| A couple of factors affect the contrast (intensity) of elemental measurements, including EELS and EDS. The main factors are:
i) The concentration of the specific element,
ii) The local mass thickness variations,
iii) Diffraction effects if it is a crystal. Some technique can be used to minimize the diffraction effects:
iii.a) Rocking beam illumination can smooth out the strong diffraction contrast, [1]
iii.b) Record elemental maps under hollow cone illumination [2],
iii.c) Use precession electron diffraction to record the spectrum,
iii.d) Use a large convergence angle.
[1] F. Hofer and P. Warbichler, “Improved imaging of secondary phases in solids
by energy-filtering TEM,” Ultramicroscopy 63, 21–25 (1996).
[2] J. Marien, J.M. Plitzko, R. Spolenak, R.-M. Keller, and J. Mayer, “Quantitative
electron spectroscopic imaging studies of microelectronic metallization layers,”
J. Microsc. 194, 71–78 (1999).
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