Ultrafast Electron Diffraction Reveals Rapid Motions of Atoms and Molecules
A new scientific instrument at the Department of Energy’s SLAC National Accelerator Laboratory promises to capture some of nature’s speediest processes. It uses a method known as ultrafast electron diffraction (UED) and can reveal motions of electrons and atomic nuclei within molecules that take place in less than a tenth of a trillionth of a second – information that will benefit groundbreaking research in materials science, chemistry and biology.
“We’ve built one of the world’s best UED systems to create new research opportunities in ultrafast science,” says SLAC’s Xijie Wang, who is in charge of developing the new instrument described in a paper published July 24 inReview of Scientific Instruments. “Our apparatus delivers electron beams with a better quality than any other UED machine. For example, it allows us to study chemical processes in the gas phase that are up to four times faster than those we can examine with current UED technologies.”
The technique complements ultrafast studies with SLAC’s X-ray free-electron laser. Similar to X-ray light, highly energetic electrons can take snapshots of the interior of materials as they pass through them. Yet, electrons interact differently with materials and “see” different things. Both methods combined draw a more complete picture that will help researchers better understand and possibly control important ultrafast processes in complex systems ranging from magnetic data storage devices to chemical reactions.
‘Seeing’ Ultrafast Processes with Electrons
The superior performance of the new UED system is due to a very stable “electron gun” originally developed for SLAC’s X-ray laser Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility. This electron source produces highly energetic electrons, packed into extremely short bunches. It spits out 120 of these bunches every second, generating a powerful electron beam that the researchers use to probe objects on the inside.
But how can scientists actually catch a glimpse of the interior of materials with particles like electrons?
The method works because particles have a second nature: They also behave like waves. When electron waves pass through a sample, they scatter off the sample’s atomic nuclei and electrons. The scattered waves then combine to form a so-called diffraction pattern picked up by a detector. The whole apparatus works like a high-speed camera, capturing differences in diffraction patterns over time that scientists use to reconstruct the sample’s inner structure and how it changes.
Since electron bunches in SLAC’s UED instrument are extremely short, they reveal changes that occur in less than 100 quadrillionths of a second, or 100 femtoseconds, for instance in response to ultrashort laser pulses.
“UED has been under development for the past 10 to 15 years, but the repulsive forces between electrons in the electron beam limited the time resolution of previous experiments,” says the paper’s first author Stephen Weathersby, the facility manager of SLAC’s Accelerator Structure Test Area (ASTA), where the UED machine is installed. “LCLS expertise in electron gun technology and ultrafast laser systems gives our system the performance and stability needed to study much faster processes.”
Electrons Plus X-rays for Ultrafast Science
Electrons behave similarly to X-rays in the way they explore speedy phenomena in nature. Electrons scatter off both electrons and atomic nuclei in materials. X-rays, on the other hand, interact only with electrons. Therefore, electron and X-ray studies of very fast structural changes complement each other.
The SLAC-led team has already begun to combine both approaches to better understand the link between the magnetic behavior of certain materials and their structural properties in studies that could help develop next-generation data storage devices.
Electrons also provide a path to studies that are very challenging to perform with X-rays.
“Electrons interact with materials much more strongly than X-rays do,” says SLAC’s Renkai Li, the paper’s lead author. “We were able to analyze samples such as very thin films whose X-ray signals would be very weak.”
For instance, the researchers studied a single atomic layer of a material that is interesting for future electronic devices.
“Another interesting case is gas phase samples,” Li says. “Due to the almost 1,000-fold shorter wavelength of electrons compared to X-rays, UED can see much finer structural details. We’re able to see how atoms in molecules move with UED, which is an important step toward making molecular movies of ultrafast chemical reactions.”
Read more: SLAC Builds One of the World’s Fastest ‘Electron Cameras’
The Latest on: MUltrafast Science
[google_news title=”” keyword=”Ultrafast Science” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Ultrafast Science
- Study reveals flaw in long-accepted approximation used in water simulationson May 7, 2024 at 1:34 pm
Computational scientists at the Department of Energy's Oak Ridge National Laboratory have published a study in the Journal of Chemical Theory and Computation that questions a long-accepted factor in ...
- Two facilities team up for structural biology advances with X-ray free-electron lasers and exascale computingon May 6, 2024 at 7:42 am
Plans to unite the capabilities of two cutting-edge technological facilities promise to usher in a new era of dynamic structural biology. Through DOE's Integrated Research Infrastructure, or IRI, ...
- Max Planck develops method to speed up spectroscopic analysison April 29, 2024 at 5:00 pm
The results of the project led by Hanieh Fattahi, Research group leader at the Max Planck Institute of the Science of Light, based in Erlangen, Germany, in collaboration with partners from Germany and ...
- Pump-probe high-harmonic spectroscopy could catch geometric phase effect around conical intersection in molecule: Studyon April 29, 2024 at 1:52 pm
A collaborative research team from Nanjing University of Science and Technology (NJUST) and East China Normal University (ECNU) has theoretically proposed that a pump-probe high-harmonic spectroscopy ...
- Speeding up spectroscopic analysison April 28, 2024 at 5:00 pm
Research group leader at the Max-Planck-Institute of the Science of Light, in collaboration with industrial partners from Germany and France, were recently published in the Journal of Ultrafast ...
- I tested a ’10 second toothbrush’ to save time in the mornings – it’s ultra-fast but here’s why I’m not convertingon April 28, 2024 at 3:30 am
THE Y-Brush – dubbed the ’10 second toothbrush’ – cleaned my gnashers in record time, even if I did feel a little silly while using it. It’s made for the people who ...
- Chinese scientists want to use lasers to power ultrafast, stealthy submarines. A laser expert says there's a major flaw in their plan.on April 28, 2024 at 3:28 am
Chinese scientists from Harbin University say they've made a breakthrough in underwater laser propulsion technology.
- BREAKTHROUGH : Lightsolver Makes Ultrafast Laser Based Computerson April 27, 2024 at 5:00 pm
Aerospace: Optimize material design and enhance decision intelligence for mission-critical processes in which ultra-fast processing times are needed ... Brian Wang is a Futurist Thought Leader and a ...
- A Paradigm Shift in RAM Is About to Make Computing Unstoppableon April 24, 2024 at 5:30 am
Every computer needs Random Access Memory (or RAM) for an operating system’s temporary storage, and there’s many ways to achieve this need for memory speed. One of the leading methods is ...
- Development of organic semiconductors featuring ultrafast electronson April 22, 2024 at 10:22 am
Collaboration has led to the successful observation of these ultrafast electrons within conducting two-dimensional polymers.
via Bing News