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.

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.

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.

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 inverse photoemission spectroscopy apparatus is configured to detect a light generated by the relaxation of electrons to an unoccupied state of a sample. The apparatus includes an electron source for generating electrons with which a sample is irradiated, a wavelength selector for extracting a light having a certain wavelength from the light generated in the sample, a photodetector for detecting the light extracted by the wavelength selector; and a focusing optics disposed between the sample and the photodetector. The electron source contains yttrium oxide as a thermionic emission material.

A charged particle emission device includes a pre-emission state detector configured to detect a pre-emission charged state which is a charged state of the charged object before charged particles are emitted, an emission time generator configured to generate an emission time based on a past emission time of charged particles and a charged state of the charged object after the emission, emission processor circuitry configured to emit charged particles to the charged object which is in the pre-emission charged state based on the generated emission time, a post-emission state detector configured to detect a post-emission charged state which is a charged state of the charged object after the charged particles are emitted, machine learning processor circuitry configured to cause a machine learning model to learn a correspondence among the pre-emission charged state, the post-emission charged state, and the emission time generated by the emission time generator.

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.

According to one embodiment, an X-ray tube includes an anode target, a cathode including a filament and a convergence electrode which includes a groove portion, and an envelope. The groove portion includes a pair of first bottom surfaces which are located in the same plane as the filament and between which the filament is interposed in a width direction of the groove portion, and a pair of second bottom surfaces between which the filament and the pair of first bottom surfaces are interposed in a length direction of the groove portion and which are located closer to an opening of the groove portion than the pair of first bottom surfaces.

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.

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.