X-ray inspection using co-planar pencil and fan beams

• US 6,453,007 B2
• Filed: 02/16/2001
• Issued: 09/17/2002
• Est. Priority Date: 11/30/1998
• Status: Expired due to Term

• Current Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Original Assignee: American Science and Engineering Incorporated (OSI Systems Incorporated)
• Inventors: Adams, William L., Grodzins, Lee
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): Ho, Allen C.
• Application Number:
  US09/785,672
• Publication Number:
  US 20010016028A1
• Time in Patent Office: 578 Days
• Field of Search: 378/57, 378/90, 378/146, 378/147, 378/149, 378/160
• US Class Current: 378/90
• CPC Class Codes: G01N 23/203 Measuring back scattering

Abstract

An inspection system is for inspecting an object with penetrating radiation. A source of penetrating radiation provides a beam of radiation. The beam alternates between a first beam shape and a second beam shape, the first and second beam shapes being coplanar. A first detector arrangement is for detecting penetrating radiation from a portion of the beam transmitted through the object and generating a transmitted radiation signal. A second detector arrangement is for detecting penetrating radiation from a portion of the beam scattered by the object and generating a scattered radiation signal. A processor determines at least one characteristic of the object based at least on the transmitted and scattered radiation signals.

Claims

1. An inspection system for inspecting an object with penetrating radiation, the system comprising:

a source of penetrating radiation for providing a beam of radiation, the beam alternating between a first beam shape and a second beam shape, the first and second beam shapes being coplanar;

a first detector arrangement for detecting penetrating radiation from a portion of the beam transmitted through the object and generating a transmitted radiation signal;

a second detector arrangement for detecting penetrating radiation from a portion of the beam scattered by the object and generating a scattered radiation signal; and

a processor for determining at least one characteristic of the object based at least one of the transmitted and scattered radiation signals.

2. The inspection system as set forth in claim 1, wherein the source of penetrating radiation is an x-ray source.

3. The inspection system as set forth in claim 2, wherein the source of penetrating radiation is a pulsed x-ray source.

4. The inspection system as set forth in claim 2, wherein the source of penetrating radiation is an x-ray tube.

5. The inspection system as set forth in claim 2, wherein the source of penetrating radiation is a linear accelerator.

6. The inspection system as set forth in claim 1, further including a rotating chopper wheel that determines the beam shape.

7. The inspection system as set forth in claim 1, further including a rotating disk and slit arrangement that determines the beam shape.

8. The inspection system as set forth in claim 1, wherein the first beam shape is a pencil-shape, and the second beam shape is a fan-shape.

9. The inspection system as set forth in claim 8, further including a collimator for producing the fan shape.

10. The inspection system as set forth in claim 8, further including a scanner arrangement for varying the orientation of the pencil shape with respect to the object.

11. The inspection system as set forth in claim 8, further including an absorber associated with producing the fan-shape beam, the absorber reducing the intensity of low-energy components of the beam, while not significantly affecting the intensity of high-energy components of the beam.

12. The inspection system as set forth in claim 1, wherein the object is in motion with respect to the beam.

13. The inspection system as set forth in claim 1, wherein the system is in motion with respect to the object.

14. A method for characterizing an object, the method comprising:

illuminating the object with penetrating radiation formed into a beam,

the beam alternating between a first beam shape and a second beam shape, the first and second beam shapes being coplanar;

detecting penetrating radiation from a portion of the beam that is transmitted through the object so as to generate a transmitted radiation signal;

detecting penetrating radiation from a portion of the beam that is scattered by the object so as to generate a scattered radiation signal; and

determining at least one characteristic of the object based at least on the transmitted and scattered radiation signals.

15. The method as set forth in claim 14, wherein the source of penetrating radiation is an x-ray source.

16. The method as set forth in claim 15, wherein the source of penetrating radiation is a pulsed x-ray source.

17. The method as set forth in claim 15, wherein the source of penetrating radiation is an x-ray tube.

18. The method as set forth in claim 15, wherein the source of penetrating radiation is a linear accelerator.

19. The method as set forth in claim 14, wherein illuminating the object further includes determining the beam shape with a chopper wheel arrangement.

20. The method as et forth in claim 14, wherein illuminating the object further includes determining the beam shape with a rotating disk and slit arrangement.

21. The method as set forth in claim 14, wherein the first beam shape is a pencil-shape, and the second beam shape is a fan-shape.

22. The method as set forth in claim 21, wherein the fan shape is produced by a collimator arrangement.

23. The method as set forth in claim 21, wherein illuminating the object further includes varying the orientation of the pencil shape with respect to the object.

24. The method as set forth in claim 21, wherein the fan-shape beam is produced using an absorber that reduces the intensity of low-energy components of the beam, while not significantly affecting the intensity of high-energy components of the beam.

25. The method as set forth in claim 14, wherein the object is in motion with respect to the beam.

26. The method as set forth in claim 14, wherein the beam is in motion with respect to the object.