Dose and dose rate dependence of time-resolved OSL from Korean paleosol quartz

Using a newly developed small X-ray irradiator equipped with a mini X-ray generator (Varian VF-50J) and TR-OSL measurement system attached to an MCS (ORTEC MCS-PCI), the influence of dose and dose rate of X-ray radiation on TR-OSL was investigated in paleosol quartz from the Chungdang-dong paleolithic site, Korea. All lifetimes were calculated by a curve-fitting method using a single stretched-exponential function with beta = 0.86. Physical characteristics, natural lifetime, thermal quenching activation energy Delta E, and thermal assistance activation energy E-a were firstly determined. From the results of the investigation of dependence on dose and dose rate of X-ray radiation using fully bleached samples, the lifetime decreased significantly to about 20 its: when the X-ray dose was increased to 300 Gy at a dose rate of 0.5 Gy/s. Also, despite different radiation dose rates, at a dose of 50 Gy both lifetime and related intensity were independent of dose rate change. (C) 2011 Elsevier Ltd. All rights reserved.