Improving LER Coupling and PEP-II Luminosity with Model-Independent Analysis
The PEP-II storage ring at SLAC houses electrons (in the High-Energy Ring, or HER) and positrons (in the Low-Energy Ring, or LER) for collision. The goal of this project was to improve the linear optics of the LER in order to decrease coupling, thereby decreasing emittance and increasing luminosity. To do this, we first took turn by turn BPM (Beam Position Monitor) data of a single positron bunch at two betatron resonance excitations, extracted orbits from this data using Model-Independent Analysis, and from these orbits formed a virtual model of the accelerator. We then took this virtual model and found an accelerator configuration which we predicted would, by creating vertical symmetric sextupole bumps and adjusting the strengths of several key quadrupole magnets, improve the coupling and decrease the emittance in the LER. We dialed this configuration into the LER and observed the coupling, emittance, and luminosity. Coupling immediately improved, as predicted, and the y emittance dropped by a dramatic 40%. After the HER was adjusted to match the LER at the Interaction Point (IP), we saw a 10% increase in luminosity, from 10.2 x 10{sup 33}cm{sup -2}sec{sup -1} to 11.2 x 10{sup 33}cm{sup -2}sec{sup -1}, and achieved a record peak specific luminosity.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 918943
- Report Number(s):
- SLAC-TN-07-020; TRN: US0806257
- Journal Information:
- Submitted to Journal of Undergraduate Studies, Journal Name: Submitted to Journal of Undergraduate Studies
- Country of Publication:
- United States
- Language:
- English
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