PEPITES: AN ULTRA-THIN BEAM PROFILER WITH WIDE DYNAMIC RANGE FOR CHARGED PARTICLE BEAMS

PEPITES is an ultra-thin profiler with wide dynamics range for charged particle beams. Secondary Electron Emission (SEE) is used for its signal, which provides these assets. A first, 10 µm Water Equivalent Thickness (WET), monitor has been permanently installed at ARRONAX, Saint-Herblain, France, in May 2022. It is used in routine operations with continuous and “FLASH” beams, the latter referring to a promising radiotherapy modality based on short and intense pulses. A second profiler is developed with CNAO, Pavia, Italy, in view of being integrated in the beam control protocol for conventional patient irradiation. The monitor is foreseen 6.5 m upstream the patient, contraining its material budget to a few µm WET, to maintain the beam dispersion at a tolerable level. Researches on the FLASH modality explore irradiation durations from O(100 ms) down to O(10 fs), for a same delivered dose. The intense beams used challenge the beam instrumentation, calling for innovation in the domain. This contribution presents results on PEPITES at ARRONAX, the development for the CNAO version, and a series of measurements to assess the viability of the SEE signal for µs down to 10 fs long beams.