A cold cathode field-emission electron gun includes: an emitter; an extraction electrode which extracts electrons from the emitter; and a biased electrode which is disposed closer to the emitter than the extraction electrode. A voltage applied to the biased electrode is variable.

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.

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

The present disclosure provides a method of manufacturing an electron source. The method includes forming one or more fixed emission sites on at least one needle tip, the fixed emission sites including a reaction product formed by metal atoms on a surface of the needle tip and gas molecules.

The present disclosure provides an electron source, including one or more tips, wherein at least one of the tips comprises one or more fixed emission sites, wherein at least one of the tips includes one or more fixed emission sites, wherein the emission sites includes a reaction product of metal atoms on a surface of the tip with gas molecules.

The present disclosure provides a method of regenerating an electron source, the electron source including at least one emission site fixed on a needle tip, and the emission site including a reaction product formed by metal atoms and gas molecules. The method includes regenerating the electron source in situ if an emission capability of the electron source satisfies a regeneration condition.

The present disclosure provides an electron source operating method, the electron source including at least one emission site fixed on a tip, the emission site being a reaction product formed by metal atoms of a surface of the tip and gas molecules under an electric field, and the operating method comprises emitting electrons by controlling operating parameters of the electron source.

An electron gun for an electron microscope or similar device includes a field emitter cathode having a field emitter protrusion extending from the output surface of a monocrystalline silicon substrate, and electrodes configured to enhance the emission of electrons from a tip portion of the field emitter protrusion to generate a primary electron beam. A thin, contiguous SiC layer is disposed directly on at least the tip portion of the field emitter protrusion using a process that minimizes oxidation and defects in the SiC layer. Optional gate layers may be placed at, slightly lower than or slightly higher than the height of the field emitter tip portion to achieve high emission current and fast and accurate control of the primary emission beam. The field emitter can be p-type doped and configured to operate in a reverse bias mode, or the field emitter can be n-type doped.

Charged particle beams (CPBs) are modulated using a beam blanker/deflector and an electrically pulsed extraction electrode in conjunction with a field emitter and a gun lens. With such modulation, CPBs can provide both pulsed and continuous mode operation as required for a particular application, while average CPB current is maintained within predetermined levels, such as levels that promote X-ray safe operation. Either the extraction electrode or the beam blanker/deflector can define CPB pulse width, CPB on/off ratio, or both.