Measurement of mass yields from the 241Am(2nth,f) reaction at the Lohengrin Spectrometer

The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides ( 235 U, 239 Pu) in the thermal neutron-induced fission, only few measurements have been performed on 242 Am. The interest of 242 Am concerns the reduction of radiotoxicity of 241 Am in nuclear wastes using transmutation reactions. This paper presents the measurement of the fission mass yields from the reaction 241 Am(2n th ,f) performed at the Lohengrin mass spectrometer (ILL, France) for both the light and the heavy peaks: a total of 41 mass yields have been measured. The experiment was also meant to determine whether there is a difference in mass yields between the isomeric state and the ground state as it exists in fission and capture cross sections. The method used to address this question is based on a repeated measurement of a set of fission mass yields as a function of the ratio between the 242g Am and the 242m Am fission rates. The presented experiment is also a first step towards the measurement of the isotopic fission yields of 242 Am.