"What we have accomplished," Steele said, "is to make an instrument that is very sensitive, with a very low false alarm rate, but very fast. That's unique. Other systems that are just as fast and sensitive have higher false alarm rates."
Besides Frank and Steele, other researchers on the SPAMS team include chemists Eric Gard, David Fergenson, Keith Coffee and George Farquar; forensic chemist and graduate student Audrey Martin; microbiologist Sue Martin; and electronics engineer Vincent Riot.
In lab experiments, SPAMS was tested against four types of materials terrorists might use -- spores of a non-pathogenic strain of Bacillus anthracis (other strains of this bacteria cause anthrax); diethyl phthalate (a nerve agent surrogate), natural cobalt powder (a surrogate for Cobalt 60 and other radioactive metals) and trinitro-1,3,5-triazinane (RDX, a high explosive). Additionally, it was tested against pseudoephedrine (used to synthesize methamphetamine).
In single- and multiple-agent tests, SPAMS accurately identified each substance and set off the correct alarms within an average of 34 seconds after their release against a background of air as the system was open to the environment. All of the measurements were achieved within 26 to 46 seconds after the compounds' release.
The two multiple-agent tests involved the use of natural cobalt powder and RDX, and a non-pathogenic strain of Bacillus anthracis and RDX.
In field experiments, SPAMS has been tested at San Francisco International Airport. As part of a background study, the mass spectrometry system analyzed the air for about seven weeks in 2004-05, recording data, though it lacked the capability to set off alarms. The system records were later analyzed in the lab to evaluate whether any alarms, false or real, would have been triggered.
The researchers determined that while a few particles showed up as spores among the almost one mil
|Contact: Steve Wampler|
DOE/Lawrence Livermore National Laboratory