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This study presents the dosimetric commissioning of a laser-driven proton beamline at ELI Beamlines, establishing methods to accurately measure radiation dose delivery using 23.4 MeV protons. The researchers cross-calibrated multiple detection systems, including radiochromic films, Faraday Cup, and ionization chambers, finding approximately 7% agreement between independent dose measurements after applying Monte Carlo-derived correction factors. The beam produced a 5.5 mm field size with an energy spread of 2.6 MeV, suitable for initial radiobiological applications.
Why it matters
This work establishes the foundation for using laser-driven proton beams in medical and biological research, potentially enabling more compact and cost-effective particle therapy systems compared to conventional accelerators. The validated dosimetry chain is essential for ensuring safe and reproducible radiation doses in future preclinical studies.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: The development of laser-driven proton beamlines for biomedical and radiobiological applications requires traceable dosimetry and reliable online monitoring at the irradiation point. In this work, we report the relative and absolute dosimetric commissioning of the ELIMAIA–ELIMED laser-driven proton beamline at ELI Beamlines using an energy-selected proton beam with an average energy of about 24~MeV. Radiochromic-film measurements were used to characterize the transverse dose distribution, the depth–dose profile, and the proton energy spectrum at the irradiation point. The reconstructed spectrum was centred at $23.45~mathrm{MeV}$ with a FWHM of $2.60~mathrm{MeV}$, while the transverse dose distribution showed an approximately $5.5~mathrm{mm}$ field size with a millimetre-scale homogeneous region. The Faraday Cup was used as the absolute reference detector for dose to water determination and for cross-calibrating the Dual-Gap Ionization Chamber, which was operated as the primary online dose monitor. The Integrating Current Transformer and Secondary Electron Monitor were evaluated as upstream relative beam monitors. An independent RCF–FC dose comparison performed over fifty consecutive shots yielded $30.45 pm 3.5~mathrm{cGy}$ from the FC and $36.46 pm 1.8~mathrm{cGy}$ from the EBT3 film. Dedicated G4ELIMED Monte Carlo simulations showed that the RCF positioned upstream of the FC perturbs the FC measurement through proton losses outside the FC acceptance and through an increase in the effective beam area at the FC entrance. Applying the resulting correction factor, $C_{mathrm{MC}}=1.109$, reduced the residual difference between the FC- and RCF-derived doses to about $7%$. These results establish the dosimetric chain of the ELIMAIA–ELIMED beamline under the present low-fluence commissioning conditions and identify the operational limits of the online monitoring system.