Low power schottky emitter

A method of making an electron source, comprising:

• providing an emitter base, the emitter base including at least two holes, each hole having a counterbore sufficiently deep to significantly reduce heat flow from the emitter post to the emitter base;
• inserting a filament post into each of the holes, each filament post fitting securely into its corresponding hole, the portion of the filament post surrounded by the counterbore not contacting the interior of the hole in the emitter base;
• attaching a heating filament to two of the filament posts;
• and
• attaching an emitter to the heating filament.

A method of providing a thermal field emitter for use in an electron beam system, comprising:

• providing an emitter for emitting electrons when heated;
• providing a heating filament including rhenium, titanium, or alloys of either, the filament in thermal contact with the emitter to heat the emitter when electrical current is passed through the heating filament;
• providing at least two filament posts including rhenium, titanium, or alloys thereof, in electrical contact with the heating filament to provide electrical current to the filament;
• providing a base supporting the filament posts, the filament posts extending through the base in a first direction toward the heating filament to support and provide an electrical current to the heating filament and the filament posts also extending through the base in the direction away from the electron emitter to provide electrical contacts for connecting a power supply, the base having two bores, one for passing each filament post through the base, each bore having a first cross section over a first portion of the bore to contact at a contact area and provide support for the corresponding filament post and second cross section over a second portion of the bore, the second cross section providing a gap between the filament post and the base material the gap opening in the direction of the filament and increasing the distance between the filament and the contact area which the filament posts contact the base, thereby reducing heat flow between the filament post and base and reducing power consumption of the thermal field emitter.

A method of providing an electron source for an electron beam system, comprising:

• providing an emitter for emitting electrons when heated;
• providing a heating filament in thermal contact with the emitter to heat the emitter when electrical current is passed through the heating filament, the electron emitter having extending from the filament and having a distal end converging to an emitter tip;
• providing multiple filament posts in electrical contact with the heating filament to provide electrical current to heat filament;
• and
• providing a base supporting the filament posts, the base providing a surface area sufficient for firmly securing the base within the electron beam system and having a top surface and a bottom surface through which the filament posts extend, the base including a contact area between each filament post and the base, the contact area having a length in a direction parallel to the filament post, the contact area length being significantly less than the distance between the top and bottom surfaces, thereby reducing the thermal contact area between the base and the filament post and reducing heat losses of the electron source.