Abstract: 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.

Abstract: A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

Abstract: A cathode mechanism of an electron gun includes a crystal to emit a thermal electron from an end surface by being heated, a holding part to hold the crystal in a state where the end surface is exposed and at least a part of other surfaces of the crystal is covered, a first supporting post and a second supporting post each to support the holding part and extend while maintaining an unchanged sectional size, a first base part to fix the first supporting post, and a second base part to fix the second supporting post, wherein the holding part, the first supporting post, the second supporting post, the first base part, and the second base part are formed in an integrated structure made of the same material, and the crystal is heated by supplying a current to the integrated structure.

Abstract: A cathode obtaining method includes producing a plurality of cathodes each including an electron emission member and a cover part, provided with a gap, which covers a side surface of the electron emission member, measuring an outer dimension of the upper surface of the electron emission member, for each of a plurality of cathodes, measuring an outer dimension of the gap at the same surface as the upper surface of the electron emission member, for each of a plurality of cathodes, calculating an area ratio by dividing the area of the gap, for each of a plurality of cathodes, obtaining an upper limit of the area ratio corresponding to a desired brightness by using a correlation between brightness and the area ratio, and selecting a cathode having the area ratio less than or equal to the upper limit from a plurality of cathodes that have been produced.

Abstract: A thermionic cathode of an embodiment includes a carbon coating applied to an outer surface of the side, the carbon coating comprising a contiguous extended portion surrounding the upper section and spaced apart from said upper section by a gap having 1 ?m or more and 10 ?m or less in width and having a difference of 1 ?m or less in the width between a maximum value and a minimum value in a periphery of the electron emitting surface.

Abstract: A method for producing a thermoelectron emission source for an electron gun used in an electron beam writing apparatus, the thermoelectron emission source producing method comprising, preparing a first material that emits a thermoelectron, coating the first material with a second material having a work function larger than that of the first material, exposing the first material from part of the second material by machine processing, and decreasing a diameter of the exposed portion of the first material by heating treatment when the diameter of the exposed portion is larger than a predetermined diameter value.

Abstract: A cathode obtaining method includes producing a plurality of cathodes each including an electron emission member and a cover part, provided with a gap, which covers a side surface of the electron emission member, measuring an outer dimension of the upper surface of the electron emission member, for each of a plurality of cathodes, measuring an outer dimension of the gap at the same surface as the upper surface of the electron emission member, for each of a plurality of cathodes, calculating an area ratio by dividing the area of the gap, for each of a plurality of cathodes, obtaining an upper limit of the area ratio corresponding to a desired brightness by using a correlation between brightness and the area ratio, and selecting a cathode having the area ratio less than or equal to the upper limit from a plurality of cathodes that have been produced.

Abstract: A method for producing a thermoelectron emission source for an electron gun used in an electron beam writing apparatus, the thermoelectron emission source producing method comprising, preparing a first material that emits a thermoelectron, coating the first material with a second material having a work function larger than that of the first material, exposing the first material from part of the second material by machine processing, and decreasing a diameter of the exposed portion of the first material by heating treatment when the diameter of the exposed portion is larger than a predetermined diameter value.

Abstract: A thermionic cathode of an embodiment includes a carbon coating applied to an outer surface of the side, the carbon coating comprising a contiguous extended portion surrounding the upper section and spaced apart from said upper section by a gap having 1 ?m or more and 10 ?m or less in width and having a difference of 1 ?m or less in the width between a maximum value and a minimum value in a periphery of the electron emitting surface.