X-ray tube with semiconductor coating

• US 8,792,619 B2
• Filed: 03/23/2012
• Issued: 07/29/2014
• Est. Priority Date: 03/30/2011
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Miller, Eric J.
• Primary Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US13/429,111
• Publication Number:
  US 20130077758A1
• Time in Patent Office: 858 Days
• Field of Search: 378119-144
• US Class Current: 378/139
• CPC Class Codes: H01J 2235/081 Target material
• CPC Class Codes: H01J 35/14 Arrangements for concentrating, focusing, or directing the cathode ray
• CPC Class Codes: H01J 35/147 Spot size control
• CPC Class Codes: H01J 35/16 Vessels; Containers; Shields associated therewith
• CPC Class Codes: H01J 35/186 used as targets or X-ray converters

Abstract

An x-ray tube with a semiconductor coating disposed over an exterior the tube. The semiconductor material reduces voltage gradients.

Claims

1. An x-ray tube comprising:

a) an evacuated enclosure;

b) a cathode attached to the evacuated enclosure and configured to emit electrons within the enclosure;

c) an anode attached to the evacuated enclosure, configured to receive electrons emitted from the cathode, and configured to emit x-rays in response to impinging electrons;

d) a semiconductor coating disposed over an exterior of the evacuated enclosure; and

e) an electrically insulative potting material disposed over an outer surface of the semiconductor coating.

2. The x-ray tube of claim 1, wherein the semiconductor coating comprises silicon.

3. The x-ray tube of claim 1, wherein a thickness of the semiconductor coating is between 10% and 75% of an outer diameter of the evacuated enclosure.

4. The x-ray tube of claim 1, wherein a thickness of the semiconductor coating is between 10% and 60% of an outer diameter of the evacuated enclosure and a thickness of the potting is between 20% and 70% of the outer diameter of the evacuated enclosure.

5. The x-ray tube of claim 1, wherein a thickness of the semiconductor coating is between 10% and 100% of a thickness of the potting.

6. The x-ray tube of claim 1, wherein a maximum change in voltage per unit distance

7. The x-ray tube of claim 1, wherein a maximum change in voltage per unit distance

8. The x-ray tube of claim 1, wherein a maximum change in voltage per unit distance

9. The x-ray tube of claim 1, wherein a maximum change in voltage per unit distance

10. The x-ray tube of claim 1, wherein a maximum change in voltage per unit distance

11. The x-ray tube of claim 1, wherein the semiconductor coating covers substantially all of the exterior of the evacuated enclosure and a junction between the evacuated enclosure and the cathode.

12. The x-ray tube of claim 1, wherein the semiconductor coating covers at least 75% of the exterior of the evacuated enclosure and substantially all of a junction between the evacuated enclosure and the cathode.

13. The x-ray tube of claim 1, wherein the semiconductor coating is disposed directly on top of and attached directly to the evacuated enclosure and the potting material is disposed directly on top of and attached directly to the semiconductor material.

14. The x-ray tube of claim 1, wherein the semiconductor coating has a substantially uniform thickness across a surface of the evacuated enclosure.

15. The x-ray tube of claim 1, wherein:

a) a semiconductor coating thickness is approximately proportional to a voltage gradient between the evacuated enclosure and the ground; and

b) the semiconductor coating is thicker near the cathode than near the anode.

16. The x-ray tube of claim 1, wherein the semiconductor coating and the potting are different materials.

17. The x-ray tube of claim 1, further comprising at least one layer of graphene disposed over an exterior of the evacuated enclosure.

18. An x-ray tube comprising:

a) an evacuated enclosure;

b) a cathode attached to the evacuated enclosure and configured to emit electrons within the enclosure;

c) an anode attached to the evacuated enclosure, configured to receive electrons emitted from the cathode, and configured to emit x-rays in response to impinging electrons; and

d) at least one layer of graphene disposed over an exterior of the evacuated enclosure.

19. The x-ray tube of claim 18, further comprising an electrically insulative potting material disposed over at least one layer of graphene.

20. An x-ray tube comprising:

a) an evacuated enclosure having an internal pressure of less than 10<sup>−

7</sup> atm;

b) a cathode attached to the evacuated enclosure and configured to emit electrons within the enclosure;

c) an anode attached to the evacuated enclosure, configured to receive electrons emitted from the cathode, and configured to emit x-rays in response to impinging electrons;

d) a semiconductor coating comprising silicon disposed over and attached directly to the evacuated enclosure;

e) the semiconductor coating covering at least 50% of an exterior of the evacuated enclosure;

f) the semiconductor coating covering a junction of the cathode and the evacuated enclosure; and

g) an electrically insulative potting material disposed over at least 80% of an outer surface of the semiconductor coating.