Measurement of the Neutron Capture Cross Section of the Fissile Isotope ~(235)U with the CERN n_TOF Total Absorption Calorimeter and a Fission Tagging Based on Micromegas Detectors

摘要

Current and future nuclear technologies require more accurate nuclear data on (n,γ) cross sections and the α-ratios of fissile isotopes. Their measurement presents several difficulties, mainly related to the strong fission γ-ray background competing with the weaker γ-ray cascades used as the experimental signature of the (n,γ) process. A specific setup was used at the CERN n_TOF facility in 2012 for the measurement of the (n,γ) cross section and a-ratios of fissile isotopes and used for the case of the ~(235)U isotope. The setup consists of a set of micromegas fission detectors surrounding the ~(235)U samples all placed inside a segmented BaF_2 Total Absorption Calorimeter.