Computer study of the electron beam emittance in a grid-controlled gun

The triode type gun is intended for an rf accelerator with an injection energy of 50 keV. An oxide cathode of 8 mm diameter is used in the source. The cathode current is limited by the space charge and is controlled with the voltage applied to the grid electrode. The grid meshes are 0.6× 0.6 mm in size. The results of the beam self-consistent dynamics simulation are presented. The grid voltage dependence of the emittance has been studied.