2011•Unpublished venueRequires access
EXPERIMENTAL INVESTIGATION OF PHOTOCATHODE THERMAL EMITTANCE COMPONENTS WITH A COPPER CATHODE
Houjun Qian, Yinghua Du, Lu Yan, Jianfei Hua, Huang Wei, Chuanxiang Tang
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Abstract
With progress of photocathode RF gun technology, thermal emittance has become one of the primary limitations of electron beam brightness [1]. Extensive efforts have been devoted to study thermal emittance, but experiment results diverge between research groups and few can be well interpreted [2]. In this paper, we report an experiment of characterizing online photocathode work function, field enhancement factor and surface roughness effect by measuring electric field dependence of photoemission quantum efficiency (QE) and thermal emittance in a Cu-cathode RF gun. Preliminary experiment results reveal huge thermal emittance contributed by surface roughness for the first time, and are in reasonable consistency with theoretical model prediction [3].