Berkeley Lab

BELLA Reaches 4.2 GeV, A Record Energy for Laser-Plasma Accelerators


Nine-cm-long capillary discharge waveguide used to generate multi-GeV electron beams. Plasma plume made more prominent with HDR photography. (LBNL photo by Roy Kaltschmidt.)

BELLA has set a new energy record for these compact accelerators by reaching 4.2 giga-electron-volts.

Some resources for learning more…

  • LBNL news release
  • “Power to the Electrons,”, a Viewpoint article by Georg Korn of Europe’s Extreme Light Infrastructure project, puts the achievement in context. It appears in Physics, an American Physical Society publication that spotlights exceptional research from APS journals.
  • This article by Matteo Rini, Deputy Editor of Physics, looks at the x-ray free-electron lasers of today and tomorrow, and where laser plasma accelerators and a next generation of our facility, “k-BELLA,” might fit in.
  • The technical paper announcing this result: Leemans et al., “Multi-GeV Electron Beams from Capillary-Discharge-Guided Subpetawatt Laser Pulses in the Self-Trapping Regime,” Physical Review Letters 113, 245002 (8 December 2014).

Media Attention Accelerating: The news of this latest BELLA achievement has garnered widespread coverage, including a story provided to newspapers by the wire service UPI, and articles in trade-news and popular websites such as,,,,,, and (The picture of the accelerating channel in operation, by Roy Kaltschmidt of LBNL’s Public Affairs Creative Services Office, accompanies almost all the stories.)

BELLA Center study points to easing of laser-pulse quality requirements for pulse combining in LPAs


3D map of the longitudinal wakefield generated by the incoherent combination of 208 low-energy laser beamlets.

One attractive approach to producing powerful laser pulses, as required in laser-plasma accelerators, involves combining many lower-powered pulses. Theory-guided modeling at the BELLA Center suggests that when the destination is the plasma of an LPA, the similarity of these pulses does not need to be as rigorous as previously thought—welcome news for the cost and complexity of LPA systems.

Their work is the cover story in the May 2014 issue of the refereed journal Physics of Plasmas, and is summarized and interpreted in this news release by American Institute of Physics staff and this story by LBNL Public Affairs.

BELLA Laser achieves world record power at one pulse per second

The BELLA laser bay at a late stage of construction, "front end" in foreground.

The BELLA laser bay at a late stage of construction, “front end” in foreground.

July 20, 2012—On this night the BELLA laser system delivered a petawatt of power in a pulse just 40 femtoseconds long at a pulse rate of one hertz—one pulse every second. A petawatt is 1015 watts, a quadrillion watts, and a femtosecond is 10-15 second, a quadrillionth of a second. No other laser system has achieved this peak power at this rapid pulse rate. For further information, see the LBNL press release and this Scientific American news item.

Wim Leemans wins AAC 2012 Prize


Wim Leemans

June 14, 2012—The third Advanced Accelerator Concepts (AAC) Prize was awarded to Dr. Wim Leemans of Lawrence Berkeley National Laboratory (LBNL), head of the BELLA Center, “for outstanding contributions to the science and technology of laser-plasma accelerators.” More information can be found at the AAC 2012 website.

State-of-the-Art Beams From Table-Top Accelerators


Spectroscopy apparatus

August 2010—Laser-plasma accelerators can produce high-energy electron beams with an emittance as good as beams from state-of-the-art conventional accelerators for free electron lasers and gamma-ray sources. The emittance of LPA beams has been measured using a new technique based on single-shot x-ray spectroscopy. The research appears in Physical Review Letters: “Low-emittance electron bunches from a laser-plasma accelerator measured using single-shot x-ray spectroscopy,” by G.R. Plateau, C.G.R. Geddes, D.B. Thorn, M. Chen, C. Benedetti, E. Esarey, A. J. Gonsalves, N.H. Matlis, K. Nakamura, C. B. Schroeder, S. Shiraishi, T. Sokollik, J. van Tilborg, Cs. Toth, S. Trotsenko, T. S. Kim, M. Battaglia, Th. Stöhlker, and W.P. Leemans, August 2010. For more information, see this LBNL press release. The technical paper is available here.

BELLA Center Members Win 2010 Dawson Award

L-R: Csaba Toth, Eric Esarey, Wim Leemans, Cameron Geddes, and Carl Schroeder

L-R: Csaba Toth, Eric Esarey, Wim Leemans, Cameron Geddes, and Carl Schroeder

July 12, 2010—”For experiments and theory leading to the demonstration of high-quality electron beams from laser-plasma accelerators,” the American Physical Society’s 2010 John Dawson Award for Excellence in Plasma Physics Research has been given to (from left) Csaba Toth, Eric Esarey, Wim Leemans, Cameron Geddes, and Carl Schroeder of the BELLA Center, which Leemans heads. Simon Hooker of Oxford University collaborated in the research that inspired the award, and shares the prize. The award was presented at the APS Division of Plasma Physics meeting in Chicago, November 8-12, 2010. To learn more, see this issue of Today at Berkeley Lab.

Wim Leemans Wins 2009 E.O. Lawrence Award


Wim Leemans

December 16, 2009—Wim Leemans, head of the BELLA Center, is one of six 2009 recipients of the U.S. Department of Energy’s highest honor, the Ernest Orlando Lawrence Award, for his pioneering research with laser wakefield accelerators. For more information, see the LBNL press release.

GeV electron beams from a cm-scale accelerator

1 GeV in only 3.3 cm

1 GeV in only 3.3 cm

October 2006—BELLA Center researchers, together with colleagues from the University of Oxford, have accelerated electrons to more than 1 GeV in only 3.3 cm. This is the highest energy achieved with laser-wakefield acceleration, which harnesses the electric field of a plasma wave driven by a laser beam. Results have been published in “GeV electron beams from a cm-scale accelerator”, W. P. Leemans, B. Nagler, A. J. Gonsalves, Cs. Toth, K. Nakamura, C.G.R. Geddes, E. Esarey, C.B. Schroeder, and S.M. Hooker, Nature Physics 2 (October 2006), pp. 696-699. More information can be found in this LBNL press release. The technical paper describing the achievement is here.

High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding

High-quality 100 MeV beams

High-quality 100 MeV beams

September 2004—High-quality electron beams have been obtained by first shaping a channel through hydrogen gas with powerful, precisely timed laser pulses, then accelerating bunches of electrons through the plasma inside the channel. Because of the controlled accelerator length and the characteristics of the channel, there are several billion electrons in each bunch within a few percent of the same high energy, more than 80 MeV. Results have been published in “High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding”, C.G.R. Geddes, Cs. Toth, J. van Tilborg, E. Esarey, C. Schroeder, D. Bruhwiler, C. Nieter, J. Cary, and W.P. Leemans, Nature 431 (September 2004), pp. 538-541. For more information, see the LBNL press release. The technical journal article is here.