Advanced metal alloy systems for massive high-current photocathodes

The physical principles of precise alloying are formulated with the aim of increasing the low quantum efficiency (QE) of suitable simple metals (Mg, Al, Cu) as well as of decreasing their electron work function ( e φ ) in the UV spectral range. The new approach provides valuable information for elucidating the origin of photoemission enhancement in bulk metal-based alloy systems. Bulk in-situ nanoclustering promises to be the most effective way of producing a much higher QE and a lower e φ in simple metals. In this article we show that the quantum efficiency of the metal-based alloys Mg–Ba, Al–Li, and Cu–BaO is considerably higher than the simple metals Mg, Al, and Cu, respectively. The spectral characteristics of the Mg–Ba, Al–Li and Cu–BaO systems obey the well-known Fowler square law for a near-free-electron model. The advanced metal alloys systems are promising photocathode materials usable for generation of high brightness electron beams.