The Secret Behind NIST's New Gas Detector? Chirp Before Sniffing

From NIST Tech Beat: May 10, 2011
Contact: Chad Boutin
301-975-4261

Trace gas detection, the ability to detect a scant quantity of a particular molecule—a whiff of formaldehyde or a hint of acetone—in a vast sea of others, underlies many important applications, from medical tests to air pollution detectors to bomb sniffers. Now, a sensor recently developed* at the National Institute of Standards and Technology (NIST) that is hundreds of times faster and more sensitive than other similar technologies may make such detectors portable, economical and fast enough to be used everywhere.

Graph shows the NIST detector’s linear increase in frequency as a function of time, sweeping from 550-561 Gigahertz in frequency over 100 nanoseconds. Click on the image to see an animation of the process, slowed to 5 seconds and using an audio chirp as an analogy to the terahertz chirp. Credit: Douglass, NIST View hi-resolution image

According to the NIST investigators, the new sensor overcomes many of the difficulties associated with trace gas detection, a technique also used widely in industry to measure contaminants and ensure quality in manufacturing. A trace level of a particular gas can indicate a problem exists nearby, but many sensors are only able to spot a specific type of gas, and some only after a long time spent analyzing a sample. The NIST sensor, however, works quickly and efficiently.
“This new sensor can simultaneously detect many different trace gases at very fast rates and with high sensitivity,” says NIST chemist Kevin Douglass. “It’s also built from off-the-shelf technology that you can carry in your hands. We feel it has great commercial potential.”

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