pyirena 0.6.4

Python tools for small-angle scattering data analysis.

pyIrena

Coded by Claude from SAXS_IgorCode Irena. Planned, defined, debugged, and validated by Jan Ilavsky.

Python tools for small-angle scattering (SAS) data analysis. A port of the Igor Pro Irena package. Includes interactive GUI tools for fitting, modeling, data merging, and visualization of SAXS/SANS/USAXS data.

Current release: v0.6.4 (public beta)

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Installation

From PyPI (recommended):

pip install pyirena[gui]

This installs pyirena with all GUI dependencies (PySide6, pyqtgraph, etc.). For the core library only (no GUI), use pip install pyirena.

From source (for development):

git clone https://github.com/jilavsky/pyirena.git
cd pyirena
pip install -e ".[gui]"

With conda:

git clone https://github.com/jilavsky/pyirena.git
cd pyirena
conda env create -f environment.yml
conda activate pyirena

See docs/installation.md for full details, troubleshooting, and platform notes.

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Running the GUI

pyirena-gui

This launches the Data Selector, the main entry point for all analysis tools. See docs/gui_quickstart.md for a walkthrough.

Individual tools can also be launched directly:

Command	Tool
pyirena-gui	Data Selector (main entry point)
pyirena-viewer	Data Explorer
pyirena-modeling	Modeling tool (standalone)
pyirena-datamerge	Data Merge tool (standalone)
pyirena-contrast	Scattering Contrast Calculator

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Analysis Tools

Modeling

Parametric forward-modeling of SAS data. Combine up to 10 populations, each of which can be a Size Distribution, Unified Fit Level, or Diffraction Peak. Fits the combined model to experimental data using least-squares optimization.

• 5 distribution functions: Gaussian, LogNormal, LSW, Schulz-Zimm, Ardell
• 9 form factors: Sphere, Spheroid, Cylinder (aspect ratio / fixed length), Core-Shell Sphere and Spheroid (by core R / shell t / total R)
• 2 structure factors: Born-Green interferences, Hard Sphere (Percus-Yevick)
• Monte Carlo uncertainty estimation
• Modeling GUI guide

Unified Fit

Beaucage hierarchical model (1995, 1996) with 1-5 structural levels, each combining Guinier and power-law contributions. Optional Born-Green correlation function.

• Unified Fit GUI guide
• Unified Fit features & parameters

Size Distribution

Indirect Fourier transform to recover particle size distributions from SAS data. Four inversion methods: MaxEnt, Regularization, TNNLS, and Monte Carlo.

• Size Distribution methods

Simple Fits

13 direct analytical models: Guinier, Guinier-Porod, Porod, Sphere, Spheroid, Debye-Bueche, Treubner-Strey, Power Law, and more. Each with linearization plots and Monte Carlo uncertainty estimation.

• Simple Fits GUI guide

WAXS Peak Fit

Fit diffraction peaks (Gaussian, Lorentzian, Pseudo-Voigt, Log-Normal) on linear I vs Q scale. Auto-detect peaks via Savitzky-Golay + scipy.signal.find_peaks. Simultaneous background fitting (constant, linear, cubic, or 5th-order polynomial).

• WAXS Peak Fit GUI guide

Data Merge

Merge two SAS datasets (e.g., SAXS + WAXS) onto a common Q scale. Optimizes scale factor, flat background, and optional Q-shift using Nelder-Mead.

• Data Merge GUI guide

Data Explorer

Browse NXcanSAS HDF5 files, inspect raw data and analysis results, extract and plot datasets, and export to Igor Pro h5xp format. Supports all pyIrena result types (Unified Fit, Sizes, Simple Fits, WAXS Peaks, Modeling).

• Data Explorer guide

Scattering Contrast Calculator

Look up X-ray and neutron scattering length densities for materials by chemical formula. Computes contrast (Delta-rho-squared) between two materials.

• Contrast Calculator guide

Data Selector

Central GUI panel for managing data files and launching analysis tools. Load HDF5 files, select datasets, tabulate results across files, and generate reports.

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Batch Scripting API

All analysis tools can be run headlessly from Python scripts or JSON configuration files:

from pyirena.batch import fit_pyirena

results = fit_pyirena(
    data_file='sample.h5',
    config_file='pyirena_config.json',
)

Individual functions: fit_unified, fit_sizes, fit_simple, fit_waxs, fit_modeling, merge_data.

See docs/batch_api.md for the full scripting guide.

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NXcanSAS I/O

All data and results are stored in HDF5 files using the NXcanSAS format. Fit results are saved alongside raw data, making files self-contained and shareable.

• NXcanSAS format details

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Documentation

Topic	File
Installation	docs/installation.md
Quick start (GUI)	docs/gui_quickstart.md
Modeling GUI guide	docs/modeling_gui.md
Unified Fit GUI guide	docs/unified_fit_gui.md
Unified Fit features & parameters	docs/unified_fit_features.md
Size Distribution methods	docs/sizes_methods.md
Simple Fits GUI guide	docs/simple_fits_gui.md
WAXS Peak Fit GUI guide	docs/waxs_peakfit_gui.md
Data Merge GUI guide	docs/data_merge_gui.md
Data Explorer guide	docs/hdf5_viewer_gui.md
Contrast Calculator guide	docs/scattering_contrast_gui.md
NXcanSAS file format	docs/NXcanSAS_UnifiedFit_Format.md
Batch fitting API	docs/batch_api.md
Usage guide (scripting)	docs/usage_guide.md
Developer: adding form factors	docs/developer_adding_form_factors.md
Developer: adding structure factors	docs/developer_adding_structure_factors.md
Testing	docs/testing.md
Distribution / packaging	docs/distribution.md
Contributing	CONTRIBUTING.md
Changelog	CHANGELOG.md

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License

MIT -- see LICENSE.

Contact

• Author: Jan Ilavsky -- [e-mail]
• Affiliation: X-ray Science Division, Argonne National Laboratory
• Issues: https://github.com/jilavsky/pyirena/issues