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Yayın Investigating the thermally transferred optically stimulated luminescence source trap in fired geological quartz(Pergamon-Elsevier Science Ltd, 2014-03) Koul, Dileep K.; Patil, Pravinkumar G.; Oniya, Ebenezer O.; Polymeris, George S.The pre-dosed thermoluminescence (TL) emission of quartz has been found to be useful in retrospective dosimetry and archaeometry. Though the pre-dosed optically stimulated luminescence (OSL) and emissions have been reported to be similar, the former has been found to be un-reliable for the equivalent dose estimation. As this measurement protocol involves thermal heating at around 400 degrees C, the work reported in this paper investigated the influence of this heating on the OSL using fired specimens from various regions. The results suggested that the discrepancy in the behaviour of two emissions is caused by the presence of the thermally transferred optically stimulated luminescence (TT-OSL) induced by thermal-activation involved in the pre-dose treatment. This transferred signal was observed to be very significant in the case of samples containing a prominent higher-temperature TL peak at similar to 375 degrees C. The characterization of this signal based on (i) the nature of the glow curves, (ii) thermal-annealing of the OSL trap, (iii) observation of the TT-OSL, (iv) bleaching of the source trap and (v) the correlation between TL and OSL seems to suggest that the trap corresponding to this TL peak is the source trap in the TT-OSL emission mechanism.Yayın In-homogeneity in the pre-dose sensitization of the 110 degrees C TL peak in various quartz samples: The influence of annealing(Elsevier Science BV, 2012-03-01) Polymeris, George S.; Oniya, Ebenezer O.; Jibiri, Nnamdi N.; Tsirliganis, Nestor C.; Kitis, GeorgeThe pre-dose sensitization effect of the 110 degrees C TL glow-peak of quartz is a basic tool in thermoluminescence and optically stimulated luminescence dating and retrospective dosimetry. In the present work, a homogeneity study was performed on pre-dose sensitization in grains obtained from large quartz crystals samples collected from 10 different origins. The aliquot - to - aliquot scatter of the pre-dose sensitization of the 110 degrees C TL peak within each quartz crystal was monitored. The influence of the annealing on this scattering was also studied. Therefore, the investigation was applied to the un-fired "as is" samples as well as to samples annealed at 900 degrees C for 1 h following cooling to room temperature in air. The results showed that in the case of "as is" quartz the sensitization effect vary strongly within each aliquot of the same quartz sample. This strong variation is removed by both the high temperature annealing as well as heating up to 500 degrees C, involved in the TL measurements. These results are generally discussed in the framework of existing models and applications of the effect.Yayın Preliminary results towards the equivalence of transformed continuous-wave Optically Stimulated Luminescence (CW-OSL) and linearly-modulated (LM-OSL) signals in quartz(Versita, 2011-09) Kitis, George; Polymeris, George S.; Güneç Kıyak, Nafiye; Pagonis, VasilisThe present paper presents a comparative experimental study of two commonly measured Optically Stimulated Luminescence (OSL) signals in quartz. The experimental study measures both the continuous wave OSL (CW-OSL) and the linearly modulated (LM-OSL) signals from the same quartz sample for a range of stimulation temperatures between 180 and 280A degrees C, while the former is transformed to pseudo LM-OSL (ps LM-OSL). A computerized deconvolution curve analysis of the LM-OSL and ps LM-OSL signals was carried out, and the contributions of several OSL components to the initial OSL signal (0.1 s) were shown to be independent of the stimulation temperature used during the measurement. It was also found that the composite OSL (0.1 s) signal consists mainly of the first two OSL components present in the OSL curves. The equivalence of the ps LM-OSL (transformed CW-OSL) and of LM-OSL measurements was also examined by an appropriate choice of the experimental stimulation times, and of the stimulation power of the blue LEDs used during the measurement.
