CERN LHC Project Report 188 (1998),
presented at the Sixth European Particle Accelerator Conference
(EPAC98, session MOP10C), Stockholm, 22-26 June 1998
Beam-Induced Electron Cloud in the LHC and possible Remedies
V. Baglin, O. Brüning, R. Calder,
F. Caspers, I.R. Collins, O. Gröbner, N. Hilleret,
J.-M. Laurent, M. Morvillo, M. Pivi,
and F. Ruggiero
June 1998
Abstract:
Synchrotron radiation from proton bunches in the LHC creates
photoelectrons at the beam screen wall. These photoelectrons are
accelerated towards the positively charged proton bunch and drift
across the beam pipe between successive bunches. When they hit the
opposite wall, they generate secondary electrons which can in turn be
accelerated by the next bunch if they are slow enough to survive. We
summarize the results of an intensive research program set up at CERN
and discuss recent multipacting tests as well as the importance of
several key parameters, such as photon reflectivity, photoelectron and
secondary electron yield. Then, based on analytic estimates and
simulation results, we discuss possible solutions to avoid the fast
build-up of an electron cloud with potential implications for beam
stability and heat load on the cryogenic system.
Keywords: multi-bunch-effects synchrotron-radiation cryogenics
RF-structure beam-losses
F. Ruggiero
28 June 1998