Masterarbeiten / Master theses

Mögliche Themen für Masterarbeiten (Stand September 2026):

• XENONnT detector characterization, data analysis and modeling
  The XENONnT Dark Matter detector is the latest and largest dual-phase (liquid and gas) time projection chamber (TPC) in the XENON experiment series, operating at the INFN Laboratori Nazionali del Gran Sasso. XENONnT hosts 5.9 tons of liquid xenon in its target mass (8.5 tons in total) and it has been collecting data since 2021, producing world leading results in searches for Dark Matter, as well as ⁸B and pp-chain solar Neutrinos. In 2026 the XENONnT detector went through an extensive upgrade, with the main improvement being a completely new set of electrodes whose development was led by KIT-IAP. This upgraded detector is expected to operate over the course of next years, collecting even more data with highly improved detector conditions. With the newly obtained and the already collected data we will be able to explore new parameter spaces for Neutrino studies and Dark Matter searches, and probe the recently announced Dark Matter signal hint. Several master's thesis projects are available, covering different and unique aspects of XENONnT detector operation, data analysis, simulation and modeling.
  Available topics:

  1. Study and modeling of spurious electron backgrounds for Dark Matter and Neutrino searches: The origin of spurious electron emission in xenon-based TPC detectors is still poorly understood, yet such emission represents a key background especially for rare event searches for low-mass Dark Matter, and in extreme cases electron emission can even impact detector operation. In this project you will use existing analysis software and will devise new algorithms to analyze the data acquired with the upgraded XENONnT detector. You will study the origin of electron emission background, characterizing and modeling its behavior, distribution and impact on rare event searches.

  2. Electrodes and electrical fields characterization in XENONnT: The ~1.5 m in diameter high-voltage electrodes that lie at the heart of XENONnT detector produce electrical fields that are imperative for signal generation and detection. Understanding the behavior of these electrodes, their functional limits and any detector effects that are associated with their operation is crucial for the long-term stability of the XENONnT detector and for data analysis. In this project you will study XENONnT commissioning and scientific data, and perform COMSOL electrical field simulations to characterize the performance of the newly installed electrodes and the fields that they produce in the detector.

  3. Investigation of mysterious contaminants in XENONnT and their effects on detector performance: XENONnT is one of the most radio-pure and contaminant free detectors on the planet, allowing it to have extremely low detector backgrounds. However, during the upgrade of the XENONnT detector, several types of contaminants were observed on key detector components. Understanding the origin and nature of these contaminants and their implications for detector operation is imperative for the current and next generation of xenon-based TPCs. In this project you will examine components that were extracted from the XENONnT detector and investigate the contaminants on their surface with optical microscopy, spectroscopy and chemical techniques. You will also study XENONnT detector data, investigating the effects these contaminants can have on the acquired data.

  4. Characterization of the "cathode background" for low-mass Dark Matter searches: The so-called "cathode background" is one of the most dominant backgrounds for ionization-only rare event searches for low-mass Dark Matter, yet, it's origin is still poorly understood. It is thought to originate from beta decays in the Rn220 and Rn222 chains close to the cathode electrode. Due to the exotic electric field shape near the cathode, the energy depositions produced by such beta decays suffer from scintillation light and ionization electrons loss, and could mimic low-mass Dark Matter signals. In this project you will perform COMSOL electrical field simulations and use XENONnT data to characterize the signals forming the "cathode background", contributing to our understanding of its microphysics and facilitating efforts for modeling it for rare event searches.

  Your work will be carried out as part of the international XENON Collaboration, providing you with a unique opportunity to take part in cutting-edge research and gain experience of working in a diverse international research environment. Additionally, your work will contribute to the development of the next-genertation XLZD Observatory in the scope of the international XLZD Collaboration.
  Basic knowledge of particle physics, as well as solid programming skills in Python or C++ are required.
  Project key topics: XENONnT data analysis, detector backgrounds phenomenology and scientific searches
  Project work scope: Closely supported by KIT-IAP researchers and experts working on the XENONnT detector
  Project timeline: Available immediately
   

• Sensitivity study of XLZD to Axion-Like particles

  The XLZD Observatory is a next-generation liquid xenon (LXe) time projection chamber (TPC) aiming to explore the parameter space available of Weakly Interactive Massive Particles (WIMPs) with Standard Model particles. With its envisioned 60 to 100 tonnes, the experiment will not only be sensitive to common candidates for dark matter, but also to other exotic interactions. For example, Axion-Like Particles (ALPs) are alternative candidates consisting of Nabu-Goldstone bosons with properties similar to the axion proposed as a solution to the CP problem. Axion-like particles can deposit their energy in LXe TPCs not only through the axio-electric effect, but also through Compton-like scattering, appearing in its electronic recoil channel.
  In this project you will work on signal modelling of Axion-Like interactions in LXe, background characterisation and simulations utilising the FlameNEST library in Python. The goal of the work is to perform statistical inference to determine how the sensitivity of the XLZD Observatory to these particles improves by expanding the cross-section with the Compton-like scattering at different assumed masses.
  Project key topics: Signal and background modelling, Statistics, data analysis
  Project timeline: Available immediately

• Development of High-voltage electrodes for the XLZD observatory
  The XLZD collaboration aims to design and construct the ultimate liquid xenon-based observatory for the direct detection of particle Dark Matter and studies of Neutrino physics. The performance of 3m in diameter mesh and wire electrodes, which will lie at the heart of the detector and will produce the fields necessary for signal generation is of paramount importance. The Dark Matter group plays a key role in R&D for the XLZD detector and established a dedicated program aimed at developing and testing such electrodes. One fundamental question about designing such enormous electrodes is: “How to strike the balance between scientific requirements and mechanical feasibility? In other words, how can we make grid electrodes sufficiently good for signal generation and propagation, while also making them mechanically stable and robust enough on 3m scales.”  
  In this project you will participate in the design, simulation and experimental testing of new techniques and technologies for the construction of 3m-wide electrodes. Supported by KIT engineers and the researchers in the Dark Matter group you will participate in the assembly and testing of a prototype of a modular electrode frame, measuring 3m in diameter. You will take part in performing electrostatic simulations for optimizing the configuration of the wire grids, establishing the requirements for wire diameter and spacing. Additionally, you will develop new techniques for mechanical and chemical (e.g. epoxy resin used by NASA) fixation and assembly of wire grids onto the electrode frame. Subsequently, you will test and analyse the performance of the fixation methods, under mechanical stress and in cryogenic conditions.
  You should enjoy working with hardware and have basic programming skills in languages such as Python or C++.
  Project key topics: Hardware development, simulations, data analysis.
  Project work scope: Closely supported by KIT-IAP engineers and electrode experts
  Project timeline: Available immediately

• Exploring High-voltage Microphysics to Enhance XLZD Electrode Performance
  The international XLZD collaboration aims to design and construct the ultimate liquid xenon-based astroparticle observatory for the direct detection of particle Dark Matter and studies of Neutrino physics. Development of electrodes that will lie in the heart of the future XLZD detector is of paramount importance. Any such electrodes must withstand very large electric fields without causing detrimental electron emission or breakdown. A key component of the Dark Matter's group R&D towards XLZD electrodes is the work on high-volate (HV) microphysics, exploring ways for improving electrode performance. To that end we have constructed the bite-sized High Voltage setup for Electrodes (bHiVE), which allows us study the performance of cm-scale samples of electrodes in vacuum and gaseous environments. With bHiVE we aim to explore on smaller scales different electrode configurations and materials, as well as ways of mitigating electron emission from electrode surfaces via new coating and treatment methods. Lessons learned on these small scales will be then applied to the ongoing R&D of full-scale XLZD electrodes. The project is conducted in cooperation with University of Alabama and MPIK Heidelberg. Additionally, depending on your interests and project's timeline, your thesis project could be carried out in cooperation with the Institut für Angewandte Materialien (IAM) at KIT.
  In the scope of the project, supported by KIT engineers, you will participate in the upgrade of the bHiVE setup, working both on hardware components and software development. You will conduct a series of tests of electrode samples under varying conditions in terms of pressure, gaseous atmosphere and electric fields, studying the effects of defects, treatment methods and coating variation on electrode performance. Subsequently, building upon existing python-based software, you will develop the analysis tools for statistical interpretation of the obtained data, comparing the results with expectations from computational models and theoretical predictions.
  You should enjoy working with hardware and have basic programming skills in languages such as Python or C++.
  Project key topics: Hardware and software development, electric fields, data analysis
  Project work scope: Closely supported by KIT engineers and HV experts
  Project timeline: Available immediately
   

• Electrode surface measurements with confocal techniques
  

  

  MOTION, a 70 kg liquid xenon (LXe) TPC at the Karlsruhe Institute of Technology, serves as a dedicated platform to test new technologies in LXe. MOTION enables systematic studies of dielectric breakdown in LXe under controlled conditions, identifying factors that trigger and propagate discharges. Inside the detector, different electrodes samples can be placed and tested on their charge density distributions when stressed with high voltages, electroluminesce and spurious emission in LXe. Crucial for the understanding of these processes is the characterisation of the topology and surface quality of the electrode.
  In this project you will work on microscopic topographic stitching with tilt compensation and roughness topography via supervised learning with confocal laser scanning microscope. The goal is to develop image stitching methods to automatise the scanning of surfaces, and derive different data analysis techniques to characterise the roughness of the conductor.
  Project key topics: Image acquisition, microscopy, data analysis, machine learning
  Project timeline: Available immediately
   

• Untersuchung eines Flüssig-Xenon-Vetos für das XLZD Experiment
  Für den Erfolg des XLZD Experiments ist die Identifikation und Unterdrückung aller möglichen Untergrundquellen essenziell. Deshalb werden mehrere Strategien der Untergrundunterdrückung angewandt: Identifikation von Elektron- bzw. Kernrückstößen über das S1/S2-Signalverhältnis, Verwendung hochreiner Materialien in der TPC-Umgebung und aktive und passive Abschirmung des Detektors (Vetozähler, Wassertank und Untergrundlabor). Aufgrund der Konstruktion der TPC innerhalb eines doppelwandigen Kryostaten ergibt sich eine dünne Außenschicht von Xenon-Flüssigkeit („liquid Xe skin“), die als ein zusätzliches Veto-System instrumentiert werden kann.
  In dieser Arbeit untersuchen Sie in detaillierten Simulationen die Wirksamkeit eines solchen „liquid Xe skin veto“ mithilfe des Programmpakets GEANT4. Dabei implementieren Sie zunächst die komplexe Geometrie inklusive möglicher Lichtsensoren (PMTs) im äußeren Bereich des Kryostaten, modellieren Untergrundreaktionen in diesem Bereich wie auch in der TPC und bestimmen, inwieweit diese Untergrundreaktionen in den PMTs registriert und somit letztendlich unterdrückt werden können.
  Wir erwarten die Bereitschaft zur intensiven Auseinandersetzung mit dem Thema und Freude, sich in ein modernes, spannendes und für Sie neues Wissenschaftsfeld einzuarbeiten. Grundkenntnisse der Kern- und Teilchenphysik sowie von Teilchendetektoren sind notwendig. Grundkenntnisse in der Programmiersprache C++ sind Voraussetzung, Grundkenntnisse in Python und ROOT sind hilfreich.
   

• Spektrale Vermessung des Neutronenflusses im Untergrundlabor Laboratori Nazionali del Gran Sasso (LNGS)
  Unsere Arbeitsgruppe hat im Rahmen eines vom BMBF geförderten Projekts einen mobilen Neutronendetektor für das LNGS Untergrundlabor (ALMOND: An LNGS Mobile Neutron Detector) entwickelt und aufgebaut. Da Neutronen für viele Suchen nach seltenen Prozessen (z.B. Dunkle Materie-Wechselwirkungen, neutrinolose Doppel-Beta-Zerfälle) eine wesentliche Untergrundquelle darstellen, ist die verlässliche Bestimmung des Neutronenflusses am Ort des jeweils durchgeführten Experiments notwendig. Nach Kalibrationsmessungen am KIT und am Neutronengenerator des INFN-Labors in Frascati bei Rom befindet sich das Detektorsystem seit Anfang 2025 im LNGS und nimmt Daten. Der Neutronendetektor besteht aus 36 Szintillatormodulen, die von jeweils einem Photomultiplier (PMT) ausgelesen werden. Die Daten werden in digitaler Form zunächst am LNGS zwischengespeichert und dann in das lokale Rechnercluster transferiert. Für die nächsten Monate sind Langzeitmessungen des spektralen Neutronenflusses in den verschiedenen Hallen des LNGS geplant.
  In dieser Arbeit analysieren Sie die aufgenommenen Daten und erstellen Spektren des Neutronenflusses an verschiedenen Stellen des LNGS. Dazu entwickeln Sie die Analyse-Softwarepakete weiter, Sie untersuchen u.a. die Langzeitstabilität des Gesamtsystems wie auch der Einzelmodule, Sie nutzen bereits erstellte Simulationen und Analysen zur Nachweiseffizienz der Neutronen in ALMOND und extrahieren die effektive Nachweisschwelle für durch Neutronen erfolgte Kernrückstöße im Szintillatormaterial.
  Wir erwarten die Bereitschaft zur intensiven Auseinandersetzung mit dem Thema und Freude, sich in ein modernes, spannendes und für Sie neues Wissenschaftsfeld einzuarbeiten und in einem deutsch-italienischen Team mitzuarbeiten. Grundkenntnisse der Kern- und Teilchenphysik sowie von Teilchendetektoren sind notwendig. Grundkenntnisse in Python und ROOT sind hilfreich. Arbeiten direkt im Untergrundlabor LNGS in Italien sind ggf. möglich und erwünscht.
  Project key topics: software development, data analysis
  Project timeline: available immediately
   

• Crystal-based detectors for Dark Matter & Neutrinos
  Project is conducted in cooperation with Laboratory for Electron Microscopy (KIT-LEM) and Institute of Nanotechnology (KIT-INT)

  

  Artificial and natural crystal detectors represent a novel method for detection of exotic and standard model particles. Nuclear recoils, with energies as low as tens of electronvolt. of particles off crystal’s atoms can produce persistent damage features in the crystalline structure (“tracks”). These tracks could be then imaged with modern high-resolution microscopy, thus allowing us to study the nature of the interacting particles. An exciting extension of the crystal detectors concept are the so-called “paleo-detectors”, where instead of synthetic crystals we could use natural crystals that can be excavated and imaged. Tracks from particle interactions that were accumulated in such ancient crystals over millions of years, may allow us to not only detect signatures left by particle dark matter, neutrinos and cosmic rays, but also to study their flux variations. Whether using crystals as “paleo-detectors” or as mundane real-time passive particle detectors, the key aspect of the detection technique revolves around the ability to identify, image and analyse nanometre-scale damage tracks. Taking advantage of KIT’s state-of-the-art microscopy facilities, the Dark Matter group at KIT-IAP is performing a wide range of experimental studies towards the realization of the concept of crystal detectors.
  In this project you will continue the substantial experimental and simulation work that was done in our group, by performing irradiation studies of Silicon, Biotite and Mica crystal samples with a range of particle sources with known energies (neutrons, alpha particles). Subsequently, you will image the crystal samples with high-resolution electron and x-ray microscopy and will use ML-assisted techniques to study in detail the formed tracks. You will also contribute to development of the simulation framework for modelling particle interactions in crystals, extending it to molecular dynamics simulations, with the goal of validating simulations results against the microscopy data that you would collect. Throughout the project you will be assisted and supported by experts from the Laboratory for Electron Microscopy (KIT-LEM) at campus south, and Institute of Nanotechnology (KIT-INT) at campus north.
  You should enjoy working in a lab and have basic programming skills, in either Python and/or C++.
  Project key topics: Experimental lab work, simulations, image processing, data analysis.
  Project timeline: available immediately
   

Für weitere Informationen wenden Sie sich gerne auch direkt an Prof. Dr. Kathrin Valerius oder Dr. Klaus Eitel.