A nuclear reaction

A Reaction object represents a single reaction channel for a nuclide with an associated cross section and, if present, a secondary angle and energy distribution.


mt (int) – The ENDF MT number for this reaction.

  • center_of_mass (bool) – Indicates whether scattering kinematics should be performed in the center-of-mass or laboratory reference frame. grid above the threshold value in barns.

  • redundant (bool) – Indicates whether or not this is a redundant reaction

  • mt (int) – The ENDF MT number for this reaction.

  • q_value (float) – The Q-value of this reaction in eV.

  • xs (dict of str to – Microscopic cross section for this reaction as a function of incident energy; these cross sections are provided in a dictionary where the key is the temperature of the cross section set.

  • products (Iterable of – Reaction products

  • derived_products (Iterable of – Derived reaction products. Used for ‘total’ fission neutron data when prompt/delayed data also exists.

classmethod from_endf(ev, mt)[source]

Generate a reaction from an ENDF evaluation


rx – Reaction data

Return type

classmethod from_hdf5(group, energy)[source]

Generate reaction from an HDF5 group

  • group (h5py.Group) – HDF5 group to read from

  • energy (dict) – Dictionary whose keys are temperatures (e.g., ‘300K’) and values are arrays of energies at which cross sections are tabulated at.


Reaction data

Return type


Write reaction to an HDF5 group


group (h5py.Group) – HDF5 group to write to