Beam instability and correction for "DRAGON-I"

"Dragon-I" is a high current pulsed electron linear induction accelerator designed and constructed in IFP/CAEP. It generates a 20 MeV, 2.5 kA, 60ns pulsed electron beam. The whole facility has three parts: injector; accelerator and beam focus system. The accelerator consists of 72 induction cells and 18 connection cells. A solenoid was installed inside each cell forming the beam transport system. During the initial beam test both high frequency and low frequency beam centroid oscillation were found. A lot of simulation and experiment investigations were done to obtain the transverse impedance of the cells and to reduce the corkscrew motion of the electron beam. Details of both the simulation and the experimental methods to control the instability are presented.