摘要:
An electron-emitting cathode (6) consists of an electrically conducting emitter layer (7) attached to a side wall (2) which consists of stainless steel and a gate (9) which is fixed at a mall distance inside a concave emitter surface of the emitter layer (7). The cathode (6) surrounds a reaction area (3) containing a cylindrical grid-like anode (5) and a central ion collector (4) which consists of a straight axial filament. An ion collector current (lie) reflecting the densitiy of the gas in the reaction region (3) is measured by a current meter (11) while a gate voltage (VG) is kept between the ground voltage of the emitter layer (7) and a higher anode voltage (VA) and is regulated in such a way that an anode current (IA) is kept constant. The emitter layer (7) may consists of carbon nanotubes, diamond-like carbon, a metal or a mixture of metals or a semiconductor material, e.g., silicon which may be coated, e.g., with carbide or molybdenum. The emitter surface can, however, also be a portion of the inside surface of the side wall roughened by, e.g., chemical etching. The gate (9) may be a grid or it may be made up of patches of metal film covering spacers distributed over the emitter area or a metal film covering an electron permeable layer placed on the emitter surface.
摘要:
An electron-emitting cathode (6) consists of an electrically conducting emitter layer (7) attached to a side wall (2) which consists of stainless steel and a gate (9) which is fixed at a mall distance inside a concave emitter surface of the emitter layer (7). The cathode (6) surrounds a reaction area (3) containing a cylindrical grid-like anode (5) and a central ion collector (4) which consists of a straight axial filament. An ion collector current (lie) reflecting the densitiy of the gas in the reaction region (3) is measured by a current meter (11) while a gate voltage (VG) is kept between the ground voltage of the emitter layer (7) and a higher anode voltage (VA) and is regulated in such a way that an anode current (IA) is kept constant. The emitter layer (7) may consists of carbon nanotubes, diamond-like carbon, a metal or a mixture of metals or a semiconductor material, e.g., silicon which may be coated, e.g., with carbide or molybdenum. The emitter surface can, however, also be a portion of the inside surface of the side wall roughened by, e.g., chemical etching. The gate (9) may be a grid or it may be made up of patches of metal film covering spacers distributed over the emitter area or a metal film covering an electron permeable layer placed on the emitter surface.
摘要:
An electron-emitting cathode (6) consists of an electricaly conducting emitter layer (7) attached to a side wall (2) and a gate (9) which is fixed at a mall distance inside a concave emitter surface of the emitter layer (7). The cathode (6) surrounds a reaction area (3) containing a cylindrical grid-like anode (5) and a central ion collector (4) which consists of a straight axial filament. An ion collector current (I IC ) reflecting the densitiy of the gas in the reaction region (3) is measured by a current meter (11) while a gate voltage (Vc) is kept between the ground voltage of the emitter layer (7) and a higher anode voltage (V A ) and is regulated in such a way that an anode current (T A ) is kept constant. The emitter layer (7) may comprise an array of metal, e.g., nickel or molybdenum tips or consist essentially of a semiconductor material like silicon, preferably coated by, e.g., carbide, diamond-like carbon or molybdenum, or of carbon nanotubes or it may be a roughened surface portion of the side wall surface. The gate (9) may be a grid or it may be made up of patches of metal film covering spacers distributed over the emitter area or a metal film covering an electron permeable layer placed on the emitter surface.
摘要:
In the discharge chamber (21) of a device for generating plasma, used in the space sector for ion propulsion or for the discharging of satellites and in applications on the ground, suitable ionizing radiation sources (47) are provided, capable of improving the performance of said device. The radiation emitted by the sources creates constant ionization of the gas with advantages both during the preionization phase, ie. starting of the device, and during the operating phase, standardizing the performance thereof in particular in terms of continuity and regularity of operation.
摘要:
Detecteur de fumee a chambre d'ionisation dans lequel une premiere electrode (11) est recouverte d'un isolant (12) sauf a une extremite ou elle est opposee a une electrode de mesure (15); la majeure partie de la surface de l'isolant (12) porte un conducteur (41) non connecte a la premiere electrode (11) pour reduire l'effet nuisible de condensation sur l'isolant (12).