Simulation and modelling of diamond emitters in compact sources for high brightness beams*

Diamond emitters manufactured from the semiconductor process is a candidate as an electron beam source for advanced compact accelerators and electron microscopy. The micron-scale pyramid structure of the emitter allows enhancement of the external field leading to emission with small beam size. We investigate the dependence of field enhancement due to the shape of the emitter and the resulting emission characteristic. The beam dynamics are simulated with the LSP PIC code to characterize the beam size and divergence. To account for electron transport in the bulk material and the tunnelling through the surface, a semi-classical Monte-Carlo (MC) emission model is developed for the diamond pyramid. We apply such emission model in our simulations and compare with experiments. The presence of a nano-scale tip from its fabrication process can introduces electronic structure size quantization affecting its transport and tunnelling processes which are accounted for in our nanowire emission model.