An X-ray tube of an embodiment includes an anode; and an electron emission device. In an embodiment, the electron emission device includes at least one electron emitter including at least one emission surface and at least one barrier grid, the at least one barrier grid being spaced apart from the at least one emission surface of the electron emitter and includes a definable number of individually controllable grid segments. According to an embodiment, at least one individually definable grid voltage is applicable to each of the grid segments. In a simple manner, an electron-emission device of an embodiment permits the image quality to be adjusted with minimal anode loading.

An apparatus includes: a structure having a lumen for accommodating a beam (e.g., electron beam, proton beam, or a charged particle beam), wherein the structure is a component of a medical radiation machine having a target for interaction with the beam to generate radiation; and a first beam position monitor comprising a first electrode and a second electrode, the first electrode being mounted to a first side of the structure, the second electrode being mounted to a second side of the structure, the second side being opposite from the first side; wherein the first beam position monitor is located upstream with respect to the target.

An apparatus includes: a structure having a lumen for accommodating a beam (e.g., electron beam, proton beam, or a charged particle beam), wherein the structure is a component of a medical radiation machine having a target for interaction with the beam to generate radiation; and a first beam position monitor comprising a first electrode and a second electrode, the first electrode being mounted to a first side of the structure, the second electrode being mounted to a second side of the structure, the second side being opposite from the first side; wherein the first beam position monitor is located upstream with respect to the target.

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 gas field ionization source for forming an electric field for ionizing gas comprises: an emitter tip having a tip end; an extraction electrode facing the emitter tip and having an aperture at a position distant therefrom; a gas supply means for supplying the gas in the vicinity of the emitter tip; a vacuum partition made of a metal having a hole; and a high voltage power source for applying voltage between the emitter tip and the extraction electrode. The hole is constructed so that the tip end of the emitter tip can pass therethrough and the vacuum partition has a micro protrusion, around the hole, protruding toward a side of the extraction electrode.

A gas field ionization source for forming an electric field for ionizing gas comprises: an emitter tip having a tip end; an extraction electrode facing the emitter tip and having an aperture at a position distant therefrom; a gas supply means for supplying the gas in the vicinity of the emitter tip; a vacuum partition made of a metal having a hole; and a high voltage power source for applying voltage between the emitter tip and the extraction electrode. The hole is constructed so that the tip end of the emitter tip can pass therethrough and the vacuum partition has a micro protrusion, around the hole, protruding toward a side of the extraction electrode.

An electron gun includes a cathode including an electron emitting portion, an extraction electrode for extracting electrons emitted from the electron emitting portion, and a focusing electrode for focusing the electrons extracted by the extraction electrode. The focusing electrode includes an outside electrode having a tubular shape, and an inside electrode arranged inside the outside electrode. The inside electrode defines a first space having a columnar shape, and includes a first surface on a side of the cathode, and a second surface on an opposite side of the first surface. An inside surface of the outside electrode and the second surface of the inside electrode define a second space. The inside electrode includes an electron passage hole, and a communicating portion which makes the first space and the second space communicate with each other.

Disclosed embodiments include vacuum electronics devices and methods of fabricating a vacuum electronics device. In a non-limiting embodiment, a vacuum electronics device includes: an electrode; a first film layer disposed on the electrode about a periphery of the electrode; and a second film layer disposed on the first film layer, the second film layer including a plurality of electrically conductive grid lines patterned therein that are supported only at the periphery of the electrode by the first film layer.

Disclosed embodiments include vacuum electronics devices and methods of fabricating a vacuum electronics device. In a non-limiting embodiment, a vacuum electronics device includes: an electrode; a first film layer disposed on the electrode about a periphery of the electrode; and a second film layer disposed on the first film layer, the second film layer including a plurality of electrically conductive grid lines patterned therein that are supported only at the periphery of the electrode by the first film layer.

Disclosed embodiments include vacuum electronics devices and methods of fabricating a vacuum electronics device. In a non-limiting embodiment, a vacuum electronics device includes: an electrode; a plurality of grid supports disposed on the electrode, each of the plurality of grid supports having a first width; and a plurality of grid lines, each of the plurality of grid lines being supported on an associated one of the plurality of grid supports, each of the plurality of grid lines having a second width that is wider than the first width.