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US 10,373,792 B2Granted
Cathode assembly for use in X-ray generation
AssigneeGeneral Electric Company
InventorsJohn Scott Price, Xi Zhang
Life of this patent
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Abstract
A cathode assembly design is provided that includes two flat emitters, a longer emitter filament and a shorter emitter filament. In one implementation the focal spot sizes produced by the long and short emitters overlap over a range. Thus, one emitter filament may be suitable for generating small and concentrated focal spot sizes while the other emitter filament is suitable for generating small and large focal spots sizes.
Claims15
A cathode assembly, comprising:
- at least two flat filaments each comprising an electron emissive surface when heated, wherein a first flat filament has an electron emissive area that is less than an electron emissive area of a second flat filament;
- a set of width bias electrodes positioned along a first dimension of the flat filaments, wherein the set of width bias electrodes controls the width of a focal spot generated by the flat filaments during operation;
- a set of length bias electrodes positioned along a second dimension of the flat filaments, wherein the set of length bias electrodes controls the length of the focal spot during operation;
- and
- a septum positioned between the first flat filament and the second flat filament, wherein the septum is at the same potential as the width bias electrodes during operation.
2 more elements
An X-ray tube, comprising:
- an anode;
- and
- a cathode, comprising:
- a pair of flat filaments that emit electrons when heated, wherein a first flat filament is longer than a second flat filament of the pair of flat filaments;
- a pair of width bias electrodes positioned on opposite sides of the pair of flat filaments along a first dimension;
- a pair of length bias electrodes positioned on opposite sides of the pair of flat filaments along a second dimension perpendicular to the first dimension;
- and
- a septum positioned between the pair of flat filaments and running in the same direction as the pair of width bias electrodes, wherein the septum is at the same potential as the width bias electrodes during operation.
5 more elements
A method for generating an electron beam focal spot on a target, comprising:
- receiving an input specifying a size of the electron beam focal spot on the target;
- and
- selectively operating a first emitter filament or a second emitter filament of a cathode assembly to generate an electron beam focal spot of the size specified by the input on the target, wherein the first emitter filament and the second emitter filament differ in length, by:
- selecting the first emitter filament when the input specifies a first focal spot size;
- selecting the first emitter filament and the second emitter filament when the input specifies a second focal spot size;
- and
- selecting the second emitter filament when the input specified a third focal spot size
- wherein selecting the first emitter filament and the second emitter filament when the input specifies a second focal spot size comprises taking into account a failure of the first emitter filament or the second emitter filament so as to allow generation of the second focal spot size when one of the first emitter filament or the second emitter filament is inoperative.
5 more elements
Dependencies are inferred from the claim text.