Determination of Ni59(n,xp) reaction cross sections using surrogate reactions

Abstract

The $^{59}\mathrm{Ni}(n,xp)$ reaction cross sections have been measured following the surrogate reaction ratio method in the equivalent neutron energy range of 11.9--15.8 MeV by populating the compound nucleus $^{60}\mathrm{Ni}^{*}$ through transfer reaction $^{56}\mathrm{Fe}(^{6}\mathrm{Li},d)$ at ${E}_{\text{lab}}=35.9$ MeV. The $^{59}\mathrm{Co}(^{6}\mathrm{Li},\ensuremath{\alpha})^{61}\mathrm{Ni}^{*}$ transfer reaction at ${E}_{\text{lab}}=40.5$ MeV has been used as the reference reaction which is the surrogate of $^{60}\mathrm{Ni}(n,xp)$ reaction populating the compound nucleus $^{61}\mathrm{Ni}^{*}$. The proton decay probabilities have been determined by measuring evaporated protons at backward angles in coincidence with projectile like fragments (PLFs, either $d$ or $\ensuremath{\alpha}$) detected around grazing angles. The cross sections for the reference reaction $^{60}\mathrm{Ni}(n,xp)$ are taken from jendl-4.0 library, which closely reproduce the available experimental data. The cross sections for the desired $^{59}\mathrm{Ni}(n,xp)$ reaction so obtained compare well with the nuclear-reactions-model code talys-1.8 using microscopic level densities. The present experimental data are consistent with the evaluated data library of rosfond-2015 but not with tendl-2015 and endf/b-viii, indicating the need of new evaluations for this reaction of importance to fusion technology.