High Energy High Intensity Hadron Beams EXPERIMENTS ON LHC LONG-RANGE BEAM-BEAM COMPENSATION IN THE CERN SPS

Long-range beam-beam collisions may limit the dynamic aperture and the beam lifetime in colliders. Their effect can be compensated by a current-carrying wire mounted parallel to the beam. A compensation scheme based on this principle has been proposed for the Large Hadron Collider (LHC). To demonstrate its viability, a prototype wire was installed at the CERN SPS in 2002. First successful machine experiments explored the dependence of beam loss, beam size, and beam lifetime on the beam-wire distance and on the wire excitation. They appear to confirm the predicted effect of the long-range collisions on the beam dynamics. In 2004, two further wires will become available, by which we can explicitly demonstrate the compensation, study pertinent tolerances, and also compare the respective merits of different beam-beam crossing schemes for several interaction points. Contribution to the conference EPAC 04, Lucerne, Switzerland Work supported by the European Community-Research Infrastructure Activity under the FP6 “Structuring the European Research Area” programme (CARE, contract number RII3-CT2003-506395). EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH European Laboratory for Particle Physics EXPERIMENTS ON LHC LONG-RANGE BEAM-BEAM COMPENSATION IN THE CERN SPS Long-range beam-beam collisions may limit the dynamic aperture and the beam lifetime in colliders. Their effect can be compensated by a current-carrying wire mounted parallel to the beam. A compensation scheme based on this principle has been proposed for the Large Hadron Collider (LHC). To demonstrate its viability, a prototype wire was installed at the CERN SPS in 2002. First successful machine experiments explored the dependence of beam loss, beam size, and beam lifetime on the beam-wire distance and on the wire excitation. They appear to confirm the predicted effect of the long-range collisions on the beam dynamics. In 2004, two further wires will become available, by which we can explicitly demonstrate the compensation, study pertinent tolerances, and also compare the respective merits of different beam-beam crossing schemes for several interaction points. Large Hadron Collider Project Abstract J.P. Koutchouk, J. Wenninger, F. Zimmermann CERN, Geneva, SwitzerlandJ.P. Koutchouk, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland Presented at EPAC 2004, Lucerne, Switzerland, 5 to 9 July 2004 LHC Project Report 777 CERN, CH-1211 Geneva 23, Switzerland