Electron Cloud Clearing - Electron Cloud Effects and Technological Consequences

This report contains the Proceedings of the joint CARE-HHH-APD, CARE ELAN, and EUROTEV-WP3 Mini-Workshop on ‘Electron Cloud Clearing Electron Cloud and Technological Consequences’, “ECL2”, held at CERN in Geneva, Switzerland, 1-2 March 2007). The ECL2 workshop explored novel technological remedies against electron-cloud formation in an accelerator beam pipe. A primary motivation for the workshop was the expected harmful electron-cloud effects in the upgraded LHC injectors and in future linear colliders, as well as recent beam observations in operating facilities like ANKA, CESR, KEKB, RHIC, and SPS. The solutions discussed at ECL2 included enamel-based clearing electrodes, slotted vacuum chambers, NEG coating, and grooves. Several of the proposed cures were assessed in terms of their clearing efficiency and the associated beam impedance. The workshop also reviewed new simulation tools like the 3D electron-ion build-up code ‘Faktor2’, modelling assumptions, analytical calculations, beam experiments, and laboratory measurements. Several open questions could be identified. The workshop reinforced interlaboratory collaboration on electron-cloud suppression, and it concluded with a discussion of the next steps to be taken. CERN-AB-2007-064-ABP CARE-Conf-07-007-HHH CARE/ELAN document-2007-004 EUROTEV-Report-2007-060