A charged particle beam apparatus (100) is described. The charged particle beam apparatus includes a first vacuum region (121) in which a charged particle beam emitter (105) for emitting a charged particle beam (102) along an optical axis (A) is arranged, a second vacuum region (122) downstream of the first vacuum region and separated from the first vacuum region by a first gas separation wall (132) with a first differential pumping aperture (131), wherein the first differential pumping aperture (131) is configured as a first beam limiting aperture for the charged particle beam (102); and a third vacuum region (123) downstream of the second vacuum region and separated from the second vacuum region by a second gas separation wall (134) with a second differential pumping aperture (133), wherein the second differential pumping aperture (133) is configured as a second beam limiting aperture for the charged particle beam (102). Further described are a scanning electron microscope and a method of operating a charged particle beam apparatus.

A charged particle beam apparatus (100) is described. The charged particle beam apparatus includes a first vacuum region (121) in which a charged particle beam emitter (105) for emitting a charged particle beam (102) along an optical axis (A) is arranged, a second vacuum region (122) downstream of the first vacuum region and separated from the first vacuum region by a first gas separation wall (132) with a first differential pumping aperture (131), wherein the first differential pumping aperture (131) is configured as a first beam limiting aperture for the charged particle beam (102); and a third vacuum region (123) downstream of the second vacuum region and separated from the second vacuum region by a second gas separation wall (134) with a second differential pumping aperture (133), wherein the second differential pumping aperture (133) is configured as a second beam limiting aperture for the charged particle beam (102). Further described are a scanning electron microscope and a method of operating a charged particle beam apparatus.

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.

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.

An electron gun device according to the present invention emits an electron beam by means of heating to a high temperature in a vacuum. According to the present invention, the surface of a material (108, 125), which emits an electron beam, is a hydrogenated metal that is melted and in a liquid state during a high-temperature operation; the liquid hydrogenated metal is contained in a hollow cover tube container (102, 124), which is in a solid state during the high-temperature operation, in the form of a hydrogenated liquid metal or in the form of a liquid metal before hydrogenation, and heated together with the cover tube container (102, 124) to a high temperature; subsequently, the hydrogenated liquid metal is exposed from the cover tube container (102, 124) and forms a liquid surface where gravity, the electric field and the surface tension of the liquid surface are balanced; and an electron beam is emitted from the exposed surface of the hydrogenated liquid metal.

An electron gun device according to the present invention emits an electron beam by means of heating to a high temperature in a vacuum. According to the present invention, the surface of a material (108, 125), which emits an electron beam, is a hydrogenated metal that is melted and in a liquid state during a high-temperature operation; the liquid hydrogenated metal is contained in a hollow cover tube container (102, 124), which is in a solid state during the high-temperature operation, in the form of a hydrogenated liquid metal or in the form of a liquid metal before hydrogenation, and heated together with the cover tube container (102, 124) to a high temperature; subsequently, the hydrogenated liquid metal is exposed from the cover tube container (102, 124) and forms a liquid surface where gravity, the electric field and the surface tension of the liquid surface are balanced; and an electron beam is emitted from the exposed surface of the hydrogenated liquid metal.

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 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 arrangement of conduction-cooled travelling wave tubes includes multiple travelling wave tubes mounted on a common base, wherein the travelling wave tubes are thermally connected to the base so that during operation of the travelling wave tubes the base forms a heat sink for the travelling wave tubes, and the base is designed to accommodate multiple travelling wave tubes in terms of their dimensions along their beam axes so as to increase the number of travelling wave tubes per surface area unit of the base.

The invention provides an electron source including a columnar chip of a hexaboride single crystal, a metal pipe that holds the columnar chip of the hexaboride single crystal, and a filament connected to the metal pipe at a central portion. The columnar chip of the hexaboride single crystal is formed into a cone shape at a portion closer to a tip than a portion held in the metal pipe, and a tip end portion having the cone shape has a (310) crystal face. Schottky electrons are emitted from the (310) crystal face. According to the invention, it is possible to provide a novel electron source having monochromaticity, long-term stability of an emitter current, and high current density.