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PDFGetX3 / xdfpsuite / diffpy

PDFGetX3 / xdfpsuite / diffpy

For users unfamiliar with PDF processing software and wanting to take a look at PDFs during their beamtime, we recommend using the xPDFsuite software installed on the ws004 computer in the I15-1 control room.

xPDFsuite Instructions

  1. Log on to ws004 with your FedID and password. (Windows machine on the right in the control room).

  2. Map your visit directory to the Z: drive.

    1. Navigate to your visit folder and copy the directory address (e.g. \\dc.diamond.ac.uk\dls\i15-1\data\2025\cy12345-1).

    2. Click on “This PC”, then “Computer” (top left), then “Map network drive”. Paste the directory name into the “Folder:” box.

  3. Open xPDFSuite via the shortcut on the desktop:

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  4. Set up the “Basic” options.

    1. Set Source type to “Custom”.

    2. Set wavelength to 0.161669 (76.69 keV), 0.189578 (65.40 keV), or 0.3309574 (40.05 keV).

    3. Set your background to the relevant measured background.

    4. Input the composition of your measured sample.

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  1. Open data files (for one given sample).

    image-20250919-100406.png

    1. Set path as Z:/processed/tth_pe2

    2. Select files for processing (recommend using “norm” files).

    3. Click Open.

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Opened files will appear in the left column:

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  1. Select (left click) the files you wish to process and then click “Plot selected data”:

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By default this will plot “Gr” but it’s useful to see “Xrd”, “Sq” and “Fq” whilst optimising the PDF parameters to check all of these at the top right of the window.

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  1. Go to the “PDF” tab and edit the parameters to produce a corrected PDF.

    1. Background scale

      • Scales the background intensity before subtraction.

    2. Qmax-inst

      • Defines the upper limit of reliable Q values based on instrument performance.

      • Cuts off noisy/unreliable data at high Q values.

      • Ensures that only meaningful data is used in the Fourier transform.

      • Too high = introduces artifacts, too low = reduction in resolution.

      • Defines the range over which the correction polynomial is fitted.

    3. Q-max

      • Sets the maximum Q value used in the Fourier transform to generate the PDF.

      • Should be less than or equal to Qmax-inst.

    4. R-poly

      • Controls the degree of polynomial used to normalise the S(Q) function.

      • A low-r cutoff for reliable G(r) values.

      • Helps to correct systematic error in S(Q) and improves the quality of the PDF at low r values.

    5. Q-min

      • Sets the minimum Q value used in the Fourier transform.

      • Removes low-Q data that may be affected by experimental artifacts or background.

      • Affects the long-range behavior of the PDF.

  1. Once the PDF processing parameters have been optimised:

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The data can then be saved by clicking on the gear button.

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