New explosives detection technologies show promise
only present at 2 parts per trillion. Researchers at various universities and DARPA have been working for decades to duplicate what nature has achieved with the canine nose.
Straw writes that those efforts have borne fruit, in particular the ion mobility spectroscopy and chemiluminescence technologies used in today’s explosive trace detection devices, like the hand-held and bench-top machines already in use at airports and security checkpoints around the world. Other technologies that function at the micro and nano levels have also shown promise at detecting small quantities, and, at least one researcher says that they hold the promise of exceeding the sensitivity of canine olfaction. Another research effort that is making progress is headed by scientist Tom Bruno at the National Institute of Standards and Technology (NIST). That team is developing what Bruno calls “headspace analysis,” meaning simply a sampling of the air over a test substance.
Terahertz scanning. Terahertz radiation, is non-ionizing and eye-safe, which means that it could be used safely to scan both liquids and individuals for explosives (see “NJIT physicist: Terahertz imaging is the ultimate defense against terrorism,” 13 April 2010 HSNW; and “Remote terahertz scanners could, in theory, see what is in your pockets from miles away,” 15 July 2010 HSNW). More recent research on liquid-explosives detection at the Jülich center involves radiation at a higher frequency, in from the gigahertz to the terahertz range. Using a newer method of spectroscopy called Hilbert spectroscopy, the technology can measure transmission, reflection, and absorption of substances being tested, which increases accuracy.
Technology employing terahertz scanning, developed by TeraView Ltd. of Cambridge, England, holds the promise of scanning individuals for either trace or bulk explosives, even those concealed under clothing, according to TeraView CEO Don Arnone (“U.K. firm says its scanning technology meets security, privacy concerns,” 13 January 2010 HSNW). TeraView’s product, called the TPS Spectra 3000, is housed on a pair of wheeled carts, each about the size of an airline beverage cart. One cart bears a display monitor and the system’s analytic hardware; the other holds the equipment necessary for actual sampling via a sensor placed at the end of a fiber-optic cable.
Straw notes that as with all forms of spectroscopy, the process involves reading radiation. In this case, TeraView’s device emits a beam of radiation that passes unencumbered through clothing. At specific frequencies, however, the energy is absorbed by specific explosive molecules. The technology is already under evaluation at the U.S. Naval Surface Warfare Center at Indian Head, Maryland.
