Theoretical and experimental estimation of the relative optically stimulated luminescence efficiency of an optical-fiber-based BaFBr:Eu detector for swift ions

The reliability of dose assessment with radiation detectors is an important feature in various fields, such as radiotherapy, radiation protection, and high-energy physics. However, many detectors irradiated by high linear energy transfer (LET) radiations exhibit decreased efficiency called the quenching effect. This quenching effect depends not only on the particle LET but also strongly on the ion species and its microscopic pattern of energy deposition. Recently, a computational method for estimating the relative efficiency of luminescence detectors has been proposed following the analysis of microdosimetric specific energy distributions simulated using the particle and heavy ion transport code system (PHITS). This study applied the model to estimate the relative optically stimulated luminescence (OSL) efficiency of BaFBr:Eu detectors. Additionally, we measured the luminescence intensity of BaFBr:Eu detectors exposed to He-4, C-12, and Ne-20 ions to verify the calculated data. The model reproduced the experimental data in the cases of adopting a microdosimetric target diameter of approximately 30-50 nm. The calculated relative efficiency exhibits ion-species dependence in addition to LET. This result shows that the microdosimetric calculation from specific energy is a successful method for accurately understanding the results of OSL measurements with BaFBr:Eu detectors irradiated by various particles.

Automated summary

The reliability of dose assessment using radiation detectors is crucial in radiotherapy, radiation protection, and high-energy physics. However, detectors exposed to high linear energy transfer (LET) radiations often exhibit a decrease in efficiency known as the quenching effect. This study proposes a computational method to estimate the relative efficiency of luminescence detectors based on analysis of specific energy distributions simulated using the particle and heavy ion transport code system (PHITS). The model was successfully applied to estimate the efficiency of BaFBr:Eu detectors and the experimental data showed good agreement with the calculations.