| Project Detail |
Pioneering insight into the behaviour of exotic neutron-rich nuclei
Elements heavier than iron, and particularly neutron-rich atomic species of these, are formed primarily by the rapid neutron-capture process, or r-process. This nucleosynthesis process likely occurs in the stars and is still an enigma six decades after it was proposed to occur. Accurate modelling requires better experimental understanding of its exotic neutron-rich nuclei. These nuclei undergo a process called beta (ß)-decay to restore the optimal neutron–proton ratio. The resulting daughter nuclei can subsequently emit a neutron in what is called ß-delayed neutron emission. With the support of the Marie Sklodowska-Curie Actions programme, the BeLaPEx project is building a pioneering European ß-decay spectroscopy station to experimentally characterise these critical ß-decay related processes.
Objective
The goal of the BeLaPEx project is to study ß decay of exotic nuclei relevant to the astrophysical r-process. We will build the first European ß-decay spectroscopy station dedicated to measurements with spin-polarised radioactive beams. Our setup, DeVITO, will be coupled to the new beamline for laser-induced nuclear orientation, called Versatile Ion-Polarised Techniques Online (VITO). We will apply a novel technique that utilises anisotropic ß decay of spin-polarised nuclei, allowing to firmly assign spins and parities of excited states populated through allowed transitions based on the ß-decay asymmetries measured in coincidence with the delayed radiations. The BeLaPEx project will help to clarify the sensitivity of ß-delayed neutron emission to the details of nuclear structure. We will provide experimental data that can benchmark nuclear models and improve the understanding of ß-delayed neutron emission.
The BeLaPEx project will be carried out at the Isotope Mass Separator On-Line facility (ISOLDE) at CERN, where a wide range of radioactive ion beams is available, including those relevant to the r-process. The first part of the project will focus on the construction and commissioning of the DeVITO station allowing for measurements of ß-particle, ?-ray and neutron emission from spin-polarised nuclei. Subsequently, we will start the physics program aimed at studying neutron-rich indium isotopes around N=82. These nuclei are important for the r-process calculations since the A=130 peak in the r-process abundance pattern is linked to the closure of the N=82 shell. |
