Fig. 4: Acceleration of high-quality electron beams with density transition injection.
From: Controlled acceleration of GeV electron beams in an all-optical plasma waveguide
a Schematic view of the gas target. b Density profile obtained from a fluid simulation for our experimental parameters and measured density profile in the shock region (inset). c Ten angularly resolved electron spectra sorted by charge (charge in the peak for d2N/dEdθ > 0.1(d2N/dEdθ)max). d Two examples of angularly-integrated spectra corresponding to spectra marked by blue and green lines in (c). The black segment indicates the uncertainty on the energy due to fluctuations of beam pointing
