xdart 0.21.0

A pyFAI-based GUI for X-ray diffraction data reduction and visualization

xdart — X-ray Diffraction Analysis in Real Time

A pyFAI-based desktop GUI for real-time azimuthal integration and visualization of synchrotron X-ray diffraction data. Built with PySide6 and pyqtgraph for high-performance interactive plotting.

Overview

xdart enables fast, intuitive analysis of X-ray diffraction (XRD) data from synchrotron sources. Whether you're monitoring a live experiment or processing batch data offline, xdart integrates seamlessly with pyFAI's proven azimuthal integration algorithms while providing a responsive graphical interface optimized for detector images and reciprocal space visualization.

Key Capabilities

• Real-time 1D/2D azimuthal integration using pyFAI
• Batch processing of image series with parallel multicore support
• Grazing incidence diffraction (GID) integration using pyFAI FiberIntegrator
• Live monitoring of ongoing experiments with directory-watched file ingestion
• NeXus/HDF5 data format with full metadata preservation
• Interactive 2D detector image visualization with zoom, pan, and masking tools
• Unit conversion between Q (Å⁻¹) and 2θ (°) with wavelength awareness
• Background subtraction (single file, series average, or directory-matched)
• Masking tools for bad pixels, beamstop shadows, and detector edges
• Calibration management via PONI files with visual feedback
• Raw image preview thumbnails for quick file browsing

Installation

Prerequisites

• Python ≥ 3.10
• A working pyFAI installation (installation can be platform-dependent; conda is recommended)

Recommended: Conda

conda create -n xdart python=3.12
conda activate xdart
pip install xdart --upgrade

pip

pip install xdart

Development Installation

git clone https://github.com/v-thampy/xdart.git
cd xdart
pip install -e ".[interactive]"

Quick Start

Launch the GUI

conda activate xdart
xdart

Or from Python:

from xdart.xdart_main import main
main()

Basic Workflow

1. Launch xdart and wait for the main window to open
2. Set calibration: Browse and select your PONI calibration file in the right panel
3. Select data: Choose an image file or directory containing images
4. Choose processing mode: Pick from Batch 1D, Live 1D, Batch 2D, Live 2D, or Viewer
5. Configure parameters (optional): Set background subtraction, masking, or advanced integration options
6. Click Start: Processing begins; monitor progress and view results in real time

Usage Guide

Loading and Processing Data

Batch Mode (Batch 1D, Batch 2D)

Process all frames in a selected image file or directory at once. Ideal for complete datasets acquired in a single experiment.

1. Select your PONI file
2. Select your image file or directory
3. Choose "Batch 1D" or "Batch 2D" from the mode dropdown
4. Adjust processing parameters as needed
5. Click Start

Results are saved as NeXus HDF5 files (.nxs) in the output directory.

Live Mode (Live 1D, Live 2D)

Monitor a directory for new image files and integrate them as they arrive. Perfect for real-time feedback during an active beamline experiment.

1. Set PONI file and image directory
2. Choose "Live 1D" or "Live 2D"
3. Click Start
4. xdart watches the directory and processes new files automatically

Viewer Mode

Browse and display previously saved NeXus files without re-integrating.

Integration Axes and Units

The 1D integration panel's axis dropdown lets you choose between:

• Q (Å⁻¹): Scattering vector magnitude; independent of wavelength
• 2θ (°): Scattering angle; depends on the wavelength in your PONI file

The 2D integration panel offers:

• Q-χ: Radial-azimuthal in reciprocal space
• 2θ-χ: Radial-azimuthal in angle space

Unit conversion respects your calibration file's wavelength automatically.

Grazing Incidence Diffraction (GID)

For surface-sensitive measurements, xdart supports grazing incidence geometry using pyFAI's FiberIntegrator:

1. In the Grazing Incidence section of the parameter tree, enable GI mode
2. Specify the incident angle and sample normal direction (if using advanced geometry)
3. The integrator panel switches to GI-specific modes:
   • 1D modes: Qip (in-plane), Qoop (out-of-plane), Q-total
   • 2D modes: Qip-Qoop, Q-χ
4. Process as normal; output will reflect the rotated reciprocal space axes

Advanced Integration Settings

Click "Advanced..." next to the processing mode dropdown to access detailed pyFAI parameters:

• Solid angle correction: Account for detector solid angle variations
• Dummy values: Mark pixels to ignore in integration
• Polarization factor: Apply polarization correction for synchrotron radiation
• Integration method: Choose the algorithm (e.g., histogram, csr, full-split)
• Radial range: Manually clip Q or 2θ range (overrides auto-detection)
• Azimuthal range: Select only certain χ sectors

Background Subtraction

Configure in the Background section of the parameter tree:

• No background: Raw data only
• Single file: Subtract a single dark image
• Series average: Average all images in a background directory, then subtract
• Directory-matched: Match each sample image to a background image by filename pattern

Background frames are integrated using the same parameters as sample frames for consistency.

Calibration and Masking

The integrator panel includes Calibrate and Make Mask buttons at the bottom:

• Calibrate launches the pyFAI-calib2 module for interactive detector calibration. Use a calibration standard (e.g., LaB6, CeO2) image to refine detector geometry and generate a PONI file.
• Make Mask launches the pyFAI mask drawing tool, where you can interactively draw regions on a detector image to create or edit a bad-pixel mask file.

Additional masking options are available in the parameter tree:

• Preset masks: Load a mask file from disk
• Threshold masking: Automatically mask pixels above or below intensity thresholds
• Detector masks: Apply detector-specific dead-pixel maps

Masks are saved with your results in the NeXus file for reproducibility.

Data Export and Saving

• Automatic export: Processed 1D/2D data is saved as NeXus HDF5 (.nxs) files during batch processing
• Manual export: Use the Save button in the display area to export the currently displayed pattern
• Metadata: All integration parameters, calibration info, and masking are stored in the HDF5 structure

Architecture

xdart is built on top of ssrl_xrd_tools, a standalone library for X-ray diffraction data processing. The GUI provides interactive access to the library's integration, I/O, and analysis capabilities, while maintaining tight integration with pyFAI for proven, well-tested algorithms.

Configuration and Calibration

PONI Files

xdart uses pyFAI PONI (PyFAI Object Containing Necessary Information) files for detector calibration. A PONI file contains:

• Detector geometry (pixel size, shape, name)
• Incident beam center location
• Sample-to-detector distance
• Wavelength
• Detector rotation (if any)

You can generate a PONI file using the Calibrate button in xdart's integrator panel (which launches pyFAI-calib2), or from the command line:

pyFAI-calib2

Refer to the pyFAI documentation for detailed calibration procedures.

Dependencies

Core Libraries

• pyFAI: Fast azimuthal integration and geometry handling
• PySide6: Modern Qt6 bindings for the GUI
• pyqtgraph: High-performance plotting and image visualization
• ssrl_xrd_tools: XRD data I/O and integration utilities
• h5py & silx: NeXus/HDF5 file support
• fabio: Image file I/O (CBF, EDF, TIFF, etc.)
• numpy, scipy, scikit-image: Numerical and image processing
• pandas: Data manipulation and analysis
• matplotlib: Publication-quality plotting

Optional for Advanced Use

• lmfit: Peak fitting and parameterization
• xrayutilities: Additional X-ray geometry utilities
• hvplot, holoviews, panel: Interactive Jupyter visualization

See pyproject.toml for the complete dependency list.

Troubleshooting

Common Issues

pyFAI installation fails on macOS/Windows: Try installing via conda instead of pip; conda packages include pre-built binaries.

conda install -c conda-forge pyfai

GUI doesn't appear or crashes on startup: Check that PySide6 is properly installed and your Qt plugins are accessible:

python -c "from PySide6 import QtWidgets; print('PySide6 OK')"

Slow integration or freezing: Ensure multicore processing is enabled in advanced settings, and reduce the image resolution or integration radial resolution if working with very large detectors.

PONI file not recognized: Verify the PONI file is in the correct format (text-based key=value pairs) and paths are absolute or relative to the working directory.

Contributing

Contributions are welcome! Please:

1. Fork the repository on GitHub
2. Create a feature branch (git checkout -b my-feature)
3. Make your changes and add tests
4. Submit a pull request with a clear description

For bug reports or feature requests, open an issue on GitHub.

License

xdart is released under the MIT License. See the LICENSE file for details.

Citation

If you use xdart in your research, please cite:

xdart: X-ray Diffraction Analysis in Real Time
https://github.com/v-thampy/xdart

(Formal publication citation coming soon)

Acknowledgments

Developed at the Stanford Synchrotron Radiation Lightsource (SSRL), SLAC National Accelerator Laboratory. Grateful thanks to the pyFAI community and all collaborators and users who provide feedback and improvements.

Contact

For questions, feedback, or collaboration inquiries, reach out to:

Vivek Thampy [e-mail]

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xdart v0.15 | Python ≥ 3.10 | Repository | Manual