Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

When electrons ride a wave

08.09.2017

Physicists at HZDR discover optimum conditions for laser plasma acceleration

Conventional electron accelerators have become an indispensable tool in modern research. The extremely bright radiation generated by synchrotrons, or free electron lasers, provides us with unique insights into matter at the atomic level. But even the smallest versions of these super microscopes are the size of a soccer field.


In a so-called target chamber, the light pulse of the high-performance laser DRACO hits a gas-jet. The aim is to accelerate electrons to almost the speed of light on a distance shorter than a pencil's width.

Credit: HZDR / F. Bierstedt

Laser plasma acceleration could offer an alternative: with a much smaller footprint and much higher peak currents it could be the basis for the next generation of compact light sources. So far, the challenge with laser accelerators has been to create a reliable and stable electron beam, which is the prerequisite for possible applications. Physicists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have now developed a method to increase both beam stability and quality.

The basic principle of laser acceleration seems quite simple: A bundled, ultra-strong laser beam hits a trace of gas, which instantly creates plasma - an ionized state of matter or, in other words, a whirling mix of charged particles. The power of the light pulse pushes electrons away from their parent ions, creating a sort of bubble-like structure with a strong electric field in the plasma.

This field, which the laser pulse drags behind itself like a stern wave, traps the electrons, accelerating them to nearly the speed of light. "These speedy particles allow us to generate x-rays," Dr. Arie Irman from the HZDR Institute of Radiation Physics explains the purpose of the procedure. "For instance, when we make these electron bundles collide with another laser beam, the impact generates bright, ultra-short x-ray flashes - an immensely valuable research tool for examining extreme states of matter."

Right Time + Right Place = Perfect Acceleration

The strength of the secondary radiation greatly depends on the particles' electrical current. The current, in turn, is mostly determined by the number of electrons fed into the process. Laser-powered acceleration therefore holds great potential, because it reaches significantly higher peak currents in comparison with the conventional method. However, as physicist Jurjen Pieter Couperus points out, the so-called beam loading effect kicks in:

"These higher currents create an electric self-field strong enough to superimpose and disturb the laser-driven wave, distorting thereby the beam. The bundle is stretched out and not accelerated properly. The electrons therefore have different energies and quality levels." But in order to use them as a tool for other experiments, each beam must have the same parameters. "The electrons have to be in the right place at the right time," summarizes Couperus, who is a Ph.D. candidate in Irman's team.

Together with other colleagues at the HZDR, the two researchers were the first to demonstrate how the beam loading effect can be exploited for improved beam quality. They add a bit of nitrogen to the helium at which the laser beam is usually directed.

"We can control the number of electrons we feed into the process by changing the concentration of the nitrogen," Irman explains. "In our experiments, we found out that conditions are ideal at a charge of about 300 picocoulomb. Any deviation from it - if we add more or fewer electrons to the wave - results in a broader spread of energy, which impairs beam quality."

As the physicists' calculations have shown, experiments under ideal conditions yield peak currents of about 50 kiloamperes. "To put this in context, only about 0.6 kiloamperes flow through the standard overhead line for a German high-speed train," Jurjen Pieter Couperus explains. He is confident that they can beat their own record: "Using our findings and a laser pulse in the petawatt range, which our high-intensity laser DRACO can achieve, we should be able to generate a high-quality electron beam with peak currents of 150 kiloamperes. That would exceed modern large-scale research accelerators by about two orders of magnitude." An achievement which the researchers from Dresden believe would pave the way for the next generation of compact radiation sources.

###

Publication: J. P. Couperus, R. Pausch, A. Köhler, O. Zarini, J. M. Krämer, M. Garten, A. Huebl, R. Gebhardt, U. Helbig, S. Bock, K. Zeil, A. Debus, M. Bussmann, U. Schramm, A. Irman: Demonstration of a beam loaded nanocoulomb-class laser wakefield accelerator, in Nature Communications, 2017 (DOI: 10.1038/s41467-017-00592-7)

For more information:
Dr. Arie Irman | Jurjen Pieter Couperus
Institute of Radiation Physics at HZDR
phone: +49 351 260-3043 | 3005
email: a.irman@hzdr.de | j.couperus@hzdr.de

Media contact:
Simon Schmitt | Science Editor
phone: +49 351 260-3400 | email: s.schmitt@hzdr.de

The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) performs research in the fields of energy, health, and matter. We focus on answering the following questions:

  • How can energy and resources be utilized in an efficient, safe, and sustainable way?
  • How can malignant tumors be more precisely visualized, characterized, and more effectively treated?
  • How do matter and materials behave under the influence of strong fields and in smallest dimensions?

To help answer these research questions, HZDR operates large-scale facilities, which are also used by visiting researchers: the Ion Beam Center, the High-Magnetic Field Laboratory Dresden, and the ELBE Center for High-Power Radiation Sources. HZDR is a member of the Helmholtz Association and has five sites in Dresden, Freiberg, Grenoble, Hamburg and Leipzig with approximately 1,100 members of staff, of whom about 500 are scientists, including 150 Ph.D. candidates.

Media Contact

Simon Schmitt
s.schmitt@hzdr.de
49-351-260-3400

 @HZDR_Dresden

http://www.hzdr.de/db/Cms?pNid=

Simon Schmitt | EurekAlert!

Further reports about: Electrons HZDR Radiation acceleration laser beam nitrogen

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>