diffpy.labpdfproc_

Tools for processing x-ray powder diffraction data from laboratory sources.

PDFgetX3 has revolutionized how PDF methods can be applied to solve nanostructure problems. However, the program was designed for use with Rapid Acquisition PDF (RAPDF) data from synchrotron sources. A key approximation inherent in the use of PDFgetX3 for RAPDF data is that absorption effects are negligible. This is typically not the case for laboratory x-ray diffractometers, where absorption effects can be significant.

This app is designed to preprocess data from laboratory x-ray diffractometers before using PDFgetX3 to obtain PDFs. The app currently carries out an absorption correction assuming a parallel beam capillary geometry which is the most common geometry for lab PDF measurements.

The theory is described in the following paper:

An ad hoc Absorption Correction for Reliable Pair-Distribution Functions from Low Energy x-ray Sources, Yucong Chen, Till Schertenleib, Andrew Yang, Pascal Schouwink, Wendy L. Queen and Simon J. L. Billinge, in preparation.

The related experimental data acquisition protocols are described in the following paper:

Protocols for Obtaining Reliable PDFs from Laboratory x-ray Sources Using PDFgetX3, Till Schertenleib, Daniel Schmuckler, Yucong Chen, Geng Bang Jin, Wendy L. Queen and Simon J. L. Billinge, in preparation.

For more information about the diffpy.labpdfproc library, please consult our online documentation.

Citation

If you use diffpy.labpdfproc in a scientific publication, we would like you to cite this package as

> diffpy.labpdfproc Package, >

Installation

The preferred method is to use Miniconda Python and install from the "conda-forge" channel of Conda packages.

To add "conda-forge" to the conda channels, run the following in a terminal. :

conda config --add channels conda-forge

We want to install our packages in a suitable conda environment. The following creates and activates a new environment named diffpy.labpdfproc_env :

conda create -n diffpy.labpdfproc_env diffpy.labpdfproc
conda activate diffpy.labpdfproc_env

To confirm that the installation was successful, type :

python -c "import diffpy.labpdfproc; print(diffpy.labpdfproc.__version__)"

The output should print the latest version displayed on the badges above.

If the above does not work, you can use pip to download and install the latest release from Python Package Index. To install using pip into your diffpy.labpdfproc_env environment, type :

pip install diffpy.labpdfproc

If you prefer to install from sources, after installing the dependencies, obtain the source archive from GitHub. Once installed, cd into your diffpy.labpdfproc directory and run the following :

pip install .

Example

Navigate to the directory that contains 1D diffraction patterns that you would like to process. Activate the conda environment (conda activate diffpy.labpdfproc_env) that contains the package and run the following command :

labpdfproc