A method is provided for forming a three-dimensional article through successively depositing individual layers of powder material that are fused together so as to form the article, the method comprising the steps of: providing at least one electron beam source emitting an electron beam for at least one of heating or fusing the powder material, where the electron beam source comprises a cathode, an anode, and a Wehnelt cup between the cathode and anode; providing a guard ring between the Wehnelt cup and the anode and in close proximity to the Wehnelt cup, where the guard ring is having an aperture which is larger than an aperture of the Wehnelt cup; protecting the cathode and/or the Wehnelt cup against vacuum arc discharge energy currents when forming the three-dimensional article by providing the guard ring with a higher negative potential than the Wehnelt cup and cathode.

The invention provides an exposure apparatus (100) including a formation module (122) which forms charged particle beams with different irradiation positions on a specimen. The formation module (122) includes: a particle source (20) which emits the charged particle beams from an emission region (21) in which a width in a longitudinal direction is different from and a width in a lateral direction orthogonal to the longitudinal direction; an aperture array device (60) provided with openings (62) arranged in an illuminated region (61) in which a width in a longitudinal direction is different from a width in a lateral direction orthogonal to the longitudinal direction; illumination lenses (30, 50) provided between the particle source (20) and the aperture array device (60); and a beam cross-section deformation device (40) which is provided between the particle source (20) and the aperture array device (60), and deforms a cross-sectional shape of the charged particle beams into an anisotropic shape by an action of a magnetic field or an electric field.

The invention relates to a device (20) for producing an electron beam (4), which comprises a hot cathode (1), a cathode electrode (2), an anode electrode (3) having an opening (6) through which an electron beam (4) produced by the device can pass, wherein during the operation of the device (20) a voltage for accelerating the electrons exiting from the hot cathode (1) is applied between the cathode electrode (2) and the anode electrode (3), and further comprising deflection means that can deflect the electron beam (4) that has passed through the opening of the anode electrode (3), wherein the deflection means comprise at least one deflection electrode (8, 12), which can reflect the electron beam (4) and/or which comprises a deflection surface (9) that is inclined towards the propagation direction of the electron beam (4).

An electron gun includes a cathode that is heated to emit thermions; a cathode heating power supply that supplies a cathode heating current for heating the cathode; a grid that has a first aperture formed therein and that has a grid voltage applied thereto, the grid voltage having a potential lower than that of the cathode, wherein the grid converges the thermions passing through the first aperture by the grid voltage; an anode that has a second aperture formed therein and that has an anode voltage applied thereto, wherein the anode causes the thermions extracted from the cathode to pass through the second aperture as an electron beam by the anode voltage; an anode-voltage power supply that applies the anode voltage to the anode; and a controller that causes the anode voltage having a positive potential to be applied from the anode-voltage power supply to the anode.

An electron beam writing apparatus comprising, a cathode configured to emit an electron beam, a condition controller configured to change a condition under which the electron beam is emitted from the cathode in a plurality of ways, and a prediction unit configured to predict a life span of the cathode based on a temporal change in an amount of fluctuation of a beam characteristic of the electron beam to a change in the condition when the condition is changed.

Electron emitters and method of fabricating the electron emitters are disclosed. According to certain embodiments, an electron emitter includes a tip with a planar region having a diameter in a range of approximately (0.05-10) micrometers. The electron emitter tip is configured to release field emission electrons. The electron emitter further includes a work-function-lowering material coated on the tip.

An object is to provide an electron beam applicator suitable for an electron gun having a photocathode and an electron beam emission method in the electron beam applicator. The object can be achieved by an electron beam applicator including: an electron gun section; a main body section; and a control unit. The electron gun section includes a light source, a photocathode that emits an electron beam in response to receiving excitation light emitted from the light source, and an anode. The main body section includes an objective lens that converges an electron beam emitted from the electron gun section. The control unit controls at least convergence power of the objective lens in accordance with a size of an electron beam emitted from the photocathode.

Electron emitters and methods of fabricating the electron emitters are disclosed. According to certain embodiments, an electron emitter includes a tip with a planar region having a diameter in a range of approximately (0.05-10) micrometers. The electron emitter tip is configured to release field emission electrons. The electron emitter further includes a work-function-lowering material coated on the tip.

A method for controlling operation of an electron emission source includes acquiring, while varying an emission current of an electron beam, a characteristic between a surface current of a target object at a position on the surface of the target object irradiated with the electron beam, and the emission current, calculating, based on the characteristic, first gradient values each obtained by dividing the surface current of the target object by the emission current, in a predetermined range of the emission current in the characteristic, calculating a second gradient value by dividing a surface current of the target object by an emission current in a state where the electron beam has been adjusted, and adjusting a cathode temperature to make the second gradient value in the state where the electron beam has been adjusted be in the range of the first gradient values in the predetermined range of the emission current.

An emitter according to the present disclosure includes: first and second heaters generating heat by energization; an electron source comprising a first material emitting an electron by being heated by the first and second heaters; and an intermediate member interposed between the electron source, and the first and second heaters, the intermediate member comprising a second material lower in thermal conductivity than the first material.