Performance analysis of upgrading optical klystron for FEL

The parameters of an upgraded optical klystron (OK) were given by 3-dimensional finite element electromagnetic computation for free electron laser (FEL) research in Hefei electron storage ring. The Hefei Light Source (HLS) is routinely operated at 800 MeV by ramping up the injected 200 MeV electron beam. In order to match the routine operated energy of HLS and get more FEL photos, the symmetry OK is being upgraded to asymmetry structure for harmonic generation (HG) FEL experiments. Several HG FEL experimental groups of matched parameters of the upgraded OK were listed at the HLS injected energy as well as the maximum experimental energy. Primary computation shows that the energy spread of HLS in FEL experiments is below 2.05×10-4, the correction factor due to it for FEL radiation is over