Contact: Diane Greenberg or Mona S. Rowe
Mailed 12/1/97



Sensor Identifies Chemical in Eight Minutes


Upton, NY - When New York City's Office of Emergency Management staged a drill last month to test the city's response to a possible terrorist attack involving chemical weapons, the U.S. Department of Energy's Brookhaven National Laboratory demonstrated a novel chemical sensor as a part of the exercise. The Brookhaven sensor successfully detected the chemical used in the drill - acetone, the active ingredient in nail polish remover - from a distance of about 15 feet.

Brookhaven Lab scientist Arthur Sedlacek, who was instrumental in designing the sensor system, said, "The sensor performed well in just eight minutes, under difficult conditions, specifically, at night, in a driving rain. We are excited about its potential as an invaluable tool for assessing unknown chemicals in the field."

Besides using the sensor in response to terrorist attacks, potential applications include identifying chemical weapons production, monitoring industrial emissions, investigating environmental crimes, determining the effectiveness of environmental cleanups and assessing the hazards of chemical fires.

The Brookhaven-designed mini sensor, the size of a two-foot cube, works at short distances of a few feet to tens of feet. The device combines the latest laser and detector technology with a phenomenon known as Raman scattering. Laser light is aimed at a target and scatters off its molecules. An instrument called a spectrometer analyzes the scattered light, revealing a chemical fingerprint. That signature fingerprint is then compared with a computerized library of fingerprints.

The mini sensor is an offshoot of a large, chemical sensor system developed at Brookhaven - a 33-foot-long mobile detection van that can identify chemicals in the atmosphere from several miles away. While the larger sensor system is best used for atmospheric applications, the mini sensor is most efficient in determining ground or surface contamination. A big advantage of both sensors is that they can identify chemicals from a safe distance.

Brookhaven National Laboratory carries out basic and applied research in physical, biomedical and environmental sciences and in selected energy technologies. Associated Universities, Inc., a nonprofit research management organization, operates the Laboratory under contract with the U.S. Department of Energy.