Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8961398 | Journal of Luminescence | 2019 | 6 Pages |
Abstract
We report phototransferred thermoluminescence (PTTL) and thermally-assisted optically stimulated luminescence (TA-OSL) of α-Al2O3:C,Mg annealed at 1200â¯Â°C. PTTL is TL measured from an irradiated phosphor after its exposure to light. The other theme of this study, TA-OSL is the additional amount of luminescence optically stimulated from a sample over and above the amount that would be measured at room temperature. A sample irradiated to 10â¯Gy and preheated to 230â¯Â°C at 1â¯Â°C/s followed by illumination by 470â¯nm blue light produced four PTTL peaks at 53, 80, 102 and 173â¯Â°C. The PTTL peaks occur at the same positions as the corresponding conventional TL peaks. Their kinetic parameters are also similar. The intensity of the PTTL peaks increased with duration of illumination to a maximum within 200â¯s for doses between 1â¯Gy and 10â¯Gy. The dose response of each of the PTTL peaks at 80, 102 and 173â¯Â°C is linear within 1-15â¯Gy. The rate of fading is low and the peaks are reproducible. When the irradiated sample is optically stimulated at temperatures between 30â¯Â°C and 300â¯Â°C, after preheating to 500â¯Â°C, the intensity of its TA-OSL goes through a peak with temperature at 200â¯Â°C. Using the rising edge of the plot, activation energy of thermal assistance for a deep electron trap was estimated as (0.21â¯Â±â¯0.02) eV. The TA-OSL dose response is sublinear from 10-250â¯Gy and saturates thereafter. The PTTL and TA-OSL analyses signify that the concentration of deep traps in α-Al2O3:C,Mg increased after annealing at 1200â¯Â°C. As a result, the sample produced better PTTL and TA-OSL response than when annealed at lower temperature.
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Authors
J.M. Kalita, M.L. Chithambo,