| Autor: |
W. von Oertzen, K. D. Schilling, V. E. Zhuchko, V. G. Tishchenko, D. V. Kamanin, Yu. V. Pyatkov, Claus-Michael Herbach, W. Wagner, D. Hilscher, Y. E. Penionzhkevich, H.-G. Ortlepp, P. Gippner, G. Renz, O. V. Strekalovsky |
| Rok vydání: |
2002 |
| Předmět: |
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| Zdroj: |
Nuclear Physics A. 712:207-246 |
| ISSN: |
0375-9474 |
| DOI: |
10.1016/s0375-9474(02)01242-3 |
| Popis: |
Ternary fission of heavy hot composite systems with excitation energies of 1.5–2.5 MeV / amu has been studied in the reactions of 14N(53 A MeV) with 197Au and 232Th. The ternary yields have been explored as a function of the charge Z L of the lightest fragment: while Z L increases from 6 to 25, the cross sections decrease from 5 to 0.08 mb for N + Au and from 15 to 0.8 mb for N + Th. The velocity vector v → L of the lightest fragment has been investigated in the rest frame of the other two heavier fragments. Two different components are observed: (i) an isotropic one with values of v L corresponding to the Coulomb repulsion from the combined heavier fragments before separation and, (ii) an anisotropic contribution with the lightest fragment emitted with lower v L perpendicular to the scission axis of the two heavier fragments. The latter component is distinguished from the isotropic one by an enhanced fraction of mass-symmetric ternary events and by up to 50 MeV lower total kinetic fragment energies. These features are indicative of a collinear stretched scission configuration, where the lightest fragment is positioned between the two heavier ones. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect