| 摘要 |
PURPOSE:To determine the structure in a material surface by positioning an energy analyzer at 180 deg. or around 180 deg. scattering angle (+ or -20 deg.) thereby determining empirically the shape of a shadow cone and using the resulted shadow cone. CONSTITUTION:The empirical determination of the shape of a shadow cone is accomplished by detecting scattering ions under a direct bombardment condition with respect to the material surface of which the distance (d) between atoms A is exactly determined. The dependency of the intensity of the scattering ions on an incident angle alpha is as shown by the solid line in the figure (alphac is a critical angle). The shadow cone of the atom A1 when the incident angle is alphac passes always the vertex of the shadow cone of the neighboring atom A2. If the distance (d) between the surface atoms is known in this stage, the radius A2X of the shadow cone is obtained as dsinalphac with good approximation by measuring the incident angle alphac. If the shape of the shadow cone is determined, the structure of the surface atoms, the structure of the defect of the surface atoms and the thermal oscillation amplitude of the atoms are quantitatively determined. |
