No abstract

No abstract

Natural gadolinium is widely used for its excellent thermal neutron capture cross section, because of its two major isotopes: $^{\rm 155}$Gd and $^{\rm 157}$Gd. We measured the $\gamma$-ray spectra produced from the thermal neutron capture on targets comprising a natural gadolinium film and enriched $^{\rm 155}$Gd (in Gd$_{2}$O$_{3}$ powder) in the energy range from 0.11 MeV to 8.0 MeV, using the ANNRI germanium spectrometer at MLF, J-PARC. The freshly analyzed data of the $^{\rm 155}$Gd($n, \gamma$) reaction are used to improve our previously developed model (ANNRI-Gd model) for the $^{\rm 157}$Gd($n, \gamma$) reaction [K. Hagiwara et al. [ANNRI-Gd Collaboration], Prog. Theor. Exp. Phys. 2019, 023D01 (2019)], and its performance confirmed with the independent data from the $^{\rm nat}$Gd($n, \gamma$) reaction. This article completes the development of an efficient Monte Carlo model required to simulate and analyze particle interactions involving the thermal neutron captures on gadolinium in any relevant future experiments.

No abstract

We systematically measured the differential cross sections of inelastic α scattering off self-conjugate A = 4n nuclei at two incident energies E α = 130 MeV and 386 MeV at Research Center for Nuclear Physics, Osaka University. The measured cross sections were analyzed by the distorted-wave Born-approximation (DWBA) calculation using the single-folding potentials, which are obtained by folding macroscopic transition densities with the phenomenological αN interaction. The DWBA calculation with the density-dependent αN interaction systematically overestimates the cross sections for the ΔL = 0 transitions. However, the DWBA calculation using the density-independent αN interaction reasonably well describes all the transitions with ΔL = 0-4. We examined uncertainties in the present DWBA calculation stemming from the macroscopic transition densities, distorting potentials, phenomenological αN interaction, and coupled channel effects in 12 C. It was found that the DWBA calculation is not sensitive to details of the transition densities nor the distorting potentials, and the phenomenological density-independent αN interaction gives reasonable results. The coupled-channel effects are negligibly small for the 2 + 1 and 3 − 1 states in 12 C, but not for the 0 + 2 state. However, the DWBA calculation using the density-independent interaction at E α = 386 MeV is still reasonable even for the 0 + 2 state. We concluded that the macroscopic DWBA calculations using the density-independent interaction are reliably applicable to the analysis of inelastic α scattering at E α ∼ 100 MeV/u.