1. Observation of fission modes in heavy ion induced reactions
- Author
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K. Lukashin, Yu. Ts. Oganessian, E. M. Kozulin, E. Liatard, C. Agodi, L. Stuttge, D. O’Kelly, A. Huck, A. Ya. Rusanov, R.P. Schmitt, V. S. Salamatin, I. V. Pokrovsky, M. G. Itkis, V.V. Pashkevich, F. Hanappe, Luciano Calabretta, B. Hurst, G. Bellia, C. Maiolino, N. A. Kondratiev, and G. Chubarian
- Subjects
Mass distribution ,Isotope ,Chemistry ,Fission ,Excited state ,Saddle point ,Nuclear structure ,Mass spectrum ,Atomic physics ,Nuclear Experiment ,Excitation - Abstract
The fission of the systems 220,224,226Th was investigated by measuring the mass-energy distributions of the fission fragments. The corresponding excitation energies at the saddle point, Esp*, ranged from 16 to 40 MeV. As Esp* decreases, an asymmetric mass component becomes visible on the predominately symmetric mass distribution. The contribution of the asymmetric mode is characterized by the total yield ratio Ys/Ya, which decreases rapidly for the heavier isotopes of thorium. This behavior of Ys/Ya is in qualitative agreement with theoretical calculations. For all isotopes studied, the subtracted asymmetric fission component, Ya=Y1−Ys, exhibits a complex structure, actually showing two components, Ya=Ya1+Ya0, which have average masses Ma1=132 and Ma0=140.
- Published
- 1998