A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

The present disclosure provides a magnetic immersion electron gun and a method of generating an electron beam using a magnetic immersion electron gun. The electron gun includes a magnetic lens forming a magnetic field, a cathode tip disposed in the magnetic field, and a multi-filament heater configured to directly heat the cathode tip to emit electrons through the magnetic lens. The multi-filament heater includes a first filament connected at each end to first and second positive terminals of a power source and a second filament connected at each end to first and second negative terminals of the power source. The first positive terminal, the second positive terminal, the first negative terminal, and the second negative terminal are arranged alternately around the cathode tip such that the first filament and the second filament intersect at the cathode tip and a resultant magnetic force applied to the cathode tip is reduced.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means for generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

The purpose of the present invention is to provide a charged particle source that exhibits small energy dispersion for charged particle beams emitted under a high angular current density condition and allows stable acquisition of large charged particle currents even for a small light source diameter. The charged particle source according to the present invention has a spherical virtual cathode surface from which charged particles are emitted, and the virtual cathode surface for charged particles emitted from a first position on a tip end surface of an emitter and the virtual cathode surface for charged particles emitted from a second position on the tip end surface of the emitter match each other (see FIG. 4).

An electron gun includes a cathode that is heated to emit thermions; a cathode heating power supply that supplies a cathode heating current for heating the cathode; a grid that has a first aperture formed therein and that has a grid voltage applied thereto, the grid voltage having a potential lower than that of the cathode, wherein the grid converges the thermions passing through the first aperture by the grid voltage; an anode that has a second aperture formed therein and that has an anode voltage applied thereto, wherein the anode causes the thermions extracted from the cathode to pass through the second aperture as an electron beam by the anode voltage; an anode-voltage power supply that applies the anode voltage to the anode; and a controller that causes the anode voltage having a positive potential to be applied from the anode-voltage power supply to the anode.

Electron emitters and method of fabricating the electron emitters are disclosed. According to certain embodiments, an electron emitter includes a tip with a planar region having a diameter in a range of approximately (0.05-10) micrometers. The electron emitter tip is configured to release field emission electrons. The electron emitter further includes a work-function-lowering material coated on the tip.

There is provided a control method for an electron microscope including a thermionic-emission gun of self-bias type using a fixed bias resistor, an accelerating voltage power supply supplying an accelerating voltage to the thermionic-emission gun, and an optical system for irradiating a specimen with an electron beam. The control method includes: obtaining a value of a load current which is a current passing through an accelerating voltage power supply; determining a filament height of the thermionic-emission gun based on the value of the load current; and setting a condition of the optical system based on the filament height.

A method of plasma processing comprises generating electrons in a source chamber, generating an electric potential gradient between the source chamber and a processing chamber by applying a first negative direct current (DC) voltage to the source chamber and a ground voltage to the processing chamber, accelerating the electrons from the source chamber through a dielectric injector and into the processing chamber using the electric potential gradient, and generating an electron-beam sustained plasma (ESP) in the processing chamber using the electrons from the source chamber.

A filament assembly can include: a button having a planar emitter region with one or more apertures extending from an emission surface of the planar emitter region to an internal surface opposite of the emission surface; an inlet electrical lead coupled to the button at a first side; an outlet electrical lead coupled to the button at a second side opposite of the first side; and a low work function object positioned adjacent to the internal surface of the planar emitter region and retained to the button. The planar emitter region can include a plurality of apertures. The low work function object can include a porous ceramic material having the barium, and may have a polished external surface. An electron gun can include the filament assembly. An additive manufacturing system can include the electron gun having the filament assembly.