Super-Sensitive Explosives Detector Demonstrated By ORNL

Tag : Tributyl Phosphate

"We match the pulse frequency of the illuminating light withthe mechanical resonant frequency of the quartz crystal tuningfork, generating acoustic waves at the tuning fork's air-surfaceinterface," said Charles Van Neste of ORNL's BiosciencesDivision. "This produces pressures that drive the tuning forkinto resonance."
The amplitude of this vibration is proportional to the intensity ofthe scattered light beam falling on the tuning fork, which becauseof the nature of quartz creates a piezoelectric voltage.
Van Neste and co-authors Larry Senesac and Thomas Thundat note thatother advantages of quartz tuning fork resonators include compactsize, low cost, commercial availability and the ability to operatein field conditions environments.
For their experiments, researchers used tributyl phosphate andthree explosives - cyclotrimethylenetrinitromine, trinitrotoluene,commonly known as TNT, and pentaerythritol tetranitrate. They wereable to detect trace residues with lasers 100 times less powerfulthan those of competing technologies.
While the researchers have been able to detect explosives at 20meters, using larger collection mirrors and stronger illuminationsources, they believe they can achieve detection at distancesapproaching 100 meters.
This research was funded by DOE's Office of NonproliferationResearch and Development and the Office of Naval Research.UT-Battelle manages Oak Ridge National Laboratory for theDepartment of Energy.