Patent ID: 9575019
Date: 2017-02-21
CPC Classifications: G01N,G01R

Claim:
1. A method for detecting hazardous materials, the method comprising: positioning a non-metallic container holding a liquid sample in a static magnetic field; applying a first nuclear magnetic resonance (NMR) pulse sequence to the liquid sample having a frequency corresponding to a proton NMR frequency in the static magnetic field; receiving a first plurality of NMR measurement signals from the liquid sample responsive to the proton NMR frequency; measuring relaxation times of the plurality of NMR measurement signals received, wherein said measuring comprises measuring spin-lattice relaxation times (T applying a second NMR pulse sequence to the liquid sample having a frequency corresponding to a receiving a second plurality of NMR measurement signals from the liquid sample responsive to the measuring signal amplitudes of the second plurality of NMR measurement signals; calculating ratios of the T comparing each of the ratios determined from the first plurality of NMR measurement signals received to corresponding predetermined thresholds; generating an alarm indication if any of the ratios exceeds the corresponding predetermined threshold that indicates the presence of explosive precursors in the liquid sample; after generating the alarm indication, applying a third NMR pulse sequence having a frequency corresponding to a proton NMR frequency to the liquid sample providing a higher sensitivity scan; receiving a third plurality of NMR measurement signals; and measuring additional relaxation times and signal amplitudes of the third plurality of NMR measurement signals received.