Improved Ultrafast Scintillators for Nuclear Physics

40094 November 8, 1996 ALEM Associates Of all the applications in which scintillators are used, none puts more rigorous demands on the material than high energy physics. The high radiation fluxes characteristic of these experiments requires both extremely short decay times (to enable high timing resolution) and minimal contribution from long decay components (to prevent count pile-up). Barium fluoride is the most effective inorganic scintillator for such applications, largely because of the unusually rapid decay (0.6 ns) of its fast component. Unfortunately, it has two major deficiencies: a long-lived slow component, which comprises over 85% of the total emission, and a particular sensitivity to damage by the very radiation it is measuring. This project explores a new approach to achieving improved ultrafast scintillators for high-energy radiation detection. A significant quantity (approximately 15 mole percent) of optically inert rare earth trifluorides are substituted into the basic alkaline earth difluoride lattice, and the host is doped with small amounts of other rare earths capable of d-f emission. Most of the energy that now goes to the undesirable long component should be diverted into a much more rapid emission in the 1-10 ns range, enhancing both timing resolution and radiation hardness without reducing the contribution from the fast component itself. The validity of the approach will be confirmed through spectroscopic and kinetic measurements on specially grown specimens, and the expected performance improvement will be assessed. Anticipated Results/Potential Commercial Applications as described by the awardee: The project will develop a scintillator material whose performance exceeds that of BaF2 in all three critical ways: enhanced timing resolution, reduced background, and greater radiation hardness. This will not only provide nuclear physicists with a superior measurement tool, but lead the way to improved materials for medical and industrial uses as well.