Two colliding nuclei (red and blue) stick, dissipate energy, and can “ascend the mountain” towards a fully equilibrated compact compound nucleus (CN). If the CN avoids fission decay, the result is an evaporation residue (ER) and a new atom.
Atomic nuclei are fundamentally quantum-mechanical objects, and like atoms, they have a shell-structure and families of excited states. When nuclei collide, they are in a superposition of these excited states. This model of nuclear collisions has been wildly successful but suffers from a fatal flaw – it does not realistically describe how nuclei evolve from a coherent superposition of excited states to an irreversibly fused compound nucleus.
The fundamental limitation in understanding the quantum processes that cause energy dissipation and thermalisation means that calculations can disagree with measurements by up to a factor of 100 for collisions of heavy nuclei! Experimental information is sorely needed to guide the development of a more realistic model of nuclear fusion, which should include the exchange (transfer) of many neutrons and protons.
This project involves:
1. The development, characterisation and optimisation of a new gas ionization detector system.
2. Using this new system, and our 15 million Volt heavy ion accelerator, make precision measurements of the earliest stages (taking about 10-21 s) of energy dissipation through the measurement of multi-nucleon transfer reactions, identifying the mass, charge and kinetic energies of nuclear reaction products.
3. Using these data to inform the development of a hybrid quantum-classical model for thermalisation.
No specific background knowledge is required.
As an PhB, Vacation scholar or 3rd year project, this project will suit students who enjoy experimental 'hands-on' projects. Engineering students with relevant skills are also encouraged to engage with aspects of the project.
As an MSc or PhD project, this project has components ranging from hands-on experimental work to intensive data analysis and model calculations.
Students will also have the opportunity to be involved in the other accelerator-based experimental activities of the nuclear reaction dynamics group.