Menlo Park, Calif. Researchers at the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory have captured the most detailed images to date of airborne soot particles, a key contributor to global warming and a health hazard.
The discovery reveals the particles' surprisingly complex nanostructures and could ultimately aid the understanding of atmospheric processes important to climate change, as well as the design of cleaner combustion sources, from car engines to power plants.
The study, published in the June 28th issue of Nature, also pioneers a method for studying a broad range of individual particles, such as cells or proteins, and opens up exciting possibilities in the study of aerosol dynamics using highly focused X-ray lasers, such as SLAC's Linac Coherent Light Source (LCLS).
"Our study shows that LCLS can drive a paradigm shift in imaging airborne particles, allowing us to look at them one at a time instead of using a composite of many different particles," said Duane Loh, the lead author of the study and a postdoctoral scholar at SLAC and Stanford University's PULSE Institute for Ultrafast Energy Science. "We now have a richer imaging tool to explore the connections between their toxicity and internal structure."
Soot and similar particles especially those 2.5 microns or less in diameter, which are the most dangerous to human health are difficult to image while airborne. When placed on a surface for examination with a microscope, they tend to clump together and lose their shape.
In this experiment, researchers wafted individual soot particles up to 3.25 microns in diameter into the path of the LCLS laser beam. Its laser pulses are so brief that they captured information about the particles, only millionths of a meter across, in the quadrillionths of a second before they blew apart.
They found that no two are alike. Like magnified snowflakes, soot particles exhibit simi
|Contact: Andy Freeberg|
DOE/SLAC National Accelerator Laboratory