Dose dependence and fading effect of the thermoluminescence signals in γ-irradiated paprika

The thermoluminescence (TL) method can be used to discriminate irradiated and non-irradiated paprika. This study reports the polymineral composition of the dust adhered to paprika; radiation-specific luminescence is emitted by the inorganic material (mainly quartz, feldspars and calcite). On the basis of the shape of the TL curves (or glow curves) some physical parameters are evaluated. Natural TL curves, from non-irradiated samples, show three very low intensity peaks while induced TL curves, from irradiated paprika, seem to consist of five overlapping peaks. TL spectra reveal a very important difference in intensity and in the position of the peaks between irradiated and non-irradiated paprika. Fading observations of TL after irradiation at 5, 10 and 21 kGy, show the same behaviour in all the cases: an initial rapid decay to maintain a certain stability from 300–400 h onwards. © 1998 SCI.