X-Ray Sound; December 1997; Scientific American Magazine; by Gibbs; 2 Page(s)

Here¿s a puzzle: You¿re handed an artillery shell filled with either ordinary explosive or deadly nerve gas. How do you determine what it contains without risking total nervous shutdown? The question is not as hypothetical as it may seem. United Nations inspectors enforcing the Chemical Weapons Convention Treaty face this problem all too often. Fortunately, they now have an answer: a device that when pressed against a container of almost any shape or size can identify its contents using sound. The technique, which has already spawned 12 patent applications, may have myriad industrial and environmental uses.

Dipen N. Sinha and his colleagues built the sensor at Los Alamos National Laboratory and described it at the American Chemical Society meeting in Las Vegas this past September. In about 20 seconds, Sinha claims, a soldier using the five-pound, battery-powered gadget can reliably distinguish not only whether a shell contains chemical weapons but also which of the wide variety of toxic cocktails it holds.