PhD project: Neutron desctruction of 40K
Project description
The radioactive isotope 40K has a half-life of 1.25 billion years and is a primordial isotope naturally occuring on earth. 40K is one of the main isotopes responsible for heat generation in planets, by energy released when it β-decays (so-called radiogenic heating), and has been found to dominate the heating in young exoplanets [1], which is essential to sustain the crustal recycling (e.g. plate tectonics), Radiogenic heating also impacts on CO2 outgassing rates, which need to be at the right level to sustain habitability (too small rates cause global surface glaciation , while to high rates a too hot climate) [2]. Hence, the initial quantity of 40K in an exoplanet is a critical parameter to determine its habitability. 40K is produced in massive stars during oxygen burning when lighter elements fuse in the cores of massive stars and in the slow neutron capture process (s-process). In the s-process, it is produced by neutron capture reactions on stable 39K. Besides radiative neutron capture, (n, α) and (n, p) reactions are considered the main destruction channels for 40K, with (n, α) predicted to have the largest reaction rate at the relevant stellar temperatures of 0.4 and 1 GK [5].
In this project, you will plan and perform an experiment to measure the 40K(n, α) and 40K(n, p) reactions at CERN, using the high flux neutron time of flight facility n_TOF EAR-2. You will be involved in designing and testing a silicon detection system for the detection of protons and alphas, performing the experiment, and analysing the data.
[1] E.A. Frank, B.S. Meyer, S.J. Mojzsis. Icarus 243, 274-286 (2014).
[2] B. J. Foley and A. J. Smye, Astrobiology 18, 873 (2018).
Project supervisor
- Dr Claudia Lederer-Woods (School of Physics & Astronomy, University of Edinburgh)
The project supervisor welcomes informal enquiries about this project.
Find out more about this research area
The links below summarise our research in the area(s) relevant to this project:
- Find out more about Nuclear Astrophysics.
- Find out more about Nuclear Physics.
- Find out more about the Institute for Particle and Nuclear Physics.
What next?
- Find out how to apply for our PhD degrees.
- Find out about fees and funding and studentship opportunities.
- View and complete the application form (on the main University website).
- Find out how to contact us for more information.