Luminescence response to irradiation using mini X-ray generators

Determination of equivalent doses in retrospective dosimetry involves calibration by irradiation of the dosimeters in the laboratory. In the Riso TL/OSL measurement system, laboratory irradiations make use of a radionuclide (Sr-90/Y-90 beta) source. In this paper we investigate the possibility of replacing the radionuclide source with an X-ray tube. Two different X-ray tubes are tested; a filament type (50 kV, 1 mA, 50 W) and a cold cathode type (30 kV, 0. 1 mA, 3 W). We show that the horizontal dose uniformity and irradiation crosstalk are improved compared to the beta source and that the reproducibility is comparable, The relationship between X-ray dose rate and tube current is highly linear for both tubes. OSL decay curves, growth curves and dose distributions from various thermally annealed quartz samples are also presented. Finally it is shown that, unlike for a beta source, the calibration factor obtained using low energy X-rays is sample dependent. (c) 2006 Elsevier B.V. All rights reserved.