Photoneutron cross sections for Mo isotopes: A step toward a unified understanding of(γ,n)and(n,γ)reactions

Abstract

Photoneutron cross sections were measured for ${}^{94}$Mo, ${}^{95}$Mo, ${}^{96}$Mo, ${}^{97}$Mo, ${}^{98}$Mo, and ${}^{100}$Mo near the neutron threshold with quasi-monochromatic laser-Compton scattering $\ensuremath{\gamma}$ rays. The photoneutron data were analyzed with the Skyrme Hartree-Fock-Bogoliubov (HFB) plus quasiparticle random phase approximation (QRPA) model and the axially symmetric-deformed Gogny HFB plus QRPA model of $E1$ $\ensuremath{\gamma}$-ray strength. Combining the $\ensuremath{\gamma}$-ray strength function constrained by the present photoneutron data with either the nuclear resonance fluorescence data or the updated Oslo data to supplement the data below the neutron threshold, a thorough analysis of the reverse $(n,\ensuremath{\gamma})$ cross sections is made whenever measurements are available. The Oslo data and the corresponding uncertainties are updated based on the latest results of the $s$-wave neutron spacing and the average radiative width determined in particular for ${}^{96}$Mo. Finally, radiative neutron capture cross sections for two radioactive nuclei, ${}^{93}$Mo and ${}^{99}$Mo, are deduced with the $\ensuremath{\gamma}$-ray strength function method.