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'Electron Camera' Available To Scientists Worldwide
July 17, 2019

Over the past few years, the Department of Energy’s SLAC National Accelerator Laboratory has developed a new tool to visualize physical and chemical processes with outstanding clarity: an ultra-high-speed “electron camera” capable of tracking atomic motions in a broad range of materials in real time. Recently, the lab has made this tool available to researchers worldwide.

SLAC staff scientist Alexander Reid, the first user of the lab's instrument for ultrafast electron diffraction (MeV-UED) since it became available to the international community as part of the LCLS facility, handles an interchangeable sample card used to hold samples during UED experiments. Credit: Jacqueline Orrell/SLAC National Accelerator Laboratory.

The tool is an instrument for ultrafast electron diffraction (MeV-UED). It uses a beam of highly energetic electrons to probe matter and is especially useful for understanding atomic processes occurring on timescales as short as about 100 femtoseconds, millionths of a billionth of a second. These rapid snapshots provide completely new insights into processes in nature and technology, benefitting applications in biology, chemistry, materials science and other fields.

The first proposal-driven experimental run of the MeV-UED instrument is scheduled through December this year and will deliver those powerful electron beams to 16 user groups from over 30 institutions. Experiments will initially focus on materials science and hot, dense states of matter.

MeV-UED complements the lab’s suite of world-leading methods for studies of ultrafast science, including SLAC’s flagship X-ray laser, the Linac Coherent Light Source (LCLS). Utilizing the whole breadth of these methods, scientists can explore very different, yet equally important aspects of speedy processes.

“In response to a DOE workshop on the future of electron scattering and diffraction in February 2014, SLAC launched an ultrafast electron diffraction initiative with the goal to develop a world-leading instrument whose capabilities would complement those of LCLS,” says Xijie Wang, director of the MeV-UED instrument. “Making our cutting-edge technique available to the broad scientific community and supporting SLAC’s program in ultrafast science is an exciting milestone for us.”

The MeV-UED instrument has been incorporated into the LCLS user facility, adding to the experimental stations that use X-rays.

“Over the past four years, we have demonstrated that MeV-UED can lead to a paradigm shift in ultrafast electron diffraction, in part due to its versatility to probe a broad range of solid and gaseous samples,” Wang says. “The high energy of the electrons, which is unique to our instrument, has transformed ultrafast electron diffraction from a qualitative science to a quantitative one, and our experiments are now employed to validate theoretical predictions and push new theoretical developments.”

The team’s latest R&D is devoted to exploring science in liquid states, the natural environment for many biochemical processes, so scientists will soon be able to home in even more on some of the most gripping details of biology and chemistry.

With LCLS, scientists can track molecular changes that occur extremely quickly – within just a few femtoseconds. With MeV-UED, they can unearth crisp images of molecules with unparalleled atomic resolution during these quick reactions. Both – extraordinary resolution in space and in time – help develop a complete picture of speedy fundamental processes.

According to information, now, SLAC has opened access to the instrument to virtually everyone. Researchers can submit proposals for experiments, which are then evaluated by a committee of experts, ranked and, if successful, given time to conduct the experiment. That’s the same way LCLS and other X-ray light sources handle access to their instruments.

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