Dose response linearity and practical factors influencing minimum detectable dose for various thermoluminescent detector types

Abstract

The minimum detectable dose (MDD) limit was examined in four different ways for groups of LiF:Mg,Ti thermoluminescent dosimeters, and two ways for CaF2:Dy, CaF2:Tm, CaF2:Mn, and CaSO4:Dy dosimeters. All types were irradiated and read out at dose intervals from 8.8 μGy to 6.6 mGy. Dose response linearity was never lost even for the lowest dose tested. As an ideal MDD, the signal arising from a zero applied dose readout was compared to calibration from true doses, resulting in signal corresponding to 0.04–0.1 μGy. The effects of fading and high ambient radon exposure on the MDD were examined.