Pairing effects in 232Th neutron-induced fission cross section

✍ Scribed by V.M. Maslov

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 287 KB
• Volume: 743
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/j.nuclphysa.2004.08.007

✦ Synopsis

The fission cross section of 232 Th(n, F) is calculated consistently with the 232 Th(n, 2n) reaction cross section up to 20 MeV. The fission probability of the 232 Th nuclide, fissioning in 232 Th(n, nf) reaction is shown to be compatible with the surrogate 230 Th(t, pf) fission probability data. The 232 Th(n, nf) reaction contribution to the observed 232 Th(n, F) cross section up to E n ∼ 9 MeV is defined by the collective levels of the 232 Th at saddle deformations, lying within the pairing gap. The importance of the negative parity octupole K π = 0 -band levels at saddle deformations is demonstrated. The shoulder or small step-like structure in the observed fission cross section of the 232 Th(n, F) above E n ∼ 9 MeV is correlated with the excitation of the two-quasiparticle states at saddle deformations of the fissioning 232 Th nuclide. Influence of the multiple-chance fission on the 232 Th prompt fission neutron spectra is demonstrated.