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在电子管领域里,一般称为阴极的电子源,通常是由一个金属表面构成的。并且能够承受适当的温度,如1000°K左右。在这个金属表面上覆盖着发射电子能力大的物质,如某些碱土氧化物。工作时,发射材料渐渐蒸发和消失,而这种电子源能够发射电子的时间的(即“寿命”)长短取决于整个发射材料的数量。这就是为什么当人们希望一种长寿命时,人们采用了一种提供发射成份的储备结构,特别是采用了一种浸渍着上述成份的海绵状金属结构。这种结构是一般的园柱体形状。在其两
In the field of electron tubes, an electron source, commonly known as a cathode, is usually made of a metal surface. And can withstand the appropriate temperature, such as 1000 ° K or so. The surface of this metal is covered with materials that have a high electron-emitting capacity, such as some alkaline-earth oxides. In operation, the emissive material gradually evaporates and disappears, and the length of time (ie, “lifetime”) that such an electron source can emit electrons depends on the amount of the entire emissive material. This is why, when one wishes a long life, one uses a reserve structure that provides the emissive component, in particular a spongy metallic structure impregnated with the above ingredients. This structure is a general cylinder shape. In its two