Atomic resolution with a megavolt electron microscope

A major aim in the development of new instruments and novel techniques in rransmission electron microscopy is the improvement of the spatial resolution for structural studies on an atomic scale. Reducing the wavelength of the electrons by increasing the accelerating voltage is the route towards higher resolution followe since a long time. Compared to other techniques available at present, it offers the advantage of a more direct interpretation of the micrographs. By employing accelerating voltages of 1.25 MV or 1.3 MV, the new generation of high-voltage atomic resolution microscopes approaches now a point resolution of 0.1 nm, provided the electrical and mechanical stability of the instruments is high enough, to realise the theoretical performance. The JEM-ARM1250 high-voltage atomic resolution microscope in Stuttgart is the only instrument of this generation installed outside of Japan. In extended resolution tests it has been shown to reach its theoretical point resolution of 0.105 nm at an accelerating voltage of 1.25 MV. Owing to the proper installation conditions and a specially developed high-voltage stabilising system, an information transfer limit of 0.085 nm has been realised. Examples for the application of this instrument to structural studies in various materials demonstrate the performance of the instrument and the benefits of its atomic resolving power.

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