World record: Plasma accelerator operates right around the clock
Milestone towards first practical applications of this innovative
accelerator technology

Date:
August 19, 2020
Source:
Deutsches Elektronen-Synchrotron DESY
Summary:
Researchers have reached an important milestone on the road to the
particle accelerator of the future. For the first time, a laser
plasma accelerator has run for more than a day while continuously
producing electron beams. The LUX beamline achieved a run time of
30 hours.



FULL STORY ==========================================================================
A team of researchers at DESY has reached an important milestone on
the road to the particle accelerator of the future. For the first time,
a so-called laser plasma accelerator has run for more than a day while continuously producing electron beams. The LUX beamline, jointly developed
and operated by DESY and the University of Hamburg, achieved a run time
of 30 hours. "This brings us a big step closer to the steady operation
of this innovative particle accelerator technology," says DESY's Andreas
R. Maier, the leader of the group. The scientists are reporting on their
record in the journal Physical Review X. "The time is ripe to move laser
plasma acceleration from the laboratory to practical applications,"
adds the director of DESY's Accelerator Division, Wim Leemans.


========================================================================== Physicists hope that the technique of laser plasma acceleration will
lead to a new generation of powerful and compact particle accelerators
offering unique properties for a wide range of applications. In this
technique, a laser or energetic particle beam creates a plasma wave
inside a fine capillary. A plasma is a gas in which the gas molecules
have been stripped of their electrons. LUX uses hydrogen as the gas.

"The laser pulses plough their way through the gas in the form of narrow
discs, stripping the electrons from the hydrogen molecules and sweeping
them aside like a snow plough," explains Maier, who works at the Centre
for Free-Electron Laser Science (CFEL), a joint enterprise between DESY,
the University of Hamburg and the Max Planck Society. "Electrons in the
wake of the pulse are accelerated by the positively charged plasma wave
in front of them -- much like a wakeboarder rides the wave behind the
stern of a boat." This phenomenon allows laser plasma accelerators to
achieve acceleration strengths that are up to a thousand times greater
than what could be provided by today's most powerful machines. Plasma accelerators will enable more compact and powerful systems for a wide
range of applications, from fundamental research to medicine. A number of technical challenges still need to be overcome before these devices can
be put to practical use. "Now that we are able to operate our beamline
for extended periods of time, we will be in a better position to tackle
these challenges," explains Maier.

During the record-breaking nonstop operation, the physicists accelerated
more than 100,000 electron bunches, one every second. Thanks to this
large dataset, the properties of the accelerator, the laser and the
bunches can be correlated and analysed much more precisely. "Unwanted variations in the electron beam can be traced back to specific points
in the laser, for example, so that we now know exactly where we need to
start in order to produce an even better particle beam," says Maier. "This approach lays the foundations for an active stabilisation of the beams,
such as is deployed on every high performance accelerator in the world," explains Leemans.

According to Maier, the key to success was combining expertise from two different fields: plasma acceleration and know-how in stable accelerator operation." Both are available at DESY, which is unparalleled in the
world in this respect," Maier emphasises. According to him, numerous
factors contributed to the accelerator's stable long-term operation, from vacuum technology and laser expertise to a comprehensive and sophisticated control system. "In principle, the system could have kept running for even longer, but we stopped it after 30 hours," reports Maier. "Since then, we
have repeated such runs three more times." "This work demonstrates that
laser plasma accelerators can generate a reproducible and controllable
output. This provides a concrete basis for developing this technology
further, in order to build future accelerator-based light sources at
DESY and elsewhere," Leemans summarises.


========================================================================== Story Source: Materials provided by
Deutsches_Elektronen-Synchrotron_DESY. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Andreas R. Maier, Niels M. Delbos, Timo Eichner, Lars Hu"bner,
So"ren
Jalas, Laurids Jeppe, Spencer W. Jolly, Manuel Kirchen, Vincent
Leroux, Philipp Messner, Matthias Schnepp, Maximilian Trunk,
Paul A. Walker, Christian Werle, Paul Winkler. Decoding Sources of
Energy Variability in a Laser-Plasma Accelerator. Physical Review X,
2020; 10 (3) DOI: 10.1103/ PhysRevX.10.031039 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200819102820.htm

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