Study of the 17O(n,a)14C reaction: extension of the Trojan Horse Method to neutron induced reactions

Abstract

Neutron induced reactions play a key role in several astrophysical scenario. In particular, the importance of 17 O(n,α) 14 C reaction is twofold: in the Inhomogeneous Big Bang Nucleosynthesis (IBBN), in which 14 C may act as a bottleneck in the heavy-element production, and during the weak component of the s-process, for which the determination of the ratio between the 17 O(α,n) 20 Ne and 17 O(n,α) 14 C reaction rates is important to pin down the neutron flux for the nucleosynthesis. The experimental study of the 17 O(n,α) 14 C reaction has been performed in the energy range 0-350 keV via the Trojan Horse Method (THM). The reaction has been deduced by applying the THM to the 2 H( 17 O,α 14 C) 1 H quasi-free reaction induced at the laboratory energy of 43.5 MeV, using deuteron as the Trojan Horse nucleus. The preliminary results show that the contribution of the 166 keV and 236 keV resonances is in energy agreement with the available direct data. A clear contribution of the -7 keV subthreshold level is also apparent. Moreover, this TH measurement allows one to study the ℓ=3, 75 keV resonance (E*=8.125 MeV, J π =5 -) suppressed in the 17 O(n,α) 14 C direct measurements.