Electron Cloud Effects in the CERN PS

The beam-induced electron cloud build-up is one of the major concerns for the SPS and the design of the future LHC. Recently, this effect has been observed also in the PS with the nominal LHC-type beam, consisting of a batch of 72 bunches of 1.1´1011 p/b spaced by 25 ns. The electron cloud induces baseline distortion in electrostatic pick-up signals that is observed, both in the last turns of the PS when the full bunch length is reduced to less than 4 ns, and in the transfer line between the PS and the SPS rings. Experimental observations are presented and compared to simulation results and predictions from theory. Furthermore, possible cures, such as variation of the bunch spacing, inserting gaps in the bunch train and applying weak solenoidal fields, are also discussed.