HIGH BRIGHTNESS ELEC TRON BEAMS FROM A MULTI- FILAMENTARY NIOBIUM-TIN PHOTOCATHODE

High-brightness electron sources are of fundamental interest for particle accelerators and modern free electron lasers. Inspired by the micro-structure of field emitter arrays [1,2] we report on a new type of metallic photo-cathode consisting of thousands of Nb3Sn micro-columns. With this metallic photocathode we could demonstrate quantum efficiencies up to 0.5% under stable operation [3,4 ]. Preliminary emittance measurements on a 50 keV table-top electron gun are presented.