With each terrorist attack on another airport, train station or other public space, the urgency to find new ways to detect bombs before they’re detonated ratchets up.
Chemical detection of explosives is a cornerstone of aviation security. Typically called “trace detection,” this approach can find minuscule amounts of residue left behind after someone handles an explosive. A form of this technology called ion mobility spectroscopy is what Transportation Security Administration officers are using when they swab and test your laptop, hands or other items at the airport. In a few seconds, a sample is vaporized, and the resulting chemical ions are separated by molecular size and shape, triggering an alarm if an explosive compound is detected.
But this method is labor-intensive and slow for large volumes of stuff, and its effectiveness can depend on the sampling skill of the officer. It relies on contact sampling, which requires security personnel to have access to surfaces where residue may have been left. That’s not useful if a bomber has no intention of going through a security line and having his personal effects searched.
Source: Manufacturing Net