Beam Loading in a Proton Driven Plasma Wakefield Accelerator

The Advanced Wakefield Experiment (AWAKE) at CERN is the first plasma wakefield experiment to exploit the self-modulation instability in a long proton bunch in order to accelerate electrons to high energies. The first run saw electrons accelerated from 19 MeV to 2 GeV in just 10 metres of ionised Rubidium vapour, achieving a gradient of nearly 200 MV/m. A challenge facing such accelerator designs is the final quality of the accelerated bunch. Retaining a low spread in energy and emittance, while achieving a high accelerating gradient, are goals that to an extent are in conflict. This thesis shows, using computer simulations, that it is possible to accelerate 30–70 pC of electrons up to 1.8–2 GeV in a 4 metre plasma stage, with an energy spread of less than 2 percent, and with no significant emittance growth. Low energy spread is achieved by finely tuning the witness bunch size and density to fit the plasma parameters as well as the wakefields generated by the drive bunch. Low emittance growth is achieved by exploiting the wake generated by the head of the witness bunch to create a stable condition for its tail. This provides a potential experiment setup for the next stage of AWAKE

SixTrack Version 5: Status and New Developments

SixTrack Version 5 is a major SixTrack release that introduces new features, with improved integration of the existing ones, and extensive code restructuring. New features include dynamic-memory management, scattering-routine integration, a new initial-condition module, and reviewed post-processing methods. Existing features like on-line aperture checking and Fluka-coupling are now enabled by default. Extensive performance regression tests have been developed and deployed as part of the new-release generation. The new features of the tracking environment developed for the massive numerical simulations will be discussed as well