Atomic resolution with a 600-kV electron microscope [3]

The resolution that may be achieved with an electron microscope can be improved by increasing the accelerating voltage, provided that the electrical and mechanical design is of a sufficiently high standard to realise the theoretical performance^1,2. Several such microscopes have been constructed in recent years^3-5 and have produced images containing information which can be interpreted directly to a higher resolution than any yet obtained at 100 kV (refs 6, 7). The Cambridge University 600-kV high resolution electron microscope is now yielding high quality micrographs with directly interpretable resolution approaching 0.2 nm. We describe here some of the novel features of this microscope and give some measurements which establish its electron-optical performance. We also show some examples of recent observations which demonstrate the benefits of its atomic resolving power. A more detailed description of the instrument and more references are given elsewhere^2,8.