EDS measurement of gold (Au)
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The most intense EELS signal from gold (Au) can be obtained from Au M4,5-edges at 2206 eV in the high core-loss spectrum, and the optimized EDS signal from Au is obtained from Au Lα1 (9.711 keV) and Au Lα2 (9.628 keV). With such EELS and EDS signals with the same dwell time (e.g. in simultaneous EDS and EELS measurements), for a thin TEM sample the EELS signal is more than twice as sensitive as the EDS data and the signal-to-noise ratio (SNR) for EELS measurement is four times better than that for EDS data.

The second choice for Au EDS elemental analysis is that the Au Mα line at 2.12 kV can be used.

Table 1357a lists the comparison of EELS and EDS measurements on thin TEM samples with Au elements. The comparisons are based on the same data acquisition condition, consequently the same electron dose used.

Table 1357a. Comparison of EELS and EDS measurements on TEM samples with Au elements.
Measurement Signal Energy Signal ranking
EELS M4,5-edges 2206 eV Most intense EELS signal, more intense than EDS signal
EDS Lα1 9.711 keV Most intense EDS signal, weaker than EELS M4,5-edges signal
Lα2 9.628 keV

As discussed on page4650, X-ray absorption is a function of the energy of X-rays. Low energy peaks will be more strongly absorbed than high energies ones. For thick TEM samples, k-factor correction due to X-ray absorption is needed in order to accurately quantify EDS measurements. Table 1357b lists Au-examples of thicknesses at which the thin-film approximation is no longer valid due to X-ray absorption effects in specific materials.

Table 1357b. Examples of limits to the thin-film approximation caused by X-ray absorption: Maximum thicknesses of thin specimens for which the absorption correction (or error) is less than ±10% and ±3%.


10% error in kAB
3% error in kAB
Absorbed X-ray lines
Primary X-ray lines
Thickness (nm)
  11 Cu Kα and Au Mα Cu Kα (8.027) and Au Lα (9.628 keV)