Thermionic emission device, focus head, x-ray tube and x-ray radiator

Patent metadata

Field	Value
Publication number	US-10043632-B2
Application number	US-201715679648-A
Country	US
Kind code	B2
Filing date	Aug 17, 2017
Priority date	Aug 17, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A thermionic emission device includes an indirectly heatable main emitter, which is constructed as a flat emitter with a main emission surface, and at least one connectible heat emitter with a heat emission surface. The heat emission surface is disposed at a predefinable distance from the main emission surface. The main emission surface can be asymmetrically heated by the heat emission surface. In the operating state, the main emitter is at a main potential and the heat emitter is at a heating potential which differs from the main potential. An x-ray tube with the thermionic emission device has a longer service life with a consistent image quality.

First claim

The invention claimed is:

1. A thermionic emission device, comprising:
an indirectly heatable main emitter being constructed as a flat emitter having a main emission surface; and
at least one connectible heat emitter having a heat emission surface;
said heat emission surface being disposed at a predefinable distance from said main emission surface;
said heat emission surface being configured to asymmetrically heat said main emission surface;
in an operating state, said main emitter being at a main potential and said heat emitter being at a heating potential differing from said main potential.

2. The thermionic emission device according to claim 1 , wherein said heat emission surface is disposed asymmetrically relative to said main emission surface.

3. The thermionic emission device according to claim 1 , wherein said heat emission surface is configured to be switched asymmetrically relative to said main emission surface.

4. The thermionic emission device according to claim 1 , wherein said heat emitter includes at least two individually switchable sub-heat emitters.

5. The thermionic emission device according to claim 1 , wherein said heat emitter is a flat emitter.

6. The thermionic emission device according to claim 1 , wherein said heat emitter is a coil emitter.

7. The thermionic emission device according to claim 1 , which further comprises a focusing apparatus disposed between said main emitter and said heat emitter.

8. The thermionic emission device according to claim 1 , which further comprises at least one grid for at least partially blocking said heat emitter.

9. The thermionic emission device according to claim 1 , wherein said main emitter has two longitudinal sides, and an electrical contact is disposed at one of said two longitudinal sides.

10. A focus head, comprising a thermionic emission device according to claim 1 .

11. An x-ray tube, comprising an anode and a thermionic emission device according to claim 1 .

12. An x-ray tube, comprising an anode and a focus head including a thermionic emission device according to claim 1 .

13. The x-ray tube according to claim 10 , wherein said anode is a rotary anode.

14. An x-ray radiator, comprising:
a radiator housing; and
an x-ray tube disposed in said radiator housing, said x-ray tube including an anode and a thermionic emission device according to claim 1 .

Assignees

• Siemens Healthcare Gmbh

Inventors

• Fritzler Anja
• Geithner Peter

Classifications

• H01J35/10

  Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes · CPC title

• H01J2235/06

  Cathode assembly · CPC title

• H01J35/065

  Field emission, photo emission or secondary emission cathodes · CPC title

• H01J1/20 Primary

  Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment · CPC title

• H01J9/04

  of thermionic cathodes · CPC title