التفاصيل البيبلوغرافية
| العنوان: |
Thermal stabilities and sensitivities to dose of the low and high temperature components of ESR signals in quartz. |
| المؤلفون: |
Naoya Obata, Shin Toyoda |
| المصدر: |
Ancient TL; Jun2023, Vol. 41 Issue 1, p136-136, 1p |
| مصطلحات موضوعية: |
THERMAL stability, LOW temperatures, HIGH temperatures, ELECTRON paramagnetic resonance, QUARTZ, PHYSIOLOGICAL effects of cold temperatures |
| مستخلص: |
Electron spin resonance (ESR) dating of quartz has been applied to fault gouges, volcanic ashes and fluvial sediments being expected to be able to date samples older than the luminescence method does due to the high saturation dose. However, the ESR dating of quartz has still several problems. One of them is that, sometimes incorrected equivalent doses are obtained for older tephra samples [1], the characteristic of unbleachable Al center is not well understood [2], there are no clear evidence for whether or not preheating is necessary. The thermal stability may be related to them, however it is different from sample to sample [3, 4, 5, 6], and systematically investigations have not been done. We have investigated the thermal stability of quartz from different origins under several conditions, such as irradiation, annealing and bleaching. The results indicate that there are two components below and above 280°C both in Al and Ti-Li center with different thermal stabilities and saturation doses. We found that the unbleachable signal of the Al center is thermally more stable than the bleachable component, that the kinetics of signal decay is compatible with mixed first and second order reaction, and that the signal lifetime of the low temperature component is shorter than previously believed. In addition, we also found that high gamma ray dose modifies the thermal characteristics of the signals in tephra, i.e, predose effect. It enhances the sensitivity of both low temperature and high temperature components of the Al center but it reduces for Ti center. The measurement protocols should be considered depending on the samples. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
