Science News Archive

Light-fingerprint Helps To Pick Up Explosives From a Distance

Would-be terrorists could have their evil work made harder in the future, thanks to new advances in explosive detection by Florida scientists. Security forces need to find explosives quickly, inexpensively and reliably: there is no room for error when you are dealing with determined terrorists. Also, false positives- thinking that there is a bomb when there isn't one- could cause panic and delays. Current explosive detection methods require a swab or sample to be taken from a person or object that might have been in contact with explosives, which is then analysed in the lab. Now, researchers have been applying a technique called photoluminescence spectroscopy, where light is shone on a substance, and a detector measures the characteristics of the light that gets sent back. The chemical structure of the material affects what happens to the light, so every chemical has a special spectroscopic signature. The Florida team found that TNT and other common explosives shared a highly specific signature. This means that in theory, light shone at a distance on objects such as boats, people or suitcases could reveal whether they had been in contact with explosives, marking them out as a suspect and allowing security forces to swoop. Rolf Hummel, the brains behind the project, says that once it is fully developed, the new method would be cheap, accurate and quick.
Radio Show about the science of light including Raman spectroscopy

16th Oct 2004