Thermoluminescence glow curve analysis of UV irradiated long persistence CaS: Pr3+ phosphor through computerized glow curve deconvolution technique

Thermoluminescence of Pr3+ doped CaS phosphor has been investigated and reported in this manuscript. The TL studies on polycrystalline sample of this phosphor show a double peak structure with maxima centered at 89 °C and a shoulder at around 133 °C when excited with UV radiation. Maximum TL intensity is observed at Pr concentration of 0.25 mol%. The UV exposure time is varied in a wide range from 10 s to 24 h and practically no shift in Tm is observed. Tm–Tstop and E–Tstop methods suggest that there are eight trapping levels operative in this phosphor with energy values varying between 0.5 and 1.0 eV. These values are used as input for CGCD procedure and trapping parameters are evaluated. The glow curve is found to be composed from linear superposition of eight peaks. The figure of merit (FOM) during fitting procedures is found to be around 1.6%. Higher fading rates are observed for peak centered on 89 °C while the peak at 133 °C is found to show 30% fading after 6 days of storage time. Decay studies carried out on the present phosphor reveal a multi-exponential contribution.