A prototype
elemental identification system has been developed for the
inspection of commodities shipped on pallets. The system is called
NELIS (Neutron Elemental Inspection System), and it identifies all
major and minor chemical elements of the items on a pallet. Since
the elemental composition of illicit drugs is quite different from
that of innocuous materials, NELIS is to inspect the contents of the
pallet, looking for elemental compositions that are either different
from the "background" elemental composition, or are very similar to
the elemental composition of illicit drugs. The "background" is
defined as the elemental composition of the commodities on a pallet
in the absence of hidden drugs within the commodity.
The measurement of
the major and minor chemical elements takes place with the
non-destructive, non-intrusive pulsed fast-thermal neutron analysis
technique. 14 MeV neutrons produced with a pulsed sealed tube
neutron generator are the interrogating particles. Neutrons
impinging upon an object can induce any of several nuclear reactions
in the elements found in the object. These reactions can be used to
identify the chemical elements of interest by examining the
characteristic gamma rays emitted from the object. These gamma
rays have different energies for each element, and act as their
fingerprints.
(See also detailed description of the
PFTNA techniques)
NELIS Laboratory Setup.
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NELIS Schematic.
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NELIS.
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For more detailed
information, please see the
Publications
portion of this web site.