Searching for (γ,α)/(γ,n) branching points in the γ-process path near A=100

Four $(\ensuremath{\alpha},\ensuremath{\gamma})$ cross-section measurements on stable nuclei in the $A=100$ mass range were performed at the University of Notre Dame Nuclear Science Laboratory. The $^{102}\mathrm{Pd}(\ensuremath{\alpha},\ensuremath{\gamma})^{106}\mathrm{Cd}$ and $^{110}\mathrm{Cd}(\ensuremath{\alpha},\ensuremath{\gamma})^{114}\mathrm{Sn}$ reactions were measured for the first time. The $^{90}\mathrm{Zr}(\ensuremath{\alpha},\ensuremath{\gamma})^{94}\mathrm{Mo}$ and $^{108}\mathrm{Cd}(\ensuremath{\alpha},\ensuremath{\gamma})^{112}\mathrm{Sn}$ results extended the measured range down to energies lower than those of the previous experiments. These reactions were studied as possible branching points in $\ensuremath{\gamma}$-process reaction networks. The measured cross-section values were compared to the nonsmoker database as well as to calculations performed with talys 1.9. The combination of parameters available in talys that gave the best fit to the data was found and the corresponding reaction rates were obtained. The inverse $(\ensuremath{\gamma},\ensuremath{\alpha})$ rates were then obtained and compared to the corresponding $(\ensuremath{\gamma},n)$ rates to investigate the relative strength between the two reaction pathways. It was found that in all four cases the $(\ensuremath{\gamma},\ensuremath{\alpha})$ reaction pathway begins to dominate within the 1.5--3.5 GK temperature range.