Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

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

Physics

Measuring the Smallest Magnets July 28th, 2014

News and information

Measuring the Smallest Magnets July 28th, 2014

WITec to host the 11th Confocal Raman Imaging Symposium from September 29th - October 1st in Ulm, Germany July 28th, 2014

FEI adds Phase Plate Technology and Titan Halo TEM to its Structural Biology Product Portfolio: New solutions provide the high-quality imaging and contrast necessary to analyze the 3D structure of molecules and molecular complexes July 28th, 2014

Imaging

WITec to host the 11th Confocal Raman Imaging Symposium from September 29th - October 1st in Ulm, Germany July 28th, 2014

FEI adds Phase Plate Technology and Titan Halo TEM to its Structural Biology Product Portfolio: New solutions provide the high-quality imaging and contrast necessary to analyze the 3D structure of molecules and molecular complexes July 28th, 2014

Discoveries

Seeing is bead-lieving: Rice University scientists create model 'bead-spring' chains with tunable properties July 28th, 2014

Measuring the Smallest Magnets July 28th, 2014

Production of Toxic Gas Sensor Based on Nanorods July 28th, 2014

Stanford team achieves 'holy grail' of battery design: A stable lithium anode - Engineers use carbon nanospheres to protect lithium from the reactive and expansive problems that have restricted its use as an anode July 27th, 2014

Announcements

Measuring the Smallest Magnets July 28th, 2014

WITec to host the 11th Confocal Raman Imaging Symposium from September 29th - October 1st in Ulm, Germany July 28th, 2014

FEI adds Phase Plate Technology and Titan Halo TEM to its Structural Biology Product Portfolio: New solutions provide the high-quality imaging and contrast necessary to analyze the 3D structure of molecules and molecular complexes July 28th, 2014

Production of Toxic Gas Sensor Based on Nanorods July 28th, 2014

Tools

WITec to host the 11th Confocal Raman Imaging Symposium from September 29th - October 1st in Ulm, Germany July 28th, 2014

FEI adds Phase Plate Technology and Titan Halo TEM to its Structural Biology Product Portfolio: New solutions provide the high-quality imaging and contrast necessary to analyze the 3D structure of molecules and molecular complexes July 28th, 2014

Bruker Announces Acquisition of High-Speed, 3D Super-Resolution Fluorescence Microscopy Company Vutara July 28th, 2014

Malvern Instruments completes acquisition of MicroCal and announces purchase of Archimedes product from Affinity Biosensors July 25th, 2014

Photonics/Optics/Lasers

NUS scientists use low cost technique to improve properties and functions of nanomaterials: By 'drawing' micropatterns on nanomaterials using a focused laser beam, scientists could modify properties of nanomaterials for effective applications in photonic and optoelectric applicat July 22nd, 2014

Carbyne morphs when stretched: Rice University calculations show carbon-atom chain would go metal to semiconductor July 21st, 2014

Tiny laser sensor heightens bomb detection sensitivity July 19th, 2014

Future Electronics May Depend on Lasers, Not Quartz July 17th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE