摘要:
An electrically heated planar cathode for use in miniature x-ray tubes may be spiral design laser cut from a thin tantalum alloy ribbon foil (116) with grain stabilizing features. Bare ribbon is mounted to an aluminum nitride substrate (110) in a manner that is puts the ribbon in minimal tension before it is machined into the spiral pattern (118). The spiral pattern can be optimized for electrical, thermal, and emission characteristics.
摘要:
It is possible to provide an electron emission cathode, an electron emission source having a high-luminance and narrow energy width by using diamond and an electronic device using them. The diamond electron discharge cathode has a monocrystal diamond at least at a part of it. The diamond electron emission cathode includes a sharpened section and a heating section. The diamond electron emission cathode has a columnar shape having the sharpened section having an electron emission section and is formed by at least two types of semiconductor having different electric characteristics. One of the types constituting the semiconductor is an n-type semiconductor containing 2 × 10 15 cm -3 of n-type impurities or above and the other type is a p-type semiconductor containing 2 × 10 15 cm -3 of p-type impurities or above. The p-type semiconductor is in contact with the n-type semiconductor. A pair of current introduction terminals directly heats the heating section in parallel to the contact surface and emits a part of the introduced electrons from the electron emission section.
摘要:
It is possible to provide an electron emission cathode, an electron emission source having a high-luminance and narrow energy width by using diamond and an electronic device using them. The diamond electron discharge cathode has a monocrystal diamond at least at a part of it. The diamond electron emission cathode has a columnar shape having a sharpened portion at a part of the electron emission section and is formed by at least two types of semiconductor having different electric characteristics. One of the types constituting the semiconductor is an n-type semiconductor containing 2 × 10 15 cm -3 of n-type impurities or above and the other type is a p-type semiconductor containing 2 × 10 15 cm -3 of p-type impurities or above. The p-type semiconductor is in contact with the n-type semiconductor and negative potential is applied to the n-type semiconductor with respect to the p-type semiconductor so that electrons flow from the n-type semiconductor to the p-type semiconductor by a pair of current introduction terminals, and the n-type semiconductor contains such a component that the electrons flow into the electron emission unit.
摘要:
In a direct heated grid cathode shaped as a one-piece hollow metallic cylinder the working surface has a form of intercrossing spiral-like filaments (3 and 4) with openings (5) between them, the thickness of each of the filaments (3 and4) increasing in steps in the direction from the edges to the centre of the cathode. A method of making the cathode comprises manufacturing an electrode-instrument out of a plate by means of electro-erosion cutting out slots on the butt-end of the plate and thus forming, therebetween, protrusions corresponding by their form to the openings (5) between the filaments (3 and 4) of the cathode and subsequent broaching with this electrode-instrument lengthwise rows of openings (5) in the hollow cylindrical workpiece which is turned after each operation at an angle equal to a double angular distance between the middle lines of the adjacent rows of the openings (5) in the cathode. The slots in the plate are cut in such a manner that after each operation of the electrode-instrument through the workpiece are formed full openings (5) of one lengthwise row, halves of the openings (5) of the two adjacent rows and the corresponding sections of the filaments (3 and 4) located therebetween.
摘要:
The invention relates to a cathode arrangement (20) comprising: • - a thermionic cathode comprising an emission portion (30) provided with an emission surface for emitting electrons, and a reservoir (38) for holding a material, wherein the material, when heated, releases work function lowering particles that diffuse towards the emission portion and emanate at the emission surface at a first evaporation rate; • - a focusing electrode (40) comprising a focusing surface for focusing the electrons emitted from the emission surface of the cathode; and • - an adjustable heat source (50) configured for keeping the focusing surface at a temperature at which accumulation of work function lowering particles on the focusing surface is prevented.
摘要:
A method of making cathodes (28) includes forming a first intermediate assembly (16) having a current wire (10) in juxtaposition with an outer mandrel wire (12) and a basket wire (14) wound around the first two wires (10 and 12). The first intermediate assembly (16) is wound around a central mandrel (18) to form a second intermediate assembly (20). Pulses of energy are used to produce an alloy solder joint (24) between the current wire (10) and the basket wire (14) at selected locations. The second intermediate assembly (20) is cut into segments, and the mandrels (18) are removed. This results in a cathode (28) having a coiled current wire (10) and a basket wire (14) wound around the current wire (10), with the basket wire (14) being bonded to the current wire (10) by the alloy solder joints (24). The cathode (28) includes a central bore (30) that is substantially free of the alloy solder joint (24).
摘要:
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.
摘要:
The invention relates to a cathode arrangement (20) comprising: • - a thermionic cathode comprising an emission portion (30) provided with an emission surface for emitting electrons, and a reservoir (38) for holding a material, wherein the material, when heated, releases work function lowering particles that diffuse towards the emission portion and emanate at the emission surface at a first evaporation rate; • - a focusing electrode (40) comprising a focusing surface for focusing the electrons emitted from the emission surface of the cathode; and • - an adjustable heat source (50) configured for keeping the focusing surface at a temperature at which accumulation of work function lowering particles on the focusing surface is prevented.