Proton Electron Accelerator at CERN

AWAKE is a proton driven plasma-wakefield acceleration at CERN*, that uses long proton bunches ~ 400 ps from the SPS. In a dense plasma, a long proton bunch is subject toμbunching at plasma period due to the self-modulation instability, SMI**. The self-modulated proton bunch generates large amplitude charge separation through resonant wakefield excitation. Numerical simulations show that when seeded the SMI can grow and saturate over ~4 m in a plasma with density in the (1-10) *10¹⁴/cc range. Seeding also allows for deterministic injection of witness bunches in the focusing and accelerating phase of the wakefields. The SPS proton bunch carrying kJ of energy is a unique driver for generation of ~ GeV/m wakefields through 10’s of meters of plasma. The side-injected electrons ~15 MeV can reach GeV energies. The AWAKE experimental layout, the physics of self-modulation, simulation results, plasma source under study, diagnostics plan for bunch modulation measurement using transverse coherent transition radiation***, and phasing of the witness bunch respect to the wave and synchronisation with diagnostics will be presented.****