Investigating the thermal stability of TT-OSL main source trap. (December 2018)

• Record Type: Journal Article
• Authors: Faershtein, Galina; Guralnik, Benny; Lambert, Renske; Matmon, Ari; Porat, Naomi
• Is Part Of: Radiation measurements. Volume 119(2018:Dec.)
• Page Start: 102
• Page End: 111
• Publication Date: 2018-12
• Subjects: TT-OSL -- Thermal stability -- Kinetic parameters; Nuclear emulsions -- Periodicals; Particle tracks (Nuclear physics) -- Periodicals; Thermoluminescence -- Periodicals; Cosmic rays -- Periodicals; Radiation -- Measurement -- Periodicals; Radiometry -- Periodicals; Radiation Monitoring -- Periodicals; Émulsions nucléaires -- Périodiques; Particules (Physique nucléaire) -- Traces -- Périodiques; Thermoluminescence -- Périodiques; Rayonnement cosmique -- Périodiques; Radiométrie -- Périodiques; 539.77
• DOI: 10.1016/j.radmeas.2018.09.010
• Languages: English
• ISSNs: 1350-4487

Abstract

Abstract: Thermally-Transferred Optically Stimulated Luminescence (TT-OSL) from quartz is an extended-range luminescence dating technique, with an assumed potential to date sediments as old as early Pleistocene (0.8–2.6 Ma). However, one of the main drawbacks of the TT-OSL signal is its relatively low thermal stability. The few and scattered estimates in the literature of the relatively low thermal stability highlight the possibility that some reported TT-OSL ages are thermal artefacts (i.e. minimum ages only). In this study, we rigorously investigate the thermal stability of the main TT-OSL source trap, using a combination of laboratory and analytical techniques (varying heating rates, isothermal decay, alongside several models) on multiple aliquots of a modern sand sample from the eastern Mediterranean coastal plain. The varying heating rates method constrains the Arrhenius parameters of the TT-OSL main trap to E = 1.50 ± 0.06 eV and s = 10 12.8±0.6 s −1 ; these values translate into a trap lifetime of 3 . 2 − 1.9 + 4.8 Ma at 10 °C. Isothermal decay data further exhibits significant departures from first-order kinetic behavior, which can be well captured by either the general order kinetics model, or a Gaussian distribution of first-order systems. However, extrapolations of these models to geological timescales are at odds with a large volume of observations, thus suggesting that the deviation from first-order kinetics may be a laboratory artefact. Overall, our study reinforces the concern, that thermal loss progressively affects the TT-OSL signal in the Ma-scale age range, and that some previously reported results may be "minimum ages" only. Highlights: The kinetic parameters and lifetime of the main TT-OSL source trap were investigated. A combination of analytical techniques and different models were used. The kinetic parameters were constrained to E = 1.50 ± 0.06 eV and s = 10 12.8±0.6 s −1 . The lifetime of the main TT-OSL source trap was calculated to . 3 . 2 − 1.9 + 4.8 Ma at 10 °C. Over geological timescale the trap's behavior is best described by first order kinetics.