2.1. Introduction to Cross Sections

OpenSn is not supplied with cross-section libraries.

Users are expected to supply their own cross-section data.

One may use other open-source software to generate multigroup cross sections (e.g., NJOY, Dragon, OpenMC).

We allow 3 cross-section input modes:

• using a built-in method to generate isotropic one-group cross sections

• reading an ASCII (text) file

• reading an HDF5 file generated by OpenMC <https://docs.openmc.org/en/stable/index.html>`_