Back to search

FRINATEK-Fri prosj.st. mat.,naturv.,tek

Dust from the Stars: Radiative Neutron Capture Rates Relevant to the Intermediate and Rapid Neutron-Capture Process

Alternative title: Støv fra stjernene: nøytron-innfangningsrater for den "raske" og "mellomste" nøytroninnfangingsprosessen

Awarded: NOK 12.0 mill.

We live in a Universe composed of a large variety of chemical elements. The element distribution we observe tells a fascinating story of nucleosynthesis events throughout its 13.7-billion-year-long history since the Big Bang. Although we now know that heavy elements must have been made inside stars during their lives and deaths, many questions still remain unanswered about exactly how and when these elements were made. This project aims at providing some new pieces to this big puzzle. By measuring quantum-mechanical properties of atomic nuclei that have never been measured before, we will obtain new experimental information on astrophysical reaction rates needed to understand the nucleosynthesis events in stars, supernovae, and neutron star collisions. Our overarching goal is to significantly reduce the presently very large uncertainties of some key cases, using the recently commissioned gamma-ray instrument OSCAR at the Oslo Cyclotron Laboratory. A newly developed measurement technique, the beta-Oslo method, will also be applied. Our aim is that the new results will lead to improved nucleosynthesis calculations as well as Galactic chemical evolution models.

We live in a Universe composed of a large variety of chemical elements. The element distribution we observe tells a fascinating story of nucleosynthesis events throughout its 13.7-billion-year-long history since the Big Bang. We now know that the lightest elements were formed in the primordial Big-Bang nucleosynthesis, and that heavier elements must have been “cooked” inside stars during their lives and deaths – indeed, as Joni Mitchell put it, “We are stardust”. However, many questions remain when it comes to the creation of elements heavier than iron. The focus of this project is the intermediate (i) and the rapid (r) neutron-capture processes; their intricate details remain a huge challenge to understand. For long, the astrophysical site of the r process resisted a unique identification, until the live observation of a neutron-star collision in 2017. This event proved that neutron-star mergers produce r-process elements. At present, possible sites for the i process are under debate, but element observations for example in some very old stars are hard to explain with any other nucleosynthetic process. From a nuclear-physics point of view, both the i and the r processes present enormous challenges as they involve very short-lived, unstable nuclei that quickly transform to another nuclear species, making them notoriously hard to study on Earth. This project aims at providing new experimental constraints on radiative neutron-capture rates of exotic, neutron-rich nuclei. The goal is to significantly reduce the presently very large uncertainties of some key cases, using the recently commissioned gamma-ray instrument OSCAR at the Oslo Cyclotron Laboratory. A newly developed measurement technique, the beta-Oslo method, will also be applied. New normalisation approaches and unfolding techniques will further be developed. The goal is that the new results will help improve nucleosynthesis calculations and Galactic chemical evolution models.

Publications from Cristin

No publications found

No publications found

No publications found

No publications found

Funding scheme:

FRINATEK-Fri prosj.st. mat.,naturv.,tek