ESTRO 2024 - Abstract Book

S3180

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Fig. 1: Proton-dose deposition along the beam axis measured in a water phantom with Ce-, Gd- et N- doped silica fiber. The fiber curves are normalized to the diode ratio. The background has been subtracted.

Fig. 2: Radioluminescence intensity for Ce-and Gd-doped probes of 220µm in function of the proton flux for three energies.

When comparing depth dose distributions obtained with the different fibers and with the diode, Figure 1 shows that fiber-based detectors exhibit increasing quenching with increasing LET. Due to the experimental set-up, measure at z = 0 mm is not available, hence normalization was done at 1 cm depth. The diode and MC simulation of the depth dose distribution have a peak/plateau ratio of 4.5. The Ce and Gd-doped fibers have a ratio of 3.1 and the N-doped fiber single-mode has a ratio of 1.7. Both fibers show noise background around 30%, due to residual light and particle interaction in the electronical system, which were subtracted. This difference of peak/plateau ratio seems to indicate an energy dependence of the radioluminescence effect at higher LET. Figure 2 represents the Gd- and Ce- response as a function of the dose rate for different energies. For each energy, the radioluminescence intensity is linear with