Nanotechnology Now

Our NanoNews Digest Sponsors







Heifer International

Wikipedia Affiliate Button


Home > Press > Steps towards filming atoms dancing

An electromagnetic field accelerates photoelectrons emitted from neon atoms irradiated by an X-ray free-electron laser

Jörg Harms/MPSD at CFEL
An electromagnetic field accelerates photoelectrons emitted from neon atoms irradiated by an X-ray free-electron laser

Jörg Harms/MPSD at CFEL

Abstract:
With their ultra short X-ray flashes, free-electron lasers offer the opportunity to film atoms in motion in complicated molecules and in the course of chemical reactions. However, for monitoring this motion, the arrival time and the temporal profile of the pulses which periodically illuminate the system, must be precisely known. An international team of scientists has now developed a measurement technique that provides complete temporal characterization of individual FEL (free-electron laser) pulses at DESY's soft-X-ray free-electron laser, named FLASH. The team, led by Adrian Cavalieri from the Center for Free-Electron Laser Science (CFEL) in Hamburg, was able to measure the temporal profile of each X-ray pulse with femtosecond precision (a femtosecond is a quadrillionth of a second). The Ikerbasque Research Professor Andrey Kazansky from Donostia International Physics Center (DIPC) and the University of the Basque Country (UPV/EHU), as well as Nikolay Kabachnik from the Lomonosov State University in Moscow who is a regular visiting fellow at DIPC, were members of the team. The technique developed in this investigation can be implemented at any of the world´s X-ray free-electron lasers, ultimately allowing for most effective utilization of these sources. The results are published in the current issue of the scientific journal Nature Photonics.

Steps towards filming atoms dancing

Usurbil, Spain | Posted on December 4th, 2012

X-ray pulses delivered by free-electron lasers provide unique research opportunities, because the pulses are ultra-intense and ultra-short. At FELs trillions of X-ray photons are packed within a single burst - or pulse - which lasts for only several tens of femtoseconds, or even less. However, the precise arrival time and even the temporal profile of the FEL pulse can change dramatically from one pulse to the next. Therefore, to use the FEL to "film" ultrafast dynamical processes, the arrival time of each pulse must be measured to reorder the individual frames or snapshots captured with each individual FEL pulse.

Provided with accurate timing information, femtosecond FEL X-ray pulses are short enough to study atoms in motion, chemical reactions, and phase transitions in materials with time resolution on the femtosecond scale.

With simultaneous measurement of the FEL X-ray pulse profile, it will be possible to go even further, to explore processes that evolve within the X-ray exposure. On these timescales the motion of electrons and electronic state dynamics become significant. Electronic dynamics drive damage processes in biomolecules, which may destroy them before they can be recorded in a crystal clear image.

For their measurements, the team adapted a technique used in attosecond science called "photoelectron streaking" (an attosecond is a thousandth of a femtosecond). Andrey Kazansky, Ikerbasque research Professor at DIPC and UPV/EHU, explains that "the streaking technique permits recording temporal profiles of varying light signals by creating photoelectron bursts and measuring the energy distribution of these electrons". A photoelectron is the electron emitted from matter (gas, solid, liquids) as a consequence of the absorption of a high energy photon. In other words, is the electron that has been kicked out by a photon.

By taking advantage of the ultra-high intensities available at FELs the researchers were able to perform the streaking measurement on a single-shot basis at FLASH. For this, the X-ray flashes were shot through neon gas on their way to their target. Each X-ray pulse ejects a burst of photoelectrons from the noble gas and it turns out that the temporal profile of the photoelectron bursts is a replica of the FEL pulse that ejected them.

Then, a very intense electromagnetic field is used to accelerate or decelerate the photoelectrons, depending on the exact instant of their ejection. The strength of this effect is measured and combining all the information appropriately the temporal profile and arrival time of the individual X-ray pulses from FEL can be obtained with a precision of about 5 femtoseconds.

"Simultaneous measurement of the arrival time and pulse profile, independent of all other FEL parameters, is the key to this technique," explains Adrian Cavalieri, who is a professor at the University of Hamburg and a group leader in the Max Planck Research Department for Structural Dynamics (MPSD). Until now, no other measurement has provided this complete timing information - yet it is exactly this information that will be crucial for future application of these extremely perspective X-ray light sources.

The FEL pulse characterization measurements presented by the team are made without affecting the FEL beam - only a negligible number of photons is lost for creating photoelectrons. Therefore, they can be applied in any experiment at almost any wavelength. In the immediate future, laser-driven streaking will be used to monitor and maintain the FEL pulse duration at FLASH to study a wide variety of atomic, molecular and solid-state systems. For further experiments, the researchers plan to use these high precision measurements as critical feedback for tailoring and manipulating the X-ray pulse profile.

####

For more information, please click here

Contacts:
Aitziber Lasa

34-943-363-040

Nora Gonzalez
Donostia International Physics Center (DIPC)

(+34) 943 01 5624

Copyright © Elhuyar Fundazioa

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Internet reference dx.doi.org/10.1038/nphoton.2012.276

Related News Press

News and information

Nano-needles for cells May 25th, 2013

How do cold ions slide May 24th, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Glowing Plant Releases Maker Kit, Enabling Anyone to Make a Glowing Plant at Home: Glowing Plant seeks funds via crowdfunding and raises almost $400,000 May 23rd, 2013

Physics

How do cold ions slide May 24th, 2013

Imaging

Heinrich Rohrer dies at 79; a father of nanotechnology: With IBM colleague Gerd Binnig, Rohrer invented the scanning tunneling microscope, which can show individual atoms on a surface and move them around May 23rd, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Discoveries

Nano-needles for cells May 25th, 2013

How do cold ions slide May 24th, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Atomic-Scale Investigations Solve Key Puzzle of LED Efficiency: MIT and Brookhaven Lab scientists use electron microscopy imaging techniques to settle a solid-state controversy and raise new experimental possibilities May 22nd, 2013

Announcements

Nano-needles for cells May 25th, 2013

How do cold ions slide May 24th, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Glowing Plant Releases Maker Kit, Enabling Anyone to Make a Glowing Plant at Home: Glowing Plant seeks funds via crowdfunding and raises almost $400,000 May 23rd, 2013

Tools

Heinrich Rohrer dies at 79; a father of nanotechnology: With IBM colleague Gerd Binnig, Rohrer invented the scanning tunneling microscope, which can show individual atoms on a surface and move them around May 23rd, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Researchers Stitch Defects into the World’s Thinnest Semiconductor May 22nd, 2013

Whirlpools on the Nanoscale Could Multiply Magnetic Memory: At the Advanced Light Source, Berkeley Lab scientists join an international team to control spin orientation in magnetic nanodisks May 22nd, 2013

Photonics/Optics/Lasers

How do cold ions slide May 24th, 2013

Gold nanocrystal vibration captured on billion-frames-per-second film May 23rd, 2013

Rice unveils method for tailoring optical processors: Arranging nanoparticles in geometric patterns allows for control of light with light May 21st, 2013

Moth-Inspired Nanostructures Take the Color Out of Thin Films May 17th, 2013

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More












ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project








abbigliamento uomo
Computer Accessories
© Copyright 1999-2013 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE