Published 1900
NDS Staff Publication
Modelling Neutron-induced Reactions on 232-237U from 10 keV up to 30 MeV
Description
Comprehensive calculations of cross sections for neutron-induced reactions on 232−237U targets
are performed in the 10 keV–30 MeV incident energy range with the code EMPIRE–3.2 Malta.
The advanced modelling and consistent calculation scheme are aimed at improving our knowledge
of the neutron scattering and emission cross sections, and to assess the consistency of available
evaluated libraries for light uranium isotopes. The reaction model considers a dispersive optical
potential (RIPL 2408) that couples from five (even targets) to nine (odd targets) levels of the groundstate
rotational band, and a triple-humped fission barrier with absorption in the wells described
within the optical model for fission. A modified Lorentzian model (MLO) of the radiative strength
function and Enhanced Generalized Superfluid Model nuclear level densities are used in Hauser-
Feschbach calculations of the compound-nuclear decay that include width fluctuation corrections.
The starting values for the model parameters are retrieved from RIPL. Excellent agreement with
available experimental data for neutron emission and fission is achieved, giving confidence that the
quantities for which there is no experimental information are also accurately predicted. Deficiencies
in existing evaluated libraries are highlighted.