The Destruction of 26Al in Stars investigated with the Trojan Horse Method

The radioisotope 26Al is of outstanding importance in astrophysics, as it plays a key role in constraining the circumstances and conditions of the solar system birth and of the chemical evolution of the Galaxy. It is also considered the most probable heat source for melting, differentiation and crust formation of planetary bodies in the early Solar System. Furthermore, 26Al abundance is used to constrain the neutron star formation rate in our Galaxy. To better understand the most likely nucleosynthesis scenarios for 26Al, its destruction mechanisms were investigated in the energy range up to approximately 1 MeV. This experiment was conducted at the TRIUMF laboratory (Vancouver, Canada) using a 26Al beam at an energy of 3.5 MeV/u and the NEFASTA (NEar FAr Silicon Telescope Array) detection system. The aim is to perform a precision measurement of the cross sections for the 26Al+n reactions, using the Trojan Horse Method (THM) -- an indirect technique that offers significant advantages over direct measurements. The THM uses deuterons to transfer a neutron, populating excited states of 27Al that subsequently decay into p+26Mg and alpha+23Na, while the proton within the deuteron is emitted without taking part in the reaction (quasi-free process). This approach allows measurements at energies closer to those typical of astrophysical environments, while also avoiding the typical challenges of direct measurements involving neutron beams and targets of radioactive materials.