Electron emitter and method of making same

1. An electron emitter comprising:

a conductive member that defines a plurality of filament segments that are integral with each other, each filament segment including an intermediate portion and an interconnecting portion attached to an adjacent filament segment;

wherein:

the intermediate portions are substantially coplanar with each other;

each intermediate portion includes a substantially planar electron emission surface; and

the plurality of filament segments are arranged in a ladder-type configuration with a substantially planar emitting side collectively defined by the substantially coplanar intermediate portions.

2. The electron emitter of claim 1 , wherein the conductive member comprises a ribbon wire or a wire having a square or rectangular cross-section.

3. The electron emitter of claim 1 , wherein the conductive member comprises one or more selectively carburized thoriated tungsten regions.

4. The electron emitter of claim 3 , wherein the selectively carburized thoriated tungsten regions coincide with the substantially planar electron emission surfaces.

5. The electron emitter of claim 1 , wherein the plurality of filament segments are arranged in a spiral configuration having a substantially semicircular profile, a substantially planar emitting side of the semicircular profile collectively defined by the substantially coplanar intermediate portions.

6. The electron emitter of claim 1 , wherein the plurality of filament segments are arranged in a spiral configuration having a quasi-elliptical profile with a substantially planar emitting side that includes the substantially coplanar intermediate portions.

7. The electron emitter of claim 1 , wherein the conductive member comprises a wire having a substantially circular cross-section except where the substantially planar electron emission surfaces are formed in the intermediate portions of the wire, the intermediate portions of the wire having a substantially semicircular cross-section.

8. The electron emitter of claim 7 , wherein the thickness of each intermediate portion is between 50% and 70% of the diameter of the circular cross-section.

9. An x-ray tube, comprising:

an evacuated enclosure;

an electron emitter disposed within the evacuated enclosure, the electron emitter comprising:

a conductive member arranged in a spiral configuration having a profile with a substantially planar emitting side;

a plurality of filament segments that are integral with each other and that are defined by the conductive member, each filament segment including an intermediate portion and an interconnecting portion attached to an adjacent filament segment, the filament segments being arranged such that the intermediate portions collectively define the substantially planar emitting side of the profile, wherein the plurality of filament segments are arranged in a spiral configuration having a trilobed profile with the substantially planar electron emission surface on each intermediate portion collectively defined by the substantially planar intermediate portions; and

a substantially planar electron emission surface included on each intermediate portion; and

an anode positioned within the evacuated enclosure so as to receive electrons emitted by the electron emitter.

10. The electron emitter of claim 9 , wherein the conductive member comprises one or more of: tungsten, tungsten-rhenium, lanthanated tungsten, hafnium, hafnium carbide, lanthanum hexaboride, or thoriated tungsten.

11. The electron emitter of claim 9 , wherein the substantially planar emitting side and the substantially planar electron emission surfaces enable the electron emitter to emit a substantially collimated beam of electrons.

12. The electron emitter of claim 1 , wherein each filament segment further comprises a first end and a second end, wherein the first end is disposed opposite the second end.

13. The electron emitter of claim 12 , wherein the ladder-type configuration is defined by the interconnecting portion attaching to an adjacent filament segment by connecting the second end of the filament segment to the second end of the adjacent filament segment.

14. The electron emitter of claim 9 , wherein each filament segment further comprises a first end and a second end disposed opposite the first end.

15. The electron emitter of claim 14 , wherein the spiral configuration having a trilobed is defined by the interconnecting portion attaching to an adjacent filament segment by connecting the second end of the filament segment to the first end of the adjacent filament segment.

16. The electron emitter of claim 9 , wherein the spiral configuration having a trilobed profile defines the shape of the spiral as viewed from one end of the filament being substantially triangular having three corners rounded into three lobes.

17. An electron emitter comprising:

a conductive member that defines a plurality of filament segments that are integral with each other, each filament segment including an intermediate portion and an interconnecting portion attached to an adjacent filament segment;

wherein:

the intermediate portions are substantially coplanar with each other;

each intermediate portion includes a substantially planar electron emission surface; and

the conductive member comprises a wire having rectangular cross-section.

18. The electron emitter of claim 17 , wherein the rectangular cross-section defines a square shape.

19. The electron emitter of claim 17 , wherein the rectangular cross-section defines a ribbon wire.