Performance of cesium telluride photocathodes as an electron source for the Los Alamos FEL [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1994. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 9 pages : digital, PDF file
- Additional Creators:
- Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- The Los Alamos Advanced FEL was successfully operated with a Cs₂Te photocathode driven by a frequency quadrupled Nd:YLF laser as the electron source. Lasing was achieved at 5-6 microns. Cs₂Te photocathodes with quantum efficiencies of 12-18% at 254 nm were fabricated in an ultrahigh-vacuum chamber and transferred under high vacuum to the FEL. 263 mn light from the drive laser was focused to an 8 mm spot on the center of the photocathode. The authors estimated the operational life time of Cs₂Te photocathodes to be at least 20 times that for K₂CsSb photocathodes. The measured dark current of 0.3 mA in an electric field of 22-24 MV/m is well within the acceptable level. The maximum amount of charge extracted was observed to be limited by space charge to about 3.5 nC per micropulse. The emittance of the beam was estimated by fitting the data from a quadrupole scan. The authors measured an emittance that is comparable with the emittance measured with a K₂CsSb photocathode in their system. A pulse length of 9.3 ± 2 ps for 1.3 ± 0.2 nC electron micropulses and a pulse length of 7.1 ± 0.7 ps for the laser pulses were measured with a streak camera. Therefore, the response of the Cs₂Te photocathode to the laser pulse is sufficiently fast for FEL applications.
- Published through SciTech Connect., 09/01/1994., "la-ur--94-2850", " conf-9408146--3", "DE94018302", 16. international free electron laser conference,Stanford, CA (United States),21-26 Aug 1994., and Weber, M.E.; Kong, S.H.; Kinross-Wright, J.; Sheffield, R.L.; Nuguyen, D.C.
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