On the reassessment of doses in TL-dosimetry by measuring the residual dose

Abstract

Second readouts and the photo-transferred thermoluminscence (PTTL) method are sometimes used to reassess high doses. When using the common LiF:Mg,Ti, if the second readout is performed by a regular readout cycle of 13.3 s, its efficiency is low and the estimations cannot be obtained with acceptable accuracy for low doses in the 10-100 mSv range. By applying the PTTL method, the efficiency is much higher, but a high background is also present, deteriorating the quality of the reassessment. A simple and efficient method was studied, which consists of expanding the heating time to 30 s. Although the efficiency relative to a standard readout is improved by only a factor of 3, the low background enables to obtain results with the same uncertainty as the more complicated PTTL method. By applying region of integration discrimination, the errors can be further diminished.

The photo-transferred thermoluminescence phenomenon in case of emergency dose assessment

“…TL thermoluminescence (color figure online) 6 Relationship between the number of counts obtained from the glow curves after the second readout in the dose range from 100 to 1000 mGy, for an UV exposure of 2 h, 3 h and 4 h at 70 °C. Measurement uncertainties-standard error of the mean (SEM) Abraham et al in 2007 and other authors observed a high TL background signal after UV exposure (Abraham et al 2007(Abraham et al , 2008Budzanowski et al 2013;Bhasin et al 1987). They also emphasized that it is necessary to subtract the high background before re-evaluating the dose.…”

A Photo-transfer Thermoluminescence (PTTL) Study of TLD-100 over a Wide Dose Range

“…The PTTL behavior of TLD-100 has been investigated by various researchers for a long time [5,8,9,[11][12][13][14][15][16][17][18][19][20]. Initial studies performed with TLD-100 have shown that dose reassessment with PTTL is possible for doses higher than 10mGy [11].…”