• J.P. Dai, M. Hou, G. Pei, J.R. Zhang
  IHEP Beijing, Beijing
• Q. Gu, M.H. Zhao, S.P. Zhong
  SINAP, Shanghai

Transverse RF deflectors are widely used for the measurements of ultra-short bunch length and other slice parameters. This paper presents the development of an S-band LOLA-type RF deflector and the bunch length measurement of the electron beam produced by the photocathode RF gun of Shanghai DUV-FEL facility. The deflector’s VSWR is 1.06, the whole attenuation 0.5dB, and the bandwidth 4.77MHz for VSWR less than 1.1. With laser pulse width of 8.5ps, beam energy of 4.2 MeV, bunch charge of 0.64 nC, the bunch lengths for different RF input power into the deflector were measured, and the averaged rms bunch length of 5.25 ps was obtained.