Studies on TL of LiF: Mg and/or Cu Exposed to Gamma and UV Rays

Abstract

The thermoluminescence (TL) of LiF doped with different concentrations of Mg and/or Cu has been investigated. The glow peaks for the samples submitted to a thermal treatment and exposed to 0.26 mC.kg-1 of gamma rays or 0.4 J.cm-2 of UV or to both consecutively are analysed. The experimental results suggest that UV radiation fills the traps directly, and that each radiation, gamma or UV, fills preferentially different depth traps. UV induced peaks appear at a lower temperature than those due to gamma rays. Samples doped only with Mg (0.1 mol%) present the highest TL sensitivity to gamma rays and a further increase of Mg concentration drastically reduces the TL sensitivity. In contrast, the sensitivity to UV light is enhanced when the concentration of Mg is increased from 0.1 to 0.4 mol%. TL sensitivity to both UV and gamma rays for samples doped only with Cu decreases with the increase of Cu concentration from 0.03 to 0.12 mol%. Higher Mg and Higher Cu concentrations, when alone, reduce the TL induced by gamma rays, but Cu co-doping of Mg doped sample seems to help improve TL sensitivity.