Detection of Explosives Using Nuclear Quadrupole ResonanceMarch 21, 2007
American Center for Physics
College Park, MD
Karen L. Sauer, George Mason University
Nuclear quadruple resonance (NQR), long considered the poor cousin to the powerhouse nuclear magnetic resonance, inherently suffers from low sensitivity as transition frequencies are typically on the order of a MHz. Nevertheless, the convenience of working without a large static field makes NQR attractive for certain applications, most notably explosives detection. Our recent work shows how the sensitivity of this technique can be significantly enhanced by improvements in both the excitation of the sample and the detection of the NQR signal. Through the use of small radio- frequency and static field pulses, the heterogeneous and homogeneous couplings between neighboring nuclei in the crystalline solid can be exploited to increase the resulting signal. The use of an atomic magnetometer, instead of the traditional Faraday coil, can improve the detection of this femtoTesla signal by an order of magnitude.
Karen L. Sauer received the B.A. (Bachelor of Arts) in Physics in 1992 from Cornell University in Ithaca, New York. She pursued graduate studies in Physics at Princeton University in New Jersey, where she received the Ph.D. degree in 1998 for work on laser-polarized liquid xenon in the Atomic Physics group. She was a Chateaubriand Postdoctoral Fellow at Ecole Normale Superieure in Paris, France from 1998-2000 working on dipolar field effects in highly magnetized fluids with the Quantum Fluids group at Laboratoire Kastler-Brossel. From 2000-2002, she was an NRC Postdoctoral Fellow at the Naval Research Laboratory in Washington D.C., working on three-frequency nuclear quadrupole resonance. In Sept. 2002, she joined the Dept. of Physics and Astronomy at George Mason University where she is currently an Assistant Professor. She received an NSF Early Faculty CAREER award in 2006 and an NSF ADVANCE award in 2002. Her main research interests lie in experimental atomic and molecular physics, with an emphasis on magnetic resonance phenomena.