Post-doctorate fellowship in Nuclear Astrophysics: “Study of fission properties of exotic nuclei of astrophysical interest”

One of the major issues in modern astrophysics concerns the analysis and understanding of
the present composition of the Universe and its various constituting objects. Nucleosynthesis
models aim to explain the origin of the different nuclei observed in nature by identifying the
possible processes able to synthesize them. Though the origin of most of the nuclides lighter
than iron through the various hydrostatic and explosive burning stages in stars is now quite
well understood, the synthesis of the heavy elements (i.e. heavier than iron) remains
unexplained in many respects.

The rapid neutron-capture process, or r-process, is known to be of fundamental importance
for explaining the origin of approximately half of elements heavier than iron observed in
nature. Despite important efforts, the astrophysical site of the r-process remains unidentified.
For this reason, the r-process has been considered as one of the top eleven questions in
Physics and Astronomy by the USA national research council of the national academies.
Supernovae have for long been envisioned as the dominant producer of r-process nuclei, but
so far have failed to provide the right conditions for a successful nucleosynthesis. Recently,
special attention has been paid to neutron star mergers following the confirmation by
hydrodynamic simulations that a non-negligible amount of matter can be ejected and by
nucleosynthesis calculations combined with the predicted astrophysical event rate that such
events can account for the majority of r-material in our Galaxy. The recent observation of the
gravitational wave signal GW170817 and its optical counterpart in August 2017 has
confirmed the efficient contribution of binary neutron star mergers to Galactic
nucleosynthesis, though a great part of this observation still remains to be explained.

The present post-doctorate fellowship will focus on the developments of mean-field models
recently developed at the ULB for nuclear structure physics and their applications to nuclear
aspects of the r-process nucleosynthesis. More specifically, the project includes the largescale
calculation and analysis of nuclear fission properties for exotic neutron-rich and superheavy
nuclei of astrophysical interest, within the mean-field approach, as well as their impact
on spontaneous, beta-delayed and neutron-induced fission probabilities.

At the same time, this project, in collaboration with the experimental nuclear physics group
of the KU Leuven, will contribute to the interpretation of new measurements of nuclear
structure properties obtained at ISOLDE-CERN, in particular concerning super-heavy
elements. Such measurements also aim at validating global mean-field models developed for
astrophysics applications.

The Post-doctorate position is available at the Institut d’Astronomie et d’Astrophysique
(IAA) of the Université Libre de Bruxelles and is part of the EOS (Excellence of Science)
research project MANASLU in collaboration with the KU Leuven University. The position is
funded for 2 years. Screening of applications begins immediately and continues until an
outstanding candidate is selected. The position is to start as soon as possible.

Profile requested:
• The candidate must have a PhD in nuclear physics (for less than 5 years)
• The candidate must have programming skills and a strong interest in numerical
simulations; knowledge of programming languages Fortran, C/C++ and Python is
desirable.
• The applicant should have good organizational skills, a taste for interdisciplinary
research, excellent scientific writing and presenting skills and be able to work
independently.
• Working in our international team requires capacity of team work as well as good
English language skills

Interested candidates should send their CV and request two referees to send their
recommendation letter directly to S. Goriely at stephane.goriely@ulb.be and W. Ryssens at
wouter.ryssens@ulb.be.

Contact:
S. Goriely & W. Ryssens
Institut d’Astronomie et d’Astrophysique
Université Libre de Bruxelles
Campus de la Plaine CP 226
B-1050 Brussels, Belgium
Email: stephane.goriely@ulb.be & wouter.ryssens@ulb.be