We report on electron-beam collimation using a passive plasma lens, integrated directly and conveniently into a laser wakefield-accelerator stage operating in the high-charge regime. The lens is created by the reshaping of the gas-density profile of a supersonic jet at the beam’s exit side through an obstacle mounted above the jet. It reduces the beam’s divergence by a factor of 2 to below 1 mrad (rms), while preserving the total charge of $170\mathrm{pC}$ and maintaining the energy spread. The resulting spectral-charge density, defined here as the charge per energy bandwidth and emission angle, of up to $7\mathrm{pC}$/$\mathrm{MeV}\mathrm{mrad}$ played a key role in the recent experimental demonstration of free-electron lasing. The simple and robust gas-shaping technique presented holds the potential to generate specific density profiles, which are essential for the application of adiabatic focusing or staging of accelerators.

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• Collimation
• Electron beams & optics
• High-energy-density plasmas
• Laser driven electron acceleration
• Laser-plasma interactions
• Plasma acceleration & new acceleration techniques
• Lenses
• Particle accelerators