Detection and classification of liquid explosives using NMR

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, T₂, and diffusion constant, D, thereby allowing for a unique classification of the liquid. The proposed detectors are evaluated using both simulated and measured data sets.