CATHODE ASSEMBLY FOR AN X-RAY TUBE

• US 20120027182A1
• Filed: 07/30/2010
• Published: 02/02/2012
• Est. Priority Date: 07/30/2010
• Status: Active Grant

• Current Assignee: Varex Imaging Corporation
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Canfield, Bradley D.
• Granted Patent: US 8,451,976 B2
• Time in Patent Office: Days
• US Class Current: 378/136
• CPC Class Codes: H01J 35/064 Details of the emitter, e.g. material or structure H01J35/065 takes precedence
• CPC Class Codes: H01J 35/066 Details of electron optical components, e.g. cathode cups
• CPC Class Codes: H01J 35/147 Spot size control

Abstract

A cathode assembly for an x-ray tube. In one example embodiment, a cathode assembly includes a cathode head, a filament, and first and second focusing tabs. The cathode head defines a recess having first and second open ends, a slot within the recess, and first and second tab stops within the recess. The filament is positioned within the slot. The first focusing tab is positioned in the first open end of the recess abutting the first tab stop. The second focusing tab is positioned in the second open end of the recess abutting the second tab stop.

Claims

1. A cathode assembly comprising:

a cathode head defining a recess having first and second open ends, a slot within the recess, and first and second tab stops within the recess;

a filament positioned within the slot;

a first focusing tab positioned in the first open end of the recess abutting the first tab stop; and

a second focusing tab positioned in the second open end of the recess abutting the second tab stop.

2. The cathode assembly as recited in claim 1, wherein the first and second focusing tabs are not coextensive with an outer periphery of the cathode head.

3. The cathode assembly as recited in claim 1, wherein:

the cathode head further defines a second slot within the recess; and

the cathode assembly further comprises a second filament positioned within the second slot.

4. The cathode assembly as recited in claim 3, wherein the cathode head further defines third and fourth tab stops within the recess.

5. The cathode assembly as recited in claim 4, wherein the first focusing tab further abuts the third tab stop and the second focusing tab further abuts the fourth tab stop.

6. The cathode assembly as recited in claim 5, wherein the first and second focusing tabs cover more of the slot than the second slot.

7. A cathode assembly comprising:

a cathode head defining a recess having first and second open ends, first and second slots within the recess, and first, second, third, and fourth tab stops within the recess;

first and second filaments positioned within the first and second slots, respectively;

a first focusing tab positioned in the first open end of the recess abutting the first and third tab stops; and

a second focusing tab positioned in the second open end of the recess abutting the second and fourth tab stops.

8. The cathode assembly as recited in claim 7, wherein the first and second slots each define a pair of feed through holes through which the first and second filaments extend, respectively.

9. The cathode assembly as recited in claim 7, wherein the cathode head further defines first and second grooves running the length of either side of the recess.

10. The cathode assembly as recited in claim 9, wherein the first and second focusing tabs are each partially positioned within the first and second grooves.

11. The cathode assembly as recited in claim 7, wherein the first and second focusing tabs are not coextensive with an outer periphery of the cathode head.

12. The cathode assembly as recited in claim 7, wherein the first and second focusing tabs cover more of the first slot than the second slot.

13. An x-ray tube comprising:

an evacuated enclosure;

an anode at least partially positioned within the evacuated enclosure; and

a cathode assembly at least partially positioned within the evacuated enclosure, the cathode assembly comprising;

a cathode head defining a recess having first and second open ends, a slot within the recess, and first and second tab stops within the recess;

a filament positioned within the slot;

a first focusing tab positioned in the first open end of the recess abutting the first tab stop; and

a second focusing tab positioned in the second open end of the recess abutting the second tab stop.

14. The x-ray tube as recited in claim 13, wherein the first and second focusing tabs are not coextensive with an outer periphery of the cathode head.

15. The x-ray tube as recited in claim 13, wherein:

the cathode head further defines third and fourth tab stops within the recess; and

the first focusing tab further abuts the third tab stop and the second focusing tab further abuts the fourth tab stop.

16. The x-ray tube as recited in claim 13, wherein

the cathode head further defines a second slot within the recess;

and

the cathode assembly further comprises a second filament positioned within the second slot.

17. The x-ray tube as recited in claim 16, wherein the first and second focusing tabs cover more of the slot than the second slot.

18. The x-ray tube as recited in claim 16, wherein the first and second slots each define a pair of feed through holes through which the first and second filaments extend, respectively.

19. The x-ray tube as recited in claim 16, wherein the cathode head further defines first and second grooves running the length of either side of the recess.

20. The x-ray tube as recited in claim 19, wherein the first and second focusing tabs are each partially positioned within the first and second grooves.