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Explosive Detection Method and Apparatus Using Selective Gamma Ray Resonance Absorption

Abstract: 

An apparatus and method for determining the presence of certain elements or compounds within an object, wherein the object under examination contains both nuclei of a first type which exhibit nuclear magnetic resonance and nuclei of a second type which exhibit nuclear quadrupolar resonance. The apparatus and method involve subjecting the object to a magnetic field and to a radiation beam whose characteristics in the presence of a magnetic field and in the absence of a magnetic field can be measured. The radiation transmission and/or absorption "fingerprint" of a particular substance is experimentally determined and recorded in the presence of a magnetic field calculated to optimize a cross coupling between nuclei of the first (NMR) type and nuclei of the second (NQR) type. This reference is then utilized later as a basis on which to identify an unknown compound exhibiting the same radiation absorption and/or transmission characteristics in response to the same or similar magnetic field intensity. Specific types of radiation and specific magnetic field intensities are pre-selected as optimizing the detectability of specific NMR/NQR element pairs.

Patent Number: 
5,159,617
Date Of Issue: 
10/27/1992
Inventors: 

Derwin J. King;Colin I. Nichols