![]() To counter this, fragile samples, such as biological macromolecules, can be pretreated by instant freezing and analyzed by cryo-TEM. ![]() TEM samples are also vulnerable to radiation damage from the electron beam. This can be achieved with the help of FIB sample preparation and cross-sectional TEM analysis, which focuses on studying sub-sections of particles that are too large for regular transmission electron microscopy. Larger samples can, however, be processed to fit the requirements. Samples must be electron-transparent, which means that sample thickness must be 100 nm or less. Limitations of transmission electron microscopyÄespite the wide range of applications, TEM has some limitations. In some cases, it is even possible to distinguish individual atoms with TEM and its variation, STEM (scanning transmission electron microscopy). The final image is highly detailed and shows the sample's internal structures. Because electrons have a smaller wavelength than light, the formed image has a considerably higher resolution compared to traditional light microscopy. The basic principle of transmission electron microscopy is similar to that of optical microscopy, but instead of light TEM uses a transmitted electron beam that penetrates the sample. The formation of images in a TEM can be explained by an optical electron beam diagram in Figure 8.2.1 8.2. In addition, TEM may be used to characterize nanomaterials in food by EFSA guidelines. Transmission electron microscopy (TEM) is a form of microscopy which in which a beam of electrons transmits through an extremely thin specimen, and then interacts with the specimen when passing through it. TEM enables studying the inner biological structures of very small objects like microbes and viruses, which makes it a popular analysis technique in medical and microbiological research. ![]() TEM is also used in electron diffraction to determine the crystal structure of solid samples and reveal crystallographic orientations with high accuracy. ![]() The method is commonly used to search for imperfections, failures, and impurities. The electronics industry and nanotechnology laboratories use TEM to examine thin film materials. ![]()
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