Detection of Explosives and Biological Warfare Agents using Nuclear Quadrupole Resonance

(Faculty Mentor: Jeff Schiano)

 

There is an acute need for a system that can detect biological threat materials and explosives in luggage or carried by an individual entering a protected area or crossing a protected border. We are developing technology based on quadrupole resonance (QR) that reveals the presence of anthrax spores and/or explosives within sealed containers. QR systems detect and discriminate specific nitrogen compounds. They perform this task using a search coil similar to those found in metal detectors. After the coil emits an oscillating magnetic field at a frequency identified with a specific nitrogen compound, it then detects a return signal if the target compound is present. QR detection systems present no health hazards to nearby workers and will not damage materials sensitive to ionizing radiation as they use non-ionization magnetic fields below 5 MHz.

 

QR technology has been actively developed since 1994 at Penn State for the detection of explosives, and more recently, biological warfare agents. Our primary research objective is to increase the probability of correct detection and reduce the false alarm rate while simultaneously minimizing the detection time. To achieve this goal we use feedback control concepts to automatically optimize detection performance, are developing low-power detection methods, and employ high-temperature superconducting search coils that significantly improve the signal-to-noise ratio. Our laboratory facility includes a versatile QR detection test bed, a wet chemistry area for synthesizing model compounds, a small machine shop for fabricating search coils, and an electronics station for assembling and testing instrumentation.

 

Several opportunities exist in our laboratory for undergraduate engineering students, including the design and development of electronic instrumentation, the synthesis of model compounds such as CaDPA for testing QR detection systems, and searching for unknown QR transition frequencies in compounds of interest. As an example, during the 2002 summer we employed a high school student who characterized the high-frequency impedance of a high-temperature superconductor search coil.