Author: Ji, D.
Paper Title Page
TUPPP034 BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS 1686
  • C.-X. Wang, G. Decker, H. Shang, C. Yao
    ANL, Argonne, USA
  • D. Ji
    IHEP, Beijing, People's Republic of China
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.
WEPPR058 The Vertical Impedance Distribution Measurement Using Response Matrix Method at BEPCII BPR 3057
  • Y. Wei, D. Ji
    IHEP, Beijing, People's Republic of China
  Funding: Work supported by the Chinese National Foundation of Natural Sciences, contract 111100512108.
In the last run of BEPCII, the single bunch current is limited to about 8mA by the beam-beam effect. To obtain the design luminosity, larger number of bunches are necessary. But higher total current may be limited by the collective effects. A good understanding of the transverse impedance distribution around the BEPCII storage ring is required. Response matrix method has been applied successfully in BEPCII to fit the quadrupole errors and restore the optics. We can also calculate the variation of betatron phase advance around the ring with different single bunch current using the response matrix method and the transverse impedance distribution is thus deduced. In this paper, the first measurement of transverse impedance in BEPCII is presented.