Speaker
Description
The brief experience with 25 ns beam in the LHC at the end of Run 1 suggested that the electron cloud effects were set to pose important challenges to the machine operation during Run 2. In spite of four weeks of dedicated scrubbing run, the 2015 proton run of the LHC fully confirmed this expectation, with the electron cloud severely degrading the beam quality at the beginning of the scrubbing run and then limiting the number of bunches at 6.5 TeV, due to strong heat load in the cold regions. This contribution will first describe the main e-cloud observations and limitations encountered during the 2015 run. The dedicated scrubbing periods at 450 GeV, the intensity ramp up with 25 ns beams at 6.5 TeV and tests with special beam variants (doublets, 8b+4e) will be covered. Finally, based on the acquired experience and the lesson learnt in 2015, a proposal for the scrubbing strategy and 25 ns intensity ramp up in 2016 will be presented.
