Argonne's Velociprobe takes rapid steps forward
Recent studies have taken advantage of the Velociprobe's blazing fast scanning speed to achieve high-resolution views of large sections of important devices.
Just over a year after commissioning, the Velociprobe -- an X-ray microscope at the U.S. Department of Energy's (DOE) Argonne National Laboratory -- continues to set new records as it illuminates materials ranging from integrated circuits to batteries.
The Velociprobe was built to take advantage of the upcoming upgrade to Argonne's Advanced Photon Source (APS), which will provide X-rays of a brightness more than 100 times that of the current APS and one-hundred billion times brighter than the X-rays produced in a typical dentist's office. The APS is a DOE Office of Science User Facility.
"The Velociprobe is an exciting machine for what it can already do, but it is even more promising for what it is about to be able to do." -- Argonne X-ray physicist Junjing Deng
While early experiments on the Velociprobe sought to benchmark the core capabilities of the instrument, recent studies have taken advantage of its blazing fast scanning speed to achieve high-resolution views of large sections of important devices.
"Initially, we were just focused on scanning a small area as fast as possible to see if we could do it," said Argonne X-ray physicist Jeffrey Klug. "What we've done in the past year is demonstrate that we could extend this to a comparatively large area very quickly."
With the imaging instrumentation currently in place, the Velociprobe's capabilities are primarily limited only by the number of photons provided by the APS itself. Once the Upgrade is completed, the Velociprobe will be capable of scanning large regions of materials with unparalleled resolution in short periods of time.
One additional advantage of the Velociprobe is its ability to dramatically reduce the amount of time needed to perform an experiment, said Argonne X-ray physicist Junjing Deng. "Some experiments looking at larger samples using conventional X-ray instruments can take days to complete, but with the Velociprobe, we can shrink that to an hour or two."
Initial experiments with the Velociprobe have looked at the features of integrated circuits -- also known as microchips. "Integrated circuits are, in some respects, the most perfect things humans have made," Klug said. "They have countless transistors arranged just so at nanometer distances. The Velociprobe gives us the ability to characterize them with ultimate precision."
"It is exciting to see that that the Velociprobe is working so well," said Curt Preissner, the Argonne mechanical engineer responsible for the design of the Velociprobe. "When conceptualizing the instrument we asked the question: How can we build an instrument to push both speed and resolution limits? We threw away some of the decades-old X-ray microscope conventions to break new ground, and now it is paying off."
As Klug and Deng prepare the Velociprobe for the APS Upgrade, they are readying the instrument to look at dynamic processes that occur over time. "We are hoping to move more towards in situ studies of materials," Deng said. These could include functioning devices such as a battery or chemical processes such as catalysis.
"With the Velociprobe, we can monitor how a battery material changes during the system evolution of charging and discharging," Klug added. "We can move up from looking at merely a single particle or handful of particles to looking at how the battery system behaves as a bulk material."
Recent experiments with the Velociprobe have proven its ability to scan small regions with exquisite sensitivity or larger areas with speed exceeding conventional scanning X-ray techniques. When the APS Upgrade is complete, both of these modes will become even more useful for examining a wide range of structures and devices at scales that range from tens of nanometers to a few microns.
The new Velociprobe approach is already having broader impact, with engineers adapting the technologies of the Velociprobe to other instruments both at the APS and around the world. In addition, Argonne was recently issued a U.S. patent for technology used in the Velociprobe.
"The Velociprobe is an exciting machine for what it can already do, but it is even more promising for what it is about to be able to do," Deng said.
To help enable the work at the Velociprobe, researchers at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility at Argonne, contributed to the fabrication of test samples.
A paper on the Velociprobe, "The Velociprobe: An ultrafast hard X-ray nanoprobe for high-resolution ptychographic imaging," appeared in the August 15 issue of Review of Scientific Instruments and was selected as a "Scilight" by the American Institute of Physics.
Funding for the Velociprobe comes from DOE's Office of Science.
About Argonne's Center for Nanoscale Materials
The Center for Nanoscale Materials is one of the five DOE Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit https://science.osti.gov/User-Facilities/User-Facilities-at-a-Glance.
About the Advanced Photon Source
This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.
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