Induced nuclear reactions: processes – systems – and elements – Nuclear transmutation – By neutron bombardment
Patent
1990-01-12
1991-12-31
Hunt, Brooks H.
Induced nuclear reactions: processes, systems, and elements
Nuclear transmutation
By neutron bombardment
376165, 376166, G21G 106
Patent
active
050769936
ABSTRACT:
A system and method for detecting contraband generates a highly collimated beam of pulsed fast neutrons, having a pulse width on the order of a nanosecond, and an energy of 5 to 9 MeV. An object under investigation is scanned with the collimated pulsed beam. The neutrons in the beam cause (n, .gamma.) reactions in a limited object volume or voxel, defined by the intersection of the collimated beam and the scanned object. The highly penetrating fast neutrons produce nuclear reactions with the atomic elements present within the object, causing gamma rays to be emitted. By measuring the approximate time of flight of the neutron pulse, a determination is made as to the particular voxel from which the gamma ray originated. The energy of the detected gamma rays identifies the particular elements from which the gamma rays originated. Thus, e.g., the carbon, nitrogen, oxygen, and chlorine content, which elements are commonly found in contraband, of a particular voxel can be determined directly and precisely. This voxel content information may be combined from a substantial sample of the voxels that make up the object to provide a direct indication of the elemental content of the object, and hence whether contraband is present or absent within the object.
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Gozani Tsahi
Ryge Peter
Sawa Z. Peter
Hunt Brooks H.
Science Applications International Corporation
Voss Frederick H.
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