Photostimulated luminescence process in the x-ray storage phosphor CsBr : Ga+

CsBr doped with Ga+ has previously proved to be an efficient X-ray storage phosphor with a figure of merit comparable to that of the commercially used BaFBr:Eu2+. By measuring the magnetic circular dichroism of the optical ab sorption (MCDA), the MCDA-detected electron paramagnetic resonance and the photostimulated luminescence (PSL), the paramagnetic defect centers generat ed upon x-irradiation involved in the storage and read-out process were inv estigated and found to be particularly simple: The electron traps are F cen ters, the hole trap centers are Ga2+ centers with a hyperfine interaction w ith Ga-69 of (69)A=6.5 GHz. No superhyperfine interaction was resolved. It is proposed that the PSL-active Ga2+ center is an isolated Ga2+ on a Cs+ si te. (C) 2000 American Institute of Physics. [S0021-8979(00)10901-6].