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

Abstract

Photo-transferred thermoluminescence (PTTL) is defined as the transfer of electrons from deep traps into shallow traps via optical stimulation. The importance of PTTL is that it allows for a second measurement of dose assessments for accuracy in cases such as an erroneous dose evaluation. In this study, the PTTL signal of TLD-100 was investigated in detail for a wide dose range from mGy to Gy. The investigation of PTTL signals in the order of Gy is the main innovation of this study. Based on the results of the low dose measurement (mGy), the PTTL dose-response curve has a significant sublinear characteristic in the order of mGy for the total area condition. Additionally, PTTL signals could not be distinguished from the background signal up to 5mGy. Therefore, the PTTL method can be used by taking into account the sublinear function obtained after 5mGy for the total area. On the other hand, it can be applied to TLD-100 between 0.5mGy and 50mGy using ROI. Based on the high dose measurement results (Gy), the PTTL method can be applied up to 10Gy regardless of the total area and ROI. Therefore, the dose reassessment can be performed with PTTL signal in high dose measurements (Gy) such as in the radiotherapy field. Furthermore, in future studies, heating the dosimeters during UV exposure, predose effect, or subjecting the dosimeters to fast cooling following the annealing process may provide important outputs to obtaining higher PTTL intensity, thus, it may allow measuring lower radiation doses.