Measurements of the 237Np and 240Pu neutron capture cross section at the CERN n_TOF facilitiy

In this work, the neutron capture cross sections of 237Np and 240Pu have been measured at the n_TOF/CERN facility in the energy range from 1 eV to 2 keV. Since the total absorption technique has been employed for at n_TOF for the first time in this work, a variety of analysis techniques and software tools for the data analysis had to be developed. These have been validated with experimental data and have been shown to provide a capture yield with an accuracy between 4% and 6%, depending on the particularities of the measurement. The experimental data have been analyzed with the SAMMY code in combination with the most reliable transmission data. The results have been, for each isotope, a set of resonance parameters and the associated covariance matrix as well as the corresponding point-wise and average capture cross sections. The cross sections obtained in this work have been compared with all the previous data available as well as with the most recent evaluations. It has been shown that, for both isotopes, the data presented in this work are the most accurate and have the highest resolution to date. An additional result consisted in the identification of a set of specific actions that will be implemented in future measurements at n_TOF to become even more accurate cross sections and to cover a wider energy range.