Effects of halogen ions on the X-ray characteristics of Gd2O2S : Pr ceramic scintillators

A fine powder of a Gd2O2S:Pr ceramic containing halogen ions such as F-, Cl -, Br- or I- was synthesized and its properties as a scintillator were exam ined. By adding F- at a concentration of 0.002-0.003 mole ratio, light outp ut increased to 107% and afterglow decreased to 4% compared with those of n onadditives. The effect of these additives was discussed in relation to the ion radius of halogen ions. Afterglow of Gd2O2S:Pr ceramic scintillators d ecreased with increasing annealing temperature. Analysis of weight loss dur ing heating gave a clearer understanding of this phenomenon and suggested t hat the vaporization of F elements added as a sintering aid in Li2GeF6 mini mizes traps in the crystal.