Speaker
Description
The astrophysical rapid-neutron capture process (r-process) of explosive nucleosynthesis is responsible
for the formation of half of the heavy nuclei above Fe. Actinides are produced towards
the end of this process, when the neutron flux is expected to be minimal, and it is supported also
by fission processes. Given that the r-process path runs far away from the accessible species, in
this heavy region of the chart of nuclides, experimental inputs on $\beta$ decay for nuclei beyond N=126
are particularly useful to test predictions of global nuclear models.
In this paper results from a recent experiment performed at GSI-FAIR (Darmstadt, Germany)
within the HISPEC-DESPEC experimental campaign, as part of the FAIR Phase-0 program, will
be discussed. The experiment populated 220$<$A$<$230 Po-Fr nuclei in a relativistic fragmentation
reaction induced by a 1 GeV $^{238}$U beam. The species were selected and identified using the
FRagment Separator (FRS) and implanted in the DEcay SPECtroscopy (DESPEC) station to
study their subsequent $\beta$ decay. The DESPEC station is composed of a stack of Double Sided
Silicon-Strip Detectors (DSSD) sandwiched between two plastic scintillator detectors, surrounded
by a hybrid $\gamma$-detection array consisting of high-resolution HPGe and fast timing LaBr$_3$(Ce).
The extracted $\beta$-decay half-lives are discussed with the help of recent theoretical models, to assess the impact of the measured values in the predictions of the r-process. Perspectives of future measurements in the region will be provided.
