A. Deppman, E. Andrade-II, V. Guimaraes, G. S. Karapetyan, A. R. Balabekyan, N. A. Demekhina
The intermediate energy proton-induced fission of 241Am, 238$U and 237$Np is studied. The inelastic interactions of protons and heavy nuclei are described by a CRISP model, in which the reaction proceeds in two steps. The first one corresponds fast cascade, where a series of individual particle-particle collisions occurs within the nucleus. It leaves a highly excited cascade residual nucleus, assumed to be in thermal equilibrium. Subsequently, in the second step the excited nucleus releases its energy by evaporation of neutrons and light charged particles as well. Both the symmetric and asymmetric fission are regarded, and the fission probabilities are obtained from CRISP code calculations, by means of statistical weighting factors. The fission cross sections, the fissility of the fissioning nuclei, and the number of nucleons lost by the target - before and after fission - are calculated and compared to experiments for 660 MeV protons incident on 241Am, 238$U and 237$Np. Some of the model predictions are in full compliance to the experiments. We conclude that our two step model provides a reasonable description of the medium energy proton-induced fission.
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http://arxiv.org/abs/1302.2265
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