Overview

The Dioptas software is used for 2D detector data processing at the PD beamline and can be downloaded from here. It runs on Win7, Win8, Linux systems.

To open the software on Win7&8, double click the “Dioptas.exe” icon in the software folder.

Calibration

Click the vertical “Calibration” tab on the left side of window.

A standard sample data set (e.g. LaB₆) should be collected for each experiment and a calibration performed. Within each detector/experiment setup, the calibration is performed once only.

Click “Load image” in the right top window to open the standard sample file for calibration.

Change the distance to approximately the correct sample to detector distance (e.g. 300 mm) and change the wavelength to an approximate known value (e.g. 0.8256 Å). Change Pixel width and Pixel height to the correct values (e.g. 100 x 100 um for XRpad 4343F). Select the correct calibrant (e.g. LaB₆). (Figure 1)

The standard SRM calibrants are quite old.  Newer calibrant files and instructions for their loading into the software can be found on the PD beamline ‘Data/Analysis’ web pages. 

The next step requires the user to select an appropriate ring to allow the software to fit the peak and then automatically fit all the rings to determine the calibration parameters.  In the ‘Peak Selection’ window,  select the “current ring number”, (Figure 2) then click on the ring with the left mouse button with same number as just selected. The red dots should be shown on the selected ring.

Click the “Calibration” button on the left bottom screen, it will automatically create a 360 degree cake image and an integrated pattern.  A correct calibration is achieved when straight lines appear in the cake image.  The calibration parameters can be saved as a “*.poni” file (Figure 3) for future processing of sample data sets.

If the integrated pattern lines are curved (Figure 4), this indicates that the calibration is incorrect.  Adjustment of the “Intensity min factors” and “number of rings” to suitable values are required to obtain straight lines and a correct calibration.

Mask

A mask can be used to remove features such as the beamstop or unwanted scattering from the data sets.  To create a mask, click the vertical “Mask” tab on the left side of window.

Use the “Polygon” tool to select the shadow region (red) by the beam stop or unwanted area as in Figure 5. Then save mask as a “*.mask” file.  Numerous masking options are available and the software manual should be consulted to learn more about these.

Integration

To apply the calibration correction to sample data sets, integration is required.  This can be performed for a single or multiple dataset(s).

Click the “Integration” tab on the left side of window.

Click “load images” on the right top window, to load single or multiple images, and select the file path to output the integrated patterns. Make sure “autoprocess” is selected in the right top window.

Click the “pattern” tab on the right top window and select the “autocreate” and “.xy”options.  After loading the images, the integrated files will be automatically generated.

The integrated files have the same names as the input images and have the selected formats.  (.xy format is preferred)

As an option you can click “ROI” in the left bottom window to select the region of interest (green rectangular box) to define the integration area. (Figure 6)