The present invention addresses the problem of providing an electron beam generator and an electron beam applicator for which maintenance is facilitated. The electron beam generator comprises a vacuum chamber, a photocathode holder, an activation vessel, and an internal motive power transmission member. The photocathode holder is capable of moving relative to the activation vessel.

The present disclosure provides electron source devices, electron source assemblies, and/or methods for generating electrons. The generated electrons can be used to facilitate spectroscopy, such as mass spectrometry, including mass selection or ion mobility.

An electron gun may include a cathode with an emitting surface configured to emit electrons. The cathode may include a through hole that goes through the emitting surface and is configured to allow back-streaming electrons of the emitted electrons to pass through. The electron gun may also include an anode configured to attract the emitted electrons from the cathode to the anode and focus the emitted electrons into an electron beam. The electron gun may also include a grid structure configured to facilitate the focusing of the emitted electrons, the grid structure being positioned corresponding to the through hole.

An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular; a heater; an anode being arranged to oppose the cathode; and a heat resistant member. The anode applies a positive potential relative to the cathode to extract electrons in a predetermined direction. The cathode has, in a central portion thereof, a through hole along a central axis of the cathode. The heat resistant member has a first portion to close the through hole and a second portion being positioned between the cathode and the heater.

A system and method for generating X-ray radiation in a predefined spatial distribution on an anode. The system includes an anode, a first switching device, a second switching device, a control unit, and an emitter with multiple field effect emitter needles. At least one field effect emitter needle of the multiple field effect emitter needles includes a diameter of less than 1 m and silicon. A first group of the multiple field effect emitter needles may be activated or deactivated by the first switching device. A second group of the multiple field effect emitter needles may be activated or deactivated by the second switching device. The first group differs from the second group. The control unit is configured to actuate the first switching device and the second switching device.

A method of operating a charged particle gun is described. The method includes providing an emitter at a first emitter potential within the charged particle gun and providing a trapping electrode at a first electrode potential within the charged particle gun, wherein the first emitter potential and the first electrode potential is provided to have an electrical field of essentially zero at the emitter and at the trapping electrode; switching the trapping electrode from the first electrode potential to a second electrode potential different from the first electrode potential to generate an electrostatic trapping field at the trapping electrode; and after switching the trapping electrode from the first electrode potential to the second electrode potential, switching on an electrostatic emission field at the emitter.

An external grid-controlled hot cathode array electron gun, including an insulated cathode base, a filament, a plurality of hot cathode emission elements, and a grid-controlled structure is disclosed. In one aspect, the grid-controlled structure includes an insulated grid-controlled structure body and a plurality of through holes. One side of the grid-controlled structure body abuts against the cathode base to clamp the filament between the grid-controlled structure body and the cathode base and the plurality of hot cathode emission elements are inserted into the plurality of through holes respectively.

A tunneling electro source, an array thereof and methods for making the same are provided. The tunneling electron source is a surface tunneling micro electron source having a planar multi-region structure. The tunneling electron source includes an insulating substrate, and two conductive regions and one insulating region arranged on a surface of the insulating substrate. The insulating region is arranged between the two conductive regions and abuts on the two conductive regions. Minimum spacing between the two conductive regions, which equals to a minimum width of the insulating region, is less than 100 nm.

An electron gun, an X-ray source and a CT device are provided. The electron gun includes a body having a first end portion and a second end portion opposite to each other, wherein the first end portion is a connecting end portion; an internal cavity is formed in the body and has an opening positioned on the second end portion; a cathode, a grid, a compensation electrode and a focus electrode, orderly arranged in the internal cavity in a direction from the first end portion to the second end portion.

An external grid-controlled hot cathode array electron gun, including an insulated cathode base, a filament, a plurality of hot cathode emission elements, and a grid-controlled structure is disclosed. In one aspect, the grid-controlled structure includes an insulated grid-controlled structure body and a plurality of through holes. One side of the grid-controlled structure body abuts against the cathode base to clamp the filament between the grid-controlled structure body and the cathode base and the plurality of hot cathode emission elements are inserted into the plurality of through holes respectively.