Electrons backscattered

1 Backscattered Electrons Backscattered electrons are electrons that are reflected (by elastic and inelastic scattering) from the sample at an intensity that is dependent on the atomic number of the specimen. As such, backscattered electron 

FIGURE 13.4 Polyaniline nanofibers (a) before and (b) after precipitation/adsorption of cross-linked glucose oxidase. (Reproduced with permission from Ref [9]. Copyright 2011, Elsevier.) Toray carbon paper with CVD-deposited MWCNT, modified with (c) glucose oxidase and (d) polyethylenimine. (Reproduced with permission from Ref [10]. Copyright 

FIGURE 13.5 (a) Aluminum stub viewed by a secondary electron detector (left panel) and a backscatter electron detector (right panel). (b) Carbon-gold composite electrode viewed by a secondary electron detector and a backscatter electron detector (inset). (Reproduced with permission from Ref [11]. Copyright 2012, Wiley-VCH Verlag GmbH.) ( All unattributed images taken by author KEF.) 

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Fig. 11. AI2O2—Al TiO typical microstructure showiag grain bridging, B (SEM backscattered electron image).

These signals can be used to form complementary images. As the beam current is increased, each of these currents will also increase. The backscattered electron yield 11 and the secondary electron yield 8, which refer to the number of backscattered and secondary electrons emitted per incident electron, respectively, are defined by the relationships ... 

The SEM can also be used to provide crystallographic information. Surfaces that to exhibit grain structure (fracture surfaces, etched, or decorated surfaces) can obviously be characterized as to grain size and shape. Electrons also can be channeled through a crystal lattice and when channeling occurs, fewer backscattered electrons can exit the surface. The channeling patterns so generated can be used to determine lattice parameters and strain. 

Because X-ray counting rates are relatively low, it typically requires 100 seconds or more to accumulate adequate counting statistics for a quantitative analysis. As a result, the usual strategy in applying electron probe microanalysis is to make quantitative measurements at a limited collection of points. Specific analysis locations are selected with the aid of a rapid imaging technique, such as an SEM image prepared with backscattered electrons, which are sensitive to compositional variations, or with the associated optical microscope. 

Electrons can collide with atoms in the sample and be scattered back backscat-tering becomes more effective as the mass of the atom increases. If a region of the sample contains heavier atoms (e.g. Ft) than the surroundings, it can be distinguished due to a higher yield of backscattered electrons. 

Figure 3 The SEM pictures of Pd/C type 2 catalyst a)secondary mode, b) backscattered electron.

Stump, R.F., Pfeiffer, J.R., Schneebeck, M.C., Seagrave, J.C., and Oliver, J.M. (1989) Mapping gold-labeled receptors on cell surfaces by backscattered electron imaging and digital image analysis Studies of the IgE receptor on mast cells. Am. J. Anat. 185, 128-141. 

The interaction of the electron beam with the sample is generally onion-shaped and results in a number of different processes, as shown in Fig. 8. The formation of secondary electrons and backscattered electrons is the basis for the imaging capabilities of the SEM. 

Backscattered electrons, however, do give some elemental information about the sample because they are more energetic than secondary electrons and escape from farther within the sample [45,46], On the molecular level, the electron beam can interact with the nucleus of an atom and be scattered with minimal loss of energy. These incident electrons may be scattered more than once and then ejected from the sample as backscattered electrons. The back-scattered electrons originate from a greater depth within the sample and are... 

Backscattered Electron Detectors and Applications, Amray Technical Bulletin 122-685, Amray, Bedford, Mass., 1986, pp. 89-106. 

Four samples were similarly selected for the EPMA experiments. The samples were dried and embedded in polished epoxy cylindrical plugs. Backscattered electron (BSE) images as well as elemental maps of As, Fe and Ni (EDS/WDS) were collected using a JEOL 8600 Superprobe electron microprobe analyzer (Dept, of Geological Sciences, University of Saskatchewan). 

Backscattered electron images, 24 76-77 Backscattered primary ions, 24 106 Back-scatter electron detectors, in fine art examination/conservation, 11 406 Backstaining, 10 303 Backus process, 4 810 Backward approach, to qualitative reliability analysis, 26 984 Backwash, 11 323... 

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