Thermoluminescence of electronic components from mobile phones for determination of accident doses

摘要

The dosimetric properties of resistor substrates extracted from the circuit board of mobile phones were studied in detail using Thermoluminescence for the purpose of dose reconstruction following a radiological accident or attack. Many studies have shown the usefulness of this material using Optically Stimulated Luminescence but TL studies are scarce. The typical glow curve of a set of irradiated resistors has a peak at about 170 degrees C. Unexposed resistors showed a strong zero dose signal in the higher temperature region, peaking between 300 and 350 degrees C, which also led to a minor zero dose being detected in the chosen integration window of 100-200 degrees C. Exposure to white light can significantly increase the zero dose, presumably due to phototransfer of charge carriers from deep traps into the dosimetric trap. The dose response of the TL signal was linear up to several Gy but an irreversible sensitivity, change was observed in the first thermal readout. A correction factor was therefore deduced from a number of dose recovery tests. Similar to the OSL signal, the TL signal is not stable but fades with time since irradiation. Overall, a slightly smaller fading rate up to 60 days was observed for the TL signal, as compared to the OSL signal. A protocol is proposed for TL based on the measured properties and validated in irradiation trials. (C) 2017 Elsevier Ltd. All rights reserved.