Using Overlay Spectrum Reconstruction to check what elements are in your spectra.

This INCAtip describes how to check you have identified all the elements in a spectrum correctly. The spectrum reconstruction tool, overlays a theoretical spectrum onto your acquired spectrum. The shape of this theoretical spectrum is based on the elements labelled in the acquired spectrum. If any peaks are incorrectly labelled, or any elements missed, then the theoretical spectrum will not overlay correctly on your spectrum.

Using the spectrum overlay tool is simple.

The spectrum overlay tool can be found in the Confirm Elements screen in the Analyser and Point & ID navigators.

To enable this tool, simply check the Overlay Spectrum Reconstruction box, or select Reconstruction in the Overlay drop down, situated in the top left corner of the Confirm Elements screen. A red line spectrum will be overlaid onto your spectrum.

However, if you look at the overlay more closely you will see a poor fit on one of the Cr peaks.



This is because the material contains a small amount of manganese, an element whose characteristic X-ray peaks overlap with those of Cr.

Use the show me candidate elements tool to identify the missing element

• Click on the show me candidate elements tool
• Position the cursor by pressing on the part of the spectrum where the spectrum overlay and the acquired spectrum have their greatest discrepancy. See below:

• Double click on possible elements in the show me candidates tool dropdown to add them to the element list and test if they improve the overlay fit.

• Turning off lock peaks often helps with the positioning of the cursor.

When Manganese is selected, a much better fit is achieved between the spectrum and the reconstruction.



This tool is very useful for checking for the presence of small amounts of elements whose peaks are heavily overlapped in the spectrum.

For other examples and other ideas of how to use this tool please use the link below: