John A. S. Smith

Learn More
Nuclear Quadrupole Resonance (NQR) offers an unequivocal method of detecting and identifying land mines. Unfortunately , the practical use of NQR is restricted by the low signal to noise ratio (SNR), and means to improve the SNR are vital to enable a rapid, reliable and convenient system. In this paper, we develop a non-linear least squares detector(More)
—Nuclear quadrupole resonance (NQR) is a radio-frequency technique that can be used to detect the presence of quadrupolar nuclei, such as the 14 N nucleus prevalent in many explosives and narcotics. In a typical application, one observes trains of decaying NQR echoes, in which the decay is governed by the spin echo decay time(s) of the resonant line(s). In(More)
In this work, we present a novel method for non-invasive identification of liquids, for instance to allow for the detection of liquid explosives at airports or border controls. The approach is based on a nuclear magnetic resonance technique with an inhomogeneous magnetic field, forming estimates of the liquid's spin-spin relaxation time, T 2 , and diffusion(More)