In a Schottky emitter or a thermal field emitter using a hexaboride single crystal, side emission from portions other than an electron emission portion is reduced. An electron source according to the invention includes: a protrusion (40) configured to emit an electron when an electric field is generated; a shank (41) that supports the protrusion (40) and has a diameter decreasing toward the protrusion (40); and a body (42) that supports the shank (41), in which the protrusion (40), the shank (41), and the body (42) are each made of a hexaboride single crystal, and a part including the shank (41) and the body (42) excluding the protrusion (40) is covered with a material having a work function higher than that of the hexaboride single crystal.

In a Schottky emitter or a thermal field emitter using a hexaboride single crystal, side emission from portions other than an electron emission portion is reduced. An electron source according to the invention includes: a protrusion (40) configured to emit an electron when an electric field is generated; a shank (41) that supports the protrusion (40) and has a diameter decreasing toward the protrusion (40); and a body (42) that supports the shank (41), in which the protrusion (40), the shank (41), and the body (42) are each made of a hexaboride single crystal, and a part including the shank (41) and the body (42) excluding the protrusion (40) is covered with a material having a work function higher than that of the hexaboride single crystal.

The present disclosure relates to a brazing structure. The brazing structure may comprise a first portion and a second portion. At least one of the first portion or the second portion may include a connection-reinforcing surface. The connection-reinforcing surface may include a groove region and a filler placement region. The filler placement region may be configured to hold a filler material in solid state before brazing. The groove region may include a plurality of grooves where the filler material flows into after being melted. The first portion and the second portion may be connected by a braze joint formed by the filler material.

The present disclosure relates to a brazing structure. The brazing structure may comprise a first portion and a second portion. At least one of the first portion or the second portion may include a connection-reinforcing surface. The connection-reinforcing surface may include a groove region and a filler placement region. The filler placement region may be configured to hold a filler material in solid state before brazing. The groove region may include a plurality of grooves where the filler material flows into after being melted. The first portion and the second portion may be connected by a braze joint formed by the filler material.

A cathode mechanism of an electron emission source includes a crystal that includes an upper part being columnar, truncated conical, or their combined shape, and having a first surface to emit thermoelectrons, and a lower part, integrated with the upper part, having a second surface substantially parallel to the first surface, and a diameter larger than the maximum diameter of the upper part, a holding part that is a column having, in order from the holding part upper side, different inner diameters of a first diameter and a second diameter larger than the first one, and that holds the crystal in the state where the crystal first surface is projecting from the upper surface, and the crystal second surface contacts the holding part inside the column, and a retaining part that retains the crystal, at the back of the crystal lower part, not to be separated from the holding part.

A cathode mechanism of an electron emission source includes a crystal that includes an upper part being columnar, truncated conical, or their combined shape, and having a first surface to emit thermoelectrons, and a lower part, integrated with the upper part, having a second surface substantially parallel to the first surface, and a diameter larger than the maximum diameter of the upper part, a holding part that is a column having, in order from the holding part upper side, different inner diameters of a first diameter and a second diameter larger than the first one, and that holds the crystal in the state where the crystal first surface is projecting from the upper surface, and the crystal second surface contacts the holding part inside the column, and a retaining part that retains the crystal, at the back of the crystal lower part, not to be separated from the holding part.

An ionizing device is described, comprising a tubular bulb made of electrically insulating or dielectric material extending along a longitudinal reference axis and having the two longitudinal open ends and opposite each other, a tubular cathode engaged in the bulb, a tubular anode fitted to the bulb, a pair of covers, each of which has a respective internal seat into which a respective end of the bulb is inserted so as to hermetically seal it, and a conductive electrode which extends into the bulb and is electrically connected to the cathode.

An ionizing device is described, comprising a tubular bulb made of electrically insulating or dielectric material extending along a longitudinal reference axis and having the two longitudinal open ends and opposite each other, a tubular cathode engaged in the bulb, a tubular anode fitted to the bulb, a pair of covers, each of which has a respective internal seat into which a respective end of the bulb is inserted so as to hermetically seal it, and a conductive electrode which extends into the bulb and is electrically connected to the cathode.

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the housing at the distal end thereof, a charged particle source within the housing at the proximal end thereof to direct charged particles at the target based upon a first biasing potential, and a field shaping electrode within the housing and adjacent the source to shape a field within the housing. At least one accelerator electrode may be within the housing on an opposite side of the field shaping electrode from the source to accelerate charged particles from the source to the target based upon a second biasing potential different than the first biasing potential. The field shaping electrode may be electrically floating so that the charged particles are directed from the source to the target without applying a biasing potential to the field shaping electrode.

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the housing at the distal end thereof, a charged particle source within the housing at the proximal end thereof to direct charged particles at the target based upon a first biasing potential, and a field shaping electrode within the housing and adjacent the source to shape a field within the housing. At least one accelerator electrode may be within the housing on an opposite side of the field shaping electrode from the source to accelerate charged particles from the source to the target based upon a second biasing potential different than the first biasing potential. The field shaping electrode may be electrically floating so that the charged particles are directed from the source to the target without applying a biasing potential to the field shaping electrode.