Uncertainty Propagation for Cross Sections along Isotopic Chains

Hauser Feshbach statistical theory can be used to calculate cross sections for medium-mass and heavy-mass nuclei above the resonance range. Because of the consistent modeling across outgoing reaction channels (elastic, inelastic, capture, etc.), these channels can be constrained, even when experimental data exists for only a few. Uncertainty quantification techniques and propagation allow us to understand how well these other channels are constrained based on the available data. In this talk, we will discuss a Bayesian uncertainty quantification framework for cross sections calculated with the Hauser Feshbach formulism, using the example of neutrons on ¹⁶⁹Tm. We will show how emulators can be used to speed up the calculations, and how data in several channels leads to constraints in channels where experimental data are unavailable. Additionally, we will discuss how information about multiple compound nuclei allows us to propagate parametric uncertainties along the isotopic chain, to reactions on lighter and heavier Tm isotopes. Finally, we will briefly mention how statistical techniques can be used to inform which new measurements would lead to reduced uncertainties.