REQUIREMENTS AND IMPROVING METHODS OF ELECTRON BEAM QUALITY FOR FEL

The requirements of emittance,energy spread, and stability of electron beam forFEL research are presented in this paper.The use of harmonically resonant cavity can effectivelyreduce the energy spread and emittance growth. On the basis of analysing the photocathode RFgun and super-conduction technology are used to improve the quality of electron beam. These effec-tive methods are also presented.