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K-State professor assists in war on terror with bomb detection research

July 28, 2005

The Marines are looking for a few good men ... to assist them in their efforts in the war on terrorism. A Kansas State University professor is one of those men.

Bill Dunn, a K-State associate professor of mechanical and nuclear engineering, has been recruited by the Marines to develop a way to improve bomb detection without having to get in close proximity to suspicious containers such as cars, knapsacks, briefcases, etc., that may conceal explosives.

"The Marine Corps needs what they call 'stand-off' bomb detection," Dunn said. "We're trying to detect explosives remotely, where any people and anything that might be damaged if an explosive device is detonated are far enough away so that they are not injured or can survive the blast."

The device will use pulses of both gamma and neutron radiation that go into the target. What comes back to a large extent is determined by what is inside.

"Different elements emit radiation of different characteristic energies," Dunn said. "We're trying to detect what comes back from the target and see if it looks like what you would see in an explosive."

"We know what signals come back when we interrogate an object containing an explosive substance; now we're trying to find out the best way to analyze the data to make sure we're correct, that there are explosives on board."

Dunn said the problem becomes more complicated by the size of the container. Large cars make it easier to hide explosives while it is easier to detect explosives in a briefcase or a knapsack.

"Even if you put other things in small containers, we think we're going to get a set of signals that indicate the presence of explosives if they are there," Dunn said. "With larger containers it can become very complex, but we're still hopeful."

Dunn began working on the project in November 2004 as the death toll in the war in Iraq continued to increase due to car and suicide bombings by insurgents. The recent bombings in London - although different from the car bombs the project initially focused on - give the project even more of a priority.

"The technology we are trying to develop for car bombs can also be applied to a brief case, a knapsack or a suitcase," Dunn said. "Anything that encloses contents, you want to know what those contents are."

According to Dunn, technologies such as computed tomography that image devices are not appropriate for field use because they require the object to be placed in a housing and they involve high radiation levels.

"In the field these soldiers do not have the luxury of being able to put every package inside something and inspect it that way," Dunn said. We're trying to do this from several meters away; 'interrogate' something from a distance and say 'that looks suspicious.'"

Dunn said most conventional explosives used in these types of bombs have similar amounts of nitrogen, oxygen, hydrogen and carbon and give off a signature that is characteristic of those particular elements. In the same sense you aim a flashlight and it sends a beam of light, the detector sends a beam of gamma radiation - light of a shorter wave-length, higher energy - into an object. The radiation that comes back contains information about what is inside the container. Unlike a flashlight, however, Dunn said the detector would be a little bigger than a hand-held device.

"The military would love to have a hand-held device," Dunn said. "We're not optimistic that we can develop something that would be that light and maneuverable. It's possible over time, however, as we miniaturize things. But what we're trying to develop now would probably be on rollers."

If funding for the project is "dramatically increased," he believes he can have the device ready for field use in approximately a year. If funding continues at its current rate, he predicts three to four years.

"We think we understand the technology enough. The real thing is analyzing the data in a careful way so that you eliminate false negatives; you don't say that vehicle looks OK and it really has a bomb. We want to be as certain as possible that we detect a bomb if one is present.\\\

Kansas State University