Secondary electron microscope

Fig. 2 The design of a secondary electron microscope where 1, electronic gun 2, Wehnelt cylinder 3, anode 4, beam alignment coils 5, condenser lenses 6, objective lens 7, specimen holder. (From Ref. " l)...

Fig. 4 Principle of the scanning mode of a secondary electron microscope, where 1, specimen surface 2, detector 3, video processing 4, monitor screen. (From Ref 1)...

Electron Beam Techniques. One of the most powerful tools in VLSI technology is the scanning electron microscope (sem) (see Microscopy). A sem is typically used in three modes secondary electron detection, back-scattered electron detection, and x-ray fluorescence (xrf). AH three techniques can be used for nondestmctive analysis of a VLSI wafer, where the sample does not have to be destroyed for sample preparation or by analysis, if the sem is equipped to accept large wafer-sized samples and the electron beam is used at low (ca 1 keV) energy to preserve the functional integrity of the circuitry. Samples that do not diffuse the charge produced by the electron beam, such as insulators, require special sample preparation. 

Structure of the Cell Wall. The iaterior stmcture of the ceU wall is shown in Figure 6. The interfiber region is the middle lamella (ML). This region, rich in lignin, is amorphous and shows no fibnUar stmcture when examined under the electron microscope. The cell wall is composed of stmcturaHy different layers or lamellae, reflecting the manner in which the cell forms. The newly formed cell contains protoplasm, from which cellulose and the other cell wall polymers are laid down to thicken the cell wall internally. Thus, there is a primary wall (P) and a secondary wall (S). The secondary wall is subdivided into three portions, the S, S2, and layers, which form sequentially toward the lumen. Viewed from the lumen, the cell wall frequendy has a bumpy appearance. This is called the warty layer and is composed of protoplasmic debris. The warty layer and exposed layer are sometimes referred to as the tertiary wad. 

Secondary Electron Microscopy with Polarization Analysis Scanning Force Microscopy Scanning Force Microscope... 

The surface analysis for morphology and average particle size was carried out with JEOL JSM 6301 F scanning electron microscope (SEM). The micrographs of the samples were observed at different magnifications under different detection modes (secondary or back-scattered electrons). 

J. J. Boon, K. Keune, J. van der Weerd, M. Geldof and J. de Boer, Imaging microspectroscopic, secondary ion mass spectrometric and electron microscopic studies on discoloured and partially discoloured smalt in cross sections of 16th century paintings, Chimia, 55, 952 960 (2001). 

Over the past decade increasing use has been made of the scanning transmission electron microscope (STEM) for examining catalysts(20). Owing to the increased efficiency with which scattered electrons and associated signals such as X-rays, secondary and Auger electrons may be collected, the STEM offers greater analytical flexibility compared with the CTEM (21). 

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