The topic of nuclear fission focuses on the phenomenon during which a heavy nucleus splits into two or even three fragments. This process, discovered in 1939, is at the origin of the energy produced in current nuclear reactors. Its precise characterization is a crucial issue for the control of technological applications. In addition, many fundamental questions about the very heart of this process remain topical.

Theoretical and experimental exploration of the fission mechanism is an essential part of LMCE’s activities. The development of a predictive and quantitative theory of fission remains one of the most difficult challenge in nuclear physics. It faces the resolution of a time-dependent N-body problem with a large number of open reaction channels. The effects of superfluidity and collective motion of nucleons are preponderant. We dedicate our theoretical efforts to the description of the static properties of a fissioning nucleus via a Hartree-Fock-Bogoliubov approach, the prediction of fission yields via statistical models and the simulation of the fission dynamics based on the time-dependent mean field theory or on the generator coordinate method. These studies are the subject of partnerships with IRESNE (CEA), IRFU (CEA), IJCLab (CNRS) and the Lawrence Livermore National Laboratory (USA). A part of the activity is finally dedicated to the improvement fission cross section models in close connection with our achievements on nuclear reactions.

The associated experimental studies aim at measuring fission cross sections, fission fragment distributions and characterizing the de-excitation of fission fragments by neutron and gamma ray emission. Our laboratory is expert in the measurement of fission yields in inverse kinematics, in which the fissioning nucleus is accelerated and sent to a target. This technique avoids the difficulties of identifying the charge of the fission fragments encountered in direct kinematics (neutron beam on a target of heavy nuclei). This type of experiment is carried out at GSI (Germany) and at GANIL (Caen) in the framework of international collaborations. Another part focuses on precision measurements of the energy and multiplicities of prompt fission neutrons at LANL (USA) in partnership with local teams. This activity is enriched by measurements of fission cross sections on the same beam line. Concerning the gamma emission, the LMCE carries out measurement campaigns of the energy spectra of the fission prompt gammas which inform us on the gamma force functions of the fragments. Finally, gamma calorimetry measurements for induced fission allow to improve our knowledge of the average number of gamma rays emitted per fission.