System for forming x-rays and method for using same

• US 7,218,700 B2
• Filed: 02/01/2005
• Issued: 05/15/2007
• Est. Priority Date: 05/28/2004
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Edic, Peter Michael, Vermilyea, Mark Ernest, Huber, William Hullinger, Wilson, Colin Richard, Price, John Scott
• Primary Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US11/048,158
• Publication Number:
  US 20050265520A1
• Time in Patent Office: 833 Days
• Field of Search: 378/119, 378/121, 378/124, 378/134, 378/136, 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, material emissions from the target, and electric field transients.

Claims

1. A system for forming x-rays, comprising:

a target;

at least one electron emission subsystem for generating a plurality of spots on said target, wherein said at least one electron emission subsystem comprises a plurality of electron sources and wherein each of said plurality of electron sources generates at least one of said plurality of spots on said target;

a beam focusing subsystem for focusing electron beam emissions from said plurality of electron sources prior to said electron beam emissions striking said target, and thereby forming x-rays; and

a transient beam protection subsystem comprising at least one structure configured to perform at least one of;

sink current from each of said plurality of electron sources if a potential of the target drops; and

provide protection for each of said plurality of electron sources during transient beam emissions.

2. The system of claim 1, wherein said beam focusing subsystem comprises an electrostatic focusing component.

3. The system of claim 1, wherein said beam focusing subsystem comprises a magnetic focusing component.

4. The system of claim 1, wherein each of said plurality of electron sources 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.

5. The system of claim 1, further comprising a pinching electrode configured to selectively permit and inhibit generation of said plurality of spots on said target.

6. A system for forming x-rays, comprising:

a target;

an electron emission subsystem for generating a plurality of spots on said target, thereby forming x-rays, wherein said electron emission subsystem comprises a plurality of electron sources; and

a transient beam protection subsystem for protecting said electron emission subsystem from transient beam currents, material emissions from said target, and electric field transients, wherein said transient beam protection subsystem comprises at least one structure configured to perform at least one of;

sink current from each of said plurality of electron sources if a potential of the target drops; and

provide protection for each of said plurality of electron sources during transient beam emissions.

7. The system of claim 6, wherein each of said plurality of electron sources 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.

8. The system of claim 6, wherein each of said plurality of electron sources generates at least one of said plurality of spots on said target.

9. The system of claim 6, wherein said transient beam protection subsystem comprises positioning each of said plurality of electron sources within an alcove.

10. The system of claim 6, wherein said transient beam protection subsystem comprises a channel extending between each of said plurality of electron sources and said target.

11. A system for forming x-rays, comprising:

a target; and

an electron emission subsystem comprising a plurality of electron sources, said electron emission subsystem being configured to generate a plurality of discrete spots on said target from which x-rays are emitted;

wherein said target is enclosed within a first vacuum vessel and said electron emission subsystem is enclosed within a second vacuum vessel.

12. The system of claim 11, wherein said first and second vacuum vessels are each pumped.

13. The system of claim 11, wherein said first and second pumped vacuum vessels are connected with a channel used to transport electron beams from said second vessel to said first vessel.

14. The system of claim 11, wherein said second pumped vacuum vessel is separable from said first pumped vacuum vessel with one or more gate valves.

15. The system of claim 11, wherein each said electron source is positioned within an alcove configured to inhibit damage to said electron source from a deflection of a beam of electrons from the target toward said electron source.

16. The system of claim 11, wherein each of said electron sources 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.

17. The system of claim 11, further comprising at least one detector.

18. The system of claim 17, wherein each said electron source and said target are stationary relative to said detector, which either rotates or is stationary.

19. The system of claim 17, wherein each said electron source and said target rotate relative to said detector, which either rotates or is stationary.

20. The system of claim 11 configured to detect contraband objects.

21. The system of claim 11 configured to perform medical diagnostics on a subject.

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

emitting a beam of electrons from an electron source to strike a discrete or swept focal spot on a target for creating x-rays from the discrete or swept focal spot;

focusing the beam of electrons from said electron source prior to said electron beam emissions striking said target;

detecting the x-rays created from the discrete or swept focal spots; and

providing protection to said electron source from transient beam currents, material emissions from said target, and electric field transients.

23. The method of claim 22, further comprising selectively permitting and inhibiting generation of discrete or swept focal spots on said target.

24. The method of claim 22, further comprising enclosing said target within a first vacuum vessel and enclosing said electron source within a second vacuum vessel.

25. The method of claim 24, further comprising pumping said first and second vacuum vessels.

26. The method of claim 25, further comprising connecting said first and second vacuum vessels with a channel.

27. The method of claim 26, further comprising placing gate valves in said channel between said first and second vacuum vessels.

28. The method of claim 22, further comprising positioning said electron source within an alcove configured to inhibit damage to said electron source from a deflection of a beam of ions from the target toward said electron source.