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Dark Matter

Prof. Susanne Mertens

Research Field

We study the elusive particle, the neutrino, to unlock fundamental mysteries of physics: What is our universe made of? How did structures evolve? Why is our world made of matter and not anti-matter?

Despite major discoveries in the last decades, the neutrino is still one of the most mysterious particles of the standard model of particle physics: What is its mass? Is it its own antiparticle? Does there exist a right-handed partner to the known left-handed neutrino, a so called sterile neutrino? Exploring these properties will help us understand fundamental open questions about our universe.

The Karlsruhe Tritium Neutrino (KATRIN) Experiment will directly measure the absolute neutrino mass. The knowledge of the neutrino mass will have a crucial impact on understanding the structure formation in the early universe. KATRIN is situated at the KIT in Karlsruhe and will start data taking in 2017. With an upgraded multi pixel Si-detector system, called TRISTAN, KATRIN can extend its physics goal to also search for keV-scale sterile neutrinos. This new neutrino species is an ideal candidate for Dark Matter. Our group is leading the sterile neutrino search with KATRIN

Besides KATRIN, our group is involved in the search for neutrinoless double beta decay (0nbb) with the MAJORANA experiment. The discovery of this process would proof that the neutrino is its own antiparticle, which in turn can help us understand the matter anti-matter asymmetry of the universe. MAJORANA and the closely related experiment GERDA plan to join in the near future to perform the ultimate search for this ultra-rare decay.


Föhringer Ring 6
80805 München
+49 89 32354-590

Members of the Research Group




Course with Participations of Group Members

Offers for Theses in the Group

Analysis of the first KATRIN data and investigation of systematic uncertainties

Scientific motivation: 

What is the mass of the neutrino? This is one of the most fundamental open questions in Astroparticle Physics today. We know from neutrino oscillations that neutrinos must have a mass, but its actual value is still unknown. The knowledge of the neutrino mass would be an important key to understand the formation of structures in the early universe and it could help to shed light on the fundamental origin of masses.

The Karlsruhe Tritium Neutrino (KATRIN) experiment is a direct neutrino mass experiment, which is designed to determine the neutrino mass via a precise measurement of the tritium beta decay spectrum. KATRIN just started data taking in April 2019. The goal is to reach a sensitivity to the neutrino mass of 200 meV after 3 years of data taking. So, right now is the perfect moment to join the experiment!

Thesis Topic:

In this Thesis project you participate in the analysis of the KATRIN data. A key aspect of the analysis is the understanding of systematic uncertainties and their impact on the neutrino mass. 

One of the most critical systematic uncertainties arises from the 10-m long tritium source. The gaseous source can be thought of as a plasma which exhibits a certain plasma potential. In KATRIN, we characterize this electric potential with the help of a krypton calibration source. 

The main task of the Thesis project is the analysis of the krypton calibration campaign. The goal is 1) to determine the key parameters of the source plasma, which are then used as input parameter for the neutrino mass analysis and 2) to  investigate the impact of the associated systematic uncertainties on the neutrino mass fit. You will also have the chance to participate in the actual data taking phase onsite at the KATRIN experiment. 

You will gain & learn: 

  • Participate in world-leading experiment to directly determine the neutrino mass

  • Learn about astroparticle physics 

  • In-depth knowledge on data analysis

  • Programming in C++ and Python

  • Work in a fun team with lots of social events

suitable as
  • Master’s Thesis Nuclear, Particle, and Astrophysics
Supervisor: Susanne Mertens
Characterization of the next-generation TRISTAN prototype detector

Scientific motivation: 

Does there exist an undiscovered type of neutrino, a so-called sterile neutrino? Could this particle be the Dark Matter? These are among the most topical open questions in Astroparticle physics at the moment. 

The aim of the TRISTAN project, is to develop a novel multi-pixel Silicon Drift Detector system to upgrade the KATRIN apparatus. This upgrade would allow the  KATRIN experiment to search for this hypothetical new particle. 

Thesis Topic:

The topic of this Thesis project is the characterization of the next-generation TRISTAN prototype, which will be ready for testing in September 2019. The goal of this project is a detailed understanding of the detector response to photons and electrons. For this purpose you will perform measurements with x-ray calibration sources and with an electron microscope at the Semiconductor Laboratory of the Max Planck society in Munich. For this purpose a dedicated test stand has to be designed and fabricated. The measurements and data analysis will be complemented with detailed Monte Carlo simulations of the particle interactions in the detector and the signal generation. 

You will gain & learn:

  • Learn about astroparticle physics 

  • Detailed understanding of semiconductor detector technology

  • Expertise in experimental hardware work 

  • Programming in Python and C++

  • Work in a fun team with lots of social events

suitable as
  • Master’s Thesis Nuclear, Particle, and Astrophysics
Supervisor: Susanne Mertens

Current and Finished Theses in the Group

Investigation of the Detector Response to Electrons of the TRISTAN Prototype Detectors
Abschlussarbeit im Masterstudiengang Physik (Kern-, Teilchen- und Astrophysik)
Themensteller(in): Susanne Mertens
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