to further characterize fast neutrons spectral response to irradiation.
- Nuclear Physics and Elementary Particle Physics