Speaker
Description
The $\mathrm{^{22}Ne(\alpha, \gamma)^{26}Mg}$ reaction is the competitor of the $\mathrm{^{22}Ne(\alpha, n)^{25}Mg}$ reaction, one of the main neutron sources for s-process nucleosynthesis. The knowledge of the cross sections of these reactions at relevant astrophysics energies is crucial, as their reaction rates influence the $\mathrm{^{22}Ne}$ abundance and, consequently, the neutron production in the $\mathrm{(\alpha, n)}$ channel. Several direct and indirect measurements of the cross section of the $\mathrm{^{22}Ne(\alpha, \gamma)^{26}Mg}$ reaction have been performed. However, in the low-energy region below $\mathrm{E_{\alpha} = 800 \; keV}$, only upper-limit data are available in literature, and a possible resonance at $\mathrm{E_{\alpha}}$ $\mathrm{\sim 650 \; keV}$ is still unobserved. Taking advantage of the reduced environmental background at Gran Sasso National Laboratory and the intense and stable beam provided by the Bellotti Ion Beam Facility installed there, the LUNA (Laboratory for Underground Nuclear Astrophysics) Collaboration is currently carrying out a campaign for a direct measurement of the $\mathrm{^{22}Ne(\alpha,\gamma)^{26}Mg}$ reaction. The setup consists of an extended windowless gas target and the EAS$\gamma$ detector, an array of six $\mathrm{NaI(Tl)}$ scintillators designed for $\gamma$$\gamma$ coincidence measurements. The poster will present the experimental setup, the data analysis strategy and the preliminary efficiency results.