The Surface Skirt in Gaseous Scanning Electron Microscope (GSEM)

Abstract

In this work, a novel parameter called the surface skirt (S s) is introduced. The electron beam scattering by gaseous environment is the fundamental parameter limiting the performance of the Gaseous Scanning Electron Microscopy (GSEM). The result is the enlargement of the primary beam characterized by the radius skirt R s. The scattering phenomena require a much closer re-examination. In fact, depending on the localization of EDX detector and the particles shape to analyze, the collected signal after the beam skirt will be different and R s also will be different. So, except for homogeneous materials, R s can not describe the scattering behavior. In this study, the surface skirt S s instead of the radius skirt is introduced. Unlike R s , the results show that S s is a linear function versus pressure. This may help to use S s in different scattering regimes and for a best interpretation of the consequences of electron scattering beam by gaseous environment. For demonstration, two gas environments: helium and water vapor are given but the results are valid whatever the environment used.

Methods of electron microscopy of biological and abiogenic structures in artificial gas atmospheres

“…Generally, such simulations affect the improvement of the quality of the image [97] but not the biologically orientated optimization of the physics of the process of interaction of the beam with the tissue, although it is known in biomedicine that the rational configuration of an electron beam provides the optimization of the structural-biological effect [98], while methods for site specific beam focusing have long been used in cry oelectron microscopy [99]. A so called surface skirt, beam broadening during its dispersion in a gas atmo sphere [100], can be a partial solution in the method of electron microscopy of biological specimens, although the decrease in focusing causes the deteriora tion of the quality of the image, and the latter is fraught with a well known effect on the results of semiquanti tative X ray microanalysis in a column [101]. In turn, problems with distinguishing the components of the signal in scanning electron microscopy under the conditions of an atmosphere (a gas) or natural atmo sphere and at "natural" temperature have been known since the 1970s [102], while methods for their GRADOV, GRADOVA distinguishing emerged only in the early 1990s-no sooner than the tools of computer automation made it possible to do so [103].…”