Commissioning the New LLRF System of the CERN PS Booster

The PS Booster (PSB) is the first synchrotron in the injection chain for protons. The beams produced for the LHC and various fixed target experiments cover a very large parameter space. Over the Long Shutdown 2 (LS2), the PSB was heavily upgraded as part of the LHC Injectors Upgrade (LIU) project. The low-level RF systems now drive the new Finemet-loaded cavities, control RF synchronisation for the new injection mechanism, and cope with the increased injection and extraction energies. The Finemet cavities provide exceptional flexibility, allowing an arbitrary distribution of voltage at different revolution frequency harmonics, but at the cost of significant broadband impedance. The new injection mechanism allows bunch-to-bucket multi-turn injection, which significantly reduces the amount of beam loss at the start of the cycle. The longitudinal beam production schema for each beam-type was developed based on simulations during LS2, and then adapted during the setting-up phase to suit the final operational configuration. This paper discusses the commissioning of the new LLRF, and the consequences of the LIU upgrades on the production of various beams.