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先用覆有金单晶膜、自身包含宽空间频带的无定形碳膜作为样品,在透射电镜JEM—200CX内拍摄得电子象的负底片。实验时电镜装有顶入式超高分辨率测角台THG2和超高分辨涨极靴UHP。然后利用一架装配有光电倍增管系统的简易He—Ne激光衍射仪处理底片。从清晰的明暗环状衍射花样及金的衍射点,精确地检验出电镜的极限点分辨率为0.177nm。根据衍射花样的光强度分布与PCTF的一致性,直接测定出成象参量C_1=0.76mm,(?)f=140.4nm。C_2的测定值与样本数据相比,误差为7.9％。 与直接从电子象测量点间距离来确定电镜分辨率相比,光学衍射花样实在是一种更好的分辨率检验方法。
First with a gold-covered single crystal film, its own wide-band amorphous carbon film as a sample, in the transmission electron microscopy JEM-200CX captured electronic negative film negative. Experimental electron microscope equipped with a top-mounted ultra-high resolution goniometer THG2 and ultra-high resolution rose pole UHP. The film was then processed using a simple He-Ne laser diffractometer equipped with a photomultiplier tube system. From a clear light and dark circular diffraction patterns and diffraction spots of gold, electron microscopy accurately check the limit point resolution of 0.177nm. According to the consistency of light intensity distribution of diffraction pattern and PCTF, the imaging parameters C_1 = 0.76mm and (?) F = 140.4nm were directly determined. The measured value of C_2 is 7.9% compared to the sample data. Compared with determining the resolution of the electron microscope directly from the distance between the measurement points of the electron image, the optical diffraction pattern is really a better method for checking the resolution.