A New Chicane Experiment In PEP-II to Test Mitigations of the Electron Cloud Effect for Linear Colliders

Conference · Thu Jul 03 00:00:00 EDT 2008

OSTI ID:934750

Pivi, M T.F.; Ng, J S.T.; Arnett, D; Cooper, F; Kharakh, D; King, F K; Kirby, R E; Kuekan, B; Lipari, J J; Munro, M; Olszewski, J; Raubenheimer, T O; Seeman, J; Smith, B; Spencer, C M; Wang, L; Wittmer, W; Celata, C M; Furman, M A

Beam instability caused by the electron cloud has been observed in positron and proton storage rings, and it is expected to be a limiting factor in the performance of future colliders [1-3]. The effect is expected to be particularly severe in magnetic field regions. To test possible mitigation methods in magnetic fields, we have installed a new 4-dipole chicane experiment in the PEP-II Low Energy Ring (LER) at SLAC with both bare and TiN-coated aluminum chambers. In particular, we have observed a large variation of the electron flux at the chamber wall as a function of the chicane dipole field. We infer this is a new high order resonance effect where the energy gained by the electrons in the positron beam depends on the phase of the electron cyclotron motion with respect to the bunch crossing, leading to a modulation of the secondary electron production. Presumably the cloud density is modulated as well and this resonance effect could be used to reduce its magnitude in future colliders. We present the experimental results obtained during January 2008 until the April final shut-down of the PEP-II machine.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 934750
• Report Number(s): SLAC-PUB-13283; TRN: US0803853
• Resource Relation: Conference: Presented at 11th European Particle Accelerator Conference (EPAC 08), Magazzini del Cotone, Genoa, Italy, 23-27 Jun 2008
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ALUMINIUM
CLOUDS
CYCLOTRONS
DIPOLES
ELECTRONS
INSTABILITY
LINEAR COLLIDERS
MAGNETIC FIELDS
MITIGATION
MODULATION
POSITRON BEAMS
POSITRONS
PROTONS
RESONANCE
STANFORD LINEAR ACCELERATOR CENTER
STORAGE RINGS
Accelerators
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HEPPH
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