UCLA

The dissertation is focused on composite scintillating materials for gamma-ray and fast neutron spectroscopy. The inorganic-organic composite scintillators have been successfully fabricated and investigated. By leveraging the virtues of inorganics' high stopping power and plastics' ease of fabrication, the low cost composites are potentially serving as a candidate for the next generation high energy radiation detection materials.

New polymer matrix and coupled fluors are developed to obtain plastic scintillating materials, where efficient Foster Resonance Energy Transfer (FRET) is fulfilled. This material possesses fast response time and good processibility, and the best light yield is over 5 times than that of commercial available plastic scintillators. Gamma-ray and neutron sensitizers are synthesized and investigated, including metal oxide nanocrystals and organometallics. These sensitizers are soluble in organic solvent, satisfying photophysical requirements for efficient scintillation, and are readily being incorporated into composites. Subsequently, a surface-catalyzed polymerization approach is proposed to fabricate bulk composites via UV curing. The composites are highly transparent at high loading of nanocrystals. Composites scintillators are prepared loaded with different sensitizers and different fluors. Photoelectric peak for Cs-137 gamma was obtained from these samples with an energy resolution of 10%, suggesting potential use of these composites for high energy radiation detection.