Mainz doctoral student receives the DPG dissertation prize and the “Professor Herminghaus Prize” from the Friends of Mainz University for her dissertation on the Project 8 experiment.
Dr. Christine Claessens has two reasons to be happy: the former doctoral student in Prof. Dr. Sebastian Böser’s group at the PRISMA+ Cluster of Excellence received two prizes for her doctoral thesis. The dissertation prize of the Matter and Cosmos Section of the German Physical Society was awarded at the end of March at the virtual DPG Spring Conference in Heidelberg. As part of a symposium, four finalists gave a presentation – including Christine Claessens. As a result, she was awarded the prize worth a total of 1,500 euros together with Dr. Sarah Schröder (DESY).
She was also selected as the winner of the “Professor Herminghaus Prize” of the Friends of Mainz University. The prize will be awarded for the second time in 2022 for special doctoral dissertations in the field of physics. It is named after Helmut Herminghaus, who passed away in May 2020, was a long-time professor at the Institute of Nuclear Physics at JGU and played a key role in the design and construction of the MAMI particle accelerator. The prize is endowed with €2,500 and will be awarded at the Dies Academicus on June 29.
“In my doctoral thesis, I worked on the Project 8 experiment, with which we want to measure the neutrino mass directly,” says the prizewinner. Neutrinos are elementary particles of matter. Since their creation after the Big Bang, they have influenced the structure of the universe. In the standard model of Particle Physics, neutrinos have no mass at all – similar to light particles, the photons. However, experiments have shown that neutrinos do have mass, the only question is how big – or small – it is. In the Project 8 experiment, the scientists have come up with a new Technics Department: CRES or Cyclotron Radiation Emission Spectroscopy. This involves measuring the energy of the electrons produced by the beta decay of tritium via their orbital frequency in a magnetic field.
Tritium is an unstable element consisting of one proton and two neutrons. It decays to helium, emitting an electron and an antineutrino. As neutrinos have no electrical charge, they are difficult to detect. For this reason, the energy of the electrons is measured instead and the neutrino mass is claused on the basis of the shape of the electron energy spectrum or an upper limit is set for the mass.
“As part of my doctoral thesis, I developed an event detection system consisting of a real-time trigger and an offline event reconstruction,” explains Christine Claessens. “This system searches for the characteristic CRES features in the continuously digitized and processed high-frequency signal. The reconstruction of the starting frequency of each electron event enables the high-precision recording of a tritium decay spectrum.” The analysis of the first tritium spectrum recorded with CRES with regard to systematic uncertainties was also part of Christine Claessens’ doctoral thesis – an important part of a five-year research and development program that serves as the basis for the final Project 8 experiment.
After completing her doctorate in March 2021, Christine Claessens moved to the University of Washington in Seattle (USA) as a postdoctoral researcher.
