Experimental Investigations on the High-Intensity Effects Near the Half-Integer Resonance in the PSB

Abstract

Space charge effects are the main limitation for the brightness performance of the Proton Synchrotron Booster (PSB) at CERN. Following the upgrades of the LHC Injectors Upgrade (LIU) project, the PSB delivered unprecedented brightness even exceeding the projected target parameters. A possibility for further increasing the brightness is to operate above the half-integer resonance 2Q_{y}=9 in order to avoid emittance blow-up from resonances at Q_{x,y}=4 due to the strong space charge detuning. The half-integer resonance can be compensated to a great extent using the available quadrupole correctors in the PSB, and also deliberately excited in a controlled way. The control of the half-integer resonance and the flexibility of the PSB to create a variety of different beam and machine conditions allowed the experimental characterization of space charge effects near this resonance. This contribution reports the experimental observations of the particle trapping during the dynamic crossing of the half-integer, as well as systematic studies of the beam degradation from space charge induced resonance crossing