Measurement of the decay characteristics of nuclei around A=90 relevant to the r-process nucleosynthesis

by Dr. Teresa Kurtukian-Nieto (Centre d’Etudes Nucléaires de Bordeaux Gradignan)

Thursday, 20 April 2017 from to (Europe/Rome)
at INFN-LNL ( LAE meeting room )
The study of the nuclear structure of neutron-rich nuclei along, and close to, the neutron shells N=50, 82 and 126 is of particular importance for the understanding of the astrophysical r-process around the waiting points at A ~ 80, 130 and 195 and the synthesis of trans-bismuth elements. The speed of the r-process reaction sequence and the resulting abundances of elements are significantly influenced by the β-decay properties of the nuclei involved, which are in turn directly related to the evolution of nuclear structure and deformation. In particular the nuclei around A=90 are important to explore in more detail the possibility of a spherical waiting point at N=56 that would contribute to the overproduction of stable Sr, Y, and Zr isotopes observed in some metal-poor stars. Basic properties of those nuclei such as lifetimes, β-delayed neutron emission probability (Pn) and decay schemes have to be measured. These data will provide fundamental information not only for the understanding of the progress and time scale of the stellar nucleosynthesis processes, and consequently of the final abundance patterns, but also because they can be used to benchmark nuclear models far from stability. A recent experiment carried out by our team at ILL, Grenoble, has shown the possibilities of studying the A=90 region from fission fragments using a 235U target, by performing βγ and βγγ correlations on A=88,89 and 90. Preliminary results of this experiment will be shown together with perspectives for further investigating this region of the chart of nuclides in new facilities such as SPES.
Organised by J.J. Valiente Dobon