Abstract:
A cathode for electron emission, comprising a heating device (1, 2) for generating temperatures above 300°C, an electrically conductive cathode support (3) which is connected to the heating device (1, 2), and a cathode coating which is applied to the cathode support (3) and consists of an electron-emitting material (4) comprising at least one alkali metal selected from the group consisting of sodium, potassium, rubidium and cesium, with an emission current density > 10 A/m2 at an operating temperature between 300°C and 600°C.
Abstract translation:一种用于电子发射的阴极,包括用于产生高于300℃的温度的加热装置(1,2),连接到加热装置(1,2)的导电阴极支撑件(3)和阴极涂层 施加到阴极支撑体(3)上并且由包含至少一种选自钠,钾,铷和铯的碱金属的电子发射材料(4)组成,发射电流密度> 10A / m 2 工作温度在300°C至600°C之间。
Abstract:
Impregnated cathode for a vacuum tube comprising an emissive part in the form of a porous pellet 11 impregnated with a compound of alkaline earth metals; the pellet is placed in a dish 12 made of a refractory material and covered with a porous metal foil 13 forming the emissive surface of the cathode. Moreover, the pellet has a separation surface 18 between a heavily impregnated zone and a zone 10 which is not impregnated or weakly impregnated so that the said separation surface comprises at least a hollow part facing the emissive surface. By virtue of the shape of this separation surface, the lifetime of the cathode is improved.
Abstract:
An emitter-dispenser housing (48) for a controlled porosity dispenser cathode manufactured of a single material as a unitary piece by a chemical vapor deposition process in which a configured mandrel (20) is coated with a layer of material (36 and 40) such as tungsten, for example, so that when the mandrel (20) is removed from the coating of material (36), a hollow housing (48) is formed having a side wall (36 and 40) and an end wall (42) which define a reservoir (44). In addition, intersecting strips (28 and 30) of this same material as the coating, which had been placed in the mandrel (20), extend transversely across the reservoir (44) with the edges thereof bonded by atomic-crystalline growth to the coating (36 and 40) during the chemical vapor deposition to form a unitary piece. Thereafter, an array of apertures (46) is formed in the end wall (42) of the housing by laser drilling to create an emitter-dispenser (42).
Abstract:
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.
Abstract:
A method of manufacturing an emitter (8; 10) for a thermionic dispenser cathode, includes forming a porous emitter body with substantially interconnected pores, having an emission surface (11; 16) from which, upon application of heat, electrons are emitted. The porous emitter body is suitable for transporting through the substantially interconnected pores, a compound released upon application of heat, to the emission surface (11; 16), which compound, when deposited on the emission surface (11; 16), serves to lower an effective work function of the emitter (8; 10). The porous emitter body is formed by means of a process of deposition of material. At least a region of the porous emitter body is provided with a continuously varying porosity. The porosity is continuously varied by controlling at least one parameter of the deposition process.
Abstract:
A dispenser cathode which comprises an emission surface (4), a reservoir (1) for material releasing, when heated, work-function-lowering particles, and at least one passage (7) for allowing diffusion of work-function-lowering particles from said reservoir to said emission surface, said emission surface comprising at least one emission area (9) and at least one non-emission area (8) covered with emission-suppressing material and surrounding each emission area, said non-emission area comprising at least one passage connecting said reservoir with said non-emission area and debouching within a diffusion length distance from an emission area for allowing diffusion of work-function-lowering particles from said reservoir to said emission area.
Abstract:
A dispenser cathode which comprises an emission surface, a reservoir for material releasing, when heated, work-function-lowering particles, and at least one passage for allowing diffusion of work-function-lowering particles from said reservoir to said emission surface, said emission surface comprising at least one emission area and at least one non-emission area covered with emission-suppressing material and surrounding each emission area, said non-emission area comprising at least one passage connecting said reservoir with said non-emission area and debouching within a diffusion length distance from an emission area for allowing diffusion of work-function-lowering particles from said reservoir to said emission area.