Correlation of Xanes Features with the Scintillation Efficiencies of Ce Doped Alkaline Earth Lithium Silicate Glasses

Abstract

AbstractCerium activated glasses of composition 20Li2O·15MO·64.4SiO2·0.6Ce2O3 (where M is Mg, Ca, Sr, or Ba) exhibit scintillation efficiencies that vary by more than a factor of 2.5 with the alkaline earth. Previous work has suggested a correlation between the microstructure of these glasses and scintillation efficiency. Measurements of the Ce LIII x-ray absorption edge in the Mg, Ca and Sr glasses display a feature near the absorption edge that is suggestive of the presence of Ce4+. The area of this peak is, in fact, correlated with the scintillation efficiency of the glass. The amount of Ce4+ indicated by the intensity of this feature is, however, too high to be a permanent population. We suspect that the feature is a transient phenomenon related to creation of Ce4+ and trapped electrons due to photoionization by the x-ray beam.