Investigation of Thermal Quenching Effect for Lithium Fluoride (LiF) Type Dosimeters

Abstract

Thermal quenching is described as a decrease in luminescence efficiency with increasing measurement temperature. Luminescence intensity decreases with increasing heating rates in the presence of thermal quenching. In such a case, the heating rate to be used in the measurements becomes important. Lithium fluoride (LiF) type dosimeters have been widely used in radiation dosimetry for many years. In this study, thermal quenching effect was investigated for LiF:Mg,Ti (TLD-100) and LiF:Mg,Cu,P (TLD-100H), 6LiF:Mg,Ti(TLD-600) and 7LiF:Mg,Ti (TLD-700) at two different doses (10, 1000mGy) using 90Sr/90Y beta source. TLD-100, TLD-600 and TLD-700 showed different thermal quenching behaviors according to dose values, while TLD-100H had the same characteristics at both doses. On the other hand, other dosimeters showed thermal quenching based on the total area at 10mGy, while they did not show thermal quenching when ROI was used. Again, thermal quenching was not observed at 1000mGy for all dosimeters. In conclusion, it is recommended to use ROI or low heating rate during measurements at a low dose (in the order of mGy) for TLD-100, TLD-600 and TLD-700, while desired heating rate can be used at a high dose (Gy) for all dosimeters.