High-Current Effects in The PEP-II Storage Rings
High beam currents in PEP-II have been a challenge for vacuum system and ring components. For the {approx} 1 cm long bunches peak currents exceed 100 A and modest impedance can give rise to voltage spikes and discharges. During the last two runs, difficulties arose from rf seals at the 'flex flanges' in the HER. High temperatures were seen and the seals turned out to be severely damaged by discharges. In the LER, the horizontal stripline kickers of the bunch-by-bunch feedback system experiences breakdown at high bunch current-Macor pins installed for mechanical stability turned out to be a weak spot causing discharges. Finally, in the HER an experiment to shorten the ion-clearing gap in the beam revealed signs of ion-induced instability indicating that the HER has been operating quite close to the stability limit. The effects shown here are relevant to future high-intensity electron and positron rings like SuperB and PEP-X.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 957417
- Report Number(s):
- SLAC-PUB-13677; TRN: US1000575
- Journal Information:
- Conf.Proc.C0806233:WEPP041,2008, Conference: EPAC'08, 11th European Particle Accelerator Conference, 23-27 June 2008, Genoa, Italy
- Country of Publication:
- United States
- Language:
- English
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