Measurements, Analysis, and Simulation of Microwave Instability in the Low Energy Ring of KEKB
Using a streak camera, we measured the longitudinal profiles of a positron bunch in the Low Energy Ring (LER) of KEKB at various currents. The measured charge densities were used to construct a simple Q=1 broadband impedance model. The model, with three parameters, not only gave an excellent description of longitudinal dynamics for positive momentum compaction factor but also for the negative ones, including bunch shortening below a threshold and bursting modes above the threshold. Furthermore, our study indicated that the threshold of microwave instability was about 0.5 mA in bunch current in the LER. At the nominal operating current 1.0 mA, there was a 20% increase of the energy spread. The results of measurement, analysis, and simulations will be presented in this paper.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 953000
- Report Number(s):
- SLAC-PUB-13587; TRN: US0902647
- Resource Relation:
- Conference: Presented at Particle Accelerator Conference (PAC 09), Vancouver, BC, Canada, 4-8 May 2009
- Country of Publication:
- United States
- Language:
- English
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