Speaker
Description
Where do the heaviest elements in the Universe come from? Gold, platinum,
uranium are not made on Earth, but forged in some of the most violent events in
the cosmos, such as the collisions of neutron stars. There, atomic nuclei
capture neutrons and grow heavier and heavier, until they become so unstable
that they split in two. This splitting, called \textit{nuclear fission}, sets a limit on
how heavy the elements around us can be, and shapes which ones survive to become
part of planets, and of us.
To understand that limit, we need to measure how easily these exotic nuclei
break apart, that is, how high the energy barrier is that holds each one
together. But many of the nuclei that matter most live for only a fraction of a
second and cannot be easily studied in the usual way, because they cannot be
held still as a target.
This thesis develops a new experimental method to reach them, using radioactive
beams produced at CERN and a magnetic spectrometer that catches the fragments
and particles emerging from each fission event. It is a first step towards
recreating, in the laboratory, the physics that builds the elements in the
stars.