# openmc.data.MultiLevelBreitWigner¶

class openmc.data.MultiLevelBreitWigner(target_spin, energy_min, energy_max, channel, scattering)[source]

Multi-level Breit-Wigner resolved resonance formalism data.

Multi-level Breit-Wigner resolved resonance data is identified by LRF=2 in the ENDF-6 format.

Parameters
• target_spin (float) – Intrinsic spin, $$I$$, of the target nuclide

• energy_min (float) – Minimum energy of the resolved resonance range in eV

• energy_max (float) – Maximum energy of the resolved resonance range in eV

• channel (dict) – Dictionary whose keys are l-values and values are channel radii as a function of energy

• scattering (dict) – Dictionary whose keys are l-values and values are scattering radii as a function of energy

Variables
• atomic_weight_ratio (float) – Atomic weight ratio of the target nuclide given as a function of l-value. Note that this may be different than the value for the evaluation as a whole.

• channel_radius (dict) – Dictionary whose keys are l-values and values are channel radii as a function of energy

• energy_max (float) – Maximum energy of the resolved resonance range in eV

• energy_min (float) – Minimum energy of the resolved resonance range in eV

• parameters (pandas.DataFrame) – Energies, spins, and resonances widths for each resonance

• q_value (dict) – Q-value to be added to incident particle’s center-of-mass energy to determine the channel energy for use in the penetrability factor. The keys of the dictionary are l-values.

• scattering_radius (dict) – Dictionary whose keys are l-values and values are scattering radii as a function of energy

• target_spin (float) – Intrinsic spin, $$I$$, of the target nuclide

classmethod from_endf(ev, file_obj, items)[source]

Create MLBW data from an ENDF evaluation.

Parameters
• ev (openmc.data.endf.Evaluation) – ENDF evaluation

• file_obj (file-like object) – ENDF file positioned at the second record of a resonance range subsection in MF=2, MT=151

• items (list) – Items from the CONT record at the start of the resonance range subsection

Returns

Multi-level Breit-Wigner resonance parameters

Return type

openmc.data.MultiLevelBreitWigner