|THPMF080||Physical and Chemical Roughness of Alkali-Animonide Cathodes||4259|
Over the last decade, alkali-antimonides have been investigated as high QE cathodes in green light and more recently as ultra-low intrinsic emittance cathodes in near-threshold red wavelengths at cryogenic temperatures*. Nano-meter scale surface non-uniformities (physical roughness and chemical roughness or work function variations) are thought to limit the smallest possible emittance from these materials at the photoemission threshold under cryogenic conditions**. Despite this, the surfaces of alkali-antimonides have not been well characterized in terms of the surface non-uniformities. Here, we present measurements of both the physical and chemical roughness of alkali-antimonide surfaces using several surface characterization techniques like atomic force microscopy, kelvin probe force microscopy, low energy electron microscopy and near-threshold photoemission electron microscopy and show how such non-uniformities limit the intrinsic emittance.
*L. Cultrera et al Phys. Rev. ST Accel. Beams 18, 113401 (2015)
**J. Feng et al, J. of Appl. Phys. 121, 044904 (2017)
|DOI •||reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF080|
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