Plasma-wakefield accelerator simultaneously boosts electron beam energy and brightness
- Chaojie Zhang
- Douglas Storey
- Alexander Knetsch
- Brendan D. O’Shea
- Robert Ariniello
- Gevy J. Cao
- Sébastien Corde
- Thamine N. Dalichaouch
- Claudio Emma
- Ole G. Finnerud
- Spencer Gessner
- Claire Hansel
- Elias Hansen
- Valentina Lee
- Carl A. Lindstrøm
- Michael Litos
- Nathan Majernik
- Kenneth A. Marsh
- Warren B. Mori
- Ivan Rajkovic
- Mark J. Hogan
- Chan Joshi
2025-11-28
High-energy particle colliders and X-ray free-electron lasers demand electron beams with qualities currently achieved only in kilometer-scale radio-frequency accelerators. Plasma accelerators promise a compact alternative but have faced challenges in delivering the needed beam quality at relevant energies. Here, we demonstrate that a plasma-wakefield accelerator operating in the nonlinear regime acts as a transformer to simultaneously boost the energy and brightness of an electron bunch injected from the plasma. Using a 10-GeV drive bunch and a three-stage meter-scale plasma source, we generated electron bunches exceeding 20 GeV with sub-percent energy spread, 2 mm·mrad normalized emittance, and multi-kA peak current. A significant number of drive-bunch electrons lost over 90% of their energy, a prerequisite for high energy-conversion efficiency. This demonstration of an energy transformer ratio exceeding two and a brightness enhancement over an order of magnitude opens a path towards cost-effective accelerators for future colliders and light sources.