Electron-cloud effects are generally recognized as important, but incompletely understood, dynamical phenomena that can severely limit the performance of high-intensity proton and positron storage rings. Past and present examples of accelerators where these effects have been important include the SPS, PSR, RHIC, PEP-II, KEKB and several others. Significant effects are also expected in future machines such as the LHC, its injectors, and the damping rings for linear colliders. Deleterious effects include single- and multi-bunch instabilities, emittance growth, sudden increase in vacuum pressure, excessive heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation from present experience to significantly higher intensities is uncertain given the present level of understanding of the electron-cloud dynamics.
Contact: Miguel Furman
A comprehensive R&D program including theory, simulations, measurements, diagnostics, and feedback systems is needed to better understand the phenomena, pin down essential parameters and develop remedies. Here at the Center for Beam Physics at LBNL we are approaching all aspects of the problem.