6. January 2016 Tereza Kroupová

Finding Neutrino

My fourth and last year at UCL started in October. So far, it is the most demanding, but also the most exciting year in London for me.

All my modules this year are strongly related to particle physics, which is the field I would like to pursue in the future. Furthermore, I am taking high energy astrophysics module, which will equip me with necessary basics if I decide to do particle astrophysics. Therefore, I love all the lectures and enjoy my studies even more than before.

Moreover, I am working on my masters project on the SuperNEMO experiment*, which is being built at the moment and will be placed in an underground laboratory in Southeastern France in Modane. The main task of the SuperNEMO experiment is to investigate the nature and properties of neutrinos. These are particles, which are very abundant in the Universe and are present all around us. However, it is practically impossible to observe or detect them as they do not interact very much. The 2015 Nobel Prize for Physics was awarded to two physicists for the discovery that neutrinos have non-zero mass. Experiments revealed that the mass must be very small compared to other particles we know and determined the difference in masses of different neutrino types. On the other hand, the absolute numbers of how much neutrinos weight are still unknown. Furthermore, neutrino mass do not fit our current model of particle physics. Hence the research of these tiny particles has a great potential for future discoveries.

SuperNEMO aims to find a process called neutrinoless double beta decay. As the name suggests, it is two simultaneous beta decays of heavy isotopes, where two neutrons are transformed into two protons in a nucleus. Such event was observed in several elements with the production of two electrons and two (anti)neutrinos as by-products. However, it was proposed that it may proceed also without any neutrinos being emitted. This means that all of the remaining energy of the decay would be carried away by the two electrons. This is the neutrinoless double beta decay, the subject of study of SuperNEMO, and has never been detected so far. If it is indeed observed, it would provide a measurement of the neutrino masses and also prove that neutrinos are their own antiparticles.

My task is to analyse data from sections of the so called tracking detector, which are already built. This detector will be directly surrounding a very thin foil containing the heavy elements, where the radioactive decays will take place. Particles emitted from the foil will pass the tracking detector, which will reconstruct its trajectory. Therefore, it is a tool for determining the place, where the particle was born in the foil, and can also serve to deduce the energy of the particle. The software I am developing will analyse probationary data, which were obtained when the detector was exposed to cosmic rays for the purpose of testing. From the results, we will be able to assess the alignment of the constituent parts of the detector, improve it and calculate parameters of the detector, which will be necessary after the entire SuperNEMO is switched on.

This project, as well as neutrino physics and software development in general, is very exciting for me. I hope, I will be lucky again and have the chance to work on something similarly interesting in the future – ideally next year during my PhD.

 

*For more information about SuperNEMO: http://nemo.in2p3.fr/

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