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In EDX, peak locations (kV values) give information about elemental composition of a sample.

How accurate is the position of those peaks? For example, could Pd ($L_{\alpha}$ 2.838 kV) possible show up as Ag ($L_{\alpha}$ 2.984 kV)? And vice versa? What about element pairs with even smaller difference between their characteristic peaks?

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  • $\begingroup$ It depends on the accuracy of the calibration. $\endgroup$ – Pieter Dec 16 '16 at 23:32
  • $\begingroup$ @Pieter so how accurate can this get? $\endgroup$ – Sparkler Dec 16 '16 at 23:43
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    $\begingroup$ Depends also on resolution and on the number of ADC channels, but something like 1 % of the energy should be possible. So in this case, around 30 eV. $\endgroup$ – Pieter Dec 17 '16 at 3:40
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There are various error sources to consider. First of all, the sample: For L-lines, the chemical shift can be up to a few eV.

Typically, in EDS systems, the peak-position shifts as function of count-rate. How much varies wildly between systems. Temperature variations of both the detector and electronics can also cause misalignment of the energies in the spectrum.

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  • $\begingroup$ Do you know roughly the order of magnitude? few eV, tens, hundreds..? $\endgroup$ – Sparkler Jun 18 '17 at 14:23
  • $\begingroup$ The 1% by @pieter sounds like a good ballpark figure. If you have access to a machine, at least the count-rate dependence should be easy to check. $\endgroup$ – Mr. White Jun 18 '17 at 14:27

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