Effects of annealing and radiation exposures on LiF (TDL 100) phosphors

Abstract

This paper presents the results of an investigation on the characteristics of LiF (TLD - 100). Two sets of LiF badges, the first consisting of 10 pairs of badges and the second consisting of 6 pairs were examined. The badges were pre-annealed and exposed to x ray source. The pattern of the curves obtained from the first set which was annealed with an external oven for one hour at 300C shows an appreciable response, while the second set annealed for 1 minute shows no significant response; suggesting that annealing sensitized the response of the phosphor. It was found that proper annealing at higher temperatures for longer length of time appears to improve the sensitivity of the phosphor, thus, enhancing its usefulness for radiation dosimetry. In addition, we observed that saturation sets in at higher dose. Saturation was found to set in at 4 units of exposure corresponding to 13.87mSv in the first set, while in the second set, it occurred at 5 units of exposure corresponding to 14.86mSv. The range of the dose for which LiF could be effectively used before saturation sets in lies between 13.87mSv and 14.86mSv.

Keywords: Annealing, radiation exposure, LiF (TLD-100) thermoluminescence

Nigerian Journal of Physics Vol. 18 (2) 2006: pp. 211-218