![]() The diffracted waves are recombined to form an image on the image plane. ![]() Diffracted waves scattered by the atomic potential form diffraction spots on the back focal plane after being focused with the objective lens. The main principles of electron microscopy can be understood by use of optical ray diagrams, as shown in Fig. As the result of numerous advances in optics and microscope design, modern TEMs are capable of a resolution of 1.65 Å for 300 kV (and below 1 Å for 1000 kV) electron energy-loss combined with chemical analysis (through x-ray energy and electron-loss energy spectroscopy) and a bright coherent field emission source of electrons. The elektronograf is very similar to a modern transmission electron microscope (TEM), in which the scattered transmitted beams can be also recombined to form an image. In the elektronograf, magnetic lenses were used to focus 50 keV to 100 keV electrons to obtain diffraction with scattering angles up to 3° to 5° and numerous structures of organic and inorganic substances were solved. Vainshtein and his colleagues as early as the 1940s. ![]() The use of electron diffraction to solve crystallographic problems was pioneered in the Soviet Union by B.
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