Hand-held contraband detector
First Claim
1. A portable contraband detection system for detecting contraband concealed within an object, said detection system comprising:
- gamma ray generating means for generating low energy gamma rays, said gamma ray generating means being located within a shielded housing having a collimator opening, said gamma ray generating means including means for generating gamma rays having a plurality of prescribed energies;
shutter means for selectively directing said low energy gamma rays through said collimator opening or into said shielded housing, said shutter means including a shutter assembly having a closed position wherein said gamma rays are absorbed into said shielded housing, and an open position wherein said gamma rays are directed through said collimator opening, said shutter assembly comprising;
a shaft passing through said shielded housing,a drum mounted for rotation about its longitudinal axis on said shaft,means for receiving a plurality of radioactive sources within said drum, each of said radioactive sources having a prescribed energy, each radioactive source being contained in a housing having an open end and a closed end, said closed end being held in said drum so as to be near the longitudinal axis of said drum, said open end being near a circumferencial surface of said drum,means for selectively rotating said drum 180°
, said open position corresponding to positioning said drum such that the open end of each of said radioactive source housings is the closest possible distance to said collimator opening, and said closed position corresponding to rotating said drum 180°
from said open position such that the open end of each of said radioactive source housings in the farthest possible distance from said collimator opening;
gamma ray detection means for detecting backscattered gamma rays from a source external to said shielded housing;
processing means for monitoring the number of backscattered gamma rays detected by said detecting means and displaying a count signal detecting means and displaying a count signal representative thereof;
means for detecting any significant change in said count signal as said low energy gamma rays are selectively directed towards adjacent prescribed volumes of said object, the number of backscattered gamma rays noticeably changing if one of said adjacent prescribed volumes contains contraband;
whereby contraband within one of said prescribed volumes may be detected by monitoring changes in said count signal.
1 Assignment
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Accused Products
Abstract
A light-weight hand-held contraband detection system (10) includes two different sources (74) of low energy gamma rays. Each gamma ray source selectively emits gamma rays at a different energy level, which gamma rays are directed to a specific volume (30) of an object, e.g. a vehicle, being searched. The hand-held detection system also includes a gamma ray detector (42) coupled to a visual indicator (14), which indicator visually indicates the relative number of back-scattered gamma rays reflected back from the object being searched. Back scattering of the emitted gamma rays occurs in differing degrees depending upon the density and contents of the particular volume of the object receiving the gamma rays. Certain changes in density reflect the possibility that contraband, such as drugs, may be concealed in the object being searched. In use, the system is gripped in a hand of the user and passed over the surface of the object being searched. A mechanical latch (80, 82, 90, 92, 94) allows a user to use the system without having to continually press a thumb switch (22). The indicator (14) on the device is detachable from the housing, but remains electrically connected to the housing through an umbilical cord. One embodiment of the detection system also includes audible alarm means (54, 59) for providing an audible indication to the user of the relative number of backscattered gamma rays.
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Citations
10 Claims
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1. A portable contraband detection system for detecting contraband concealed within an object, said detection system comprising:
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gamma ray generating means for generating low energy gamma rays, said gamma ray generating means being located within a shielded housing having a collimator opening, said gamma ray generating means including means for generating gamma rays having a plurality of prescribed energies; shutter means for selectively directing said low energy gamma rays through said collimator opening or into said shielded housing, said shutter means including a shutter assembly having a closed position wherein said gamma rays are absorbed into said shielded housing, and an open position wherein said gamma rays are directed through said collimator opening, said shutter assembly comprising; a shaft passing through said shielded housing, a drum mounted for rotation about its longitudinal axis on said shaft, means for receiving a plurality of radioactive sources within said drum, each of said radioactive sources having a prescribed energy, each radioactive source being contained in a housing having an open end and a closed end, said closed end being held in said drum so as to be near the longitudinal axis of said drum, said open end being near a circumferencial surface of said drum, means for selectively rotating said drum 180°
, said open position corresponding to positioning said drum such that the open end of each of said radioactive source housings is the closest possible distance to said collimator opening, and said closed position corresponding to rotating said drum 180°
from said open position such that the open end of each of said radioactive source housings in the farthest possible distance from said collimator opening;gamma ray detection means for detecting backscattered gamma rays from a source external to said shielded housing; processing means for monitoring the number of backscattered gamma rays detected by said detecting means and displaying a count signal detecting means and displaying a count signal representative thereof; means for detecting any significant change in said count signal as said low energy gamma rays are selectively directed towards adjacent prescribed volumes of said object, the number of backscattered gamma rays noticeably changing if one of said adjacent prescribed volumes contains contraband; whereby contraband within one of said prescribed volumes may be detected by monitoring changes in said count signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification