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US 6,850,595 B2Granted
X-ray generating mechanism using electron field emission cathode
AssigneeThe University of North Carolina at Chapel Hill
InventorsOtto Z. Zhou, Jianping Lu
Life of this patent
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Abstract
An x-ray generating device includes a field emission cathode formed at least partially from a nanostructure-containing material having an emitted electron current density of at least 4 A/cm2. High energy conversion efficiency and compact design are achieved due to easy focusing of cold cathode emitted electrons and dramatic reduction of heating at the anode. In addition, by pulsing the field between the cathode and the gate or anode and focusing the electron beams at different anode materials, pulsed x-ray radiation with varying energy can be generated from a single device.
Claims54
An x-ray generating device comprising:
- a chamber;
- a field emission cathode, the cathode comprising a nanostructure-containing material having an emitted electron current density of more than 1 mA/cm2 when subjected to an applied electrical field of less than 3 V/μm;
- an anode target;
- and
- an accelerating field established by an applied potential between the cathode and anode.
2 more elements
A method for producing x-rays comprising:
- providing a chamber;
- introducing a field emission cathode into the chamber, the cathode comprising a nanostructure-containing material having an emitted electron current density of more than 1 mA/cm2 when subjected to an applied electrical field of less than 3 V/μm;
- applying a control voltage to the cathode thereby causing a stream of electrons to be emitted;
- and
- providing an anode target within the chamber incident to the stream of emitted electrons thereby causing x-rays to be emitted from the anode target.
2 more elements
An x-ray generating device comprising:
- a chamber;
- a field emission cathode, the cathode comprising a nanostructure-containing electron emissive material;
- an anode target;
- and
- an accelerating field established by an applied electrical potential between the cathode and anode,
- wherein the nanostructure-containing material has an emitted electron current density of more than 1 mA/cm2 when subjected to an applied electrical field of less than 3 V/μm.
3 more elements
An x-ray generating device comprising:
- a chamber;
- a field emission cathode, the cathode comprising a nanostructure-containing electron emissive material;
- an anode target;
- and
- an accelerating field established by an applied electrical potential between the cathode and anode,
- wherein the nanostructure containing material has an emitted electron current density of more than 10 mA/cm2 when subjected to an applied electrical field of less than 5 V/μm.
3 more elements
An x-ray generating device comprising:
- a chamber;
- a field emission cathode, the cathode comprising a nanostructure-containing electron emissive material;
- an anode target;
- and
- an accelerating field established by an applied electrical potential between the cathode and anode,
- wherein an applied electrical field less than 8 V/μm produces a stable current density greater than 100 mA/cm2.
3 more elements
A method for producing x-rays comprising:
- providing a chamber;
- introducing a field emission cathode into the chamber, the cathode comprising a nanostructure-containing electron emissive material;
- applying a control voltage to the cathode thereby causing a stream of electrons to be emitted;
- and
- providing an anode target within the chamber incident to the stream of emitted electrons thereby causing x-rays to be emitted from the anode target,
- wherein the nanostructure-containing material has an emitted electron current density of more than 10 mA/cm2 when subjected to an applied electrical field of less than 4 V/μm.
3 more elements
A The method for producing x-rays comprising:
- providing a chamber;
- introducing a field emission cathode into the chamber, the cathode comprising a nanostructure-containing electron emissive material;
- applying a control voltage to the cathode thereby causing a stream of electrons to be emitted;
- and
- providing an anode target within the chamber incident to the stream of emitted electrons thereby causing x-rays to be emitted from the anode target,
- wherein the nanostructure-containing material has an emitted current density of as great as 10 A/cm2.
3 more elements
A method for producing x-rays comprising:
- providing a chamber;
- introducing a field emission cathode into the chamber, the cathode comprising a nanostructure-containing electron emissive material;
- applying a control voltage to the cathode thereby causing a stream of electrons to be emitted;
- and
- providing an anode target within the chamber incident to the stream of emitted electrons thereby causing x-rays to be emitted from the anode target,
- wherein the nanostructure-containing material has an emitted current density of at least about 100 mA/cm2 when subjected to an applied electrical field of 2-8 V/μm.
3 more elements
A method for producing x-rays comprising:
- providing a chamber;
- introducing a field emission cathode into the chamber, the cathode comprising a nanostructure-containing electron emissive material;
- applying a control voltage to the cathode thereby causing a stream of electrons to be emitted;
- and
- providing an anode target within the chamber incident to the stream of emitted electrons thereby causing x-rays to be emitted from the anode target,
- wherein the nanostructure-containing material has an emitted current density greater than 100 mA/cm2 when subjected to an applied electrical field of less than 8 V/μm.
3 more elements
Dependencies are inferred from the claim text.