Spectroscopic analysis of proton induced fluorescence from yttrium and gadolinium oxysulfides phosphors

The effect of proton-induced damage on the relative scintillation efficiency of various inorganic phosphors including Y₂O₂ S:Eu, Gd₂O₂S:Pr, and Gd₂O₂ S:Tb. Materials were selected for high efficiency, fast prompt fluorescence response, and minimal delayed fluorescence. Phosphors were exposed to a 3-MeV proton beam at ambient temperatures to control heating damage. Real-time, in-situ measurements of the fluorescence spectra permitted observation of the special characteristics for the deterioration of scintillation yield due to particle-induced damage. The light spectra emitted were nearly identical to those excited by electrons, indicating a common excitation process. Rare earth oxysulfides give intense emissions but the corresponding light intensity drops rapidly with dose. Light intensity decreases with dose, following the Birks and Black model (1951) where damage sites compete for excitons with light-producing sites. Decay of broadband and spectral peak intensity follows similar patterns. The Birks and Black deterioration relation is fitted to each spectral line with empirical decay parameters