News | Apr 10, 2019

Army researcher invents detector for buried, non-metallic bombs

The patented invention is available to businesses for product development

News Article Image of Army researcher invents detector for buried, non-metallic bombs

Dr. Benjamin Barrowes, a research physicist with the U.S. Army Engineer and Research Development Center’s Cold Regions Research and Engineering Laboratory, demonstrates the function of the High-Frequency Electromagnetic Induction instrument. (Army photo)

An Army research physicist has invented a “High-Frequency Electromagnetic Induction instrument,” which detects low and non-metallic improvised explosive devices.

Dr. Benjamin Barrowes, from the U.S. Army’s Engineer Research and Development Center’s Cold Regions Research and Engineering Laboratory, invented the novel detector for finding non-metallic, unexploded shells made of carbon fiber that had been fired on U.S. military ranges. The invention was patented in 2018. (Download the patent PDF below.)

“Carbon fiber is more conducting than the ground but less conducting than metal. Thinking about what actually happens when we bring these frequencies close to metal, I realized that the electrons in less conducting targets needed to be pushed harder in order to respond like they do in metals, because it is difficult for electrons to move in less conducting targets, kind of like moving your hand through water as opposed to moving your hand through the air.

“The way to push electrons harder at these frequencies is to use a higher frequency, so that is the direction we went in while maintaining the set of physical assumptions that we used in our models and our understanding,” Barrowes said in a recent Army report.

Because carbon fiber is at least a thousand times less conducting than metal, Barrowes developed a new sensor that operates in the higher frequencies, from 100 kHz up to 15 MHz.

“Our sensor was able to find carbon-fiber shells in the ground. It was also able to find carbon rods and wires, which are typical constituent parts of improvised explosive devices,” Barrowes said.

The sensor was tested on local soils and local targets and at Fort AP Hill, which has IED test lanes where the researchers were able to find carbon rods and wires associated with IEDs, as well as voids in the soil that can indicate an ammonium nitrate-based bomb.

News Article Image of Army researcher invents detector for buried, non-metallic bombs

A U.S. Army combat engineer uses a ground-penetrating-radar enabled metal detector to search for improvised explosive devices.

Richard Wrigley/Army

“The current handheld IED detection system used by dismounted troops in theater combines two separate sensors into one form factor. The first sensor is a low-frequency electromagnetic induction sensor which excels at finding metallic targets. The second sensor is a ground-penetrating radar sensor, which excels at finding disturbances under the soil, but it has trouble distinguishing different types of disturbances; for example, the difference between a rock and a metal target,” he said.

The high-frequency electromagnetic induction sensor bridges the gap between these two sensing modalities and enables a handheld sensor to find very thin metallic objects like wires, less conducting targets like carbon rods from D cell batteries, and voids in the soil that could indicate a nonconductive IED, such as an ammonium nitrate fuel oil IED.

“When the current handheld sensor incorporates higher frequency electromagnetic induction into the system, it will be better able to distinguish typical IED targets. The false alarm rate will go down, and the positive ID rate will go up, saving soldiers’ lives,” Barrowes said.

Business Opportunity

In coordination with the Army technology transfer program, TechLink is helping innovative companies explore the technology for commercialization.

TechLink is the Department of Defense’s national partnership intermediary for technology transfer, and for 20 years has been guiding businesses through patent licensing process at no charge.

Marti Elder, a senior technology manager at TechLink, has helped dozens of businesses find lucrative opportunities in the Engineering Research and Development Center’s patent portfolio and helped them draft the necessary application and commercialization plan.

Elder said that Barrowes’ non-metallic detector may also have non-military applications that could be useful to industry customers or the public.

“Through technology transfer, businesses can benefit from the military’s investment in research and expand an established market with new capabilities,” Elder said. “And it’s promising to see this being promoted by the Army, who’s hopeful for a transition partner that can make this a tool commercially available to warfighters.”

Licensing inquiries can be sent to Marti Elder at or she can be reached by telephone at 406-586-7621.