Excitation of Intra-bunch Vertical Motion in the SPS - Implications for Feedback Control of Ecloud and TMCI Instabilities

Conference · Fri Jun 01 04:00:00 EDT 2012 · Conf.Proc.C1205201:112-114,2012

OSTI ID:1042689

Cesaratto, J. M.; Fox, J. D.; Pivi, M. T.; Rivetta, C. H.; Turgut, O.; Uemura, S.; Hofle, W.; Wehrle, U.

Electron cloud (ecloud) and transverse mode coupled-bunch instabilities (TMCI) limit the bunch intensity in the CERN SPS. This paper presents experimental measurements in the SPS of single-bunch motion driven by a GHz bandwidth vertical excitation system. The final goal is to quantify the change in internal bunch dynamics as instability thresholds are approached, and quantify the frequencies of internal modes as ecloud effects become significant. Initially, we have been able to drive the beam and view its motion. We show the excitation of barycentric, head-tail and higher vertical modes at different bunch intensities. The beam motion is analyzed in the time domain, via animated presentations of the sampled vertical signals, and in the frequency domain, via spectrograms showing the modal frequencies vs. time. The demonstration of the excitation of selected internal modes is a significant step in the development of the feedback control techniques.

• Research Organization: SLAC National Accelerator Laboratory (SLAC)
• Sponsoring Organization: US DOE Office of Science (DOE SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 1042689
• Report Number(s): SLAC-PUB-15046
• Conference Information: Journal Name: Conf.Proc.C1205201:112-114,2012
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
Accelerators
ACCPHY
ACCSYS
CERN
CLOUDS
ELECTRONS
EXCITATION
EXCITATION SYSTEMS
FEEDBACK
INSTABILITY