In situ high resolution real-time quantum efficiency imaging for photocathodes
Abstract
Aspects of the preparation process and performance degradation are two major problems of photocathodes. The lack of a means for dynamic quantum efficiency measurements results in the inability to observe the inhomogeneity of the cathode surface by fine structural analysis and in real time.Here we present a simple and scalable technique for in situ real-time quantum efficiency diagnosis. An incoherent light source provides uniform illumination on the cathode surface, and solenoid magnets are used as lens for focusing and imaging the emitted electron beam on a downstream scintillator screen, which converts the quantum efficiency information into fluorescence intensity distribution. The microscopic discontinuity and the dynamic changes of the quantum efficiency of a gallium arsenide photocathode are observed at a resolution of a few microns. An unexpected uneven decrease of the quantum efficiency is also recorded. The work demonstrates a new observation method for photoemission materials research.
Cite
@article{arxiv.1710.08148,
title = {In situ high resolution real-time quantum efficiency imaging for photocathodes},
author = {Dai Wu and Dexin Xiao and Jianxin Wang and Qing Pan and Xing Luo and Kui Zhou and Chenglong Lao and Xiangkun Li and Sifen Lin and Peng Li and Hao Zhang and Longgang Yan and Hanbin Wang and Xingfan Yang and Ming Li Chuanxiang Tang and Dan Wang and Qilong Wang and Zhiyang Qi and Jian Zhang},
journal= {arXiv preprint arXiv:1710.08148},
year = {2017}
}
Comments
6 pages, 5 figures