Patent Number: 059303140
Section: claims

1. An apparatus for analyzing radiation emitted by an object in response to neutron bombardment, the apparatus comprising a radiation detector array for detecting the energy of gamma rays emitted by the object in response to neutron bombardment and for producing detection signals responsive to the energy of the detected gamma rays,  a coded aperture, having a predetermined configuration, disposed between the detector array and the object such that emitted radiation is detected by the detector array after passage through the coded aperture; and  a data processor for characterizing the object by substantially determining the elemental composition of the object,  disposing a coded aperture, having a predetermined configuration, in selected proximity to the object;  interrogating the nuclei of the object with an energy source, the interrogation resulting in emitted radiation, said interrogating step including bombarding said object with fast neutrons,  detecting, with a detector, at least a portion of the radiation emitted in response to the nuclear interrogation, the detector producing detection signals responsive to the radiation incident upon the detector after passage through the coded aperture; and  processing the detection signals to characterize the object based upon the emitted radiation detected by the detector, and based upon the predetermined configuration of the coded aperture.  disposing a coded aperture, having a predetermined configuration, in selected proximity to the object;  interrogating the nuclei of the object with an energy source, the interrogation resulting in emitted radiation, said interrogating step including bombarding said object with fast neutrons,  detecting, with a detector, at least a portion of the radiation emitted in response to the nuclear interrogation, the detector producing detection signals responsive to the radiation incident upon the detector after passage through the coded aperture; and  processing the detection signals to characterize the object based upon the emitted radiation detected by the detector, and based upon the predetermined configuration of the coded aperture, wherein said processing step comprises  disposing a coded aperture having a predetermined configuration in selected proximity to the object;  generating a beam of fast neutrons;  irradiating the object with the beam of fast neutrons, the fast neutrons interacting with atomic nuclei of the elements contained within the object to produce gamma-rays characteristic of the elements contained within the object;  measuring the characteristic spectral lines of the gamma-rays using a radiation detector array and a data processor, the gamma-rays having passed through the coded aperture disposed between the object and the radiation detector array;  determining density distributions of the elements contained within the object based upon the measured characteristic spectral lines and the predetermined configuration of the coded aperture;  comparing the density distributions with known density distributions of the elements of interest. 2. A method of analyzing radiation emitted by an object in response to nuclear interrogation, comprising the steps of: 3. The method of claim 2, wherein the step of interrogating nuclei of the object further comprises bombarding the object with neutrons having energies from about 1 to about 15 MeV. 4. A method of analyzing radiation emitted by an object in response to nuclear interrogation, comprising the steps of: 5. A method of analyzing the elemental composition of an object in response to neutron bombardment, comprising the steps of 6. The method of claim 5, wherein said irradiating step further comprises irradiating the object with a pulsed beam of neutrons. 7. The method of claim 5, wherein said elements of interest are selected from the group consisting of at least oxygen, carbon, nitrogen, hydrogen, and chlorine. 8. The method of claim 5, wherein the method of analyzing the elemental composition includes determining the proportion of any one or more metals in a compound, ore, or alloy. 9. The method of claim 8, wherein the metals include precious metals.