Two-dimensional imaging backscatter probe

• US 5,763,886 A
• Filed: 08/07/1996
• Issued: 06/09/1998
• Est. Priority Date: 08/07/1996
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Schulte, Robert L.
• Primary Examiner(s): Tokar, Michael J.
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US08/695,244
• Time in Patent Office: 671 Days
• Field of Search: 250/358.1, 378/57, 378/53, 378/90, 378/88
• US Class Current: 250/358.1
• CPC Class Codes: G01N 23/203 Measuring back scattering
• CPC Class Codes: G01T 7/00 Details of radiation-measuring instruments
• CPC Class Codes: G01V 5/222 measuring scattered radiation

Abstract

A two-dimensional imaging backscatter probe has a radiation source, a radiation detector, and a position sensing device to which the radiation detector is attached. A mapping circuit generates a two-dimensional map of backscattered radiation as a function of position of the radiation detector. A display displays the two-dimensional map. The two-dimensional imaging backscatter probe of the present invention facilitates non-destructive/non-intrusive inspection of a test article for contraband and/or structural integrity inspection.

Claims

1. A portable two-dimensional imaging backscatter system for performing non-destructive and non-intrusive inspection of a test article, the system comprising:

a) a radiation source for emitting radiation toward the test article;

b) a radiation detector for sensing radiation backscattered from the test article;

c) a position sensing device attached to the radiation detector for generating position information of the radiation detector as the radiation detector moves along the surface of the test article, the test article being at rest;

d) a mapping circuit in electrical communication with the radiation detector and the position sensing device for generating a two-dimensional map of backscattered radiation from the test article as a function of position of the radiation detector; and

e) a display for displaying the two-dimensional map,

2. The system as recited in claim 1 wherein the radiation source comprises a gamma radiation source.

3. The system as recited in claim 1 wherein the radiation source comprises an X-ray source.

4. The system as recited in claim 1 wherein the radiation source comprises cobalt.

5. The system as recited in claim 1 wherein the gamma radiation source comprises approximately 100 μ

Ci of ⁵⁷ Co with primary emissions at 122 keV and 136 keV.

6. The system as recited in claim 1 wherein the radiation detector comprises a cesium iodide scintillator crystal and a photomultiplier.

7. The system as recited in claim 1 wherein the mapping circuit processes position information from the position sensing device and count rate from the radiation detector to provide a drive signal for the display.

8. The system as recited in claim 1 wherein the mapping circuit comprises a general purpose microprocessor.

9. The system as recited in claim 1 wherein the mapping circuit comprises a portable computer in electrical communication with the position sensing device and the radiation detector.

10. A method for performing two-dimensional measurements of backscatter from a test article, the method comprising the steps of:

a) emitting radiation from a radiation source toward the test article;

b) sensing radiation backscattered from the test article with a radiation detector;

c) sensing a plurality of positions of the radiation detector as the radiation detector is moved about the test article;

d) generating a two-dimensional map of the backscattered radiation as a function of the positions of the radiation detector as it is moved about the test article; and

e) displaying the two-dimensional map upon a display.

11. The method as recited in claim 10 wherein the step of emitting radiation from a radiation source comprises emitting radiation from a gamma radiation source.

12. The method as recited in claim 10 wherein the step of emitting radiation from a radiation source comprises emitting radiation from an X-ray radiation source.

13. The method as recited in claim 10 wherein the step of emitting radiation from a radiation source comprises emitting radiation from a cobalt radiation source.

14. The method as recited in claim 10 wherein the step of emitting radiation from a radiation source comprises emitting radiation from a source comprising 100 μ

Ci of ⁵⁷ Co with primary emissions at 122 keV and 136 keV.

15. The method as recited in claim 10 wherein the step of sensing radiation backscattered from the test article with a radiation detector comprises sensing radiation with a cesium iodide scintillator crystal and a photomultiplier.

16. The method as recited in claim 10 wherein the step of generating a two-dimensional map of the backscatter gamma radiation as a function of the positions of the radiation detector comprises processing position information from a position sensing device and processing count rate from the radiation detector to provide a drive signal for the display.

17. The method as recited in claim 10 wherein the step of generating a two-dimensional map of the backscattered radiation as a function of the positions of the radiation detector comprises generating a two-dimensional map via a general purpose microprocessor.

18. The method as recited in claim 10 wherein the step of generating a two-dimensional map of the backscattered radiation as a function of the positions of the radiation detector comprises generating a two-dimensional map of the backscattered radiation utilizing a portable computer which is in electrical communication with the position sensing device and the radiation detector.

19. A hand-held probe for performing non-destructive and non-intrusive inspection of a test article, the probe comprising:

a) a radiation source for emitting radiation toward the test article; and

b) a radiation detector for sensing radiation backscattered from the test article, the radiation detector being a scintillator crystal having an annular shape;

wherein the radiation source is disposed in a central hole of the radiation detector such that the radiation source and the radiation detector are substantially collocated.

20. A hand-held probe for performing non-destructive and non-intrusive inspection of a test article, the probe comprising:

a) a radiation source for emitting radiation toward the test article;

b) a radiation detector for sensing radiation backscattered from the test article; and

c) a position sensing device attached to the radiation detector for generating position information of the radiation detector as the radiation detector moves along the surface of the test article, the test article being at rest.

21. The hand-help probe as recited in claim 20 wherein the position sensing device comprises an orthogonal mechanical tracking device.