Highly sensitive trigger enables rapid detection of biological agents

Good news! Very impressive!

"MIT Lincoln Laboratory researchers have developed a highly sensitive and reliable trigger for the U.S. military's early warning system for biological warfare agents. ... The RAAD has demonstrated a significant reduction in false positive rates while maintaining detection performance that matches or exceeds that of today’s best deployed systems. Additionally, early testing has shown that the RAAD has significantly improved reliability compared to currently deployed systems. ...
RAAD process
The RAAD determines the presence of biological warfare agents through a multistep process. First, aerosols are pulled into the detector by the combined agency of an aerosol cyclone that uses high-speed rotation to cull out the small particles, and an aerodynamic lens that focuses the particles into a condensed (i.e., enriched) volume, or beam, of aerosol. The RAAD aerodynamic lens provides more efficient aerosol enrichment than any other air-to-air concentrator.
Then, a near-infrared (NIR) laser diode creates a structured trigger beam that detects the presence, size, and trajectory of an individual aerosol particle. If the particle is large enough to adversely affect the respiratory tract — roughly 1 to 10 micrometers — a 266-nanometer ultravolet (UV) laser is activated to illuminate the particle, and multiband laser-induced fluorescence is collected.
The detection process continues as an embedded logic decision, referred to as the “spectral trigger,” uses scattering from the NIR light and UV fluorescence data to predict if the particle's composition appears to correspond to that of a threat-like bioagent. "If the particle seems threat-like, then spark-induced breakdown spectroscopy is enabled to vaporize the particle and collect atomic emission to characterize the particle's elemental content," ..."

Highly sensitive trigger enables rapid detection of biological agents | MIT News | Massachusetts Institute of Technology The Rapid Agent Aerosol Detector developed at Lincoln Laboratory has demonstrated excellent accuracy in identifying toxic biological particles suspended in the air.