X-ray detector system having low Z material panel

• US 7,110,493 B1
• Filed: 02/28/2002
• Issued: 09/19/2006
• Est. Priority Date: 02/28/2002
• Status: Expired due to Term

• Current Assignee: Rapiscan Systems Incorporated (OSI Systems Incorporated)
• Original Assignee: Rapiscan Security Products USA Incorporated (OSI Systems Incorporated)
• Inventors: Smith, Steven W., Kotowski, Andreas F.
• Primary Examiner(s): Wells, Kenneth B.
• Application Number:
  US10/086,473
• Time in Patent Office: 1,664 Days
• Field of Search: 378/57, 378/58, 378/62, 378 86- 87, 378/189, 378/198
• US Class Current: 378/87
• CPC Class Codes: G01V 5/222 measuring scattered radiation

Abstract

A method and apparatus for detecting concealed items on or in an object by utilizing a low Z material panel. The object to be scanned is located between an x-ray detector and the low Z material panel. The method includes producing a pencil beam of x-rays from an x-ray source directed toward the object, scanning the beam of x-rays over the object, and detecting x-rays scattered from the beam of x-rays as a result of interacting with the object and the low Z material panel. The apparatus includes an x-ray source to produce a pencil beam of x-rays directed toward the object, a scanner to scan the beam of x-rays over the object, and the detector to detect x-rays scattered from the beam of x-rays as a result of interacting with the object and the low Z material panel.

Claims

1. A method for detecting concealed items on or in an object, the method comprising:

producing a pencil beam of x-rays from an x-ray source directed toward said object;

scanning said beam of x-rays over the surface of said object; and

detecting x-rays scattered from said beam of x-rays as a result of interacting with said object and a low Z material panel, said object located between said detector and said panel, said detecting comprising differentiating x-rays back scattered by the object from those back scattered by the low Z material panel,

wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 10 microRem.

2. The method of claim 1 further comprising generating a signal representative of the intensity of the x-rays scattered.

3. The method of claim 2 further comprising presenting said signal on a display.

4. The method of claim 1 wherein said low Z material panel is made polyethylene.

5. The method of claim 1 wherein said low Z material panel is made of epoxy.

6. The method of claim 1 wherein said low Z material panel is made of water.

7. The method of claim 1 further comprising a radiation shield coupled to said low Z material panel, said low Z material panel located between said object and said radiation shield.

8. The method of claim 7 wherein said radiation shield comprises an x-ray absorbing material.

9. The method of claim 8 wherein said x-ray absorbing material is steel.

10. The method of claim 8 wherein said x-ray absorbing material is lead.

11. The method of claim 7 wherein said radiation shield is about 1 mm thick.

12. The method of claim 1 wherein said low Z material panel is located above said object.

13. The method of claim 1 wherein said low Z material panel is located below said object.

28. The method of claim 1, wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 5 microRem.

29. The method of claim 1, wherein said pencil beam of x-rays exposes said object to an x-ray dose of about 3 microRem.

30. The method of claim 1, further comprising using said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.

31. The method of claim 28, further comprising using said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.

32. The method of claim 1, wherein said pencil beam of x-rays is generated by an x-ray tube operating at about 50 KV and 5 mA.

14. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform a method for detecting concealed items on or in an object, said method comprising:

producing a pencil beam of x-rays from an x-ray source directed toward said object;

scanning said beam of x-rays over the surface of said object; and

detecting x-rays scattered from said beam of x-rays as a result of interacting with said object and a low Z material panel, said object located between said detector and said panel, said detecting comprising differentiating x-rays back scattered by the object from those back scattered by the low Z material panel,

wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 10 microRem.

33. The device of claim 14, wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 5 microRem.

34. The device of claim 14, wherein said pencil beam of x-rays exposes said object to an x-ray dose of about 3 microRem.

35. The device of claim 14, further comprising an imaging system adapted to use said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.

36. The device of claim 33, further comprising an imaging system adapted to use said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.

37. The device of claim 14, wherein said pencil beam of x-rays is generated by an x-ray tube operating at about 50 KV and 5 mA.

42. The device of claim 14, wherein said pencil beam of x-rays is generated by an x-ray tube operating at about 50 KV and 5 mA.

15. An apparatus to detect concealed items on or in an object, the apparatus comprising:

an x-ray source to produce a pencil beam of x-rays directed toward said object;

a scanner to scan said beam of x-rays over the surface of said object; and

a detector to detect x-rays scattered from said beam of x-rays as a result of interacting with said object and a low Z material panel, said object located between said detector and said panel, said detector differentiating x-rays back scattered by the object from those back scattered by the low Z material panel,

wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 10 microRem.

16. The apparatus of claim 15 further comprising a processor to generate a signal representative of the intensity of the x-rays scattered.

17. The apparatus of claim 16 further comprising a display to display said signal.

18. The apparatus of claim 15 wherein said low Z material panel is made polyethylene.

19. The apparatus of claim 15 wherein said low Z material panel is made of epoxy.

20. The apparatus of claim 15 wherein said low Z material panel is made of water.

21. The apparatus of claim 15 further comprising a radiation shield coupled to said low Z material panel, said low Z material panel located between said object and said radiation shield.

22. The apparatus of claim 21 wherein said radiation shield comprises an x-ray absorbing material.

23. The apparatus of claim 22 wherein said x-ray absorbing material is steel.

24. The apparatus of claim 22 wherein said x-ray absorbing material is lead.

25. The apparatus of claim 21 wherein said radiation shield is about 1 mm thick.

26. The apparatus of claim 15 wherein said low Z material panel is located above said object.

27. The apparatus of claim 15 wherein said low Z material panel is located below said object.

38. The apparatus of claim 15, wherein said pencil beam of x-rays exposes said object to an x-ray dose in the range of about 1 microRem to about 5 microRem.

39. The apparatus of claim 15, wherein said pencil beam of x-rays exposes said object to an x-ray dose of about 3 microRem.

40. The apparatus of claim 15, further comprising an imaging system adapted to use said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.

41. The device of claim 38, further comprising an imaging system adapted to use said detected x-rays to generate an image having a coefficient of variation (CV) in the range of about 2 to about 10 percent.