Photoneutron cross sections for Ni isotopes: Toward understanding $(n,\gamma )$ cross sections relevant to the weak s-process nucleosynthesis

Abstract

Photoneutron cross sections were measured for ${}^{58}$Ni, ${}^{60}$Ni, ${}^{61}$Ni, and ${}^{64}$Ni at energies between the one-neutron and two-neutron thresholds using quasi-monochromatic $\gamma$-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. The new photoneutron data are used to extract the $\gamma$-ray strength function above the neutron threshold complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including ${}^{63}$Ni, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained $\gamma$-ray strength functions from the Hartree-Fock-Bogolyubov plus quasi-particle-random phase approximation based on the Gogny D1M interaction for both $E1$ and $M1$ components and supplemented with the $M1$ upbend.

arXiv comment9 pages, 7 figures, re-submitted to PRC

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Cited by in corpus (5)

• Consolidating the concept of low-energy magnetic dipole decay radiation
• Photoneutron reaction cross section measurements on 94Mo and 90Zr relevant to the p-process nucleosynthesis
• Photonuclear reactions ${}^{nat}$Ni($\gamma$,xn)${}^{57}$Ni and ${}^{nat}$Ni($\gamma$,xn)${}^{56}$Ni in the energy range E${}_{\gamma max}$ = 35...94 MeV
• Nuclear Level Density and $\gamma$-ray Strength Function of ${}^{67}\mathrm{Ni}$ and the impact on the i-process
• $\gamma$-ray Strength Function for Barium Isotopes