High energy X-ray inspection system for detecting nuclear weapons materials
First Claim
1. A method of detecting nuclear weapons materials with an x-ray inspection system, the method comprising the steps of:
- providing a high energy x-ray fan beam that traverses an object under inspection;
transmission detecting x-ray energy that passes through the object under inspection, and providing detected signals indicative thereof; and
processing said detected signals to detect the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials, wherein the x-ray attenuation of the nuclear weapons material is at least one standard deviation greater than the surrounding material.
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Abstract
An x-ray inspection system for automatically detecting nuclear weapons materials generates a high energy x-ray fan beam or a traveling x-ray pencil beam that traverses an object under inspection. An x-ray detector detects x-ray energy that passes through the object and provides a detected signal indicative thereof. The detected signal is processed to detect the presence of an area of very high x-ray attenuation within the object under inspection, which is indicative of nuclear weapons materials. Because of the high atomic number (Z) and high density of nuclear weapons materials Uranium and Plutonium, both of these materials attenuate (i.e., absorb) incident x-rays significantly more than ordinary materials. That is, very high Z materials such as nuclear weapons materials, produce no x-rays outside of their block of material because the x-rays are self absorbed within the very high Z materials. Therefore, these materials can be detected by a transmission detectors, or by combining the readings from transmission and scatter detectors, if a pencil beam system is employed.
152 Citations
14 Claims
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1. A method of detecting nuclear weapons materials with an x-ray inspection system, the method comprising the steps of:
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providing a high energy x-ray fan beam that traverses an object under inspection;
transmission detecting x-ray energy that passes through the object under inspection, and providing detected signals indicative thereof; and
processing said detected signals to detect the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials, wherein the x-ray attenuation of the nuclear weapons material is at least one standard deviation greater than the surrounding material. - View Dependent Claims (2, 3, 4, 5)
providing a radioactive source that generates a cone of x-rays; and
collimating said cone of x-rays to provide said fan beam.
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4. The method of claim 2, wherein said step of providing a high energy x-ray fan beam that traverses an object under inspection, comprises the steps of:
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providing an electronic x-ray source that generates a cone of x-rays; and
collimating said cone of x-rays to provide said fan beam.
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5. The method of claim 1, wherein said step of processing includes the step of comparing the magnitude of said detected signals to determine the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials.
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6. An x-ray inspection system for inspecting an object to detect nuclear weapons materials, the system comprising:
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means for providing a high energy x-ray fan beam that traverses the object;
a transmission detector that detects x-ray energy that passes through the object under inspection using a plurality of detector elements which collectively define said transmission detector, and provides detected signals indicative thereof; and
means for processing said detected signals to detect the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials, wherein the x-ray absorption of the nuclear weapons'"'"' material is at least one standard deviation greater than the surrounding material. - View Dependent Claims (7, 8, 9, 10)
a radioactive source that generates a cone of x-rays; and
a collimator that receives said cone of x-rays and provides said fan beam.
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9. The system of claim 7, wherein said means for providing comprises:
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an electronic x-ray source that generates a cone of x-rays; and
a collimator that receives said cone of x-rays and provides said fan beam.
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10. The system of claim 9, wherein said electronic x-ray source comprises a linear accelerator.
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11. An x-ray inspection system for inspecting an object to detect nuclear weapons materials, the system comprising:
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an x-ray source that provides a high energy x-ray fan beam that traverses an object under inspection;
a detector that detects x-ray energy from the object under inspection and provides a detected signal indicative thereof; and
a signal processor that processes said detected signal to detect the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials, wherein the x-ray absorption of the nuclear weapons material is at least an order of magnitude greater than lead. - View Dependent Claims (12, 13)
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14. A method of detecting nuclear weapons materials with an x-ray inspection system, the method comprising the steps of:
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providing a high energy x-ray pencil beam that traverses an object under inspection;
transmission detecting x-ray energy that passes through the object under inspection, and providing transmission detected signals indicative thereof;
scatter detecting x-ray energy that is emitted by the object under inspection, and providing scatter detected signals indicative thereof;
processing said transmission detected signals to detect the presence of an area of very high x-ray attenuation which is indicative of nuclear weapons materials, wherein the x-ray attenuation of the nuclear weapons material is at least one standard deviation greater than the surrounding material;
processing said scatter detected signals to detect the absence of a scatter signal in the area of very high x-ray attenuation as further indication of nuclear weapons'"'"' material.
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Specification