At the Oslo Cyclotron Laboratory (OCL) we can accelerate for example protons or alpha particles to bombard thin metallic foils of specific nuclides, i.e. specific isotopes of a chemical element. This induces nuclear reactions which produce atomic nuclei in excited quantum states at high excitation energy. Such nuclear reactions “heat up” nuclei in a controlled way. Because the number of accessible quantum states increases exponentially with excitation energy, we can use statistical methods and thermodynamic concepts such as temperature to describe highly excited nuclei. There are still many open questions about how nuclei – many-body systems of protons and neutrons – behave at high excitation energy. Conversely, understanding of nuclei at high excitation energy is needed to understand and model nuclear reactions. This has applications not only in accelerator experiments, but also to understand processes in nuclear reactors, stars, and supernova explosions.
The detectors that are available for experiments at OCL, in particular the Oslo Scintillator Array OSCAR, are unique in the world. Experiments are often performed within international collaborations, with scientists from all over the world coming to Oslo to participate in this research. If you choose this topic for your master’s thesis, we will run a dedicated experiment at OCL for your thesis. You will take part in the entire process from preparing the experiment, collecting the data during the beam time, analyzing the data, and interpreting the results. Such master’s projects usually result in a scientific publication in an international journal. Besides taking an active role during the experiment, the main part of the work is related to data analysis. This will include writing code to extract relevant information from the large amount of data that is produced by the detectors. The signals from the particle and gamma detectors contain information on the density of quantum states as a function of excitation energy of the nucleus and on the probability for emitting gamma radiation of a given energy. This information can be used to extract thermodynamic properties of atomic nuclei such as entropy, temperature, and heat capacity, and to look for signatures for phase transitions in atomic nuclei. It is also possible to include theoretical calculations in the thesis work to compare with experimental results.