Au197(n,2n) reaction cross section in the 15–21 MeV energy range

Abstract

The cross section of the $^{197}\mathrm{Au}(n,2n)^{196}\mathrm{Au}$ reaction has been determined at six energies ranging from 15.3--20.9 MeV by means of the activation technique, relative to the $^{27}\mathrm{Al}(n,\ensuremath{\alpha})^{24}\mathrm{Na}$ reaction. Quasimonoenergetic neutron beams were produced via the $^{3}\mathrm{H}(d,n)^{4}\mathrm{He}$ reaction at the 5.5 MV Tandem T11/25 accelerator laboratory of NCSR ``Demokritos''. After the irradiations, the induced $\ensuremath{\gamma}$-ray activity of the target and reference foils was measured with high-resolution HPGe detectors. The cross section for the high spin isomeric state (${12}^{\ensuremath{-}}$) was determined along with the sum of the ground (${2}^{\ensuremath{-}}$), the first (${5}^{+}$), and second (${12}^{\ensuremath{-}}$) isomeric states. Theoretical calculations were carried out with the codes empire 3.2.2 and talys 1.8. Optimum input parameters were chosen in such a way as to simultaneously reproduce several experimental reaction channel cross sections in a satisfactory way, namely the ($n,\mathrm{elastic}$), ($n,2n$), ($n,3n$), ($n,p$), ($n,\ensuremath{\alpha}$), and ($n$,total) ones.