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Title: How surface roughness and work-function patchiness raise intrinsic emittance
Plain: Real cathode surfaces are bumpy and patchy at the nanometer scale, which deflects electrons as they leave. The size of this effect for real materials is not well quantified.
Precise: For a photocathode with measured topography (rms height, correlation length) and work-function variation in an extraction field $E \sim 0.1 \text{ to } 1\,\mathrm{MV}/\mathrm{cm}$, compute the contribution of slope and local transverse fields to MTE, and determine the surface quality needed for MTE below $5\,\mathrm{meV}$.
Settled by: Calculated MTE from measured surface maps compared with MTE measured on the same cathodes at several extraction fields.
Kind: well-posed
Answer type: value
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)