U237neutron-induced fission cross section

Abstract

The neutron-induced fission cross section of $^{237}\mathrm{U}$ target nuclide is calculated consistently with the $^{238}\mathrm{U}$(n,F), $^{238}\mathrm{U}$($n,2n$) and $^{238}\mathrm{U}$($n,3n$) reaction cross section up to ${E}_{n}~20$ MeV. The fission probability of the $^{238}\mathrm{U}$ nuclide, fissioning in $^{238}\mathrm{U}$($n,\mathit{nf}$) reaction is shown to be compatible with the surrogate $^{236}\mathrm{U}$($t,\mathit{pf}$) fission probability and ratio of fission probability ${P}_{f}$($^{238}\mathrm{U}$($d,d\text{'}f$))/${P}_{f}$($^{236}\mathrm{U}$($d,d\text{'}f$)), data up to ${E}_{n}~14$ MeV. The $^{238}\mathrm{U}$($n,\mathit{nf}$) reaction contribution to the observed ${}^{238}U(n,F)$ cross section up to ${E}_{n}~9$ MeV is defined by the collective levels of the $^{238}\mathrm{U}$ at saddle deformations, lying within the pairing gap. The importance of the lowering of anomalous rotational $\ensuremath{\gamma}$-band ${K}^{\ensuremath{\pi}}={2}^{+}$ band levels at saddle deformations is demonstrated. The excitation of the two-quasiparticle states at saddle deformations of the fissioniong $^{238}\mathrm{U}$ nuclide is evidenced.$^{237}\mathrm{U}$ fission cross section is predicted up to ${E}_{n}~200$ MeV.