Development and simulation of a gridded thermionic cathode electron gun for a high-energy photon source

A gridded thermionic cathode electron gun was developed for the linear accelerator of the High Energy Photon Source (HEPS). An electron gun should provide a large maximum bunch charge with a wide adjustable range. To satisfy these requirements, the shape of the electrode was optimized using a multi-objective genetic algorithm. A large bunch charge with an adjustable range was achieved using the grid-limited gun, the flow of which was analyzed using 3-D simulations. The electron gun has been manufactured and tested, and the measured data of the grid-limited current and simulation results are compared and discussed in this study.