Scanning for danger

Engineers at Los Alamos National Laboratory have created a system called MagViz, which may enhance airport security by spotting liquids that could prove to be potential threats.

If MagViz finds a chemical designated as a threat, it will mark the container with a red dot on a screen. Harmless substances get a green dot and if the machine is unable to identify the liquid, a yellow dot appears, indicating that further inspection is needed.

A prototype MagViz machine is undergoing field testing at the Albuquerque International Sunport. Should the development process continue successfully, machines could be in airports by 2012.

The ultra-low-field Magnetic Resonance Imaging (MRI) system relies on detectors called superconducting quantum interference devices (SQUIDs). While a hospital MRI detects spin with a sensor akin to a radio antenna, tuned to a specific set of frequencies, SQUIDs can pick up the oscillation of hydrogen or other atoms at any frequency.

Linked to a computer database, MagViz can now reliably identify some 50 liquids from their chemical fingerprints. And that is only the beginning. 'That's one of the beauties of this technology,' said project leader Michelle Espy. 'We can add different threats as we become aware of them.'