# openmc.data.ThermalScattering¶

class openmc.data.ThermalScattering(name, atomic_weight_ratio, energy_max, kTs)[source]

A ThermalScattering object contains thermal scattering data as represented by an S(alpha, beta) table.

Parameters
• name (str) – Name of the material using GND convention, e.g. c_H_in_H2O

• atomic_weight_ratio (float) – Atomic mass ratio of the target nuclide.

• kTs (Iterable of float) – List of temperatures of the target nuclide in the data set. The temperatures have units of eV.

Variables
• atomic_weight_ratio (float) – Atomic mass ratio of the target nuclide.

• energy_max (float) – Maximum energy for thermal scattering data in [eV]

• elastic (openmc.data.ThermalScatteringReaction or None) – Elastic scattering derived in the coherent or incoherent approximation

• inelastic (openmc.data.ThermalScatteringReaction) – Inelastic scattering cross section derived in the incoherent approximation

• name (str) – Name of the material using GND convention, e.g. c_H_in_H2O

• temperatures (Iterable of str) – List of string representations the temperatures of the target nuclide in the data set. The temperatures are strings of the temperature, rounded to the nearest integer; e.g., ‘294K’

• kTs (Iterable of float) – List of temperatures of the target nuclide in the data set. The temperatures have units of eV.

• nuclides (Iterable of str) – Nuclide names that the thermal scattering data applies to

Add data to the ThermalScattering object from an ACE file at a different temperature.

Parameters
• ace_or_filename (openmc.data.ace.Table or str) – ACE table to read from. If given as a string, it is assumed to be the filename for the ACE file.

• name (str) – GND-conforming name of the material, e.g. c_H_in_H2O. If none is passed, the appropriate name is guessed based on the name of the ACE table.

Returns

Thermal scattering data

Return type

openmc.data.ThermalScattering

export_to_hdf5(path, mode='a', libver='earliest')[source]

Export table to an HDF5 file.

Parameters
• path (str) – Path to write HDF5 file to

• mode ({'r+', 'w', 'x', 'a'}) – Mode that is used to open the HDF5 file. This is the second argument to the h5py.File constructor.

• libver ({'earliest', 'latest'}) – Compatibility mode for the HDF5 file. ‘latest’ will produce files that are less backwards compatible but have performance benefits.

classmethod from_ace(ace_or_filename, name=None)[source]

Generate thermal scattering data from an ACE table

Parameters
• ace_or_filename (openmc.data.ace.Table or str) – ACE table to read from. If given as a string, it is assumed to be the filename for the ACE file.

• name (str) – GND-conforming name of the material, e.g. c_H_in_H2O. If none is passed, the appropriate name is guessed based on the name of the ACE table.

Returns

Thermal scattering data

Return type

openmc.data.ThermalScattering

classmethod from_endf(ev_or_filename)[source]

Generate thermal scattering data from an ENDF file

Parameters

ev_or_filename (openmc.data.endf.Evaluation or str) – ENDF evaluation to read from. If given as a string, it is assumed to be the filename for the ENDF file.

Returns

Thermal scattering data

Return type

openmc.data.ThermalScattering

classmethod from_hdf5(group_or_filename)[source]

Generate thermal scattering data from HDF5 group

Parameters

group_or_filename (h5py.Group or str) – HDF5 group containing interaction data. If given as a string, it is assumed to be the filename for the HDF5 file, and the first group is used to read from.

Returns

Neutron thermal scattering data

Return type

openmc.data.ThermalScattering

classmethod from_njoy(filename, filename_thermal, temperatures=None, evaluation=None, evaluation_thermal=None, use_endf_data=True, **kwargs)[source]

Generate thermal scattering data by running NJOY.

Parameters
• filename (str) – Path to ENDF neutron sublibrary file

• filename_thermal (str) – Path to ENDF thermal scattering sublibrary file

• temperatures (iterable of float) – Temperatures in Kelvin to produce data at. If omitted, data is produced at all temperatures in the ENDF thermal scattering sublibrary.

• evaluation (openmc.data.endf.Evaluation, optional) – If the ENDF neutron sublibrary file contains multiple material evaluations, this argument indicates which evaluation to use.

• evaluation_thermal (openmc.data.endf.Evaluation, optional) – If the ENDF thermal scattering sublibrary file contains multiple material evaluations, this argument indicates which evaluation to use.

• use_endf_data (bool) – If the material has incoherent elastic scattering, the ENDF data will be used rather than the ACE data.

• **kwargs – Keyword arguments passed to openmc.data.njoy.make_ace_thermal()

Returns

data – Thermal scattering data

Return type

openmc.data.ThermalScattering