透射电子显微分析中,晶体薄膜厚度及消光距离为不可缺少的参数。通过对会聚束电子衍射双光束条件下摆动曲线的计算,给出确定晶体薄膜厚度、消光距离的方法,以及异常吸收对测量精度的影响。其测量精度可达2％,远高于计算所得到的10％的误差,并对奥氏体不锈钢在220操作衍射条件下的消光距离及薄膜厚度进行了测定。 In transmission electron microscopy, crystal film thickness and extinction distance are indispensable parameters. Through the calculation of the swing curve under the condition of double beam of convergent beam electron diffraction, the method of determining the thickness and extinction distance of the crystal film and the influence of abnormal absorption on the measurement accuracy are given. The measurement accuracy is up to 2%, which is much higher than the calculated 10% error. The extinction distance and the film thickness of austenitic stainless steel under 220 diffraction were measured.