ANOMOLOUS PATTERNS OF TUNGSTEN SAMPLES OBSERVED WITH SCANNING ELECTRON MICROSCOPE
在扫描电子显微镜中所观察到钨的奇异花样

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.