1999 Volume 48 Issue 11 Pages 673-682
The trapping energy level (E) from conduction band is well known to be intimately correlated with the mean lives (τ) of captured electrons and holes in quartz grains, resulting in the applicable criterion of thermoluminescence (TL) dating using a coarse grain method. The experimental evaluation of accurate E-values has been carried out using an initial rise method combined with radioluminscence (RL) measurements for the correction of thermal quenching effects at higher temperature. The naturally accumulated red-TL (RTL) and blue-TL (BTL) grains from quartz grains from a dune sand were subjected to the present method. As a result, the correction of the thermal quenching effects always brought the higher E-values in the range of 0.1 to 0.25eVin comparison with the low activation energies from initial rise method of glowcurve analysis alone. It was again confirmed that the E-value of RTL gives higher than that of BTL in natural quartz grains. Consequently, the finally evaluated mean lives of RTL were certainly longer than those of BTL. This result supports that the RTL-dating is more preferable for the age-determination beyond 500 ka because of high stability of RTL. The E-values were also compared with the results from the isothermal analysis of TL-glowcurves.
