0
$\begingroup$

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?

|cite|improve this question
$\endgroup$
  • $\begingroup$ 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
  • 1
    $\begingroup$ 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
1
$\begingroup$

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.

|cite|improve this answer
$\endgroup$
  • $\begingroup$ 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

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.