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.

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.

The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.

The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.

A cathode device including an emitter element for generating electrons. The emitter element can have an outer periphery and a distal tip. The tip can have a first angled surface that angles inwardly from the outer periphery, and a second angled surface that angles inwardly and is separated and inwardly offset from the first angled surface by a shoulder. A graphite cap which can be solid, extends around the emitter element and has an internal angled surface that engages the first angled surface of the tip of the emitter element, forming a gap of a controlled size separating the internal angled surface of the graphite cap from the second angled surface of the tip of the emitter element.

A cathode device including an emitter element for generating electrons. The emitter element can have an outer periphery and a distal tip. The tip can have a first angled surface that angles inwardly from the outer periphery, and a second angled surface that angles inwardly and is separated and inwardly offset from the first angled surface by a shoulder. A graphite cap which can be solid, extends around the emitter element and has an internal angled surface that engages the first angled surface of the tip of the emitter element, forming a gap of a controlled size separating the internal angled surface of the graphite cap from the second angled surface of the tip of the emitter element.

Electron beam generator comprising an electron emitting device adapted to emit an electron beam when heated to an elevated temperature, wherein the electron emitting device comprises a filament having a spiral portion.

A receptacle for receiving a plug connector of a high-voltage cable for a microfocus X-ray tube with a cathode, which has a metal filament and grid. The receptacle has a ceramic insulator with three contiguous cavities. The first cavity near the filament includes electrical contacts for the filament and the grid. The second cavity includes spring contacts for supplying current to the filament and a center pin for supplying voltage to the grid. The third cavity receives the plug connector. The insulator has a removable grid cap which is conductively connected to the grid of the cathode. The first and second cavities are surrounded in the radial direction by the grid cap, An air gap extends radially between grid cap and ceramic body. At the end of the grid cap remote from the filament is a circumferential groove in the axial direction between the grid cap and the ceramic insulator.

Methods and systems for thermal ionization of a sample and formation of an ion beam are described. The systems incorporate a thermal ionization filament that is formed of a graphene-based material such as graphite, graphene, graphene oxide, reduced graphene oxide or combinations thereof. The filament material can be doped or chemically modified to control and tune the work function of the filament and improve ionization efficiency of a system incorporating the filament. The systems can be utilized in forming an ion beam for target bombardment or analysis via, e.g., mass spectrometry.

Methods and systems for thermal ionization of a sample and formation of an ion beam are described. The systems incorporate a thermal ionization filament that is formed of a graphene-based material such as graphite, graphene, graphene oxide, reduced graphene oxide or combinations thereof. The filament material can be doped or chemically modified to control and tune the work function of the filament and improve ionization efficiency of a system incorporating the filament. The systems can be utilized in forming an ion beam for target bombardment or analysis via, e.g., mass spectrometry.