Instrumental development of a quasi-relativistic ultrashort electron beam source for electron diffractions and spectroscopies
A stable femtosecond electron beam system has been configured for time-resolved pump-probe experiments. The ultrafast electron diffraction (UED) system is designed with a sub-MeV photoelectron beam source pulsed by a femtosecond UV laser and nondispersive beamline components, including a bunch compr...
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Published in | Review of scientific instruments Vol. 88; no. 10; p. 103302 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
01.10.2017
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Online Access | Get more information |
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Summary: | A stable femtosecond electron beam system has been configured for time-resolved pump-probe experiments. The ultrafast electron diffraction (UED) system is designed with a sub-MeV photoelectron beam source pulsed by a femtosecond UV laser and nondispersive beamline components, including a bunch compressor-a pulsed S-band klystron is installed and fully commissioned with 5.5 MW peak power in a 2.5 μs pulse length. A single-cell RF photo-gun is designed to produce 1.6-16 pC electron bunches in a photoemission mode with 150 fs pulse duration at 0.5-1 MeV. The measured RF system jitters are within 1% in magnitude and 0.2° in phase, which would induce 3.4 keV and 0.25 keV of ΔE, corresponding to 80 fs and 5 fs of Δt, respectively. Our particle-in-cell simulations indicate that the designed bunch compressor reduces the time-of-arrival jitter by about an order of magnitude. The transport and focusing optics of the designed beamline with the bunch compressor enables an energy spread within 10
and a bunch length (electron probe) within <500 fs. In this paper, the design analysis and instrumental test results are presented along with the development of the quasi-relativistic UED system. |
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ISSN: | 1089-7623 |
DOI: | 10.1063/1.4994571 |