透射电镜薄样品倾转过程中的附加旋转及其计算

模拟透射电镜双倾台进行样品位向调整过程,推导出反映样品倾转前后其合成倾转轴(即共有菊池线对的法线)方向变化规律的计算公式,称为附加旋转角计算公式。指出,实现样品位向调整的双倾操作,等效于样品绕其合成倾转轴的倾转及该倾转轴绕Z轴(平行入射束方向)的旋转之和。利用双倾台对薄膜样品进行的系列倾转实验表明,由附加旋转角公式计算的附加旋转角和实测值相一致。还根据双倾操作过程导出了合成倾转角的计算公式,它可用于判断样品位向调整的准确度。

Additional Rotatinns Caused by TEM Thin Foil Tilting and the Calculations

The directional variations of the comprehensive tilt axis (i. e. the normal of the common kiluchi line pairs of the two zone axes before and after tilt) were shown and the equations to calculate these variations were derived by simulating the orientation adjustment of TEM Thin foils on a double tilt stage. It was pointed out that the double tilting around axes X and Y for attaining a certain orientation of the thin foil is equivalent to the sum of tilting the foil around the corresponding comprehensive axis and an additional rotation aronnd axis Z. A syste- matic tilt experiment of FCC thin crystals was performed on a double tilt stage. The results show that that additional rotation angles calculated by the equations derived in this paper are consistent well with the experimental measurements. Moreover, equations to calculate the comp- rehensive tilt angles in the light of tilt angles around axes X and Y during double tilt opera- tion were derived and it was used to evaluate the accuracy of the crystal orientation adjustment in present paper.