Sciencenewsline:
A new detector can sense knives hidden in packages, impurities
in chocolate, and explosive powder in pieces of mail—all
without the use of ionizing radiation. Called SAMMI, short for
standalone millimeter-wave imager, the device can see through
many nontransparent, nonmetallic materials,
according
to its developers at the Fraunhofer Institute for
High-Frequency Physics and Radar Techniques FHR in Wachtberg,
Germany. “It can even detect and monitor the dehydration
process in plants and how severely they have been stressed by
drought," says Helmut Essen, head of the FHR's millimeter-wave
radar and high-frequency sensors department. When SAMMI is
running, a conveyor belt moves a sample between two antennae
that transmit 78-GHZ electromagnetic waves. The varying degrees
to which different areas of the sample absorb the signal reveal
the sample's varying material composition. Currently in the
development stage, SAMMI may one day be adapted, for example,
to automatically inspect goods on industrial assembly
lines.
