It's bound to replace spectroscopy for the job

Apr 9, 2010 14:48 GMT  ·  By

In the summer of 2008, researchers at the US Department of Homeland Security (DHS) began working on a new bomb-detection technology. The effort was directed at constructing advanced, high-tech devices capable of detecting potentially dangerous chemicals and explosives in suitcases and other suspicious containers left behind in crowded places. The Optical Dynamic Detection (ODD) is also designed to prevent instances such as the 2004 Madrid train bombings, which were caused precisely by this type of explosive devices, left aboard congested trains.

The most common method of detecting the contents of a suspicious package is using spectroscopy to analyze the light signature of whatever is inside. “Spectroscopy is good, but it only gets you so far,” says of the method the DHS Science and Technology Directorate (S&T) Explosives Division program manager, Eric Houser. As one of those involved in the development of ODD, he is highly-familiarized with the drawbacks of spectroscopy. The new detection mechanism was therefore designed specifically to be able to exceed the performances of the previous method.

The idea was proposed at an S&T meeting in the summer of 2008, by a group of researchers from the Princeton University, and the US Department of Energy's (DOE) Los Alamos National Laboratory (LANL). A year and a half later, the proof of concept was achieved. Now, the two research institutions have three years to develop a portable prototype, ready to be tested in the field. “At this risk of oversimplifying, this is quantum control applied to explosives detection. In evaluating a potential bomb, you're looking for a needle in a haystack. ODD helps bring the needle to the forefront,” Houser says of the new analysis technique.

One of the main advantages of Optical Dynamic Detection is that it reduces background “noises” through the use of two separate lasers. The first one excites the electrons in the molecules contained in the suspicious package, and its traits can be modified in real-time, so as to test for a wide array of substances. The second laser then passes through the samples, collecting readings of the contents, and analyzing its spectrum. ODD is thus capable of also determining the location of the target chemicals inside the object of interest, the DHS states.