The objective of this research is to transfer and strengthen knowledge of intrinsic defects linked to a material's performance as a radiation detector in cerium doped yttrium aluminum garnet and other garnet materials. Defects will be linked to the crystal growth process in a fully integrated process from crystal growth, furnace temperature profiling, doping schemes and post-growth treatments to the characterization of detector performance. Neutron detection capability may be implemented during the latter part of the project. The intellectual merit of the project is the anticipated academic foundation for significant improvements in compounds through "defect engineering". It is anticipated that the advances will lead to a dramatic improvement in the energy resolution of garnet scintillating radiation detectors, competitive with the best crystal materials available, while superior in chemical and mechanical properties and easier to fabricate. The proposed work will also provide crucial understanding of microscopic defects. There are several anticipated broader impacts of the research. The project will educate expert crystal growers, a skill in dire need for the US economy and national security, and materials scientists who will understand the tight correlation of growth conditions to the quality of the crystals in applications. Students will also be exposed and educated in the use of a broad range of diagnostic tools. Open houses and general presentations to potential students and visiting high school classes are envisioned to increase the visibility of high quality crystal growth in academic and non-academic communities. Research experiences for undergraduates will also be incorporated in the project. Finally, the expected insights from "defect engineering" will, hopefully, also bring about new applications in other fields such as nuclear medicine and diagnostics through positron emission tomography.
