The emittance evolution of 3 MV injector

Summary form only given, as follows. A new linear induction electron accelerator called DRAGON-I is now being studied and designed at CAEP. The high performance required for the accelerator is tightly connected to the high performance of injector A 3.2 MV/spl sim/3.5 MV injector, extracting at 90 nanosecond (60 ns flat), 2.5 kA/spl sim/3.5 kA electron beams has been studied and the parameters indicating the beam quality have been or are being measured. Among the parameters, the emittance is regarded as most important one. This paper relates the electron beam emittance evolution by PIC code. The relationships between emittance and velvet recess, emittance and beam current, emittance and external magnetic field, emittance and transport distance, etc., are discussed by simulation using PIC method. We wish to draw a conclusion form the emittance evolution and minimize the emittance of injector.