Laser desorption and detection of explosives, narcotics, and other chemical substances
First Claim
1. A method of detecting the presence of a preselected contraband substance on a surface of an object comprising the steps of:
- a. illuminating an interrogation area of said surface with a pulsed beam of light emitted from an infrared laser, said illumination having sufficient intensity and duration to cause selective ablation of molecules of said contraband substance present on said surface without substantially damaging said surface;
b. collecting at least a portion of said desorbed molecules in a collection system;
c. analyzing said portion in a chemical analysis system, the system being associated with said collection system and comprising a detector responsive to the presence in said chemical analysis system of said contraband substance;
d. outputting an electrical signal representative of said presence of said contraband substance; and
e. activating signal means operably connected to said chemical analysis system in response to the output of said electrical signal.
1 Assignment
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Accused Products
Abstract
A compact scanning apparatus includes an optical system to deliver a beam of pulsed infrared laser light that illuminate an interrogation area of a surface. The illumination has sufficient intensity and duration to cause selective ablation of molecules of a contraband substance present on the surface without substantially damaging the surface. A collection system collects at least a portion of the ablated molecules and transfers them to a chemical analysis system having a detector. In response to the presence of a wide variety of contraband substance molecules, the detector outputs an electrical signal that activates an audible or visible alarm. Automated screening is provided in an accurate, reliable manner that virtually eliminates the vagaries of human performance. False alarms are reduced. Detection efficacy is increased. A traceable residue of the detected contraband is left on the article for subsequent forensic analysis.
68 Citations
53 Claims
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1. A method of detecting the presence of a preselected contraband substance on a surface of an object comprising the steps of:
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a. illuminating an interrogation area of said surface with a pulsed beam of light emitted from an infrared laser, said illumination having sufficient intensity and duration to cause selective ablation of molecules of said contraband substance present on said surface without substantially damaging said surface;
b. collecting at least a portion of said desorbed molecules in a collection system;
c. analyzing said portion in a chemical analysis system, the system being associated with said collection system and comprising a detector responsive to the presence in said chemical analysis system of said contraband substance;
d. outputting an electrical signal representative of said presence of said contraband substance; and
e. activating signal means operably connected to said chemical analysis system in response to the output of said electrical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An apparatus for non-destructively detecting the presence of a contraband substance on a surface of an object comprising:
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a. an infrared laser adapted to emit light;
b. an optical system adapted to deliver a pulsed beam of said light emitted from said infrared laser to illuminate an interrogation area of said surface, said illumination having sufficient intensity and duration to cause selective ablation of molecules of said contraband substance present on said surface without substantially damaging said surface;
c. a collection system adapted to collect at least a portion of said desorbed molecules;
d. a chemical analysis system associated with said collection system and having a detector responsive to the presence in said collection system of said desorbed molecules and adapted to output an electrical signal representative of said presence of said contraband substance; and
e. signal means operably connected to said chemical analysis system and responsive to the output of said electrical signal. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
a. a computer operably connected to said detector, said drive motor, and said translation means;
b. a computer display terminal associated with said computer;
c. said computer being adapted to control the operation of said drive motor and said translation means; and
d. said computer further being adapted to display on said computer display terminal a mapping representative of the positions on said surface at which said contraband substance is detected.
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48. The apparatus of claim 26, further comprising translation means adapted to move said object.
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49. An apparatus as recited by claim 26, wherein said intensity and duration of said illumination is not sufficient to cause substantial deflagration or detonation of said substance present on said surface.
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50. An apparatus as recited by claim 26, wherein said detector is a GC/MS detector.
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51. An apparatus as recited by claim 26, wherein said detector is an FIS detector.
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52. An apparatus as recited by claim 26, wherein said detector is a gas-phase infrared detector.
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53. An apparatus as recited by claim 26, wherein said detector is a photoacoustic detector.
Specification