Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Miniature X-ray source using wiggling electrons

29.09.2009
A team at the Laboratory for Attosecond Physics of Ludwig Maximilian's University of Munich and Max Planck Institute of Quantum Optics in Garching has succeeded in reducing X-ray sources of typically several kilometres in size to the dimensions of a dining table. This involved a new method using a combination of laser light and hydrogen plasma.

The potential of laser technology seems inexhaustible. Fresh proof has now been presented by an international team at Munich's Cluster of Excellence "Munich Centre for Advanced Photonics" (MAP), in the Laboratory for Attosecond Physics (LAP) of Ludwig Maximilian's University of Munich and Max Planck Institute of Quantum Optics (MPQ) in Garching.

Also involved were Dresden-Rossendorf Research Centre and Oxford University's Clarendon Laboratory (UK). The physicists are the first to succeed on the laboratory scale in producing soft X-ray radiation by means of laser light.

This is done by first generating pulses of electrons with intense laser flashes. The laser beam accelerates the electron pulses to approximately the speed of light within a distance a thousand times shorter than that required by conventional techniques. These are then focused into a short undulator with alternating magnetic fields inside it, which forces the electrons to oscillate and thus causes them to emit X-ray radiation.

The experiment shows that it is possible to produce so-called brilliant X-ray radiation by means of light. A brilliant light source contains a very large number of photons of the same wavelength that are bunched in to a beam. Such radiation affords many more applications than ordinary X-ray radiation. Up until now, however, it could only be produced with the help of kilometre-long accelerators. MAP's scientists have now opened the way to produce brilliant X-ray radiation in much more compact device. This is reported in the online edition of Nature Physics (DOI: 10.1038/NPHYS1404, 27. September 2009).

Since its discovery at the end of the 19th century, X-ray radiation has provided insights into worlds invisible to the naked eye. It is difficult to imagine today's medicine, physics, materials science and chemistry without it. Meanwhile, it is possible to image structures that are no bigger than atoms, but this calls for brilliant x-ray radiation. Currently, such radiation is produced by the use of expensive accelerators that are kilometres long, thus making it not generally accessible. There are just a few facilities in the world that are capable of producing highly brilliant X-ray radiation. Brilliant radiation contains a very large number of photons (light particles) that also move in phase.

A team around Prof. Florian Grüner and Prof. Stefan Karsch at the Laboratory for Attosecond Physics now aims to provide brilliant X-ray radiation inexpensively in a compact device.

The physicists have now reached an important milestone. By means of intense laser light and a plasma of ionized hydrogen atoms, they have for the first time succeeded at a laboratory of LMU and MPQ in producing soft X-ray radiation with a wavelength of about 18 nanometres. For this purpose the physicists used laser pulses lasting just a few femtoseconds, a femtosecond being a millionth of a billionth of a second.

On this ultrashort time scales, the light pulses reach powers of about 40 terawatts; for comparison, an atomic power plant generates powers of about 1000 megawatts, which is 40,000 times less.

The enormous powers of the pulses are only made possible by their extreme shortness. The strong electric and magnetic fields of the light pulses separate electrons from hydrogen atoms and thus produce a plasma. These electrons are accelerated with the same laser pulse to almost the speed of light within a distance of only 15 mm, which is more than a thousand times shorter than that needed by conventional technologies used to date.

The electrons then enter an undulator, a device 30 centimetres long and 5 centimetres wide. It produces magnetic fields that force the electrons to take an undulating sinusoidal path, which transversely accelerates the electrons, causing them to emit photons in the soft X-ray range. So far, only light in the visible to infrared ranges, i.e. with much longer wavelengths than that of X-radiation has been shown with similar methods. The reason underlying the desire to gain access to the shortest possible light wavelengths is to be sought in the laws of optics. They state that with light one can only image structures equivalent in size to its wavelength. That is to say, if an object is investigated with X-ray light with a wavelength of 18 nanometres, it has to be at least as big in order to be resolvable. Atoms and numerous molecules, however, are much smaller.

Reducing the wavelength of laser-produced X-ray radiation is the next objective of MAP's scientists. "In principle, our experiment has demonstrated that it is possible to produce X-ray radiation in a university laboratory by means of ultrashort light pulses", states Matthias Fuchs, one of the LAP's scientists. But the potential of undulator technology is much greater. "Our experiment paves the way to an inexpensive source of laser-driven X-ray radiation", remarks group leader Florian Grüner.

The physicists' next step is to further increase the energy of the electrons propagating through the undulator. For this purpose the scientists will increase the energy of the light pulses producing the electrons. The prime objective of Prof. Florian Grüner's group is to realise a laser-driven free-electron laser whose light is about a million times more brilliant than the undulator radiation now measured. The radiation should then have wavelength of just a few nanometres. It could afford completely new, detailed insights into the microcosm of nature. The radiation can likewise be applied in, for example, medicine to detect minute tumours before they can spread. This would greatly enhance the chances of curing cancer patients.

Text: Thorsten Naeser

Original publication:

Matthias Fuchs, Raphael Weingartner, Antonia Popp, Zsuzsanna Major, Stefan Becker, Jens Osterhoff, Isabella Cortrie, Benno Zeitler, Rainer Hörlein, George D. Tsakiris, Ulrich Schramm, Tom P. Rowlands-Rees, Simon M. Hooker, Dietrich Habs, Ferenc Krausz, Stefan Karsch and Florian Grüner.
Laser-driven soft-X-ray undulator source
Nature Physics, DOI: 10.1038/NPHYS1404
Further information available from:
Prof. Florian Grüner
Ludwig-Maximilians-Universität München
Department für Physik der LMU München
Am Coulombwall 1
D-85748 Garching, Deutschland/Germany
Phone: (+ 49 89) 2891 - 4111
Fax: (+ 49 89) 2891 - 4072
E-mail: florian.gruener@physik.uni-muenchen.de
Prof. Stefan Karsch
Ludwig-Maximilians-Universität, München
Max-Planck-Institut für Quantenoptik, Garching
Hans-Kopfermann-Str. 1
D-85748 Garching
Phone: (+ 49 89) 32905 - 322
Fax: (+ 49 89) 32905 - 649
Email: stefan.karsch@mpq.mpg.de

Christine Kortenbruck | idw
Further information:
http://www.munich-photonics.de
http://www.fel.physik.uni-muenchen.de/personen/index.html
http://www.attoworld.de/people/Karsch/SKarsch.html

More articles from Physics and Astronomy:

nachricht Two dimensional circuit with magnetic quasi-particles
22.01.2018 | Technische Universität Kaiserslautern

nachricht Meteoritic stardust unlocks timing of supernova dust formation
19.01.2018 | Carnegie Institution for Science

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>