Centre Etudes Nucléaires de Bordeaux Gradignan

Our activities

The activities of the group are within the interdisciplinary programme of CNRS called PACEN (Programme «Back End of the Cycle and Nuclear Energy») and particularly within the research community GEDEPEON (Waste Management and Novel Options for Energy Production) that coordinates the projects on national level. Some of these activities form a part of the integrated European project EUROTRANS of the 6th Framework Programme.

The group in engaged in the systematic measurements of neutron cross-sections for minor actinides (isotopes of Pu, Am and Cm) and certain heavy nuclei from Thorium cycle (Pa and U). The measurements of neutron cross-sections for these heavy nuclei very often represent a challenge for experimentalists due to their high -radioactivity, their scarcity and technical difficulties arising from the fabrication of isotopically-pure targets. According to the nature and availability of the studied elements, we use two complementary approaches to measure their cross-sections:

• Direct approach with the irradiation by neutrons.
  This is the method that we applied for the measurement of the cross-section for the reaction Am(n,f) induced by fast neutrons (1 to 8 MeV) (see Minor actinides). According to our requirements, the experiments were carried out with mono-energetic neutron beams produced by AIFIRA in CENBG, at the Van de Graaff in IRMM of Geel in Belgium or of Bruyères le Châtel from the following reactions Li(p,n)Be, D(d,n)He or H(p,n)He.
  
  
• Indirect approach through transfer reactions.
  One can use transfer reactions induced by a beam of charged particles (He) to reach the fissioning systems that are inaccessible through neutron induced reactions. The technique was put into operation at Tandem accelerator of IPN Orsay. This method was used in the measurements of fission and capture cross-sections for Pa nucleus (half-life of 27 days!) (see Thorium cycle ).