Artifacts in SEM

SEM Emission of secondary electrons Topography Cutting artifacts In vacuum... 

A principal advantage of SEM is the ease of sample preparation. In most instances, it is sufficient to coat the sample with only a thin (20 nm) layer of gold/palladium alloy to minimize charging. Platinum, carbon, and gold are also used to coat samples, but gold can puddle on some surfaces leading to the appearance of artifacts in the photomicrographs. 

Interpretation of SEM images requires assessment of the data in the micrograph in light of both potential artifacts in imaging and specimen preparation and what is known regarding specimen properties. At the risk of being controversial, SEM imaging can be too easy. With reasonable capital expenditure, rapid sample... 

WDS is another technique utilized for elemental chemical analysis in reverse engineering. EDXA and WDS are usually used in conjunction with SEM, or an electron probe microanalyzer (EPMA). EPMA is a nondestructive elemental analysis technique, similar to SEM but with a more focused analysis area. It works by rastering a micro volume of the sample with an electron beam typical of an energy level of 5 to 30 keV. It then collects the induced X-ray photons emitted by the various elemental species and quantitatively analyzes the spectrum with precise accuracy, up to ppm. In contrast to EDXA, WDS analyzes the electron diffraction patterns based on Bragg s law and has a much finer spectral resolution and better accuracy. WDS also avoids the problems associated with artifacts in EDXA, such as the false peaks and the background noise from the amplifiers. The noise intensity that appears in... 

Even though TEM and SEM played major roles in the study of IPN morphological features, there are various shortcomings, such as staining artifacts, difficulties in sample preparation for very rubbery materials, and the two-dimensional viewing limit for the former. Recently, various scattering techniques have been applied to measure the phase dimensions of IPN s via statistical treatment. The principles of neutron scattering theory as applied to the phase separated materials have been described in a number of papers and review articles [33-36]. 

Similar Pu-rich regions were identified by SEM of solids remaining from an acidic (pH = 4) flowthrough test (Fig. 10). Observation of similar Pu-rich precipitates in the acid flow through tests supports the contention that the Pu enrichment is not an artifact of the starting material. 

While trying to determine the source of a particular structural feature present on some but not all types of starch granules, Fannon et al [61] used conventional SEM and ESEM to determine if the pores in some starch varieties were a result of drying in the kernel, produced by in situ amylases, an artifact of preparation or a natural feature of the granule. While earlier work had been done in this area [62], the ESEM could provide a distinct advantage. By the use of conventional SEM and the ESEM, the list of possible causes of the pores was... 

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