Influence of primary fragment excitation energy and spin distributions on fission observables

Olivier Litaize (1) , Loïc Thulliez (1, 2) , Olivier Serot (1) , Abdelaziz Chebboubi (1) , Pierre Tamagno (1)

1 CEA Cadarache
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers

Fission observables in the case of 252Cf(sf) are investigated by exploring several models involved in the excitation energy sharing and spin-parity assignment between primary fission fragments. In a first step the parameters used in the FIFRELIN Monte Carlo code “reference route" are presented: two parameters for the mass dependent temperature ratio law and two constant spin cut-off parameters for light and heavy fragment groups respectively. These parameters determine the initial fragment entry zone in excitation energy and spin-parity (E*, Jπ). They are chosen to reproduce the light and heavy average prompt neutron multiplicities. When these target observables are achieved all other fission observables can be predicted. We show here the influence of input parameters on the saw-tooth curve and we discuss the influence of a mass and energy-dependent spin cut-off model on gamma-rays related fission observables. The part of the model involving level densities, neutron transmission coefficients or photon strength functions remains unchanged.

Domaines: Physique Nucléaire Théorique [nucl-th]

Olivier Litaize, Loïc Thulliez, Olivier Serot, Abdelaziz Chebboubi, Pierre Tamagno. Influence of primary fragment excitation energy and spin distributions on fission observables. Scientific Workshop on Nuclear Fission dynamics and the Emission of Prompt Neutrons and Gamma Rays, Jun 2017, Varna, Bulgaria. pp.00012, ⟨10.1051/epjconf/201816900012⟩. ⟨hal-01833696⟩