First measurement of neutrons at the ELIMAIA-ELIMED laser-driven ion beamline

Laser-induced ion accelerators generate broadband energy spectra of charged particles, enabling a wide range of applications in nuclear and particle physics, material science, and nuclear medicine. These ion beams are extremely intense and short in duration, making the characterization of both the primary beam and the resulting secondary radiation highly challenging. Stray radiation—particularly photons and neutrons—must be carefully monitored and minimized, as it can negatively impact experimental environments by activating surrounding materials, increasing background noise in detectors, or, in the case of radiotherapy, delivering unwanted doses to patients. Neutrons are of particular concern due to their high penetration capability and difficulty in shielding, as well as their significant contribution to unintended dose delivery. Their neutral charge and the presence of strong accompanying photon backgrounds make them especially difficult to detect. Furthermore, the exceptionally high neutron fluence rates in laser-driven beamlines limit viable detection methods. This paper presents simulations of secondary radiation produced during laser-induced ion acceleration, alongside the first measurements of neutron background at the ELIMAIA-ELIMED beamline at the ELI Beamlines Facility.