Researchers have developed a new laser-based method that can detect electric charges and chemicals of interest with unprecedented sensitivity.
Researchers have developed a new laser-based method that can detect electric charges and chemicals of interest with unprecedented sensitivity. The new approach could one day offer a way to scan large areas for radioactive material or hazardous chemicals for safety and security applications.
The new technique, called mid-infrared picosecond laser-driven electron avalanche, detects extremely low charge densities — the number of electric charges in a certain volume — in air or other gases. The researchers were able to measure electron densities in air produced by a radioactive source at levels below one part per quadrillion, equivalent to picking out one free electron from a million billion normal air molecules.
In Optica, The Optical Society's journal for high impact research, researchers from the University of Maryland report using the new method to calibrate lasers used to inspect irradiated air from 1 meter away. They say the approach could be applied to detecting other chemicals and species and could be scaled up for remote detection at distances of 10 meters and, eventually, 100 meters.
“We can determine charge densities much too low to measure with any other method,” said Daniel Woodbury, the lead author on the paper. “We demonstrate the method’s ability to detect a radioactive source, but it could eventually be used for any situation that requires measuring trace amounts of a chemical in a gas, such as helping to track pollution, chemicals or safety hazards.”
Read more at The Optical Society
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