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Abstract
| Summary The aim of AWAKE Run 2 is to demonstrate the possibility of scaling the experiment for high energy physics, i.e. reaching higher energies while controlling the emittance growth of the accelerated electron beam [1]. AWAKE Run 2 comprises four phases [2]. Run 2a, completed in 2022, demonstrated that the 18 MeV electron beam can be used to seed the proton bunch self-modulation with reproducible phase [3]. Run 2b, started in 2023, foresees the replacement of the plasma source, introducing a plasma density step to improve the efficiency of the acceleration process. Run 2c will see the installation of a second plasma source and a new 150 MeV electron line to separate the self-modulation and the acceleration stages for improved emittance preservation. A key parameter to match the experimental requirements for Run2c is the relative alignment between the proton driver bunch and the electron witness bunch, which must be kept to a minimum at the entrance of the second plasma source to guarantee emittance preservation of the accelerated bunch. The dominant source of relative misalignment lies in the shot-to-shot proton beam trajectory jitter, induced by the noise (ripple) in the power converters current powering the magnetic elements of the proton beam transfer line. This document describes the procedure used to infer the ripple in the main powering circuits and the resulting simulated beam trajectory jitter expected at the entrance of the second plasma source in Run2c configuration. |