A NEW TECHNIQUE IN RETROSPECTIVE TL DOSIMETRY - PREDOSE EFFECT IN THE230-DEGREES-C TL GLOW PEAK OF PORCELAIN

We have observed that the 230 degrees C TL glow peak in porcelain poss esses the same pre-dose properties as the 110 degrees C TL glow peak i n quartz. The pre-dose effect is the increase in TL radiation sensitiv ity observed after irradiation and subsequent heating of quartz and th e increase is proportional to the total absorbed radiation dose prior to heating. It is a useful technique in dating and authentication of a rt objects as well as in retrospective dosimetry after radiation accid ents. The disadvantage of the 110 degrees C pre-dose peak is that it r apidly becomes non-linear and can only be used for doses less than 1 G y. Porcelain contains quartz and exhibits both the 110 degrees C TL gl ow peak and a peak at 230 degrees C. Both peaks are observed to have a pproximately the same amplitude when using narrow band blue filters. T he thermal activation properties, radiation dose response and dosimetr ic applicability of 230 degrees C pre-dose TL glow peak of porcelain w ere investigated, and we found that it has the same TL properties as t he 110 degrees C peak but has advantages for dose evaluation due to it s longer half-life and linearity up to a dose of 3 Gy. (C) 1997 Elsevi er Science Ltd. All rights reserved.