The Ongoing Deep Underground Measurement of 22Ne(α,n)25Mg at the Ion Beam Facility of the INFN-LNGS

The Ne-22(alpha,n)Mg-25 reaction is of major importance in nuclear astrophysics. It is the main neutron source for the weak s-process and as such is responsible for the nucleosynthesis of 60 < A < 90 elements. In addition, it provides a strong neutron burst during the later, hottest phases of the main s-process, which modifies the final nucleosynthesis products, especially at so-called branch points, which can be used to provide insight into the stellar interior at that time. The reaction rate needs to be known below ca. 900 keV, and due to the low cross-section at these energies, a direct measurement has so far proven to be severely hampered by external neutron background at the surface of the Earth. To solve this problem, a measurement campaign (the ERC-funded SHADES project) was recently started at the deep underground Gran Sasso National Laboratory (LNGS) in Italy. We provide an overview of the experiment status and an outlook into the near future.