Reflectance spectra and thermoluminescence of KCl:KBr

The TL and optical studies on the KCl:KBr are reported. In the optical absorption spectra the broadening due to the interaction between colour centres and dislocations was less prominent in the mixed system than in the pure. TL of the mixed system is totally different. In γ-irradiated samples, a prominent glow peak (Tm) is observed at a temperature characteristic of the composition. Tm is lowered as the composition shifts from KCl to KBr. The position of this peak shows an interesting variation. Tm is minimum for the equimolar compositions. With the external bleaching another glow peak appears in the range 363-385 deg K. The high temperature peak can be phototransferred to the one at low temperature. The 'depth' values for different peaks are estimated using Chen's formulae. From these results it is seen that the interaction between colour centres and other imperfections inherent to the powders is reduced upon mixing. TL studies revealed a monomolecular decay as compared to the bimolecular processes in pure salts. (author)