Glass ceramics as X-ray storage phosphors for high spatial resolution

We found a photostimulated luminescence (PSL) effect in Eu- and Ce-doped fl uorozirconate glasses which were additionally doped with 5% Br- ions. Small BaBr2 crystallites in the hexagonal phase form in the glass upon annealing at 290 degreesC. The PSL is attributed to the 5d-4f emission of Eu2+ or Ce 3+. The PSL excitation band peaking at 570 nm is due to radiation-induced e lectron trap centres which are located either in the Eu-/Ce-doped crystalli tes or in the glass; where exactly they are located is not yet known. Measu rements of the magnetic circular dichroism of the optical absorption (MCDA) on X-irradiated Ce-doped fluorozirconate glass showed an increased paramag netic band in the range from 300 to 700 ran and a new paramagnetic band pea king at 570 nn. Electron paramagnetic resonance detected in these MCDA band s yielded two different defect centres having resonances at g = 1.90 and 1. 98, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.