Refinement: manual modifying of the fit model
This example shows manual modifying of the fit model by utilizing the fit refiner tab.
This alumina spectrum has a region where HyperLab fitted a background curve (2nd order member of the back­ground polynomial), and comple­tely eliminated the slope (1st order member). If you are curious if the fitted curve is necessary, or it may be replaced by a slope, follow the steps below:
  • switch to the fit refiner tab,
  • change Bkg curvature to “disabled”;
  • change Bkg slope to “enabled”;
  • click Set & fit button.
When you manually modify a parameter of the fitted region (and change to another editor field), HyperLab automatically displays the new model with a different color scheme. This way you can immediately check the new model. This is, however, only a visual representation, and the entered data is not used elsewhere until you click one of the Set or Set & fit buttons.
As a new fit is required now, the Set & fit button should be clicked, therefore the manually set values are used only as an initial estimate for the fit.
After the fit, the new model is displayed with a background slope instead of a curve. Chi-squared changed from 1.8 to 4.3, so in this case the experiment showed that the slope is a worse parameter to fit the background than the curve.
Click Undo button to restore the previous fit now.
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