在扫描电子显微镜中所观察到钨的奇异花样

当钨试样倾斜到不同位向以记录一系列电子通道花样时,在<111>方向,<001>方向和<011>方向的准确位置下,观察到一些奇异花样叠加在电子通道花样上。这些奇异花样颇类似于在透射电子显微镜中所观察到的Kossel花样。这种花样具有两个重要性质:(1)花样的强度分布是随着电子能量(电子的加速电压)而改变;(2)花样的几何形貌可以用来描述晶体内部结构的一些特征。最后,从异常散射效应和晶格位与入射电子间相互作用强度a的观点,定性地解释了这种花样的衬度效应来源。 关键词：

ANOMOLOUS PATTERNS OF TUNGSTEN SAMPLES OBSERVED WITH SCANNING ELECTRON MICROSCOPE

On recording a number of SACP's of tungsten specimen successively tilted -to different orientations, some anomolous patterns superimposed on the general SACP's were observed at the exact positions of <111> direction, <001> direction, and <011> direction. These anomolous patterns are similar to Kossel patterns observed with transmission electron microscope. Moreover, the present patterns have two additional important characteristics. First, the intensity distribution of patterns changes with the electron energy (the electron accelerating voltage). Second, the geometric feature of the patterns can be used to represent some characters of the internal structure of the crystal. Finally, from the view points of the anomolous scattering effect, and the parameter a, which represents the interaction strength between the crystal potential. and the incident electron, the origin of the contrast of these patterns was explained qualitatively.