Speaker
Description
The synthesis of heavy elements in explosive stellar environments, such as core-collapse supernovae, is influenced by key nuclear reactions involving unstable nuclei. In neutron-rich conditions, the α-process -a sequence of (α,xn) reactions- plays a significant part in nucleosynthesis, whereas (p,n) reactions influence element formation in proton-rich conditions, during explosive silicon burning and the νp-process. However, experimental data on such reactions remain scarce, introducing significant uncertainties in astrophysical models.
A new technique has been developed for direct measurements of both (α,n) and (p,n) reactions in inverse kinematics with SECAR (SEparator for CApture Reactions). Despite it being primarily designed for capture reactions, the development of machine learning-assisted ion-optics rendered the study of (p,n) reactions using a separator feasible, and a
$^{58}$Fe(p,n) measurement served as proof-of-principle for the method. Additionally, SECAR’s capabilities have been expanded to include (α,n) reaction measurements, as demonstrated in an initial case study of the $^{86}$Kr(α,n) reaction, which influences α-process nucleosynthesis and the elemental abundances observed in metal-poor stars.
In this talk, I will present recent (α,n) and (p,n) reaction measurements with SECAR, highlighting the experimental advancements that enabled these studies along with their astrophysical significance. These reaction studies pave the way for future direct reaction rate measurements on short-lived nuclei, which are essential for improving our understanding of heavy-element nucleosynthesis.