Studies of nuclear properties for explosive astrophysical processes (SNAPS)

How are heavy elements formed in stars? There is a fairly good understanding of how the lighter elements, such as oxygen and carbon, are created in stars, but what about elements heavier than iron? More than half of the isotopes of heavier elements are believed to have been created in explosive astrophysical events such as supernovae. The main goal of this project is to investigate the properties of proton-rich isotopes of elements in the mass region 70 - 130 (p-isotopes). These are stable proton-rich atomic nuclei that cannot be formed via neutron capture processes, as opposed to most other heavy isotopes found on Earth. By studying the nuclear properties of key isotopes in the nuclear reaction networks that are believed to create the p-isotopes, we aim to increase our understanding of how the p-isotopes are formed. The project focuses on a few key isotopes that will help to determine which mechanism produced the p-isotopes we have in our solar system. In certain astrophysical environments, such as the environments that occur during active periods of x-ray bursts, it is believed that heavier proton-rich isotopes can be created via proton capture chains. This process is called the rp-process. The second goal of this project is to study isotopes that are relevant to the rp-process. Knowledge of the properties of the atomic nuclei involved in the rp-process is the key to understanding the process and how much it contributes to the formation of the elements we find in our solar system. X-ray bursts occur when a massive celestial body collects matter from a partner star. When a critical mass is reached, there will be an explosion of nuclear reactions which results in an observable X-ray flash. Better understanding of the rp-process can also help us understand the massive objects, such as neutron stars, during an X-ray flash. In SNAPS, we study nuclear reactions that are relevant to the rp-process and use the results to calculate how quickly different isotopes will be produced, for a given certain temperature.

The experimental results obtained in SNAPS are included in astrophysical calculations to determine the impact of the experimental results on our understanding of the p- and rp-process. This project represents novel experimental and numerical studies to further our understanding of the p-process and the rp-process. The project includes experiments at the Oslo Cyclotron Laboratory with the new large volume LaBr3-scintillation gamma-detector array, OSCAR, that is currently being procured. Experiments have been also carried out at the NewSUBARU synchrotron radiation facility in Japan.

This project represents novel experimental and numerical studies to further our understanding of the p-process and the rp-process. The project will include experiments at the Oslo Cyclotron Laboratory with the new large volume LaBr3-scintillation gamma-detector array, OSCAR, that is currently being procured. Experiments will also be carried out at the NewSUBARU synchrotron radiation facility and the radioactive ion beam facility ISOLDE at CERN. In collaboration with the project leader's international collaborators, the experimental results will be included in astrophyical calculations to determine the impact of the experimental results on our understanding of the p- and rp-process.