9/15/2023 0 Comments Tem diffraction pattern analysisHigh-resolution TEM ( HRTEM) demands specimens thicknesses in the nm region. Specimen thicknesses between 10 nm to ca. Keeping inelastic scattering of the electrons small has supremacy, this demands Monochromatic electron beam is somewhere between (100 - 400) keV, special instruments go up to 1,5 MeV The lattice and the defects present modulate amplitude and phase of the primary beam and the diffracted beams The electron beam then will be only elastically scattered, i.e. Inelastic scattering (leading eventually to absorption) must be avoided In two ways: inelastic and elastic scattering. Intensity distribution of the electron waves leaving the specimen can be magnified by an electron optical system and Lenses and that means that imaging systems are not very good because lens aberrations cannot be corrected as in For very general reasons it is not possible to construct electromagnetic concave Piece of material with electron "waves," usually at high magnification.Įlectron beams exist: Magnetic fields (and, in principle, electric fields, too) can be made with gradients that act asĬonvex lenses for the electron waves. Much of what was stated before about defects would be speculative theory, or would never have been Microscopy ( TEM) is by far the most important technique for studying defects 6.3.1 Basics of TEM and the Contrast of Dislocations 6.3 TransmissionĮlectron Microscopy 6.3.1 Basics of TEM and the Contrast of Dislocations
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