An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

In one embodiment, a system includes a cathode and a thermionic emitter installed at least partially within the cathode tube of the cathode. The thermionic emitter is in a shape of a hollow cylinder. The hollow cylinder includes an outer surface and an unsmooth inner surface. The outer surface is configured to contact an inner surface of the cathode tube. The unsmooth inner surface includes a plurality of structures that provide an increase in surface area over a smooth surface.

In one embodiment, a system includes a cathode and a thermionic emitter installed at least partially within the cathode tube of the cathode. The thermionic emitter is in a shape of a hollow cylinder. The hollow cylinder includes an outer surface and an unsmooth inner surface. The outer surface is configured to contact an inner surface of the cathode tube. The unsmooth inner surface includes a plurality of structures that provide an increase in surface area over a smooth surface.

An electron source that can be used stably for a long time even when hexaboride is used, and an electron beam device using the electron source are provided. The invention is directed to an electron source which includes a filament made of a metal, a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery, and a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is in contact with a bottom of each of the plurality of recesses of the metal tube.

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

An electron emission apparatus, an electron gun, and a method of fabrication of the electron gun are provided. The electron gun includes a cathode, a Wehnelt, and an anode. The cathode is configured to provide an electron beam. The Wehnelt has a bore. The bore is configured to pass the electron beam. The anode is disposed proximate to the cathode. The diameter of the bore of the Wehnelt and the offset between the Wehnelt and the cathode satisfy a predetermined dimensional relationship. The predetermined dimensional relationship is at least a function of a diameter of the bore of the anode and a distance between the Wehnelt and the anode.

An electron emission apparatus, an electron gun, and a method of fabrication of the electron gun are provided. The electron gun includes a cathode, a Wehnelt, and an anode. The cathode is configured to provide an electron beam. The Wehnelt has a bore. The bore is configured to pass the electron beam. The anode is disposed proximate to the cathode. The diameter of the bore of the Wehnelt and the offset between the Wehnelt and the cathode satisfy a predetermined dimensional relationship. The predetermined dimensional relationship is at least a function of a diameter of the bore of the anode and a distance between the Wehnelt and the anode.

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.

An electron source capable of suppressing consumption of an electron emission material is provide. The present invention provides an electron source including: an electron emission material; and, an electron emission-suppressing material covering a side surface of the electron emission material, wherein a work function of the electron emission-suppressing material is higher than that of the electron emission material, and a thermal emissivity of the electron emission-suppressing material is lower than that of the electron emission material.