Cdex, Inc. (fka CDEX)

[d4diddy]

Sensing explosives with THz


Chemical and explosives detection remains as one of the U.S. military’s most pressing needs. Looking to answer this call is a team of engineers from the Dept. of Energy’s Argonne National Laboratory (ANL), Illinois, and their suite of chemical sensors. The sensors are based on THz spectroscopy and use that particular band of the EM spectrum to detect the energy levels of a molecule as it rotates.
Instruments in Argonne’s Terahertz Test Facility, such as the one Sami Gopalsami uses, can detect trace chemicals at the part-per-billion level. Photo: ANL


As the energy levels of a molecule are distinct, this technique can provide a “spectral fingerprint” of the target substance, ideally a chemical or explosive material. Operating at frequencies between 0.1-10 THz, the sensors offer a sensitivity four to five orders of magnitude higher and imaging resolution, according to Argonne, 100 to 300 times more possible than at microwave frequencies.

In recent tests, the team has been able to demonstrate the ability of these sensors to:
• Detect and measure poison gas precursors 60 m away to an accuracy of 10 parts per million using active sensing.
• Identify chemicals related to defense applications, including nuclear weapons, from 600 m away using passive sensing; and
• Identify the spectral fingerprints of trace levels of explosives, including DNT, TNT, PETN, RDX, and the plastics explosives semtex and C-4.

Argonne National Laboratory
www.anl.gov


http://rdmag.com/ShowPR.aspx?PUBCODE=014&ACCT=1400000100&ISSUE=0604&RELTYPE=ND&PRODC...