Cold electron number amplifier

• US 8,750,458 B1
• Filed: 11/30/2011
• Issued: 06/10/2014
• Est. Priority Date: 02/17/2011
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Wang, Dongbing, Reynolds, Dave
• Primary Examiner(s): Yun, Jurie
• Application Number:
  US13/307,559
• Time in Patent Office: 923 Days
• Field of Search: 378/119, 378/121, 378/122, 378/134, 378/136
• US Class Current: 378/122
• CPC Class Codes: H01J 2237/06358 Secondary emission
• CPC Class Codes: H01J 3/023 Electron guns using electron multiplication
• CPC Class Codes: H01J 35/064 Details of the emitter, e.g. material or structure H01J35/065 takes precedence

Abstract

A cold electron number amplifier device can provide a greater number of electrons at lower electron emitter temperature. The cold electron number amplifier device can comprise an evacuated enclosure 11, a first electron emitter 12 attached to the evacuated enclosure 11, and an electrically conductive second electron emitter 13 also attached to the evacuated enclosure. The first electron emitter 12 can be configured to emit electrons 14 within the evacuated enclosure 11. The second electron emitter 13 can have a voltage V2 greater than a voltage V1 of the first electron emitter 12 (V2>V1). The second electron emitter 13 can be positioned to receive impinging electrons 14 from the first electron emitter 12. Electrons 14 from the first electron emitter 12 can impart energy to electrons in the second electron emitter 13 and cause the second electron emitter 13 to emit more electrons 15.

Claims

1. A method of producing x-rays in an x-ray tube, the method comprising:

a) providing a voltage differential between a first electron emitter and an anode, both within the x-ray tube, of at least 1 kilovolt;

b) providing an electrically conductive second electron emitter with a voltage that is between a voltage of the first electron emitter and a voltage of the anode;

c) providing a voltage differential between the first electron emitter and the second electron emitter that is greater than a work function of the second electron emitter;

d) emitting electrons from the first electron emitter and propelling the electrons from the first electron emitter to impinge upon the second electron emitter;

e) multiplying a total number of electrons by emitting at least 10 electrons from the second electron emitter for every electron impinging upon the second electron emitter;

f) propelling the electrons from the second electron emitter towards the anode and impinging upon the anode; and

g) emitting x-rays from the anode as a result of the electrons which impinged upon the anode.

2. The method of claim 1, wherein at least 500 electrons are emitted from the second electron emitter for every electron impinging upon the second electron emitter.

3. An x-ray tube comprising:

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

6</sup> atm;

b) a first electron emitter attached to the evacuated enclosure and configured to emit electrons;

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

e) an electrically conductive second electron emitter disposed within the evacuated enclosure between the first electron emitter and the anode;

e) a voltage of the second electron emitter is greater than a voltage of the first electron emitter;

f) a voltage of the anode is greater than a voltage of the second electron emitter;

g) a voltage differential between the first electron emitter and the anode of at least 9 kilovolts;

h) a voltage differential between the first electron emitter and the second electron emitter that is greater than a work function of the second electron emitter;

i) the second electron emitter having a hole between the first electron emitter and the anode;

j) impinging electrons on the second electron emitter, from the first electron emitter, impart energy to electrons in the second electron emitter, thus causing additional electrons to be emitted from the second electron emitter;

k) at least ten times more electrons are emitted from the second electron emitter than are emitted from the first electron emitter;

l) electrons from the second electron emitter accelerate towards and impinge upon the anode; and

m) electrons impinging upon the anode cause the anode to emit x-rays.

4. The x-ray tube of claim 3 wherein the voltage differential between the first electron emitter and the second electron emitter is greater than 100 times a work function of the second electron emitter.