Use the icon to open the simplified peak modelling menu. When you open this, it will be on the background tab. You can select between a smart background, and a Tougaard background. We recommend using a smart background if you are new to XPS fitting. Click a point either side of the peak to set limit, and click create background when you are happy. If you wish to adjust the background after addition, you can click and drag the background limits by selecting the red lines on the spectra.

Use the  icon to open the peak fitting window, which by default will open to background fitting. More background types exist in this menu, such as linear, Shirley, and both 2 and 4 component Tougaard backgrounds. Click on either side of the peaks to set limits, or use the Region (Left) and Region (Right) boxes to manually set the energy limits. Advanced functions such as left and right offsets can also be used – which allow for some quick complex background modelling in the case of severe peak overlaps. The number of averaging points taken to set the Y-value for the background limits can be set, as well as a smoothing function (useful if you have noisy data, but not as many points to average out, e.g. in the case of rising backgrounds due to loss features etc).

Smart backgrounds apply an appropriate background for the range selected, and take into consideration small changes in spectral intensity due to features such as loss functions etc. These are very useful background types for new XPS practitioners.

Linear and Shirley backgrounds can be set using the dropdown. Both are fine to use in many cases, however – especially for beginners – there is little reason to choose these specifically, instead of a smart background type. Nevertheless, there are circumstances where you wish to set a specific background, and this function exists for those.

A U2 type Tougaard background may be applied, where parameters B and C may be controlled manually. This is useful if you have cross-section parameters you know work for your system, and want to apply these to your datasets.

U4 type Tougaard backgrounds have a dedicated menu to model them, based on your data. Note, this is not a robust treatment of the inelastic function, to do that you still need to determine the parameters yourself – but it is a useful tool for applying an approximate, and realistic Tougaard type function for your data.

After you have fitted the parameters, you can copy them to the background window and create a background with these cross-sections.

Multiple backgrounds can be inserted into datasets easily – and switch between using the number icons, or the tab key. These backgrounds can be viewed, edited, and deleted independently.