Author: Luo, Q.
Paper Title Page
TUPC111 Design of Cavity Beam Monitor at HLS 1278
 
  • Q. Luo, Q.K. Jia, B.G. Sun, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
 
  Funding: Work supported by the Natural Science Foundation of China, National “985 Project”, China Postdoctoral Science Foundation and “the Fundamental Research Funds for the Central Universities”
X-FEL requires precious control of beam position and transverse emittance. Non-destructive on-line beam diagnostic methods are required. During the upgrading of HLS a high brightness injector based on photocathode RF electron gun, which can also be used to study FEL, is installed. The cavity beam monitor system designed for the HLS photocathode RF electron gun consists of a cavity beam position monitor and a beam quadrupole moment monitor system. The cavity beam position monitor uses a re-entrant position cavity tuned to TM110 mode as position cavity and cut-through waveguides to suppress the monopole signal. Cold test results showed that position resolution of prototype BPM is better than 3 μm. Beam quadrupole moment monitor system consists of a square pill-box quadrupole moment cavity, a cylindrical pill-box reference cavity, a waveguide coupling network and a superheterodyne receiver used as front-end signal processing system. The whole system works at 5.712 GHz. Strength of quadrupole magnets is adjust to construct a matrix which can be used to work out beam parameters.