The SPONGE v.1.0.0: Modeling scattering of shapes by STL input, with absolute intensities and size distribution.

Synopsis:

Simulates X-ray and Neutron scattering patterns from arbitrary shapes defined by STL files. 

Features:

• Uses multithreading to compute a number of independent solutions, then uses the variance of the results to estimate an uncertainty on the output. 
• Can be launched from the command line using an excel sheet to define settings, or from a jupyter notebook. 
• Outputs scattering patterns in absolute units if the contrast is set. 
• A Gaussian size distribution is available, where the relative scaling of objects for each repetion can be varied. Recommended to be used with limited width (max. 10%) to avoid artefacts. 
• Writes results with settings to an archival HDF5 file.  

Application examples:

This software has been used in several studies to date. For example, it has been used here to simulate a model scattering pattern for a cuboid shape, which was then fed forward into the McSAS3 analysis program for analyzing scattering patterns of polydisperse cuboids. A second use is here, where it was used for the modeling of flattened helices. In this paper, scattering pattern features could be matched with particular morphological changes in the structure. Lastly, this paper has an example where it was used to validate the analytical analysis model, and explore the realistic limits of application of the analytical model.