New Airport Security
Measures
New technology at
airports will enable authorities to check
for drugs, explosives, and bombs with
unprecedented speed and sensitivity. New
scanners, so sensitive that they can tell
if you even touched these object days ago,
may soon be in airports. The walk-through
scanners are similar to metal detectors
introduced some 30 years.
Barringer Technologies and Ion Track
Instruments in the United States have
built a device able to detect and identify
microscopic amounts of over 30 explosive
or narcotic substances. When you step
through the device a light puff of air
ruffles your clothes. That air is sucked
into a sample-preconcentrator. Ion
mobility mass spectrometry is then used to
determine exactly what "heavy" substances
are present. The systems can detect a few
parts per trillion of explosives or drugs,
microscopic traces which cling to clothes
and skin even when people think they're
clean.
Ion mobility spectrometry (IMS) is capable
of separating ionic species at atmosphere
pressure and has found many applications
in detecting chemical warfare agents,
explosives, and drugs. Miniaturization of
the instruments has dramatically widened
the use of the devices. Customs officials
in some countries already use similar
products to scan checked baggage. Dogs are
also used for such purposes but are
trained to detect a limited set of
substances.
However, the makers of the human scanners
concede that sometimes "false positives"
can arise. A case in point is the
detection of drug traces on currency
carried by an unsuspecting passenger. The
main drawbacks of the technology are the
speed of analysis. The Sentinel, built be
Barringer Technologies, presently requires
seven seconds to scan each passenger. The
cost of each unit will also be a barrier
to its widespread use in the short
term.