Photostimulated luminescence studies of γ-irradiated KBr1−xIx:TlI mixed crystals

Results on photoluminescence and photostimulated luminescence studies of KBr1−xIx:TlI (0.01 and 0.05 mol%) mixed crystals grown in vacuum and air are presented. Photoluminescence spectra of the mixed crystals excited in the A-absorption band of KBr:Tl+ exhibited the characteristic emission bands of Tl+ ions in KBr:Tl+. When excited in the low energy tail of A-band absorption, additional emission bands were observed. Compared with earlier reports, excitation bands observed around 4.8, 4.6 and 4.4 eV are attributed to complex thallium centres of the form TlBr6−nIn (n = 0, 1, 2, 3). Photostimulated luminescence of γ-irradiated KBr1−xIx:TlI mixed crystals showed the presence of emission bands similar to the characteristic photoluminescence of Tl+ ions. The photostimulated luminescence slightly shifted towards the low energy side with increasing iodide composition x. The mechanism of emission in these mixed crystals is discussed. Dose response and storage stability (fading characteristics) in these mixed crystals are reported.