First Results of PEPITES, A New Transparent Profiler Based on Secondary Electrons Emission for Charged Particle Beams

Abstract

International audienceThe PEPITES project* consists of a brand new operational prototype of an ultra-thin, radiation-resistant profiler capable of continuous operation on mid-energy (O(100 MeV)) charged particle accelerators. Secondary electron emission (SEE) is used for the signal because it only requires a small amount of material (10 nm); very linear, it also offers good dynamics. The lateral beam profile is sampled using segmented electrodes, constructed by thin film methods. Gold strips, as thin as the electrical conductivity allows (~ 50 nm), are deposited on an insulating substrate as thin as possible. While crossing the gold, the beam ejects the electrons by SEE, the current thus formed in each strip allows the sampling. SEE was characterized at ARRONAX with 68 MeV proton beams and at medical energies at CPO**. Electrodes were subjected to doses of up to 10⁹ Gy without showing significant degradation. A demonstrator with dedicated electronics (CEA) is installed at ARRONAX and will be used routinely with proton beams of 17-68 MeV for intensities of 100fA to 100nA. An overview of the design and first measurements will be presented, and system performances will be assessed