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Component resolved IR bleaching study of the blue LM-OSL signal of various quartz samples

100%

Polymeris G. S. , Kiyak N. G. , Kitis G.

tom Vol. 32

79-85

The present work provides an initial component resolved analysis concerning the effect of infra-red (IR) exposure at elevated temperatures on the blue LM-OSL signal of quartz (stimulated at 470 nm). The study was performed on a total of seven quartz samples, among which five originated from Turkey, one from Greece and one synthetic quartz sample. For these quartz samples, the presence of 6 or even 7 independent LM-OSL components was previously reported, after the application of a computerized decomposition analysis. IR bleaching of each one of these components is studied and compared to the respective signal reduction due to the same thermal treatment solely. It is clearly demonstrated that IR stimulation at temperatures above 50 ° C does not deplete only the fast component in most sedimentary quartz samples studied. Net depletion of fast and medium components resulting from IR exposure is sample-dependent and occurs faster as the stimulation temperature increases. Weak IR bleaching of slow components is also reported in some cases, being more effective for stimulation temperatures up to 100 ° C. No depletion of either the medium or the slow components was detected for stimulation temperatures above 150 ° C. Finally, IR does not stimulate any of the LM-OSL components in the case of the synthetic quartz sample.

Behavior of various Nigerian quartz samples to repeated irradiation and heating

100%

Oniya E. O. , Polymeris G. S. , Tsirliganis N. C. , Kitis G.

tom Vol. 39, no. 3

212-220

In the present work the sensitization of the entire glow-curve is studied in 6 different quartz samples of Nigerian origin. The investigation was applied to the un-fired “as is” samples as well as to samples fired at 900°C for 1 hour following cooling to room temperature. The results showed that in the case of “as is” glow-curve is sensitized as a whole. There is an abrupt transition from the “natural” sensitivity without any previous heating and the artificial sensitivity induced after the first heating. The sensitization is growing up strongly to the 10th heating but to a lower rate. The sensitization fac-tor of the TL glow-peak at “110°C” was found to be linearly correlated to the higher temperature TL peaks. In the case of annealed samples there is an initial increase between the sensitivity immediately after the end of annealing and after the first heating. As the number of heating is increased up to the 10th heating the sensitization is stabilized at a constant value. The results are discussed in the frame-work of existing models and implications of the sensitization effect in various applications, while some explanations are attempted.