SUMMARYWe study the electron emission and propagation in ultrasharp tips field‐emission experiments. The intensity‐voltage characteristics as well as the angular spreading of the electron beam is analysed. We show that non‐coherent emission cannot explain the very narrow experimental electron beams. The properties of coherent electron sources and the beam spatial coherence width are discussed. The quantum mechanical current distribution of field‐emitted electrons from tubes seems to explain the experimental beam widths.
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