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Proceedings Paper

On-line measurement system of GaAs photocathodes and its applications
Author(s): Jijun Zou; Lin Feng; Gangyong Lin; Yuntao Rao; Zhi Yang; Yunsheng Qian; Benkang Chang
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Paper Abstract

The preparation process of GaAs photocathodes is very complicated, in order to prepare the high performance cathodes, it is crucial to obtain information enough to evaluate the preparation process in real time. Based on a particular transfer light setup and a flexible communication network, we develop an on-line measurement system for GaAs cathode preparation, which is used to measure the pressure of activation chamber, sample temperature, photocurrent, spectral response curves, and currents heating Cs and oxygen dispensers during the heat-cleaning or activation processes of cathodes. According to these signals, we present some simple and real-time evaluation techniques for cathode preparation. Several peaks of pressure are observed in the pressure variations measured during heat cleaning. These peaks corresponding to the desorption of AsO, As2O3, Ga2O and Ga2O3 from the sample surface at different temperatures, respectively, are used to evaluate the effect of heat cleaning very well, while the signals measured during activation can be used to analyze and optimize the activation technique. Based on a revised quantum efficiency equation, many performance parameters of cathodes are obtained from the fitting of spectral response curves. According to these parameters, the performance of cathode material and the effect of activation can be evaluated.

Paper Details

Date Published: 12 December 2007
PDF: 8 pages
Proc. SPIE 6782, Optoelectronic Materials and Devices II, 67823D (12 December 2007); doi: 10.1117/12.745945
Show Author Affiliations
Jijun Zou, Nanjing Univ. of Science and Technology (China)
East China Institute of Technology (China)
Lin Feng, East China Institute of Technology (China)
Gangyong Lin, East China Institute of Technology (China)
Yuntao Rao, East China Institute of Technology (China)
Zhi Yang, Nanjing Univ. of Science and Technology (China)
Yunsheng Qian, Nanjing Univ. of Science and Technology (China)
Benkang Chang, Nanjing Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 6782:
Optoelectronic Materials and Devices II
Yoshiaki Nakano, Editor(s)

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