The ELIMAIA–ELIMED user beamline at ELI Beamlines provides a versatile platform for acceleration, selection, and application of laser-driven ion beams. Designed to bridge laser–plasma acceleration research with multidisciplinary applications, it combines the L3 Petawatt laser with a particle beam transport, diagnostic, and dosimetry system named ELIMED. In this contribution, we present the main characteristics and capabilities of the ELIMED ion beam transport system. We also describe the initial phases of the experimental testing, highlighting key results, challenges encountered, and the solutions adopted.In particular, we report on the successful extraction of a selected ion beam with a central energy of 20 MeV with a 30% energy spread at FWHM, i.e. a spread ranging from 17 to 23 MeV, corresponding to a 7nsec bunch length at the sample location (7.5m downstream the interaction point). The achieved peak dose was of about 40mGy per laser shot which, with a 7nsec long bunch delivered to the irradiation point and successfully used for irradiation experiments of biological samples, both cells and embryos, as part of the ELI User Program. These preliminary steps were crucial for enhancing the beam diagnostics along the line, improving control over beam transport, energy selection, and final beam shaping, with the goal to offer a more reliable machine to the users from different communities.

With the growing interest in advanced radiotherapy approaches, laser-driven accelerators offer a potential alternative to conventional technologies. At ELI Beamlines, the ELIMAIA–ELIMED beamline has matured into an operational platform capable of delivering multi-shot laser-driven proton (LDP) beams for radiobiological studies. The system, powered by the L3 HAPLS 1 PW laser, currently provides protons with cut-off energies up to ~40 MeV and controlled exposures in the mGy–Gy range. Ongoing developments in stability, transport, and dosimetry continue to enhance its suitability for systematic investigations. Initial fibroblast experiments showed comparable DNA double-strand break induction between multi-shot and single-shot LDP exposures and conventionally accelerated protons. More recent campaigns target tumor cell lines grown as 3D spheroids, a physiologically more relevant model. These studies examine survival, transcriptional responses, and stress-related protein expression after LDP irradiation, supported by conventional benchmarks. Bulk RNA sequencing has been performed and is under evaluation, while protein assays—including PD-L1, HSP70, and HSP90—are underway to assess changes linked to beam’s temporal structure. Together, these activities demonstrate that ELIMAIA–ELIMED has transitioned into an actively used, user-ready platform for radiobiological research, offering unique beam characteristics and expanding experimental capabilities for ultrafast-radiobiology studies.