Quantum Magnetics Targets Landmine Explosives Using Quadrupole Resonance
by Caroleen Williams, Dr. Peter V. Czipott and Dr. Lowell J. Burnett, Quantum Magnetics
San Diego-based Quantum Magnetics did not intend to develop the world’s best landmine detection technology, but it just might turn out that way. For the past five years, the company has been working to develop landmine detection technology that would be so specific and effective that it would minimize false alarms, thus saving lives and limbs of U.S. soldiers, citizens and landmine sweepers alike. Although Quantum Magnetics is also developing other security-related technologies for applications such as bomb, drug and concealed-weapon detection, it has continued to keep its core objective on course, and its scientists continue to concentrate on solving the most important ingredient of landmine detection—identifying buried landmine explosives used in mines quickly and with few false alarms. By targeting the specific molecules of explosives (such as RDX, tetryl, PETN, and the hardest to detect, TNT), Quantum Magnetics believes its sensors alone, or in combination with other detection devices, will be instrumental in removing the estimated 60 million to 110 million landmines abandoned throughout the world.
Quadrupole resonance (QR) is the only chemically specific technology that detects the presence of explosives in bulk. In cooperation with the Naval Research Laboratory and funded by the Federal Aviation Administration (FAA), DARPA, the U.S. Army and the Office of Naval Research, Quantum Magnetics has pioneered the use of QR explosives detection technology for landmine detection and aviation security. The Department of Defense clears lanes through minefields as quickly and reliably as possible under battlefield conditions. Combining a very high probability of detection with a very low false alarm rate is the best way to achieve this objective. Obviously, the same technology holds promise for humanitarian and commercial demining situations as well, situations in which each and every mine must be found and removed.
Current detection technologies are "clutter-limited," and deminers now endure between 100 and 1,000 false alarms for every mine found. All mines are plastic-cased or metal-cased; the former typically contain a small metal firing pin. Accordingly, metal detectors have been the chosen detection device. Metal-cased mines are typically much larger than clutter items (such as cartridge cases and shell fragments) and are easier to detect. But the metal detector set to alarm small metal firing pins within plastic-encased mines, also alarms the smallest metallic clutter commonly found on battlefields. It is no mystery why there were 93 victims among the deminers in Bosnia, who were able to clear only 15 square kilometers in their first three years of work.2 Fatigue and carelessness led to these casualties. Obviously, deminers, solders and citizens alike would welcome alternative technology that promises to detect only mines—large and small, metal—or plastic-encased.
QR technology also responds to the presence of large metal objects, so it can detect both antitank (AT) and anti-personnel (AP) mines with an exceptionally high probability of detection while maintaining a very low false alarm rate. Since QR is chemically specific, the presence of other substances will not affect results adversely. And because QR detection is signal-to-noise ratio limited, not clutter limited, it is the only technology capable of resolving its own false alarms. Reducing clutter alarms by even as little as 70 to 80 percent would at least double the productivity of every deminer and reduce the fatigue element they suffer when coping with the hundreds of false alarms they now endure.
In the Bosnia tests, the QR electronics were mounted on a military vehicle and connected to the hand-held QR scanning coil by a long tether. In a 10 by 10 foot square patch of ground at Eagle Base, Tuzla, the U.S. Army buried seven lumps of military C4 explosive, containing the active chemical RDX and a metal-cased PROM mine (inert dummy). The Army also buried eight spent cartridges (5.56 mm) to simulate metallic clutter usually encountered on a battlefield.
The Bosnia tests took place in June 1999. By October in the same year, Quantum Magnetics had developed the ability to detect TNT (contained in the majority of landmines worldwide) sufficiently to test it at a test range in Fort Leonard Wood, MO. The results in Figure 6 reportedly represent the first-ever QR detection of TNT landmines in the field.
QR is User Friendly
As the QR detection probe interrogates a given area, results are presented as a simple red light/green light display to indicate either the presence or absence of a mine. QR systems require no calibration or special maintenance and are ruggedly designed to withstand many hours of uninterrupted use. Importantly, the technology is safe and does not use ionizing radiation, radioactive sources or strong magnetic fields.
Quantum Magnetics is currently developing its QR technology into a man-carried backpack configuration, for eventual use by the U.S. Marine Corps, as required by the Office of Naval Research. Once this work is completed, the 35-pound detector, including probe, electronics and batteries, will be capable of scanning all variations of terrain encountered by deminers, military or civilian.
Supported by the U.S. Army, Quantum is also developing its technology into a vehicle-mounted configuration for use in detecting antitank (AT) mines in roads. A confirmation sensor, designed to validate or clear alarms produced by other sensor technologies, will be tested this year. A primary scanning sensor will be developed and tested in 2002.
With all these advancements, however, QR is not yet ready for prime time. Quantum Magnetics is continuing to perform research to further improve detection, as are other organizations domestically and abroad. Some of the challenges that must be overcome include the following:
Future Demining Strategies
Quantum Magnetics is now working on the premise that using QR explosive detection to find plastic-cased mines and QR metal detection to locate metal-cased mines results in a system with high detection and low false alarm rates. In fact, portable QR systems could clear between 60 and 95 percent of today’s false alarms, eliminating the dangerous and time-consuming step of probing the ground, thus improving safety and increasing the area cleared per unit time per deminer. Using QR detectors as confirmation sensors would significantly reduce metal detector false alarms and subsequent probing with sticks to a minimum. Other efforts include work to suppress sources of "noise," such as electronic amplifier noise and external radio frequency interference in the QR measurement. As the company works to improve its detection capabilities, it is also engineering a backpack-configured detection system that can be carried by military deminers. In a parallel effort, Quantum Magnetics is engineering vehicle-mounted systems for both primary and confirmation scanning. Eventually, with suitable modification, both types of systems may prove valuable new tools in the arsenal of humanitarian as well as military mine clearers.
In summary, Quantum Magnetics’ success thus far in blind test environments indicate its QR-based technology will soon be capable of detecting landmines better, faster and less expensively than alternative demining processes. With government support, progress is being made every day to detect the smallest mines at the deepest depths in the shortest scanning time possible.
1. "Filling the Technology Gap in Humanitarian Demining," Dr. Regina E. Dugan, March 3, 2000.
2 . J.J. Rant, Institute J. Stefan, Ljubljana, Slovenia; private communications; October 1999.
*All photos and graphics courtesy of the author.
Peter V. Czipott
Lowell J. Burnett