A method for manufacturing an electron source includes steps of sandwiching a welding object in which a tip of an electron emission material and a tungsten filament overlap in direct contact between a pair of welding electrodes, and welding the tip and the tungsten filament by causing a current to flow while pressing forces are applied to the welding object by the pair of welding electrodes. A thickness of the welding object is within a range of 50 to 500 ?m.

An apparatus includes an ionization chamber and an electron source device at least partially disposed inside the ionization chamber. The ionization chamber is configured to receive at least one chemical and provide plasma having ionized chemicals. The electron source device includes at least one filament configured to generate electrons, and a cathode configured to emit secondary electrons from the front surface when the electrons from the at least one filament hit the back surface of the cathode. The front surface of the cathode is shaped convex facing inside the ionization chamber.

An electron-beam irradiation apparatus includes: a power source device; an accelerating tube that accelerates electrons when power is supplied from the power source device, to generate an electron beam; and a pressure tank that contains the power source device and the accelerating tube. The pressure tank is configured so as to be dividable into a first division body that contains the power source device and a second division body that contains the accelerating tube. The second division body has an outlet for emitting the electron beam emitted from the accelerating tube, to the outside of the pressure tank. In addition, the power source device has a connecting part connected to the second division body.

When an emission current is changed, a decrease in brightness of an electron beam is prevented. An electron gun includes a cathode that emits thermoelectrons, a Wehnelt electrode that focuses the thermoelectrons, a control electrode that extracts the thermoelectrons from a distal end of said cathode, an anode that accelerates the thermoelectrons and irradiates a powder with the thermoelectrons as an electron beam, and an optimum condition collection controller that changes at least one of a bias voltage to be applied to the Wehnelt electrode and a control electrode voltage to be applied to the control electrode, and decides a combination of the bias voltage and the control electrode voltage at which the brightness of the electron beam reaches a peak.

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.

An electron beam apparatus includes: a cathode configured to emit electrons; an anode that is an electrode which forms an electric field such that an electron beam is formed by the electrons emitted from the cathode, and that is formed with a first hole through which the electron beam passes; an aperture member formed with an opening that shades a part of the electron beam which passes through the anode; and a convergence electrode that is an electrode which forms an electric field such that the electron beam which passes through the opening converges, and that is configured to include one single-hole electrode formed with a second hole through which the electron beam passes.

An emitter with a protective cap layer on an exterior surface of the emitter is disclosed. The emitter can have a diameter of 100 nm or less. The protective cap layer includes ruthenium. Ruthenium is resistant to oxidation and carbon growth. The protective cap layer also can have relatively low sputter yields to withstand erosion by ions. The emitter may be part of a system with an electron beam source. An electric field can be applied to the emitter and an electron beam can be generated from the emitter. The protective cap layer may be applied to the emitter by sputter deposition, atomic layer deposition (ALD), or ion sputtering.

A filament assembly can include: a button having a planar emitter region with one or more apertures extending from an emission surface of the planar emitter region to an internal surface opposite of the emission surface; an inlet electrical lead coupled to the button at a first side; an outlet electrical lead coupled to the button at a second side opposite of the first side; and a low work function object positioned adjacent to the internal surface of the planar emitter region and retained to the button. The planar emitter region can include a plurality of apertures. The low work function object can include a porous ceramic material having the barium, and may have a polished external surface. An electron gun can include the filament assembly. An additive manufacturing system can include the electron gun having the filament assembly.

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