OAK RIDGE, Tenn., May 14, 2001 – A point-and-shoot portable instrument to protect people and the environment is a product of some 20 years of research by the Department of Energy’s Oak Ridge National Laboratory (ORNL) scientist Tuan Vo-Dinh.
What’s unique about the instrument, which analyzes chemicals in just seconds, is that it is the first battery-operated portable device with tunable filters and performance comparable to that of laboratory-scale instruments. It uses Raman technology, employing a helium neon laser, acousto-optic tunable filters and a photo sensor to detect toxic chemicals, TNT, byproducts from explosives, drugs and hundreds of chemicals. The material can be in liquid or powder form.
Raman technology involves illuminating a sample with a laser beam and measuring the reflected light. The light shows the vibration energies, which are unique to each compound in the sample, and that information helps scientists identify the substance. It’s a technology that, until the development of acousto-optic tunable filters, was impractical for use in the field.
An acousto-optic tunable filter is a solid-state optical bandpass filter that can be tuned to various wavelengths. Because the filter is solid-state and has no moving parts, it is rugged and ideal for this application.
"The recent development of acousto-optic tunable filters has made the use of Raman technology practical for applications in a variety of environments," Vo-Dinh said.
Operation of the instrument is simple, according to Vo-Dinh, who noted that he and colleagues designed it to be used by people with no special skills. The user merely points a probe at the substance to be tested and touches the start button on the touch-screen display. In 11 seconds, the prototype instrument, dubbed RAMiTS (RAMan Tunable Integrated Sensor), provides a spectral analysis. The final product will translate that into a readout identifying the chemical or compound.
Vo-Dinh, a group leader and corporate fellow in the Life Sciences Division, expects the instrument to be useful for environmental monitoring, medical diagnostics, health protection, food inspection, law enforcement and military applications.
"Instead of taking a sample and having to send it off to a laboratory, where it may take days to get the results, this instrument will enable people to get an instant analysis of samples in the field," Vo-Dinh said. "This will result in a great reduction not only in time but also in cost."
Vo-Dinh envisions RAMiTS being used to monitor environmental pollution, detect chemical agents, and inspect meat and other food products more quickly and accurately than is possible with conventional technologies. Its potential uses for medical applications, ranging from screening for diseases to diagnostics, are also significant, said Vo-Dinh, who has developed several technologies and won six R&D 100 awards for products designed to protect people and the environment.
Other developers of the technology and product are Brian Cullum, Joel Mobley and David Stokes of the Life Sciences Division and Alan Wintenberg, Shane Franks and Bob Maples of the Instrumentation and Controls Division.
The project was funded by DOE and the Department of Justice. ORNL is a DOE multiprogram facility operated by UT-Battelle.
Materials provided by Oak Ridge National Laboratory. Note: Content may be edited for style and length.
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