Plasma-density-gradient injection of low absolute-momentum-spread electron bunches.
Plasma density gradients in a gas jet were used to control the wake phase velocity and trapping threshold in a laser wakefield accelerator, producing stable electron bunches with longitudinal and transverse momentum spreads more than 10 times lower than in previous experiments (0.17 and 0.02 MeV/c FWHM, respectively) and with central momenta of 0.76+/-0.02 MeV/c. Transition radiation measurements combined with simulations indicated that the bunches can be used as a wakefield accelerator injector to produce stable beams with 0.2 MeV/c-class momentum spread at high energies.
Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. cgrgeddes@lbl.gov
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Geddes
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Nakamura
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Plateau
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Toth
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Cormier-Michel
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Esarey
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Schroeder
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Cary
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Leemans