Argonne National Laboratory

Nuclear Astrophysics

Nuclear Astrophysics

Nuclear astrophysics includes the study of how all the elements in the universe were created and how stars evolve during their lifetime. Using the ATLAS facility, we study nuclear reactions that play a role in stars and try to answer fundamental questions such as: How are stars born and how do they die? How do they produce the energy that keeps them burning for billions of years? How do they create the elements we observe today?

Using the MUSIC detector (multi-sampling ionization chamber), we study the fusion of nuclei in stars, including helium nuclei that are relevant for the study of explosive stellar phenomena such as X-ray bursts and superbursts.

Our understanding of how half the elements heavier than iron were created in the universe is enriched through our measurements with ion traps, including the Canadian Penning Trap (CPT) and the Beta-decay Paul Trap (BPT). Ion traps are used to study properties of nuclei involved in the astrophysical r process, thought to be responsible for nucleosynthesis in supernovae or merging neutron stars.

Key reaction rates in stars involving medium-to-heavy nuclei are measured by accelerator mass spectrometry, a technique that allows us to measure atoms with very low abundances (~10-16 ).

The astrophysical rp process that involves the capture of protons by nuclei during X-ray burst and superburst events is studied using Gammasphere.

One of the most important open questions in stellar nucleosynthesis is how carbon is converted to oxygen. Experiments at the Jefferson Laboratory using a high-pressure bubble chamber are attempting to answer this question.