Spectral Dependence of Optical Bleaching of PTTL in Quartz

Abstract

The phototransferred thermoluminescence (PTTL) was studied in quartz. The PTTL was excited in X or β irradiated samples by monochromatic light between 250 and 500nm. Main PTTL peaks appeared at about 110, 160 and 200°C. The temperatures of these peaks as well as their thermal activation energies fit those of X and β induced TL peaks; emission spectra of the PTTL showed the same 370 nm and 450 nm emission bands as the regular TL. Effects of optical bleaching on the PTTL intensities were investigated. The spectral dependence of the bleaching efficiency was measured for the 110°C peak and showed maxima at 310 nm and at 280 nm. For comparison, the excitation spectrum of this PTTL peak was measured and also showed maxima at 310 and 275 nm: these results indicate that the same wavelengths, which are most efficient for the transfer of carriers from deep to shallow traps, are most efficient for optical bleaching as well.