Abstracts Astronomy & Space Science

Studio del processo di distruzione del 26Al ad energie di interesse astrofisico con il Trojan Horse Method

by FRANCESCO ANDREIS

open 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. Among others, 26Al abundance is used to constrain the neutron star formation rate in our Galaxy, which is a key parameter in the field of Multimessenger Astronomy. Also, 26Al is the most likely heat source for melting, differentiation and crust formation of planetary bodies in the early Solar System. A number of different 26Al sources have been suggested over the years: asymptotic giant branch stars, classical novae, Wolf-Rayet stars, core collapse supernovae and cosmic ray radiation in protostellar nebulae. To ascertain the most likely 26Al nucleosynthesis scenario, the 26Al production and destruction mechanisms have to be investigated, in the energy range up to about 1 MeV. Two reactions strongly affect 26Al nucleosynthesis, the 26Al(n,p)26Mg and the 26Al(n,)23Na. More details can be found in [1]. The Trojan Horse Method (THM) [2] can be effectively used for their study, using deuterons to transfer a neutron and populate 27Al excited states, later decaying to the p+26Mg and +23Na channels. Thanks to the possibility to measure the reaction Q-values, also recoils excited states can be tagged. The method offers a great advantage with respect to direct approaches, thanks to the possibility to run at energies much higher than those of astrophysical interest, and to the capability of removing background sources. Within this framework, a high granularity detection setup will be used (NEFASTA: NEar FAr Silicon Telescope Array), comprising several hundreds of electronic channels. The candidate student will work on the development of algorithms for the detector calibration, starting from a variety of experimental data including sources, reactions, and scattering processes. The detector calibration includes both the energy and the angle-of-emission reconstruction of the emitted particles; the latter is an especially key point in the THM application, fixing the new resonances discovery capability of NEFASTA. [1] C. Iliadis et al, Astrophys. J. Suppl. Series 193, 16 (2011). [2] R.E. Tribble et al., Rep. Prog. Phys. 77, 106901 (2014).