High-Density Scintillation Detector Materials

High energy physics experiments use scintillation materials for detectors. As the density of the scintillation material increases, so does the sensitivity of the experiment. Presently, the scintillation material with the highest density is lead tungstate at 8.2 g/cm3. Higher-density materials are needed for intensity frontier and colliding beam experiments. Ultramet will identify high-density transparent materials, primarily oxides and fluorides, and add glass formers to them in an effort to form them as glasses rather than polycrystalline monoliths. Combinatorial chemistry techniques will be used to screen hundreds of materials and compositions containing different parent oxides (e.g. those of rhenium and hafnium, with densities of 11.4 and 9.68 g/cm3 respectively) and different mass fractions of different glass formers (e.g. the oxides of tellurium, germanium, silicon and others). Oxides with densities greater than 6 g/cm3 will be identified. Precursors for those oxides, as well as for numerous glass formers, will be obtained and put into aqueous solution. Fixed volumes of each oxide precursor solution will be combined with varying volumes of multiple glass former solutions using combinatorial chemistry techniques, and the resulting mixtures will be dried, calcined, and characterized with respect to crystallinity, density, and transparency. For the materials with the best set of properties, larger samples will be produced and measurements made of their optical transmission and refractive index. The primary near-term application for high-density glass will be scintillation materials for high energy physics experiments. The largest markets for inorganic scintillation materials, however, are the medical industry and the nuclear power industry. A small but growing market is scintillating optical fibers, which can be used for radiation detection in applications such as nuclear monitoring, geophysical exploration, and radiotherapy.