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energy but it also yields two views spectroscopy relies on the scattering
Hydrogen
peroxide, of interior of the bag. These multiple of light – usually in or close to the
known as
views help the operator identify visible part of the electromagnetic
‘T-Stoff’,
was used by objects. In addition the Rapiscan spectrum. When the laser hits the
Germans,
Systems 620 DV-AT yields additional object it scatters. The scattered laser
together with
fuels such as X-ray attenuation and defraction data light bounces back to the device,
methanol and
that allows the deployment of more where it is analysed. Since every type of
hydrazine, to
power the sophisticated software algorithms substance, explosive or otherwise, has
pumps on
for the detection of specific types of its own unique molecular properties, it
their
V2 rockets compound. This includes liquid, aerosol scatters light in a unique way.
and gel based explosives as well as Like other X-ray technologies the
based spectral detector to tell us what bulk and solid-state explosives. device has to be calibrated by providing
it is.” Ahura Scientific, of Wilmington it with the unique diagnostic signature
Cadmium telluride is a solid-state, Massachusetts, have just unveiled a of a variety of liquids from the benign
room-temperature digital X-ray new generation of device based on to the hazardous.
detector. Its’ unique property is that it Raman spectroscopy. They claim that However, a limitation to the Ahura
is capable of spectroscopic detection at their TruScreen non-invasive sampling device is that it can only detect
higher X-ray energies. That allows it to technology offers aviation checkpoints the composition of liquids inside
detect the different X-ray energy levels high-throughput – something that transparent walled bottles. On the plus
coming out of the scanned material. passengers since the events of 2006 side, unlike the Kromek, Optosecurity
Basu points out, “The spectral nature have come to want badly. Raman and Rapiscan Systems devices which
of the detection is very important. If
we think about the world of light we
can make very quick decisions based
on our ability to see things in colour.
For example, if in the distance we see
a couple of bottles, we can easily tell
that one bottle contains water and the
other red wine even if the bottle shapes
are exactly the same because our brain
relates colour to certain materials.
X-rays have a very similar spectrum.
But most of the current X-ray detectors
in use ‘see’ in black and white so the
information that you get from existing
X-ray systems is very limited. What
Kromek does is colour X-ray. We break
down the whole spectrum … and get
out meaningful information by looking
at the various energy levels.”
To use the system the device must be
calibrated using a list of ‘threat items’.
This approach is being used by others.
Optosecurity are offering a software
upgrade that can be added to existing
X-ray machines that will identify liquids
within bottles. Like Kromek’s technology
the composition of the bottle is
immaterial. Optosecurity’s upgrade will
not add any more time (and, thus,
inconvenience) to the existing scanning
process at airports. By using existing
X-ray machines it is also a relatively
inexpensive option.
A different approach is used by
Rapiscan Systems. Their new device,
the Rapiscan Systems 620 DV-AT, like
conventional X-ray machines, is dual
December 2009 Aviationsecurityinternational www.asi-mag.com 31
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