Symmetric uranium neutron-induced fission

• Published in: Nuclear physics. A Vol. 705; no. 3; pp. 352 - 363
• Main Authors: Maslov, V.M., Hambsch, F.-J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2002
• Subjects: Fission barrier parameters; Hauser–Feshbach statistical model; Level densities; Radioactivity 235,238U(n, f); Symmetric fission yield; Radioactivity 235,238U(n, f); 24.10.Pa; Fission barrier parameters; 25.85.EC; Hauser–Feshbach statistical model; Level densities; Symmetric fission yield; 24.75.+i
• ISSN: 0375-9474
• DOI: 10.1016/S0375-9474(02)00654-1

The symmetric SL-mode fission cross sections of 235U(n, f) and 238U(n, f) are analyzed up to the emissive fission threshold within a Hauser–Feshbach statistical model. A separate outer fission barrier is assumed for the SL-mode, while the inner one is assumed to be the same for the symmetric SL- and the asymmetric S1- and S2-modes. Axial asymmetry and mass-symmetry is assumed for the outer saddle of the SL-mode, as distinct from the S1- and S2-modes, which are axially symmetric and mass-asymmetric. The observed fission cross section behaviour is modelled using the interplay of few-quasiparticle excitations in the level density of the fissioning and residual nuclei. The SL-mode fission cross section seems to be controlled by a rather high outer fission barrier with significant transparency.