A Step Closer to Detecting Landmines

Fall 2003


Finding landmines by scientific methods rather than by chance has become an urgent mission. An estimated 60 million to 100 million landmines are buried in at least 68 countries around the world. Called by some the most dangerous kind of pollution, these anti-personnel mines and devices come in more than 600 varieties. Some are the cheap and deadly remnants of recent wars and terror campaigns, but many others were strewn around as long as 50 years ago and still are dangerous.

In Cambodia, one of every 250 people has lost a limb after stepping on a landmine, reports Science News Online. The Soviets in Afghanistan spread millions of the deadly “butterfly” landmines. And millions of unexploded shells, grenades, and bombs also have made fields, forests, and even urban areas treacherous zones. Children are especially vulnerable, for their curiosity leads them to pick up unexploded ordnance. Those who aren’t killed outright suffer traumatic injuries.

At the Whiting School’s Center for Materials Sensing and Detection, researchers are looking at new ways to detect buried landmines and other explosives in real-time using chemical sensors. The center, established in 2002, is part of the Department of Defense (DoD) Multidisciplinary University Research Initiative (MURI). This new center partners several divisions of Johns Hopkins with Stanford University, the Rensselaer Polytechnic Institute, and SRI International. James B. Spicer ’91 PhD, associate professor of Materials Science and Engineering at the Whiting School, serves as principal investigator.

“We’ve selected technologies that could be applied usefully to the problem of explosive detection that haven’t been investigated before,” says Spicer. “We’re not inventing explosives detection. We’re applying different technologies to the problem.”

For Spicer, this work is all about proving these new chemical detection techniques are viable. And there’s plenty of work to be done. “The challenge is not simply finding something that can detect explosives in the laboratory. There are many techniques that will do that,” says Spicer. “The real challenge comes when an explosive is in the environment.”

In looking at how these technologies might be applied, Spicer explains that “if you have a landmine or unexploded ordnance that’s buried, explosives leak out. What we’re trying to do is detect leaked chemical components from the explosive as they exist either on the ground surface or in the air just above the unexploded ordnance.”

Most explosive materials are composed of common chemical elements, such as hydrogen, carbon, and nitrogen, which are abundant throughout nature. So the job of detection is far from an easy one, and team members must go a step further to find what they’re looking for. “How does an explosive change between the time it leaks from a landmine to the point where you can detect it in the soil or the air?” asks Spicer. As these explosive-related compounds work their way into the environment, factors such as water, bacterial action, vaporization, and even sunlight can alter their form. “It’s the explosive-related compounds that we’re looking for,” says Spicer.

In his research, Spicer applies advanced optical and ultrasonic sensor techniques to the materials systems he studies. The Whiting School alumnus has been developing laser ultrasonic techniques to measure and characterize sub-micron scale structures. It’s all part of the approach of today’s materials scientists who are working at the limits of matter itself, conducting research in the realm of nano-scales (one-billionth of a meter) to advance a science that draws from physics, chemistry, and even biology. The MURI Center is a good example of this type of interdisciplinary research.

The researchers will make use of four new techniques for the real-time detection of unexploded ordnance and landmines. These chemical analysis techniques are Terahertz (THz) Imaging and Spectroscopy, Laser-Induced Breakdown Spectroscopy (LIBS), Cavity Ring Down Spectroscopy (CRDS), and Resonance Enhanced Multiphoton Ionization (REMPI).

William R. Brody, president of the Johns Hopkins University, in a recent presentation to U.S. Army leaders at the Aberdeen Proving Ground, mentioned Spicer’s “promising research.” Brody noted how Spicer’s team is using laser spectroscopy to quickly and easily detect the presence of explosives typically used in landmines and other anti-personnel devices.

The MURI Center is in the initial stages of its five-year program. Its faculty are acquiring equipment, working out their research plans, and identifying partners. One educational component of the center will enable eight graduate students and four postdoctoral fellows to participate in the research, and undergraduates. The program will also offer internships for students at DoD labs, and provide an exchange of students among the MURI institutions.

For more information, contact Lani Hummel, director of the Whiting School’s Office of Industrial Initiatives, at [email protected] or (410) 516-8941.