3 research outputs found
Nuclear Structure Studies at ISOLDE and their Impact on the Astrophysical r-Process
The focus of the present review is the production of the heaviest elements in
nature via the r-process. A correct understanding and modeling requires the
knowledge of nuclear properties far from stability and a detailed prescription
of the astrophysical environment. Experiments at CERN/ISOLDE have played a
pioneering role in exploring the characteristics of nuclear structure in terms
of masses and beta-decay properties. Initial examinations paid attention to far
unstable nuclei with magic neutron numbers related to r-process peaks, while
present activities are centered on the evolution of shell effects with the
distance from the valley of stability. We first show in site-independent
applications the effect of both types of nuclear properties on r-process
abundances. Then, we explore the results of calculations related to two
different `realistic' astrophysical sites, (i) the supernova neutrino wind and
(ii) neutron star mergers. We close with a list of remaining theoretical and
experimental challenges needed to overcome for a full understanding of the
nature of the r-process, and the role CERN/ISOLDE can play in this process.Comment: LATEX, 38 pages, 16 figures, submitted to Hyperfine Interaction
On three topical aspects of the N=28 isotonic chain
The evolution of single-particle orbits along the N=28 isotonic chain is
studied within the framework of a relativistic mean-field approximation. We
focus on three topical aspects of the N=28 chain: (a) the emergence of a new
magic number at Z=14; (b) the possible erosion of the N=28 shell; and (c) the
weakening of the spin-orbit splitting among low-j neutron orbits. The present
model supports the emergence of a robust Z=14 subshell gap in 48Ca, that
persists as one reaches the neutron-rich isotone 42Si. Yet the proton removal
from 48Ca results in a significant erosion of the N=28 shell in 42Si. Finally,
the removal of s1/2 protons from 48Ca causes a ~50% reduction of the spin-orbit
splitting among neutron p-orbitals in 42Si.Comment: 12 pages with 5 color figure