On Question of Possibilities of NMR in Weak Magnetic Fields for Detection of Illicit Liquids

Abstract

The method of the detection and identification of different liquids on the basis of registration of NMR in the Earth magnetic field has been discussed. Some general aspects of the problem are considered to illustrate the near-term outlooks. In particular, the polarization of nuclei with an alternating magnetic field B* (B* >> B-0) at a very low frequency F (but F >> 1/T-1, where T-1 is the spin-lattice relaxation time) has been investigated. The study is directed to the development of the application of industrial power (50 Hz) for the nuclear polarization. The question of the optimization of the energy consumption during the pre-polarization is also considered. The possibilities of the method are illustrated by the observation of NMR signals from liquids with the external sample location and in aluminum closed cans.