Correcting for thermal transfer in OSL measurements of young sediment samples

Abstract

Overestimation of equivalent dose (De) values due to thermal transfer was observed for quartz when using the single-aliquot regenerative-dose protocol (SAR) to recover a small known dose (1.74 Gy) given after an optical bleach. Both the fast and medium components resulted in overestimation, with the effect being larger for the medium component and the effect could be seen in De (t) plot as stimulation time increased. The dose-generated OSL signal can be distinguished from the thermally transferred signal based on the linear relationship between the initial and final parts of the thermally transferred OSL curves. A method is proposed to correct for thermal-transfer effects using the OSL signals measured in repeated heat/OSL cycles incorporated into the SAR protocol. This approach was applied to artificially irradiated and optically bleached samples, and it was found that the thermal-transfer effects can be removed when using only a single aliquot. In dose recovery tests, the known dose (1.74 Gy) could be obtained using this approach and a value of 0.074 ± 0.026 Gy was obtained for optically bleached aliquots. © 2006 Elsevier Ltd. All rights reserved.