Nuclear astrophysics using heavy ion storage rings

Project description

One of the key aims of experimental nuclear astrophysics is to measure the cross-sections of nuclear reactions occurring in stars and stellar explosions, using laboratories here on Earth. Often, our knowledge of the observables of stellar site - for example, the isotopic patterns of tiny pre-solar grains produced in nova explosion - is limited by a small number of crucial nuclear reactions that have resisted traditional investigation methods. Heavy ion storage rings are novel and revolutionary way to investigate these nuclear reactions [1].

In a traditional experiment, a beam of ions is accelerated on a solid or gas target. The majority of the beam does not react with the target, is stopped in a backing or a beam dump, and wasted. In a storage ring, un-reacted ions after the target are instead recycled and recirculated over and over. Recirculation increases beam purity, intensity (by a factor ~10⁵), and reduces emittance, opening up the possibility to carry out studies with stable or radioactive beams, and detect nuclear reactions induced by the recirculating ions very pure on in-ring cryogenic gas targets.

In particular, the CRYRING heavy ion storage ring [2], located in GSI/FAIR laboratory (Germany) is ideal for this type of investigations. CRYRING is only ring in the world connected to a radioactive beam facility in which ions can be stored at energies of astrophysical interest. This PhD project will make use of the cutting-edge CRYRING Array for Reaction MEasurements (CARME) [3], built by the Edinburgh Nuclear Physics Group, in order to study nuclear reactions of interest for astrophysics. CARME was primarily built for investigations of reactions of interest in novae explosions and X-ray bursters using radioactive beams, but it has also been employed in studies of key reactions in Big Bang Nucleosynthesis, and quiescent scenarios such as AGB and RGB stars using stable beams [4].

This is an experimental project with a data analysis component. You will travel to GSI, take a central role in one or more experiments using CARME as part of an international scientific collaboration, and finally analyse the data that was collected.

[1] M. Lestinsky et al., Eur. Phys. J. A 225 (2016)

[2] J. Glorius and C.G. Bruno, Eur. Phys. J. A 59 (2023)

[3] C.G Bruno et al., Nucl. Inst. Meth. B, 1048 (2023)

[4] J. Marsh et al., Eur. Phys. J. A 60 (2024)