Étude des niveaux de 56Fe excités par les réactions (p, p′γ) ET (n, n′γ)

Abstract

The energy levels of 56Fe have been studied by means of the (p, p′γ) and (n, n′γ) reactions. Particle-gamma coincidences from the 56Fe(p, p′γ) reaction have been measured at 6.5, 8, 10 and 11 MeV incident proton energies. The coincident γ-rays were detected with a 100 cm 3 Ge(Li) detector and protons with cooled Si(Li) diodes. Independently, absolute differential cross sections for the production of γ-rays by inelastic neutron scattering from iron have been measured in the energy range 4.8–8.8 MeV. A 65 cm 3 Ge(Li) detector surrounded by a NaI (Tl) annulus and associated with a pulsed beam time-of-flight system was used to detect the deexcitation γ-rays. By comparing the measured angular distributions and excitation functions with those calculated on the basis of the statistical theory, spin assignments for poorly known states are made. From these two experiments, a decay scheme is constructed and proposed. The results are briefly compared with mixed-configuration shell model calculations.