System for forming x-rays and method for using same

• US 7,203,269 B2
• Filed: 02/01/2005
• Issued: 04/10/2007
• Est. Priority Date: 05/28/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hopkins, Forrest Frank, Edic, Peter Michael, Vermilyea, Mark Ernest, Huber, William Hullinger, Wilson, Colin Richard, Price, John Scott
• Primary Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US11/048,159
• Publication Number:
  US 20060002515A1
• Time in Patent Office: 798 Days
• Field of Search: 378/119, 378/121, 378/124, 378/134, 378/136, 378/4, 378/9, 378/57, 378/62, 378/137, 313309-311, 313/346.R, 313/346.DC, 313/351, 313/495
• US Class Current: 378/10
• CPC Class Codes: H01J 2235/068 Multi-cathode assembly
• CPC Class Codes: H01J 35/066 Details of electron optical components, e.g. cathode cups
• CPC Class Codes: H01J 35/147 Spot size control
• CPC Class Codes: H01J 35/153 Spot position control
• CPC Class Codes: H01J 35/16 Vessels; Containers; Shields associated therewith
• CPC Class Codes: H01J 35/30 by deflection of the cathode ray

Abstract

A system and method for forming x-rays. One exemplary system includes a target and electron emission subsystem with a plurality of electron sources. Each of the plurality of electron sources is configured to generate a plurality of discrete spots on the target from which x-rays are emitted. Another exemplary system includes a target, an electron emission subsystem with a plurality of electron sources, each of which generates at least one of the plurality of spots on the target, and a transient beam protection subsystem for protecting the electron emission subsystem from transient beam currents and material emissions from the target.

Claims

1. A system for forming x-rays to image a volume and having an input at one location and an outlet at a different location, the system comprising:

a target; and

a plurality of electron emission subsystems each comprising a single electron source, said plurality of electron emission subsystems being configured to generate a plurality of discrete or swept focal spots on said target from which x-rays are emitted, wherein a totality of said electron sources completely encircle the imaged volume.

2. The system of claim 1, wherein said electron source comprises one from the group consisting of field emitter, thermal field emitter, tungsten wire, coated tungsten wire, tungsten plate, photo-emissive surface, dispenser cathode, thermionic cathode, photo-emitter, and ferroelectric cathode.

3. The system of claim 1, wherein each of said plurality of electron emission subsystems comprises a beam focusing subsystem for focusing electron beam emissions from each said electron source prior to said electron beam emissions striking said target.

4. The system of claim 3, wherein said beam focusing subsystem comprises an electrostatic focusing component.

5. The system of claim 3, wherein said beam focusing subsystem comprises a magnetic focusing component.

6. The system of claim 1, wherein each of said plurality of electron emission subsystems comprises a beam deflection subsystem for deflecting electron beams to said plurality of spots on said target.

7. The system of claim 6, wherein said beam deflection subsystem comprises an electrostatic steering mechanism.

8. The system of claim 7, wherein said electrostatic steering mechanism comprises a plurality of free standing focusing plates, each being biased at a different potential.

9. The system of claim 6, wherein said beam deflection subsystem comprises a magnetic steering mechanism.

10. The system of claim 9, wherein said magnetic steering mechanism comprises at least one scan coil.

11. The system of claim 9, wherein said magnetic steering mechanism comprises a coil-shaped electromagnet.

12. The system of claim 9, wherein said magnetic steering mechanism comprises a fast switching magnetic-field-producing magnet.

13. The system of claim 1, wherein the target is housed within a first vacuum vessel and each of said plurality of electron emission subsystems is housed within a second vacuum vessel.

14. The system of claim 13, wherein said first vacuum vessel is separated from each said second vacuum vessel with at least one gate valve.

15. The system of claim 13, wherein said first vacuum vessel is at a first pressure and each of said second vacuum vessels is at a second pressure.

16. The system of claim 15, wherein said first and second pressures are maintainable though the use of differential pumping.

17. The system of claim 6, wherein said target includes a plurality of surfaces configured to allow deflected electron beams to strike the target at multiple points to generate multiple x-ray spots with similar x-ray intensity and distribution characteristics.

18. The system of claim 1, further comprising at least one detector.

19. The system of claim 18, wherein each of said plurality of electron emission subsystems and said target are stationary relative to said detector, which either rotates or is stationary.

20. The system of claim 18, wherein each of said plurality of electron emission subsystems and said target rotate relative to said detector, which either rotates or is stationary.

21. The system of claim 1 configured to detect contraband objects.

22. The system of claim 1 configured to perform medical diagnostics on a subject.

23. The system of claim 1 configured for performing at least one from the group of imaging applications consisting of radiographic, tomosynthesis and computed tomography.

24. A method for x-ray scanning an object, comprising:

inputting the object at one location;

emitting a first beam of electrons from each of a plurality of electron sources to strike respective first discrete focal spots on a target for creating x-rays from the respective first discrete focal spots, said plurality of electron sources completely encircling the object;

emitting a second beam of electrons from each of the plurality of electron sources toward the target, wherein the second beam of electrons strikes respective second discrete focal spots on the target for creating x-rays from the respective second discrete focal spots;

detecting the x-rays created from the respective first and second discrete focal spots; and

outputting the object at a different location.

25. The method of claim 24, wherein the plurality of electron sources each comprises one from the group consisting of field emitter, thermal field emitter, tungsten wire, coated tungsten wire, tungsten plate, photo-emissive surface, dispenser cathode, thermionic cathode, photo-emitter, and ferroelectric cathode.

26. The method of claim 24, wherein said emitting comprises deflecting at least one of the first and second beams to strike the target.

27. The method of claim 24, wherein said detecting the x-rays comprises detecting the x-rays with at least one detector.

28. The method of claim 27, wherein the plurality of electron sources and the target are each stationary relative to the detector, which either rotates or is stationary.

29. The method of claim 27, wherein the plurality of electron sources and the target each rotate relative to the detector, which either rotates or is stationary.