Author: Lu, X. H.
Paper Title Page
THPC121 Design and Cold Tests of a Prototype photocathode RF Gun for Shanghai SXFEL Facility 3170
 
  • H.J. Qian, H. Chen, Y.-C. Du, W.-H. Huang, C. Li, X.H. Liu, X. H. Lu, C.-X. Tang
    TUB, Beijing, People's Republic of China
 
  A soft X-ray (~9 nm) FEL (SXFEL) facility is going to be constructed in Shanghai, China, which requires high charge (>500 pC) electron beam with low transverse emittance (<1.5 mm-mrad) at photoinjector exit. One of the keys to achieve a low emittance with high charge is high gradient on the photocathode, so an S-band photocathode RF gun modified from BNL type gun is designed, which aims running 100 MV/m peak gradient at 10 Hz. By changing the cathode seal technique, removing the insertion RF tuner, and reducing the peak surface field, RF breakdown possibility is reduced. Besides, RF pulse width is also considered to be reduced to lower the RF breakdown possibility. Since zero mode and multipole field degrades the beam emittance, they are also suppressed in the new gun design. Design details and cold testing results are presented in this paper.