CrystalDiffract lets you define a background function for an observed pattern. You can then subtract this from your data points to reveal the underlying diffraction pattern.
Select the observed pattern whose background you wish to remove. (Note that only one pattern may be edited in this way at any time.)
Open the Background group in the Parameters Inspector.
Click the Add button (one the Curve line).
A dark line appears in the diffraction pane with two red control points, for editing the background function.
If the background isn't visible, ensure that your observed pattern is selected and the Show background checkbox in the Background group is set.
Drag a red control point to bend your background function.
Drag a tangent handle (white circle) vertically to change the slope.
Drag a handle along its tangent line (in or out) to change the radius of curvature.
To add more control points, click the Add Point button in the Background group.
To delete a selected control point, click the Remove Point button in the Background group.
To change the colour or line style of the background curve and/or its preview, use the formatting controls available on the Background Overlay group in the Format List.
To preview the background subtraction:
Set the Preview background subtraction checkbox in the Background group.
This will let you see the result of the background subtraction (as a separate curve), whilst you fine-tune the shape of your background function.
To subtract the background function:
Unset the Show background checkbox in the Background group.
The background function vanishes, and your observed pattern is replotted, minus the background.
Ensure that your pattern is selected.
Open the Background group in the Parameters Inspector.
Click the Remove button. The background function vanishes and your observed pattern is replotted.
See Also