Description
Laser-driven ion beams represent a promising tool for biomedical applications, provided that robust and traceable dosimetric protocols are established to accurately characterize beam parameters under ultra-high-dose-rate conditions. In this contribution, we report on the first dosimetric commissioning of the ELIMAIA–ELIMED beamline at ELI Beamlines (Czech Republic), performed using laseraccelerated proton beams with energies of ∼24 MeV and doses up to ∼12 mGy per shot, with ∼4 ns bunch duration, corresponding to an instantaneous dose rate up to ∼3x10^6 Gy/s.
Protons were generated and accelerated by the L3-HAPLS PW-class laser system interacting with thin solid targets and subsequently transported through the ELIMED beam transport and energyselection system to the in air irradiation point. The beam was characterized in terms of energy spectrum, fluence, lateral uniformity, and absorbed dose to water. A comprehensive dosimetric setup was deployed along the beamline, including an Integrating Current Transformer (ICT), a Secondary Electron Monitor (SEM), a Dual-Gap Ionization Chamber (DGIC), and a Faraday Cup (FC) acting as the absolute dose reference.
An energy of 23.4 ± 0.9 MeV was selected and independently verified through radiochromic film measurements and depth–dose reconstruction. Lateral dose distributions exhibited millimetre-scale uniform fields with sharp penumbrae, suitable for controlled radiobiological irradiations. The online detectors were cross-calibrated against the FC, allowing the determination of their sensitivities, linearity ranges, and operational limits under realistic laser-driven beam conditions. In particular, the DGIC demonstrated a stable and linear response after recombination correction, enabling reliable shot-by-shot dose monitoring.
The results validate the performance of the ELIMED dosimetric system and establish a traceable framework for absolute and relative dosimetry at the irradiation point. This commissioning represents a key step toward the routine use of ELIMAIA–ELIMED for radiobiology and ultra-high-dose rate studies with laser-driven proton beams.
