A specialized detection coil used in a nuclear quadrupole resonance, or NQR, system for detecting hidden narcotics and explosives has been patented by the Naval Research Laboratory. A similar system has been successfully field tested at airports in the United States and overseas. The geometry of the patented coil causes electrical and magnetic noise to be canceled, providing a larger signal-to-noise ratio in the NQR signal from the object being tested. Because of its immunity to external electrical and magnetic environmental noise, an NQR detection system with the NRL patented-coil does not require external radio frequency shielding, making it suitable for field use. NQR is a radio frequency spectroscopic technique related to nuclear magnetic resonance and magnetic resonance imaging; however, no large magnet is required by NQR. The system irradiates a specimen with radio-frequency energy at specific frequencies. The size of the return signal indicates the presence or absence of known explosives and narcotics. Dr. Allen Garroway and his colleagues pioneered the use of NQR for explosives and narcotics detection by successfully addressing the technical issues required to move NQR out of the laboratory and into the field.
This work has been funded since 1987 by the Federal Aviation Administration and Department of Defense to advance U.S. capabilities in antiterrorism and antidrug efforts and in landmine detection. Quantum Magnetics, a subsidiary of InVision Technologies, builds airport baggage scanning systems under an NRL license.