Characterization of 2D Al2O3:C,Mg radiophotoluminescence films in charged particle beams

Marijke De Saint-Hubert, Fabio Castellano, Paul Leblans, Paul Sterckx, Satoshi Kodaira, Jan Swakoń, Luana de Freitas Nascimento

Research outputpeer-review


In particle-therapy, 2D dosimetry systems require high spatial resolution and linear dose response as the patient treatment show steep gradients of dose in depth. In this work we report on the characterization of the radiophotoluminescence (RPL) response from Al2O3:C,Mg films exposed to proton (61.3 MeV, 91.5 MeV, 155.5 MeV and 230 MeV) and carbon clinical beams (110 MeV/u). The film response is evaluated in terms of properties particularly important for relative dose measurements, as dose response, film uniformity and minimum detectable dose. The films, based on coatings with average grain sizes of ˜7 µm, demonstrate a better response than those used in our previous studies, with grain sizes of ˜47 µm. Moreover, the Linear Energy Transfer (LET) changes when penetrating through material and it is known that solid-state detectors change luminescence efficiency .HT,. as a function of LET. Therefore, we performed a detailed characterization of our new film to evaluate its response as function of dose and LET. The .HT,. curve, as a function of particle LET, obtained from discrete dose points (slabs) .HT,. is compared with the .HT,. curves from Al2O3:C (OSL) and Al2O3:C,Mg (RPL) films from our previous study. The .HT,. curves are consistent with Birks’ law, where we observe expected quenching for increasing LET. Additionally, we present 2D RPL images, using a wedge phantom, from Al2O3:C,Mg films irradiated with proton and carbon beams, which resulted in a 2D depth dose distribution of the Bragg curve and a comparable LET dependence with the data obtained with the slabs. The results confirm that the images obtained can be advantageously applied to obtain dose distribution in proton and carbon therapy without many corrections.
Original languageEnglish
Article number106518
Pages (from-to)1-10
Number of pages10
JournalRadiation Measurements
StatePublished - 21 Jan 2021

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