Hidden explosives detector employing pulsed neutron and x-ray interrogation
AssigneeMartin Marietta Energy Systems, Inc.
InventorsFrederick J. Schultz, John T. Caldwell
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Abstract
Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.
Claims29
A method for detecting explosive material hidden in a package, comprising:
- the initial steps, in any order, of:
- employing pulsed thermal neutron interrogation and 10.8 MeV gamma ray detection to form a nitrogen density image of the package;
- and
- employing fast neutron interrogation and 6 and 7 MeV gamma ray detection to form an oxygen density image of the package;
- and
- then considering the images together to determine whether the package likely contains explosive material.
Apparatus for detecting explosive material hidden in a package, comprising:
- a pulsed neutron source for interrogating the package with both thermal and fast neutrons;
- an array of gamma ray detectors for detecting 10.8 MeV gamma rays emitted by nitrogen atoms within the package as a result of thermal neutron interrogation for forming a nitrogen density image of the package, and for detecting 6 and 7 MeV gamma rays emitted by oxygen atoms within the package following fast neutron interrogation for forming an oxygen density image of the package;
- and
- analysis means for determining whether the package likely contains explosive material based on the nitrogen density and oxygen density images.
A method for detecting explosive material hidden in a package, comprising:
- the initial steps, in any order, of:
- employing X-rays to form an X-ray image of the package,
- employing pulsed neutron interrogation and gamma ray detection to form a nitrogen density image of the package,
- employing neutron interrogation to form a hydrogen density image of the package;
- and
- then considering the images together to determine whether the package likely contains explosive material.
Apparatus for detecting explosive material hidden in a package, comprising:
- an X-ray imaging device for forming an X-ray image of the package;
- a pulsed neutron source for interrogating the package;
- an array of gamma ray detectors synchronized with said pulsed neutron source for detecting gamma rays emitted by nitrogen atoms within the package as a result of neutron interrogation for forming a nitrogen density image of the package;
- an array of neutron detectors for producing a hydrogen density image of the package based on scattering of neutrons by hydrogen atoms within the package;
- and
- analysis means for determining whether the package likely contains explosive material based on the X-ray, nitrogen density and hydrogen density images.
Apparatus for detecting explosive material hidden in a package, comprising:
- an X-ray imaging device for forming an X-ray image of the package;
- a pulsed neutron source for interrogating the package with both thermal and fast neutrons;
- an array of gamma ray detectors for detecting 10.8 MeV gamma rays emitted by nitrogen atoms within the package as a result of thermal neutron interrogation for forming a nitrogen density image of the package, and for detecting 6 and 7 MeV gamma rays emitted by oxygen atoms within the package following fast neutron interrogation for forming an oxygen density image of the package;
- and
- an array of neutron detectors for producing a hydrogen density image of the package based on scattering of neutrons by hydrogen atoms within the package;
- and
- analysis means for determining whether the package likely contains explosive material based on the X-ray, nitrogen density, oxygen density and hydrogen density images.
Dependencies are inferred from the claim text.