Covariance generation for the prompt neutron multiplicity of 239Pu including the (n,γf) process

Fission cross section of 239 Pu can be seen as a sum of the “immediate" fission and “two-step" (n,γ f) reactions. In the Resolved Resonance Range of the reaction cross sections, the contribution of the (n,γ f) process has an impact on the determination of the partial widths magnitude involved in the Reich-Moore approximation of the R-matrix theory. The present work aims to investigate this impact by using the CONRAD code and the partial width Γγf for the (n,γ f) reaction calculated by Lynn et al. [1]. A special attention will be paid to the covariance matrix obtained on νp .