A new technique for this purpose is available
An international team of scientists from Denmark and Tennessee, the US, have come up with an experimental new way of detecting explosives and other similar, dangerous compounds, by simply going after the smell their physical vapors give out. The new technique is currently being refined and tested in the field, and details of how it works are published in the American Institute of Physics (AIP)'s journal Review of Scientific Instruments.
“Certain classes of explosives have unique thermal characteristics that help to identify explosive vapors in presence of other vapors,” Oak Ridge National Laboratory (ORNL) researcher and University of Tennessee expert Thomas Thundat, who has been the leader of the new research, says. Colleagues from ORNL and from the Technical University of Denmark have also participated in the investigation. Their new method can easily differentiate between explosive compounds and non-dangerous ones, which is a real step forward in bomb detection.
In addition, it is also able to distinguish between various types of explosives, including TNT, PETN, and RDX, which means that bomb squads worldwide could also find out what they're up against when trying to defuse a suspect device. Other detectors, which are currently in production, are also very effective in detecting bombs, but they are very large and bulky, and very expensive as well. The goal of the new research has been to create a prototype that is equally light-weighed and accessible, in terms of price and portability.
The new line of research makes use of the knowledge that each compound, explosive and non-explosive alike, leaves behind a unique thermal signature. This signature can be detected with tiny components known as “micromechanical” devices. The drawback of these elements is that they are not very accurate in discerning what type of substance they detect. By altering existing ones, the team hopes to overcome this obstacle.
The micromechanical devices they use can be heated within a fraction of a second, and can independently trap particles of the substance they are analyzing. By allowing air to flow over these receptors, the team's device can easily distinguish between classes of explosives, or if the compounds on them pose any danger at all. As far as testing goes, Thundat says that a prototype could be ready later on in the year. The researchers are currently working to further improve the device's sensitivity to explosive compounds.