The PADME-X17 experiment is searching for a light dark matter candidate. The experiment would greatly benefit from the availability of a dedicated beam with long pulse duration and minimal instantaneous current. In this contribution, a third-order resonant slow-extraction scheme is considered, starting from the present lattice of the DAFNE damping ring. This solution, already integrated with the DAFNE complex, could provide the necessary positron-beam improvements within the existing facility. This study, currently aimed at improving the sensitivity of fixed-target experiments with positrons, could open new possibilities for beamlines based on the beam extracted from the damping ring.

FLASH radiotherapy is emerging as a transformative modality in cancer treatment, capable of achieving tumor control while significantly reducing normal-tissue toxicity, thereby improving the overall therapeutic index. To fully exploit this effect—particularly for deep-seated tumors—Very High-Energy Electrons (VHEE) in the 50–150 MeV range are required. Within this framework, and as part of the SAFEST project (aiming for a 100 MeV machine), Sapienza University of Rome in collaboration with INFN is developing a compact C-band linear accelerator prototype. The system is designed to deliver 24 MeV (loaded) electron beams capable of providing doses of 2 Gy per pulse over a 10 × 10 cm² field at a repetition rate of 100 Hz. The optimization of the accelerator has required detailed electromagnetic, vacuum and beam-dynamics studies to ensure beam parameters suitable for FLASH dose delivery. The final technical design report of the LINAC has been completed, and installation is currently underway at Sapienza University. Two irradiation configurations—pencil beam and wide-beam irradiation—are planned for the first in vivo and in vitro studies scheduled for 2026. In addition, the use of a tantalum converter to generate gamma rays is being considered to expand the irradiation machine’s capabilities and enable comparisons between gamma-ray and electron effects. This compact electron source for FLASH therapy represents a key milestone for the SAFEST project.