Neutron Capture Measurements at the n_TOF Facility

摘要

Nuclear astrophysics, advanced nuclear technology and nuclear structure physics present many cases that require neutron capture reaction data with high precision. In particular, refined data are needed for stellar nucleosynthesis, for nuclear waste transmutation studies, and for the design of generation IV reactors. The measurements take profit of the pulsed neutron beam of the n_TOF facility at CERN, which is generated by protoninduced spallation reactions on a massive lead target. The low repetition rate of the proton beam, the high instantaneous neutron flux, and the favourable background conditions in the experimental area make this facility unique for high resolution time-of-flight measurements of neutron induced reaction cross sections. The n_TOF collaboration is presently operating two different experimental set-ups. The first consists of two low-neutron sensitivity C 6D6 detectors with the analysis relying on the Pulse Height Weighting technique. In addition, a Total Absorption Calorimeter, consisting of 40 BaF2 crystals covering the whole solid angle, was used. A review of several capture measurements with these detectors on selected stable and unstable samples will be presented.