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International Journal of Optics
Volume 2011, Article ID 714265, 5 pages
Research Article

Space-Charge Limitation of a Femtosecond Photoinjector

Department of Pure and Applied Physics, Faculty of Engineering Science, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan

Received 31 May 2011; Revised 23 July 2011; Accepted 2 August 2011

Academic Editor: Marco Zangrando

Copyright © 2011 Hiroko Yamamoto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Experimental investigation of a compact 40-kV diode-type photoelectric DC gun driven by 100 fs laser pulses revealed that the space-charge-limited current density could exceed 30 kA/cm2 and that the density increased linearly with the accelerating voltage. We explained these important properties by the balance between the cathode surface field and the field produced by sheet-like electron bunches near the cathode surface. Our simple physical model agreed well with the experimental results.