Abstract: A monolithic graphite heater for heating a thermionic electron cathode includes first and second electrically conductive arms, each one of the first and second electrically conductive arms having an electrode mount at a proximal end, a thermal apex at a distal end, and a transitional region between the electrode mount and the thermal apex; a cathode mount electrically and mechanically coupling each thermal apex to form a maximum Joule-heating region at or adjacent the cathode mount and decreasing Joule heating along each transitional region; and a press-fit aperture formed in the cathode mount, the press-fit aperture sized to receive at least a portion of the thermionic electron cathode for facilitating thermionic emission produced therefrom in response to operative heat power generation provided by the maximum Joule-heating region.

Abstract: A monolithic graphite heater for heating a thermionic electron cathode includes first and second electrically conductive arms, each one of the first and second electrically conductive arms having an electrode mount at a proximal end, a thermal apex at a distal end, and a transitional region between the electrode mount and the thermal apex; a cathode mount electrically and mechanically coupling each thermal apex to form a maximum Joule-heating region at or adjacent the cathode mount and decreasing Joule heating along each transitional region; and a press-fit aperture formed in the cathode mount, the press-fit aperture sized to receive at least a portion of the thermionic electron cathode for facilitating thermionic emission produced therefrom in response to operative heat power generation provided by the maximum Joule-heating region.

Abstract: An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

Abstract: An electron source emitter is made from transition metal carbide materials, including hafnium carbide (HfC), zirconium carbide (ZrC), titanium carbide (TiC), vanadium carbide (VC), niobium carbide (NbC), and tantalum carbide (TaC), which are of high refractory nature. Preferential evaporating and subsequent development of different crystallographic planes of the transition metal carbide emitter having initially at its apex a small radius (50 nm-300 nm) develop over time an on-axis, sharp end-form or tip that is uniformly accentuated circumferentially to an extreme angular form and persists over time. An emitter manufactured to the (110) crystallographic plane and operating at high electron beam current and high temperature for about 20 hours to 40 hours results in the (110) plane, while initially not a high emission crystallographic orientation, developing into a very high field emission orientation because of the geometrical change.

Abstract: An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

Abstract: An electron source is made from mixed-metal carbide materials of high refractory nature. Producing field-enhanced thermionic emission, i.e., thermal-field or extended Schottky emission, from these materials entails the use of a certain low work function crystallographic direction, such as, for example, (100), (210), and (310). These materials do not naturally facet because of their refractory nature. The disclosed electron source made from transition metal carbide material is especially useful when installed in a scanning electron microscope (SEM) performing advanced imaging applications that require a high brightness, high beam current source.

Abstract: An electron source is made from mixed-metal carbide materials of high refractory nature. Producing field-enhanced thermionic emission, i.e., thermal-field or extended Schottky emission, from these materials entails the use of a certain low work function crystallographic direction, such as, for example, (100), (210), and (310). These materials do not naturally facet because of their refractory nature. The disclosed electron source made from transition metal carbide material is especially useful when installed in a scanning electron microscope (SEM) performing advanced imaging applications that require a high brightness, high beam current source.

Abstract: A low input power consumption, compact thermal field emitter is suitable for use in electron beam systems, particularly those systems that use an array of electron beams or a miniature electron beam system. The thermal field emitter design reduces heat loss by reducing heat transfer to the base. To achieve reduced loses the design incorporates the use of high electrical resistivity, low thermal conductivity materials for construction of the filament posts and the filaments. Such materials further reduce heat loss and reduce input current requirements. In one embodiment, the base includes counterbores that reduce the heat conduction path between the filament posts and the base, and moves the contact area further from the filament.

Abstract: An electron emitter is produced by applying a work function lowering material that does not require an extensive heating step before the material will function to lower the work function. By eliminating the extensive heating step, a small radius, highly tapered emitter tip will retain its shape to consistently produce a high angular intensity at a reasonable output power level.

Abstract: A low input power consumption, compact thermal field emitter is suitable for use in electron beam systems, particularly those systems that use an array of electron beams or a miniature electron beam system. The thermal field emitter design reduces heat loss by reducing heat transfer to the base. To achieve reduced loses the design incorporates the use of high electrical resistivity, low thermal conductivity materials for construction of the filament posts and the filaments. Such materials further reduce heat loss and reduce input current requirements. In one embodiment, the base includes counterbores that reduce the heat conduction path between the filament posts and the base, and moves the contact area further from the filament.

Abstract: A electron emission cathode includes an emitter having an apex from which electrons are emitted. The emitter is attached to a heating filament at a junction and extends from the junction both forward toward the apex and rearward. A reservoir of material that lowers the work function of the emitter is positioned on the rearward extending portion of the emitter. By positioning the reservoir on the rearward extending portion, the reservoir can be positioned sufficiently far from the junction to reduce its temperature and thereby greatly increase the useful life, of the emitter without adversely affected the emission characteristics of the source.

Abstract: An electron emitter is produced by applying a work function lowering material that does not require an extensive heating step before the material will function to lower the work function. By eliminating the extensive heating step, a small radius, highly tapered emitter tip will retain its shape to consistently produce a high angular intensity at a reasonable output power level.

Abstract: A low input power consumption, compact thermal field emitter is suitable for use in electron beam systems, particularly those systems that use an array of electron beams or a miniature electron beam system. The thermal field emitter design reduces heat loss by reducing heat transfer to the base. To achieve reduced loses the design incorporates the use of high electrical resistivity, low thermal conductivity materials for construction of the filament posts and the filaments. Such materials further reduce heat loss and reduce input current requirements. In one embodiment, the base includes counterbores that reduce the heat conduction path between the filament posts and the base, and moves the contact area further from the filament.