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采用一种特殊的化学剥离方法,把Cu-Be打拿极的表面薄膜剥离下来,用透射电镜直接观察到了BeO薄膜的微观结构,既直观、真实,又避免了大量的间接分析。观察结果表明,BeO薄膜是连续的,BeO晶粒细小、致密,呈颗粒状。但640℃与870℃激活生成的BeO薄膜有很大差异:前者BeO晶粒细小,基本在150埃左右,膜薄且均匀,后者晶粒粗大不等,大的可达1000埃,小的仅有200埃,少的仅有200埃,膜厚亦不均匀,裂纹也增多了,这说明激活温度对BeO薄膜的生长有显著影响。选区电子衍射与俄歇电子谱的分析表明,在剥离下来的表面薄膜中,确有少量的Cu_2O和CuO存在,但不是分布在最表面。通过反射电子衍射和二次电子发射系数的测量,直接证明了BeO薄膜是Cu-Be打拿极的主要二次电子发射体。
Using a special chemical stripping method, the surface film of Cu-Be dynode was peeled off. The microstructure of BeO thin film was directly observed by transmission electron microscope, which is both intuitive and real and avoids a lot of indirect analysis. The observation shows that the BeO film is continuous and the BeO grains are small, dense and granular. However, BeO films formed by activation at 640 ° C and 870 ° C are quite different: the former BeO has a fine grain size of about 150 angstroms and a thin and uniform film, the latter coarse grains ranging up to 1000 angstroms in size and small Only 200 angstroms, only 200 angstroms less, the film thickness is not uniform, cracks also increased, indicating that the activation temperature has a significant impact on the growth of BeO film. The analysis of the selected area electron diffraction and the Auger electron spectroscopy showed that a small amount of Cu 2 O and CuO did exist in the stripped surface film but not on the outermost surface. By the reflection electron diffraction and the measurement of the secondary electron emission coefficient, it is directly proved that the BeO film is the main secondary electron emitter of Cu-Be dynode.