Beam-Based Alignment And Beta Function Measurements in PEP-II
Careful optics studies and stringent lattice control have been identified as two key components to increasing PEP-II luminosity. An accurate, trusted BPM system is required for both of these strategies. To validate the existing BPM system and to better understand some optical anomalies in the PEP-II rings, an aggressive program of beam-based alignment (BBA) has been initiated. Using a quad-shunt BBA procedure in which a quadrupole's field strength is varied over a range of beam positions, relative offsets are determined by the BPM readings at which quadrupole field changes no longer induce a closed orbit shift. This procedure was verified in the HER and is well underway in the LER IR. We have found several surprisingly large BPM offsets, one over one centimeter, as well as a number of locations where the current nominal orbit is several millimeters from the design. Tune versus quadrupole field data were taken during the BBA process in the LER IR, and the non-linear response in each case is compared to simulation to infer local beta functions.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 890848
- Report Number(s):
- SLAC-PUB-11160; TRN: US0604843
- Resource Relation:
- Conference: Presented at the 9th European Particle Accelerator Conference (EPAC 2004), Lucerne, Switzerland, 5-9 Jul 2004
- Country of Publication:
- United States
- Language:
- English
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