Non-explosive Technology

Non-explosive Technology

Physicist Naughton develops sensor to find plastic landmines

By Mark Sullivan
Staff Writer

More than 100 million landmines lie buried in Afghanistan, Bosnia, sub-Saharan Africa and other war-torn areas across the world. Many of these lethal underground explosives are made of plastic with few or no metallic parts, making them difficult to locate by conventional metal-detectors.

But Prof. Michael Naughton (Physics), drawing on silicon-chip technology used in everything from computer processors to automobile airbags, has invented a sensor that can accurately detect non-metallic landmines buried in the ground.

"One can be made for every mine out there, if that's what it takes," said Naughton, who along with former student Murali Chaparala received a patent this summer for their micro-electrical-mechanical systems (MEMS) sensor.


Prof. Michael Naughton (Physics) with an oversized model of his patented chip that can detect plastic objects buried in the ground.

Naughton said the miniature sensor, the size of a computer chip, acts as a super-sensitive microphone to pick up sound waves that have been bounced off an underground object.

The device is at least a year or two away from production, said Naughton, who is studying the acoustic frequencies at which the mine sensor works best.

His research has taken him to Home Depot for several tons of play sand, in which he has buried such objects as cinder blocks, plastic toys and the plastic shell of an actual - but deactivated - anti-personnel mine, and bombarded them with low-frequency acoustic waves. The waves reverberate off the buried objects and are detected by the sensor.

"The premise is that a certain type of buried object will reflect acoustic waves at particular frequencies better than at other frequencies," he said. The sensor can be fine-tuned to the most effective frequency, he added.

Naughton, who also holds a patent on an instrument that measures magnetic forces, said he had an epiphany a few years ago while having coffee with a colleague who models sound in soil. His magnetic technology, he reasoned, could also be used to measure acoustic vibrations to locate buried mines, the proliferation of which was emerging in the international consciousness.

Naughton has since been in contact with Sandia National Laboratories, a federal lab in New Mexico that has been researching the use of radar in finding landmines, and is interested in Naughton's advances in acoustic technology.

"We have strong evidence that low-frequency acoustic sensors see plastics better than radar or ultrasound, which is what we're excited about," he said.

Acoustic sensors won't do the job alone, said Naughton, who predicted that some combination of acoustic, radar and other technology will be required to most effectively detect new generations of landmines.

But he said he is excited that an idea born in his laboratory may be used in addressing a real-world problem.

"We do what we do for the love of discovery," said Naughton. "It will be really wonderful if it works out."

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