Abstract
In a thermionic RF-gun, electrons emitted from its cathode are accelerated by the high gradient accelerating field in the microwave cavity. Since the effect of space-charge force has been compensated by the high electric field on cathode surface, low emittance electron beam can be obtained. On the other hand, a beam with linear energy chirped bunches can be generated by optimizing the electric field ratio between full-cell and half-cell of the RF-gun cavity. With the alpha-magnet as bunch compressor, these linear energy chirped bunches can be compressed into bunches with very short lengths. Simulation results showed that a beam with bunch lengths at around 30 micrometers can be obtained from this scheme. The RF-gun has been fabricated at National Synchrotron Radiation Research Center (NSRRC). Characterization of the cavity has been performed and measurement results are found to be in good agreement with those obtained from simulation. Electric field ratio between full-cell and half-cell has been optimized. Longitudinal electric field along the cavity axis is verified with bead-pull method. Cathode heater test, activation and testing of high power microwave system were completed for beam tests.