Comparison of fluorescence properties for single crystal and polycrystalline YAG:Ce

For more than a century, materials that emit visible light when exposed to ionizing radiation, or "fluors," have been used for a variety of scientific and engineering purposes. The term "half brightness dose" (N/sub 1/2/) was developed as a consistent figure of merit to evaluate the effectiveness of a material to emit fluorescence as a function of radiation exposure. Research indicates that certain properties, such as half brightness dose, fluorescence intensity, and prompt decay time, could depend on crystalline structure. The average 3 MeV proton N/sub 1/2/ for a polycrystalline YAG:Ce paint was found to be 1.28/spl times/10/sup 14/ mm/sup -2/, which is consistent with earlier research. The 3 MeV proton N/sub 1/2/ for the virgin YAG:Ce crystal was found to be 3.1 times larger than was measured for the polycrystalline paint. Subsequent N/sub 1/2/ measurements with the crystal were slightly lower than the virgin data and larger than was obtained from the polycrystalline PPMS paint.