Abstract:
Изобретение направлено на повышение эффективности ионизации органических соединений на поверхности термоэмиттера ионов в условиях атмосферы воздуха, повышение стабильности ионизации во времени и при изменении влажности воздуха, а также на упрощение способа активации термоэмиттера, включающего критерии контроля окончания процесса активации. Указанный технический эффект достигается тем, что материал термоэмиттера выбирают на основе сплава ванадия, молибдена или вольфрама, легированных цирконием или гафнием в количестве (0,1 ÷ 2,0) вес. %, рением в количестве (0,02 ÷ 0,3) вес. % и рутением или родием в количестве (0,02 ÷ 0,3) вес. %. Способ активации материала термоэмиттера включает прогрев термоэмиттера в потоке воздуха, имеющего температуру в интервале (-20 ÷ +30) 0 С и относительную влажность в интервале (10 ÷ 85)%, между термоэмиттером и вспомогательным электродом, при этом среднюю скорость прокачиваемого воздуха устанавливают в интервале (0,2 ÷ 5)м/сек, термоэмиттер нагревают до температуры в интервале (350 ÷ 600) 0 С и выдерживают при данной температуре до окончания процесса активации материала термоэмиттера, причем об окончании процесса активации материала термоэмиттера судят по величине фонового ионного тока в цепи термоэмиттера и вспомогательного электрода.
Abstract:
A tungsten wire containing 1−10 mass% of rhenium, characterized in that the point showing 2% expansion of a heated tungsten wire having a diameter of x µm and heated by application of a current of which the ratio to the fusing current (FC) of the tungsten wire of x µm diameter is y% is within the quadrilateral defined by connecting point (20, 75), point (20, 87), point (90, 75), and point (90, 58) by straight lines in a semilogarithmic coordinate system in which point (x, y) is shown, of which the horizontal axis is marked with a logarithmic scale of diameter x, and of which the vertical axis is marked with an ordinary scale of the ratio y to the fusing current. The tungsten wire expands greatly even under high−temperature condition, exhibits excellent durability when used as a constituent material of, e.g., a cathode heater and can be produced efficiently.
Abstract:
An electron source suitable for an electron beam exposure system, an Auger electronic spectrometer or the like, and provides a small total emission current amount even during a high-angular-current-density operation. An electron gun provided with a cathode (1) consisting of tungsten or molybdenum single crystal and provided on the surface thereof with a coating layer consisting of oxygen and at least one kind of metal element selected from a group consisting of 2A group, 3A group and 4A group, characterized in that the end of the cathode (1) has a conical trapezoid shape, a total conical angle of a conical trapezoid portion (8) is between 25° and 95°, and the diameter of the top face (9) is 5mum through 200mum.
Abstract:
Methods for fabricating refractory metal scandate nanocomposite powders with homogeneous microstructured refractory metal grains and a uniform nanosized dispersion of scandia are provided. The powders prepared by the sol-gel methods have a spherical morphology, a narrow distribution of particle sizes and a very uniform dispersion of nanosized scandia particles joined to the tungsten grains. The powder particle sizes can range from nanometers to micrometers. The powders can be pressed into porous cathode structures that can be impregnated with emissive materials to produce high current density and long life cathodes for high-power terahertz vacuum electron devices. The sol-gel fabrication methods allow control over the materials, particle size, particle composition and pore size and distribution of the cathode structure by manipulation of the process parameters.
Abstract:
A cathode material of an electron beam device comprising 0.5 to 9.0 % by weight of a rare-earth metal of the cerium group, 0.5 to 15.0 % by weight of tungsten and/or rhenium, 0.5 to 10 % by weight of hafnium and the balance of iridium is provided. Since the cathode material has excellent plasticity, it is easy to manufacture small-size emitters. Also, since the density of the electron emission of the cathode material is high and the working temperature is low, a long lifetime can be ensured. Also, the cathode material is useful as a cathode material of an electron beam device.