Irena introduction

Irena package capabilities

Main Irena page https://usaxs.xray.aps.anl.gov/software/irena

Irena package has been in development since about 2000 and over the years if became "toolbox" of choice among small-angle scattering community for analysis of complex systems in materials science, chemistry, physics, metallurgy, and many other fields. As of 12-2021 Google scholar lists 1400 citations of the 2009 Irena paper. Irena now provides number of tools which enable users to import data, modify as needed and analyze with various methods. Basic listing of available tools is here:

##Analysis tools

1. Unified fit
2. Modeling - Direct modeling of SAS from up to 6 populations on up to 10 data sets at once. Selection of form factors and structure factors. Can be combined with Unified fit, Fractal systems, and Diffraction peaks.
3. Size distribution using Maximum Entropy, Total Non-Negative Least Squares and Regularization methods
4. Simple Fits and Analysis - Guinier, Porod, Sphere, Spheroid, Invariant, 1D Correlation
5. System specific models - Hermans, Modified Hermans, Unified Green Born, Debye-Bueche, Ciccariello-Benedetti, and Treubner-Streus models
6. Guinier-Porod model
7. Fractal model (combination of mass and surface fractals)
8. X-ray and Neutron reflectivity using Parrat's recursive method
9. Small-angle diffraction tool (up to 6 diffraction peaks)
10. Pair distance distribution function (PDDF, P(r), see GNOM from D. Svergun for more details)
11. Powder diffraction peak fitting tool (WAXS)
12. BioSAS tools - import, subtract, average, plot, and run PDDF (including scripting gnom, if available)
13. Mass Fractal aggregate growth and scattering calculation
14. Anisotropy analysis

##Support tools

1. Scattering contrast calculator, including anomalous effects using Croman-Liberman code
2. Data import tool - imports data from ASCII, XML (CanSAS XML), and Nexus hdf5 files
3. Data manipulation tools - subtract, scale, multiply, etc. - change data as needed.
4. Merging of two overlapping data sets (SAXS curves from different distances etc.).
5. Multiple data plotting tools - 2D, 3D, can create movies of plots.
6. Desmearing using Lake method
7. Data & Metadata "mining" tool
8. Data export tool - exports data to ASCII files or Nexus hdf5 files
9. Scripting tool - scripts Unified fit, Modeling II, Plotting tool, and Size distribution to run automatically on multiple data sets