Updated design of the DC-SC photo-injector at Peking University

Based on the results of the DC-SC photocathode injector experiments at Peking University, an improved design of the injector is proposed. The new injector can provide both high average power electron beams with bunch charge of 100 pC, repetition rate of 81.25 MHz, transversal emittance lower than 2 mm·mrad, bunch length of 4 ps, and high peak current electron beams with bunch charge of 300 pC, transversal emittance lower than 3 mm·mrad and bunch length of about 9 ps. The detailed design of the injector, influence of bunch shape to the beam emittance and analysis of solenoid compensation technology are presented in this paper.