ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
This work reports on the experimental results of a Nb photocathode stimulated by two different lasers, of wavelengths 308 and 222 nm. A fast current detector, Rogowski coil, recorded the high output currents, while the beam angular distributions were measured by an array of small Faraday cups placed along the propagation axis of the beam. With p-polarized light, we found quantum efficiencies (QEs) of 1.6×10−5 and 1.0×10−6 for λ=222 nm and λ=308 nm, respectively. The efficiency of the photocathode was measured to be higher for s-polarized laser beams than for the p-polarized ones. They resulted in QEs of 5.3×10−5 and 2.1×10−6 for λ=222 nm and λ=308 nm, respectively. From the electron-beam angular divergence values, we determined the upper limit emittance. The lowest upper limit normalized emittance value found was 7 (π mm mrad), achieved by the s-polarized radiation of 308 nm. In both cases the s-polarized light generated electron beams of lower emittance. © 2001 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1391441
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