$^7$Be(n,p) cross section measurement for the Cosmological Lithium Problem at the n_TOF facility at CERN

One of the most puzzling problems in Nuclear Astrophysics is the "Cosmological Lithium Problem", i.e the discrepancy between the primordial abundance of $^7$Li observed in metal poor halo stars [1], and the one predicted by Big Bang Nucleosynthesis (BBN). One of the reactions that could have an impact on the problem is $^7$Be(n,p)$^7$Li. Despite of the importance of this reaction in BBN, the cross-section has never been directly measured at the energies of interest for BBN. Taking advantage of the innovative features of the second experimental area at the n_TOF facility at CERN, an accurate measurement of $^7$Be(n,p) cross section has been recently performed at n_TOF, with a pure $^7$Be target produced by implantation of a $^7$Be beam at ISOLDE. The experimental procedure, the setup used in the measurement and the results obtained so far will be here presented.