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I.—PROSPECTS FOR SUBSTANCE DIFFERENTIATION BY ELECTRON AND X‐RAY MICRO‐METHODS *
Author(s) -
Cosslett V. E.
Publication year - 1958
Publication title -
journal of the royal microscopical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0368-3974
DOI - 10.1111/j.1365-2818.1958.tb02031.x
Subject(s) - electron microscope , electron , transmission electron microscopy , energy filtered transmission electron microscopy , x ray , scanning transmission electron microscopy , resolution (logic) , acceleration voltage , biological specimen , chemistry , microscope , optics , microscopy , materials science , analytical chemistry (journal) , physics , computer science , cathode ray , chromatography , nuclear physics , artificial intelligence
SYNOPSIS Various methods have been considered for identifying specific elements or compounds in the electron microscope or by related techniques. X‐ray emission spectrometry has high detection sensitivity (to 10 −14 gm.) combined with an accuracy of location similar to that of the optical microscope (to 0.5 μ). Electron transmission measurements give a much higher spatial resolving power, but the prospects for quantitative analysis on unstained biological material are very limited. Recent theoretical work on electron scattering, in the conditions of electron microscopy, suggests that not only heavy element stains but the normally used organic reagents as well may prove useful in devising analytical procedures similar to the stoichiometric staining methods of optical microscopy, though with distinctly less latitude in sensitivity. The use of a much lower voltage than is usual for electron microscopy, of the order of 10 kV, would give greater image contrast and therefore better accuracy of analysis. Three other physical effects are briefly discussed which may be possible of development for quantitative analysis with electron beams: energy loss, phase shift, and secondary electron emission.