Speaker
Description
The interplay and correlation between the $^{22}$Ne$(\alpha,\gamma)^{26}$Mg and the competing $^{22}$Ne$(\alpha,n)^{25}$Mg reaction determines the efficiency of the $^{22}$Ne$(\alpha,n)^{25}$Mg reaction as a neutron source for the weak $s$-process. In both cases, the reaction rates are dominated by the strength of the $\alpha$ cluster resonance at 830 keV. This plays a particularly important role in determining the strength of the neutron flux for weak and main s-process environments. We performed the measurement of the 830 keV resonance in $^{22}$Ne$(\alpha,\gamma)^{26}$Mg at the Sanford Underground Research Facility using a $\gamma$-summing detector. We confirmed the previous studies of the resonance strength and obtained a strength of $\omega\gamma$ = 35 $\pm$ 4 $\mu$eV, however the strength of the corresponding resonance in the $^{22}$Ne$(\alpha,n)^{25}$Mg still carries large uncertainties. In a new and independent study performed at Notre Dame using a stilbene crystal detector, we confirmed previous results and demonstrate that the resonance strength in the competing $^{22}$Ne$(\alpha,n)^{25}$Mg reaction channel is significantly higher.
