Indirect determination of neutron capture cross sections on spherical and near-spherical nuclei using the surrogate method

The 92Mo(n,γ) cross section was obtained using both the absolute surrogate approach and surrogate ratio method (SRM), relative to the 94Mo(n,γ) cross section, in an equivalent neutron energy range of 80 to 890 keV. Excited 93Mo and 95Mo nuclei were populated using the 92Mo(d,p) and 94Mo(d,p) reactions, respectively. Both discrete and statistical tagging approaches were employed to identify the γ-decay channel and were examined in terms of their sensitivity to the initial angular momentum population distribution. The absolute surrogate 92Mo(n,γ) cross sections disagree with evaluated neutron capture cross section data by as much as a factor of 4, whereas the results obtained using the SRM trend more favorably with the evaluated result. Experimental results suggest that discrete and statistical tagging approaches may sample different contributions of the γ cascade for near-spherical nuclei. This work uses the surrogate method in the determination of neutron capture cross sections on spherical and quasispherical nuclei in the mass-90 region and provides a possible pathway to extend the SRM to a broader mass range.