Characterization of all-metallic field emitter arrays in combined diode-RF cavity electron gun

Recently, nanosecond electrical switching and high-acceleration-field compatibility of single-gate all-metallic field-emitter arrays (FEAs) fabricated by molding and a self-aligned gate process were reported along with the emittance measurement. Here we present further optimization of the FEA driver and successful reduction of emission current pulse below ~0.5 ns, up to 5 MeV acceleration of field emission beams by post-acceleration of 200 keV pulses using a 1.5 GHz RF cavity of the combined diode-RF cavity electron gun of the SwissFEL gun test facility. In addition, evolution of field emission distribution by in-situ Ar gas conditioning process was studied.