TL/OSL emission spectrometry of alumina substrates of electronic components in mobile phones: potential of the red TL emission for retrospective dosimetry

Emergency dosimetry using mobile phone components has become an increasingly interesting field for post-accident dose assessment. This study investigates the TL and OSL emission properties of alumina substrates from resistors and inductors found in mobile phone circuit boards, with a focus on the dosimetric potential of the red Cr 3+ -related TL emission. Spectral measurements reveal three primary emission bands around 330 nm and 410 nm, attributable to F + and F centers respectively, and a dominant emission at 695 nm, characteristic of Cr 3+ . In TL, the Cr 3+ emission clearly dominates, particularly in resistors, with intensity exceeding that of the blue/UV emissions by up to two orders of magnitude. The red TL signal exhibits a linear dose response over a wide range (from mGy to >10 Gy), low intrinsic background, and fading characteristics consistent with anomalous fading (∼20.7 %/decade). Dose recovery experiments immediately after irradiation confirm accuracy within 7 %, a minor dose overestimation caused by minor desensitization. The red TL signal is optically bleachable, similar to its blue/UV counterpart. Irradiation trials with intact smartphones demonstrated that the red TL method delivers dose estimates within 25 % of the reference dose, comparable to established methods using display glass or OSL on resistors. Importantly, dose estimation using only a single resistor achieved similar sensitivity to protocols requiring ten components in the blue/UV range. These results highlight the potential of red TL for accurate, sensitive, and minimally invasive retrospective dosimetry. The method offers distinct advantages in scenarios where only few components are available and enables the prospect of non-destructive measurements.