Electron gun systems with a particular inner width dimension, sweep electrodes, or a combination of a particular inner width dimension and sweep electrodes are disclosed. The inner width dimension may be less than twice a value of a Larmor radius of secondary electrons in a channel downstream of a beam limiting aperture, and a Larmor time for the secondary electrons may be greater than 1 ns. The sweep electrode can generates an electric field in a drift region, which can increase kinetic energy of secondary electrons in the channel.

This invention provides a charged particle source, which comprises an emitter and means of 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.

Provided is a method of adjusting an electron-beam irradiated area in an electron beam irradiation apparatus that deflects an electron beam with a deflector to irradiate an object with the electron beam, the method including: emitting an electron beam while changing an irradiation position on an adjustment plate by controlling the deflector in accordance with an electron beam irradiation recipe, the adjustment plate detecting a current corresponding to the emitted electron beam; acquiring a current value detected from the adjustment plate; forming image data corresponding to the acquired current value; determining whether the electron-beam irradiated area is appropriate based on the formed image data; and updating the electron beam irradiation recipe when the electron-beam irradiated area is determined not to be appropriate.

A charged-particle source for emission of electrons or other electrically charged particles comprises, located between the emitter electrode having an emitter surface and a counter electrode, at least two adjustment electrodes; a pressure regulator device is configured to control the gas pressure in the source space at a pre-defined pressure value. In a first cleaning mode of the particle source, applying a voltage between the emitter and counter electrodes directs gas particles towards the counter electrode, generating secondary electrons which ionize particles of the gas in the source space, and electrostatic potentials are applied to at least some of the adjustment electrodes, generating an electric field directing the ionized gas particles onto the emitter surface.

Provided are a charged particle gun and a charged particle beam apparatus that can reduce instability in the amount of emitted charged particles and deviation in the charged particle trajectory when the amount of charged particle beams is increased. A charged particle gun includes a charged particle source that generates a charged particle, an electrode portion that includes an extraction electrode for extracting a charged particle beam from the charged particle source, a voltage introduction unit that introduces voltage to the electrode portion, and a temperature adjustment unit that adjusts a temperature of the electrode portion. The temperature adjustment unit is configured to adjust the temperature of the electrode portion based on a change in a state of the electrode portion.

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.

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.

An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

Disclosed is an x-ray tube including a hybrid electron emission source, which uses, as an electron emission source, a cathode including both a field electron emission source and a thermal electron emission source. An x-ray tube includes an electron emission source emitting an electron beam, and a target part including a target material that emits an x-ray as the emitted electron beam collides with the target part, wherein the electron emission source includes a thermal electron emission source and a field electron emission source, and emits the electron beam by selectively using at least one of the thermal electron emission source and the field electron emission source.

An emitter assembly for emitting a charged particle beam along an optical axis is described. The emitter assembly being housed in a gun chamber and includes an emitter having an emitter tip, wherein the emitter tip is positioned at a first plane perpendicular to the optical axis and wherein the emitter is configured to be biased to a first potential, an extractor having an opening, wherein the opening is positioned at a second plane perpendicular to the optical axis and wherein the extractor is configured to be biased to a second potential, wherein the second plane has a first distance from the first plane of 2.25 mm and above.