Dosimetry from OSL and Residual TL with TLD 400

The aim of this work is to propose a new methodological approach, using TLD400, to perform point dosimetry in medical physics applications. It investigates the possibility of using simultaneously the luminescence signals by optical stimulation with blue diode (OSL) and residual signals by thermal stimulation (ReTL), from TLD400, CaF2:Mn, for dosimetric purposes. Artificial irradiation was performed with 90Sr-90Y, calibrated beta sources delivering 6 Gy/min and integrated in the TL-DA-15 automated RisØ readers equipped with EMI 9235QA photomultipliers. In particular, for OSL measurements, to check the correct experimental conditions, the effect of the stimulation temperature during optical stimulation and the effect of the optical stimulation time were studied. For calibration curves from OSL and ReTL signals, a double Single Aliquot Regeneration (SAR) procedure was used, in which the "sensitivity-corrected" natural stimulated luminescence signal is compared with equivalent sensitivity-corrected signals regenerated by laboratory irradiation of the same aliquot. The double OSL and ReTL combined measurements allow to have a good accuracy coverage (2%) in the whole dose range between 0 and 10 Gy.