A thermally assisted optically stimulated luminescence protocol for the use of display glass samples from mobile phones as a fortuitous dosimeter was developed. Glass samples from 16 different mobile phones from the Samsung Galaxy series were used. The protocol consists of a prebleach with LEDs of 470 nm for 500 s and an OSL reading for 500 s at an elevated temperature. The decay curves were measured at different temperatures from 100 to 400 °C in an interval of 50 °C. A significant baseline increase in the decay curves was observed above 350 °C. For the TA-OSL below 300 °C, the dose response from 10 mGy to 10 Gy was linear and the signals were reproducible within 5% for six repeated readings. Compared with the residual thermoluminescence after an isothermal reading, the TA-OSL protocol showed lower zero doses at the given temperature. By increasing the temperature of the TA-OSL protocol from 100 to 300 °C, the minimum detectable dose increased from 17 to 70 mGy, but the fading rate reduced from 64% to 36% after 41 days from irradiation. In the optical stability test, strong reductions in TA-OSL signals were observed after exposures up to 1000 s with several light sources, and it was found that violet LEDs are more effective than blue LEDs for bleaching. As a result, the TA-OSL protocols investigated showed some improvements in terms of the lower minimum detectable doses and reduced fading rates compared with the prebleached thermoluminescence protocol.
FörderungenEURADOS young scientist grant (2019) Ministry of Science and ICT, Republic of Korea Korea Foundation of Nuclear Safety (KoFONs) Federal Ministry of Education, Science and Research (BMBWF), Austria