Azimuthal integration

Azimuthal integration

For spotty diffraction patterns, it is useful to integrate diffraction image for the azimuthal ranges where spots are more clear. For weak peaks, if you integrate over the entire azimuthal range, these weak diffraction lines cannot be clearly resolved in 1D diffraction pattern.

Make a chi file for selected azimuthal angle ranges

Sometimes you have a few diffraction spots from a course grained polycrystalline samples. Although they are intense locally in the cake image, if you have only a few of them, the integration for the entire azimuthal angle range is not ideal because those peaks will become very weak in the 1D pattern. In this case, it is desirable to integrate for the azimuthal angle ranges where the diffraction spots exist.

Selecting azimuthal ranges

1. Activate zoom mode and choose an area for the azimuthal integration. It will zoom in to the area.

2. In the Cake2 tab, click the Add button. Repeat this until you include all the areas for integration. As shown above, the selected areas will be highlighted with blue rectangles.

Removing azimuthal ranges

1. Highlight the range you want to remove in the list table.

2. Click the Remove button.

Load/save the azimuthal ranges

The Save button will allow you to save the azimuthal ranges in a text file. Later you can load the azimuthal ranges into your analysis. You can also load the azimuthal ranges used for other files. In addition, you can use this azimuthal range file to keep track of some features across different cake images.

Highlight a azimuthal range

If you want to see where a range in the table actually exists in the cake image, you can highlight the range in the table and click Highlight button. You will see red rectangle highlighting the range you chose.

Invert the selection

If you have too many areas to choose for integration but much smaller area to exclude from integration, it would be easier to choose the region to exclude. You first choose regions to exclude and then press the Invert button. You will see the inversion of the selected regions.

Integrate

Once you are finished in choosing areas, click the Integrate button for integration. It will produce a new CHI file. It will also ask you if you want to add the new CHI file in the waterfall list.

(Note) I strongly recommend to maintain your_original_chi_filename.process_info.chi format for any processed data from an original chi file. If you do so, later when you open these files and make them to base pattern, PeakPo will still open the correct image file: your_original_chi_filename.tif for example.