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_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_1/2 for a polycrystalline YAG:Ce paint was found to be 1.28 × 10¹⁴ mm^-2, which is totally consistent with earlier research. The 3 MeVproton N_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 _1/2 measurements with the crystal were slightly lower than the virgin data and larger than was obtained from the polycrystalline PPMS paint.