Electron cloud effects at the CERN accelerators

Electron cloud eects have been identified as one of themain performance limitations for some of the synchrotronsof the CERN accelerator complex. The tools for the simula-tion of the electron cloud build-up and its eects on beamstability have significantly evolved in recent years, leadingto a much better understanding of all machine observations.At the same time, electron cloud mitigation measures havebeen tested (e.g. surface treatments) and implemented inoperation (e.g. beam induced scrubbing). The combinationof a deeper understanding of the electron cloud and a handleon its mitigation has been the key to reach and exceed thenominal luminosity in the LHC during Run 2 as well as todefine strategies to cope with the High Luminosity (HL)operation of the LHC as from 2026.