Measurement of the $^{25}Mg($\alpha$,n)$^{28}$Si reaction cross-section at low energy

There is uncertainty regarding the available neutron flux for the weak s-process in massive stars. In order to correctly model the s-process nucleosynthesis, one key ingredient is the rate of neutron producing reactions. The $^{22}$Ne$(\alpha,n)^{25}$Mg is the main neutron source, but other reactions also contribute. In the present work we study one such reaction, namely $^{25}$Mg$(\alpha,n)^{28}$Si, which acts as a potential neutron source for weak s-process and destroys the strongest neutron poison $^{25}$Mg. Previous measurements for this reaction suffered from two shortcomings: they were not performed at low enough energies relevant for weak s-process in massive stars and measurements using neutron counters were hindered by the contamination of targets with lower Z material. In this work, we used two different setups consisting of deuterated liquid scintillator detectors for neutrons and LaBr$_3$ for $\gamma$-rays in order to measure the $^{25}$Mg$(\alpha,n)^{28}$Si cross-section in the Gamow range 1.4-2.6 MeV. The neutron spectroscopy was performed via neutron spectrum unfolding technique which allows for a clear separation of the signal and the background. Preliminary results, including cross-sections determined from gamma-ray and neutron spectroscopy will be presented.