Application of TL-OSL from surface soil to retrospective dosimetry

Abstract

Abstract Radiation-induced luminescence dosimetry was developed using combined thermoluminescence (TL) and optically stimulated luminescence (OSL) measurements from natural quartz in Japanese soil. TL emissions from the quartz grains were observed at ∼350–450 nm (ultraviolet–violet TL; UVTL) and 630 nm (red TL; RTL) using a TL spectrometer system. The UVTL glowcurve was measured for an irradiated sample, which exhibited five peaks: at 80, 110, 130, 200 and 270 °C. On the other hand, the UVTL glowcurve was also measured for an as-received sample, which showed no peaks in any range of heating temperature. In the irradiated UVTL glowcurves, the integrated UVTL intensity at each peak temperature was proportional to the irradiation dose except for the 80 °C peak. The TL-OSL protocol was used in a recovery test for determining the irradiation dose of a sample using thermal treatment for TL measurement instead of preheat treatment before OSL measurement. In the test, the doses measured by the UVTL peak at 200 °C agreed well with the given dose and the doses measured by OSL were 80% of the given dose at an interval of 120 h between dose delivery and dose measurement. From these results, we concluded that TL-OSL dosimetry is suitable for accident evaluation although further research is required to improve the protocol.