Magnetic fields are a main issue for several precision experiments like HeXeEDM and PanEDM, which measure the electric dipole moments (EDM) of a gas mixture and the neutron. The results of these measurements can then be used to further explain the excess of matter vs. antimatter in the Universe.  To reduce the uncertainties it is necessary to map the fields with a non-magnetic field mapper.

Bachelor Thesis:
One part is the mapper head. It contains a magnetometer, whose offset is canceled by rotating the fluxgate. Before testing several issues has to be eliminated like optimizing a non-magnetic sliding contact and an optical encoder, as well as calibrating the sensor.

Master Thesis:
The other part is a cable-driven parallel robot to move the mapper head with an absolute accuracy of 55 μm and 7 · 10⁻⁴ rad in inclination. The task is to set it up and test it afterward in our lab in Garching.

If you are interested, please contact peter.fierlinger@tum.de.
 

Master Thesis Opportunity

We are looking for a master thesis student to build the science module for a pico-satellite at a 450 km orbit, to map the magnetic field of the earth at 92 km altitude in the mesosphere through laser spectroscopy of sodium atoms.

Large telescopes use laser beams at the sodium wavelength pointing into the sky to generate a bright dot, an artificial star, in the mesosphere through fluorescence of sodium atoms. This dot is used to correct for atmospheric fluctuations to improve imaging.

Our project uses this knowledge, but for a different purpose: we mount the laser on a satellite and point downwards to the earth. When the light hits the mesosphere, a bright spot is generated. If the light is modulated at the electron spin resonance frequency corresponding to the magnitude of the earth field, this is a direct measure of the magnitude of the earth’s magnetic field.

The thesis work will be the test of the laser system in the lab, generating fluorescence, detecting the fluorescent light with a silicon photomultiplier and prepare components for a space exposure test at the international space station. Here you will learn atomic and particle physics techniques and applications. If you always wanted to build your own satellite and learn how satellite technology works, contact Florian Kuchler (florian.kuchler@tum.de)

Master thesis opportunity

We are building a new platform for high sensitivity biomagnetic field mapping in a magnetically ultra-quiet environment. The setup allows flexible sensor arrangements around biological samples or phantoms and is ideal for mapping weak magnetic signals such as those generated by the human heart (magnetocardiography) or brain (magnetoencephalography).

This thesis focuses on the experimental realization and characterization of biomagnetic measurements, with an optional extension towards source reconstruction based on multichannel data.

Main objectives:

• Set up and calibrate a biomagnetic test system inside a magnetically shielded room
• Development of sample holders, phantom sources and sensor technology for the reconstruction of source movements etc.
• Acquire and map spatio-temporal biomagnetic signals from synthetic or biological sources
• Reconstruct current source distributions from measured field data (e.g. via dipole modeling or inverse solutions)

You will gain hands-on experience with optical magnetometry, biomagnetic instrumentation, and data reconstruction.

If you are interested or want to learn more about this topic – feel free to contact philipp.wunderl@tum.de!

Master Thesis Opportunity

At our lab we are currently building an electrostatic particle storage ring, initially for a dark matter search (https://arxiv.org/pdf/2211.08439.pdf). During this year, we are setting up the hardware for the first stage: a 30 kV barium ion source and the whole experimental hardware of the ring with 2 m side length, here in the lab at our chair in Garching. This includes a vacuum system, electrodes for keeping particles on their trajectories and means for monitoring the particle beam. To perform a dark matter search, we polarize the Ba+ with lasers and lock the electron spin precession to the cyclotron frequency of the beam, effectively forming a crazy magnetic field sensor. Dark matter or other exotic physics would modulate the precession, and we can observe this via laser spectroscopy.

If you are interested in this project, it’s a great time to join the project: all parts are coming in right now, and there is a lot of different physics to learn and work on. During the course of the thesis, the experiment should be assembled and tested with first particles in the ring. Depending on the interests, the work can be more focused on practical aspects or simulations of the details of the ring.

Please contact Peter Fierlinger (peter.fierlinger@tum.de) if you are interested!

Master Thesis Opportunity

Atomic magnetometers use non-linear effects in laser-driven electron-spin-resonance in Alkali atoms. Such sensors can measure Femto-Tesla level magnetic fields and have a variety of applications in fundamental physics as well as in applications, for example remote sensing or medicine.

In this project we will set up an array of atomic magnetometers, record the ambient magnetic field and analyze it for spurious effects. As the availability of robust and reliable sensors at this quality is rather new, a yet unexplored parameter region for new physics can be investigated in this way. We are in particular interested in ultra-light axion-like dark matter and dark photons. To be sensitive for such this type of new physics, sensors ultimately need to be placed at a remote and electromagnetically silent location. While some of the sensors are already operational, the experimental work will contain reliable operation of several sensors, as well as developing a mechanism to relate the individual channels e.g. by applying artificial reference signals.

In contrast to laboratory experiments with individual sensors, here the interesting aspect is the analysis of an array of sensors placed in the ambient earth magnetic field, with correlations between sensors, directional information and new possibilities for background suppression and signal identification, e.g. using independent component analysis. We expect to find new challenges in the analysis, but also a much larger amount of information. The data will be fun to interpret, as almost everything is magnetic at the Femto-Tesla scale!

Please contact Peter Fierlinger (peter.fierlinger@tum.de) or Florian Kuchler (florian.kuchler@tum.de) if you are interested.

Master thesis opportunity

In high-precision spin clock experiments—such as the ongoing HeXe EDM experiment—even tiny magnetic field variations can limit sensitivity and cause systematic errors. Understanding and controlling these effects requires detailed spatial knowledge of both external disturbances and experimentally generated magnetic signals. 

We are currently developing a 4π magnetometer array, consisting of multiple highly sensitive magnetic field sensors (e.g. optical magnetometers or fluxgates) arranged around the experiment. This array enables full 3D spatial reconstruction of magnetic fields and offers two key applications: 

1. Detection and classification of magnetic disturbances: 
    The array can detect stray fields, local gradients, or fluctuations from active elements (e.g. spin-flip coils, shielding currents). This helps identify and reduce systematic errors in spin clock data. 
2. Direct spatial measurement of spin-precession signals: 
    The array can capture the evolving magnetic signature of precessing spins (e.g. from ³He or ¹²⁹Xe) in space and time, allowing advanced reconstruction and model validation. 

Thesis objectives include: 

• Design of the 4π array and its integration with the experimental setup 
• Calibration and alignment of sensor positions and orientations 
• Implementation of spatial signal reconstruction (e.g. beamforming, model fitting, ICA) 
• Application to real-world data, including spin clock runs and controlled test sources 
• Analysis of how magnetic inhomogeneities and field drift affect precision measurements 

The project offers an excellent opportunity to combine experimental physics, signal processing, and precision measurement techniques. 

If you are interested or want to learn more about this topic – feel free to contact philipp.wunderl@tum.de! 

Master thesis opportunity

Fetal magnetocardiography (fMCG) offers the possibility of monitoring the heartbeat of fetuses in the mother's womb. This can close a significant medical gap, enabling the detection and treatment of heart defects or diseases even before birth. 

Following the successful development of a large fMCG prototype, our group is working towards a smaller, more compact version.

Possible thesis (sub-)projects are:

• Investigation and optimization of various active compensation methods for magnetic fields
• Simulation of electromagnetic shielding
• Signal processing and data analysis of noise-afflicted multidimensional data

The students learn various skills, such as handling different types of magnetic field measurement, using magnetometers, conducting simulations with COMSOL, laboratory work, and various analysis methods.
If you are interested or want to learn more on this topic - feel free to contact lena.wunderl@tum.de!

Master thesis opportunity

We are currently developing a novel free-space cesium magnetometer for integration into the panEDM experiment at the Institut Laue-Langevin (ILL) in Grenoble. The sensor will be placed directly in the central region of the experiment, between the high-voltage electrodes, enabling precise mapping of magnetic fields and field disturbances at the location of the neutron precession. 

This project involves: 

• Designing and testing a suitable magnetometer vapor cell
• Developing an optimized sensor geometry and mounting system
• Characterizing the magnetometer performance under realistic experimental conditions, including operation near HV electrodes 

The thesis offers an excellent opportunity to gain experience in sensor design, laser optics, magnetic shielding, high-voltage-compatible systems, and data acquisition. 

If you are interested or want to learn more on this topic – feel free to contact philipp.wunderl@tum.de and maximiliandominik.huber@tum.de! 

Master thesis opportunity

The HeXeEDM experiment successfully determined a new limit on the electric dipole moment (EDM) of the isotope 129-xenon in 2019 using a dual species spin-clock. 

The principal measurement method involves polarizing nuclear spins of noble gases via spin-exchange optical pumping and transfer into a high-performance magnetically shielded room, where  Larmor precession in simultaneously applied magnetic and electric fields is observed. The highly sensitive (noise level below 10 fT/sqrt(Hz)) detection of spin-precession is based on superconducting sensors located close-by but immersed in liquid helium.  

We are now developing an new version of the experiment (HeXe2) implementing several improvements on now well understood systematic effects. 

A thesis within this project involves a selection of the following developments, techniques and experimental methods: 

• polarization of noble gas nuclei via spin-exchange optical pumping using high power IR lasers 
• sensing of ultra-low magnetic fields and gradients using fluxgates, optically pumped magnetometers, SQUID sensors 
• generation of stable, low noise magnetic fields and high precision spin-flip pulses  
• new measurement cell development using glass and silicon bonding techniques 
• working in a large, world-class magnetically shielded environment 
• liquid helium handling for operation of highly sensitive SQUID sensors  

Please contact florian.kuchler@tum.de for more information and possible thesis projects. 

Student Project

We are looking for a student to assemble and commission a drone with 5 kg payload, to be used for areal magnetic field sensing. The sensors to be used are two self-oscillating Rubidium magnetometers or optionally fluxgate magnetometers, hanging on drone on a 10 m long cable. By recording GPS data together with magnetic field signals, the sensors can be used as differential probes to provide information about local magnetic field distortions underground. Applications can be (industrial) geology, archeology, finding dud shots or mines. All hardware is here, you can start immediately!

Please contact Peter Fierlinger (peter.fierlinger@tum.de) if you are interested!

Master thesis opportunity

Our group is actively developing optical atomic magnetometers, a type of sensors using light-atom interactions to detect magnetic fields.This approach, sitting on the junction of laser-optics, quantum-optics and atom-physics, offer a wide range from theoretical approaches to practical experiments.

Possible thesis (sub-)projects are: 
- Implementation and Characterization of a non-magnetic Optical Atomic Magnetometer Array at the panEDM Experiment (at ILL) 
- Development of a non-magnetic Free Space Cesium Magnetometer 
- Development of an Optical Earth Field Cesium Magnetometer 
- Characterisation and Improvement of Cesium Vapor Cells and Upgrading 
- Characterisation of a Magnetically Shielded Test Chamber for Magnetometers. 

Students can learn a variety of skills, such as handling laser optics and different measurement systems, designing sensors, or developing operating and analysis software. 

If you are interested or want to learn more on this topic - feel free to contact philipp.wunderl@tum.de! 

Bachelor Thesis Opportunity

Atomic magnetometers use non-linear effects in laser-driven electron-spin-resonance in Alkali atoms. We develop and work with such sensors, ranging from fundamental particle physics (dark matter searches and time-reversal-symmetry breaking electric dipole moment searches) to applications (novel medical diagnostic methods).

Here we look for a motivated student to set up a atomic magnetometer for operation at a remote site on a mountain without human generated noise to search for ultra-light axion dark matter or dark photons. Such phenomena would appear as tiny magnetic signals at the Femto-tesla level and cannot be found in the lab, as they would be shielded by the same electromagnetic shielding, which is needed against human generated noise.

The project consists of setting up, testing and characterizing an already operational sensor in the lab and make it run and take data autonomously with batteries. Once it works reliably, it is placed at a silent, remote location on a mountain and records data. Afterwards, the data is analyzed for signs of data matter. Depending on the quality of the data, this relatively new approach can lead to a publication.

Please contact Peter Fierlinger (peter.fierlinger@tum.de) or Florian Kuchler (florian.kuchler@tum.de) if you are interested.

The quest to detect neutrino-less double beta decay (0𝜈𝛽𝛽) stands as a top priority in contemporary particle physics. Discovering this process, which violates lepton number conservation, would not only reveal the absolute mass scale of neutrinos but also offer valuable insights into Grand Unified Theories and helps in understanding leptogenesis in the early universe. Liquid scintillator (LS) detectors, like the currently commissioned SNO+ and JUNO experiments, are highly sensitive instruments in the hunt for this very rare process. The detection method offers several advantages, including extremely low background radiation, flexibility in detector shape and size, and the capability to incorporate a large quantity of the 𝛽𝛽-decaying isotope directly within the LS.

The method currently used in the R&D project at TUM involves synthesizing an oil-soluble tellurium compound (Te-diol) using telluric acid and an organic diol (1,2-butanediol). Furthermore, N,N-dimethyldodecylamine is used as a catalyst and stabilizer in the process. To ensure good transparency, light yield, chemical stability and radiopurity of the final scintillator samples, all educt compounds need to be well purified. Therefore, distillation is foreseen among other procedures like chromatography. The construction and commissioning of a suitable fractionated vacuum distillation system for the production of purified laboratory samples of DDA and BD are the subject of this thesis. Testing the transparency of these samples using UV/Vis spectroscopy are also foreseen.

Contact:
Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Motivation

The stability of matter is one of the fundamental open questions in particle physics. Many Grand Unified Theories (GUTs) predict that protons are not absolutely stable and may decay with extremely long lifetimes. 

The Jiangmen Underground Neutrino Observatory (JUNO) is a next-generation liquid scintillator detector currently being commissioned in China. Owing to its large fiducial mass, excellent energy resolution, and outstanding timing capabilities, JUNO provides a unique opportunity to search for proton decay with unprecedented sensitivity. A crucial aspect of such a search is the detailed understanding and characterization of background events that can mimic the proton decay signature.

Objectives

The goal of this Master thesis is to investigate and quantify background processes relevant to the search for proton decay in the JUNO detector.

The project will be based on the analysis of real detector data acquired during the past year. Using these data, background rates will be studied and the achievable sensitivity of a proton decay search will be estimated under realistic experimental conditions.

Tasks

• Familiarization with the physics of proton decay and Grand Unified Theories.
• Study of the expected detector signature of the proton decay into a K⁺
• Analysis of real JUNO detector data recorded during the last year.
• Identification and classification of background events relevant to the proton decay search.
• Investigation of cosmogenic, radioactive, and detector-related background sources.
• Development and validation of event selection criteria to suppress backgrounds while maintaining high signal efficiency.
• Estimation of the expected background rate in the proton decay signal region.
• Evaluation of the proton decay sensitivity achievable with the currently available data set.
• Comparison of the obtained sensitivity with published JUNO sensitivity studies and projections.

Methods

The work will involve the analysis of experimental detector data using modern particle physics analysis techniques. Depending on the interests of the student, the project may include:

• Event reconstruction and selection,
• Statistical data analysis,
• Monte Carlo comparisons,
• Sensitivity and discovery-potential studies,
• Background modeling and uncertainty estimation.

Requirements

• Interest in particle and astroparticle physics,
• Basic knowledge of data analysis and statistics,
• Experience with Python and/or C++ is advantageous,
• Motivation to work with large experimental data sets.

Learning Outcomes

During this project, the student will gain experience in:

• Analysis of data from a large-scale international experiment,
• Rare-event searches and background characterization,
• Statistical methods used in modern particle physics,
• Sensitivity estimates and limit setting,
• Scientific programming and data analysis workflows.

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Motivation

The Diffuse Supernova Neutrino Background (DSNB) consists of neutrinos emitted by all past core-collapse supernovae throughout the history of the Universe. Its detection would provide unique insights into stellar evolution, supernova explosion mechanisms, neutrino physics, and the cosmic history of star formation. Despite decades of experimental effort, the DSNB has not yet been conclusively observed.

The Jiangmen Underground Neutrino Observatory (JUNO) is uniquely positioned to perform a highly sensitive search for the DSNB thanks to its large target mass, excellent energy resolution, and powerful event reconstruction capabilities. However, the expected DSNB signal rate is extremely low and requires sophisticated techniques to suppress a variety of backgrounds, including atmospheric neutrinos, cosmogenic isotopes, fast neutrons, and reactor antineutrinos.

Recently developed particle identification methods, such as Pulse Shape Discrimination (PSD) and Cherenkov-to-Scintillation (C/S) light separation, offer new opportunities to significantly improve the separation of DSNB signal events from background processes and thereby enhance the discovery potential of JUNO.

Objectives

The objective of this Master thesis is to perform a search for the Diffuse Supernova Neutrino Background using real detector data collected during the first year of JUNO operation.

The focus of the project will be the characterization and reduction of backgrounds through the application of newly developed PSD and Cherenkov-to-Scintillation separation techniques. Based on the available detector data, the student will evaluate the achievable DSNB sensitivity and quantify the impact of advanced background rejection methods on the overall search performance.

Tasks

• Familiarization with the physics of core-collapse supernovae and the Diffuse Supernova Neutrino Background.
• Study of the expected DSNB signal in JUNO, including inverse beta decay and associated event signatures.
• Analysis of real JUNO detector data from the first year of detector operation.
• Investigation and characterization of relevant background sources, including:
  • atmospheric neutrino interactions,
  • cosmogenic isotopes,
  • fast neutrons,
  • reactor antineutrinos,
  • accidental coincidences.
• Application and optimization of newly developed Pulse Shape Discrimination (PSD) techniques.
• Application and optimization of Cherenkov-to-Scintillation (C/S) light separation methods.
• Quantification of the background suppression achieved by PSD and C/S discrimination.
• Development of event selection criteria maximizing DSNB sensitivity.
• Estimation of the expected signal efficiency and residual background rates.
• Determination of the DSNB sensitivity achievable with the first-year JUNO data set.
• Comparison with previous JUNO sensitivity studies and projections.

Methods

The project combines experimental data analysis and modern statistical techniques. Depending on the student's interests, the work may include:

• Event reconstruction and classification,
• Multivariate event selection,
• Pulse shape analysis,
• Time-profile and topology studies,
• Statistical inference and sensitivity estimation,
• Monte Carlo validation and comparison with detector data,
• Evaluation of systematic uncertainties.

Requirements

• Strong interest in particle, neutrino, or astroparticle physics,
• Good programming skills in Python and/or C++,
• Basic knowledge of statistics and data analysis,
• Motivation to work with large experimental data sets and modern analysis frameworks.

Learning Outcomes

The student will gain experience in:

• Analysis of data from one of the world's largest neutrino experiments,
• Rare-event searches at the forefront of astroparticle physics,
• Advanced particle identification techniques,
• Statistical methods for signal extraction and sensitivity estimation,
• Detector physics and background characterization,
• Collaborative research within an international scientific collaboration.

Contact

• Dr. Hans Th. J. Steiger
• Hans.Steiger@tum.de

Motivation

Solar neutrinos have played a central role in shaping our understanding of both particle physics and astrophysics. Precision measurements of solar neutrino fluxes have led to the discovery of neutrino oscillations and continue to provide unique insights into the structure and dynamics of the Sun.

The Jiangmen Underground Neutrino Observatory (JUNO) offers unprecedented opportunities for high-precision solar neutrino measurements. Its large target mass, excellent energy resolution, and ultra-low radioactive background levels enable detailed studies of the solar neutrino energy spectrum. In particular, JUNO is expected to perform precision measurements of neutrinos from the pp-chain and the CNO cycle, providing important information on solar metallicity, neutrino oscillations in matter, and stellar energy production.

A key challenge of solar neutrino spectroscopy is the suppression and characterization of detector-intrinsic and environmental backgrounds. Advanced event reconstruction, pulse-shape analysis, and precise detector calibration are therefore essential components of the analysis.

Objectives

The goal of this Master thesis is to perform a detailed study of solar neutrino spectroscopy using real detector data from the first years of JUNO operation.

The student will analyze low-energy neutrino candidates, characterize relevant background sources, and reconstruct the solar neutrino energy spectrum. The project will contribute to JUNO's solar neutrino physics program and to precision measurements of solar neutrino fluxes.

Tasks

• Familiarization with solar neutrino physics and neutrino oscillations.
• Study of solar neutrino production mechanisms, including:
  • pp neutrinos,
  • ⁷Be neutrinos,
  • pep neutrinos,
  • ⁸B neutrinos,
  • CNO neutrinos.
• Analysis of real JUNO detector data.
• Investigation of detector response and low-energy event reconstruction.
• Identification and characterization of relevant background sources, including:
  • intrinsic radioactivity,
  • cosmogenic isotopes,
  • external gamma backgrounds,
  • detector-related backgrounds.
• Development and optimization of event selection criteria.
• Extraction of solar neutrino signals from detector data.
• Reconstruction of the solar neutrino energy spectrum.
• Determination of neutrino fluxes and associated uncertainties.
• Evaluation of the sensitivity to CNO neutrinos and solar metallicity models.
• Comparison with theoretical predictions and previous measurements from Borexino, Super-Kamiokande, and SNO.

Methods

The thesis combines experimental data analysis, detector physics, and statistical inference. Depending on the interests of the student, the project may involve:

• Event reconstruction and calibration,
• Energy spectrum analysis,
• Background modeling and subtraction,
• Statistical signal extraction,
• Monte Carlo simulations,
• Systematic uncertainty studies,
• Spectral fitting and parameter estimation.

Requirements

• Strong interest in particle, neutrino, or astroparticle physics,
• Good programming skills in Python and/or C++,
• Basic knowledge of statistics and data analysis,
• Motivation to work with large experimental data sets.

Learning Outcomes

The student will gain experience in:

• Analysis of low-energy neutrino signals,
• Precision detector calibration and response modeling,
• Background characterization in large liquid scintillator detectors,
• Statistical methods for spectral analyses,
• Modern neutrino physics and solar astrophysics,
• Scientific research within an international collaboration.

Contact

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Motivation

Despite overwhelming astrophysical evidence for its existence, the particle nature of dark matter remains one of the most important open questions in modern physics. Large liquid scintillator detectors such as the Jiangmen Underground Neutrino Observatory (JUNO) provide unique opportunities to search for a wide range of dark matter scenarios through neutrino and rare-event signatures.

Beyond its primary neutrino physics program, JUNO is sensitive to several well-motivated dark matter models, including:

• Dark matter annihilation in the Sun producing neutrinos,
• Dark matter annihilation in the Galactic Halo,
• Boosted Dark Matter (BDM),
• Dark matter interactions producing high-energy single events,
• MeV-scale dark matter scenarios,
• Indirect searches for Primordial Black Hole dark matter through Hawking-radiation neutrinos.

The large target mass, excellent energy resolution, and low-background environment of JUNO make it a powerful detector for exploring new physics beyond the Standard Model.

Objectives

The goal of this thesis is to perform a search for dark matter signatures using real detector data collected during the first year of JUNO operation.

The student will investigate several dark matter search channels and evaluate JUNO's sensitivity using measured detector backgrounds. Depending on the progress of the project, the focus may be placed on one or more of the following scenarios:

• Solar dark matter annihilation producing neutrino signals,
• Galactic dark matter annihilation into neutrinos,
• Boosted dark matter interactions,
• Large-Energy-Single (LES) signatures,
• MeV-scale dark matter scenarios,
• Primordial black hole dark matter constraints.

Tasks

• Familiarization with dark matter phenomenology and indirect detection methods.
• Study of dark matter signatures accessible in liquid scintillator detectors.
• Analysis of real JUNO detector data from the first year of operation.
• Identification and characterization of relevant backgrounds, including:
  • atmospheric neutrinos,
  • reactor antineutrinos,
  • cosmogenic isotopes,
  • fast neutrons,
  • accidental backgrounds.
• Development of event selection criteria for dark matter searches.
• Investigation of high-energy and low-energy event samples.
• Validation of background models using detector data.
• Sensitivity estimation for selected dark matter scenarios.
• Comparison with existing constraints from Super-Kamiokande, IceCube, Borexino, and other experiments.

Dark Matter Scenarios Considered

Solar Dark Matter

Dark matter particles may become gravitationally trapped inside the Sun and subsequently annihilate into Standard Model particles, producing neutrinos that can be detected at Earth. JUNO is particularly sensitive to neutrino signals from light dark matter annihilation channels through charged-current neutrino interactions.

Galactic Dark Matter Annihilation

Dark matter annihilation in the Milky Way halo may generate mono-energetic or continuum neutrino spectra. JUNO's low-energy neutrino detection capabilities provide sensitivity to MeV-scale dark matter annihilation signatures.

Boosted Dark Matter

A dark matter subcomponent may be accelerated through annihilation or decay processes and interact in the detector with energies significantly above the conventional halo dark matter expectation. JUNO's large volume and excellent reconstruction capabilities make it sensitive to such signatures.

Large Energy Single Events (LES)

Events with visible energies above approximately 15 MeV and without accompanying delayed signals constitute a promising search channel for boosted dark matter and other exotic scenarios. JUNO can provide competitive sensitivity using this event sample.

Primordial Black Hole Dark Matter

If a fraction of dark matter consists of primordial black holes, Hawking radiation may produce detectable neutrino and antineutrino fluxes. JUNO has been shown to possess significant sensitivity to such scenarios through inverse beta decay and related channels.

Methods

The project combines detector data analysis, Monte Carlo simulations, and statistical inference techniques. Possible components include:

• Event reconstruction and classification,
• Signal and background modeling,
• Multivariate analysis methods,
• Spectral and directional analyses,
• Statistical limit setting,
• Sensitivity and discovery-potential studies.

Requirements

• Strong interest in particle, astroparticle, or neutrino physics,
• Good programming skills in Python and/or C++,
• Basic knowledge of statistics and data analysis,
• Motivation to work with large experimental data sets.

Learning Outcomes

The student will gain experience in:

• Analysis of real data from a next-generation neutrino observatory,
• Indirect dark matter searches,
• Rare-event analysis techniques,
• Background characterization and suppression,
• Statistical methods used in modern astroparticle physics,
• Research within an international scientific collaboration.

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Motivation

Neutrino oscillations provide one of the clearest indications of physics beyond the Standard Model. In the standard three-flavour framework, neutrino mixing is described by the unitary Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrix. Precision tests of PMNS unitarity therefore offer a powerful way to search for new physics, including sterile neutrinos, non-standard interactions, and other deviations from the standard oscillation paradigm.

The Jiangmen Underground Neutrino Observatory (JUNO), together with the Taishan Antineutrino Observatory (TAO), will provide world-leading measurements of reactor antineutrino spectra and oscillation parameters. JUNO’s long-baseline reactor neutrino data are highly sensitive to the oscillation pattern driven by Δm²₂₁ and Δm²₃₁, while TAO provides a high-resolution reference measurement of the reactor antineutrino spectrum close to the Taishan reactor cores. The combination of JUNO and TAO enables stringent tests of the standard three-neutrino framework and searches for sterile-neutrino-induced distortions.

Objectives

The goal of this thesis is to perform precision tests of the unitarity of the PMNS matrix using JUNO and TAO data, and to investigate the sensitivity to sterile neutrino scenarios.

The project will use detector data from JUNO and TAO, complemented by simulations and external constraints. Depending on the progress of the work, the analysis may be extended towards global fits including results from other reactor, accelerator, solar, and atmospheric neutrino observatories.

Tasks

• Familiarization with three-flavour neutrino oscillations and the PMNS matrix.
• Study of PMNS unitarity tests and their connection to sterile neutrino searches.
• Analysis of JUNO reactor antineutrino data and TAO reference spectrum data.
• Investigation of deviations from the standard three-flavour oscillation framework.
• Development of sterile-neutrino oscillation models, e.g. 3+1 scenarios.
• Study of spectral distortions induced by additional mass splittings and mixing angles.
• Evaluation of systematic uncertainties, including reactor flux, detector response, energy scale, and background contributions.
• Combination of JUNO and TAO information to reduce reactor-spectrum model dependence.
• Sensitivity studies for sterile neutrino parameters such as Δm²₄₁, |U_e4|², and effective disappearance amplitudes.
• Tests of PMNS matrix unitarity using precision oscillation measurements.
• Optional extension to global analyses including external constraints from experiments such as Daya Bay, RENO, Double Chooz, KamLAND, solar neutrino experiments, atmospheric neutrino measurements, and accelerator-based oscillation experiments.

Physics Topics

PMNS Unitarity

The standard three-neutrino framework assumes that the PMNS matrix is unitary. Deviations from unitarity could indicate the presence of additional neutrino states or other new physics. JUNO’s precision measurement of oscillation parameters provides an important input to tests of the first row of the PMNS matrix.

Sterile Neutrino Searches

In 3+1 models, an additional mostly sterile neutrino state modifies the electron antineutrino survival probability. JUNO and TAO can search for sterile-neutrino-induced distortions over a broad range of mass splittings and mixing strengths.

Reactor Spectrum Constraints with TAO

TAO will measure the reactor antineutrino spectrum at very short baseline with excellent energy resolution. This enables a data-driven reduction of reactor-spectrum uncertainties in JUNO oscillation and sterile-neutrino analyses.

Global Oscillation Fits

The project may be extended towards global fits combining JUNO and TAO with external neutrino data. Such analyses can improve constraints on PMNS unitarity and sterile-neutrino parameter space.

Methods

The thesis will combine experimental data analysis, oscillation phenomenology, and statistical inference. Possible methods include:

• Reactor antineutrino spectral analysis,
• Oscillation probability modeling,
• Detector response and energy-scale modeling,
• Covariance-matrix and nuisance-parameter treatments,
• χ²-based sensitivity studies,
• Bayesian or frequentist parameter estimation,
• Combination of internal and external data sets,
• Sterile-neutrino parameter scans.

Requirements

• Strong interest in neutrino physics and physics beyond the Standard Model,
• Good programming skills in Python and/or C++,
• Basic knowledge of statistics and data analysis,
• Interest in phenomenological modeling and experimental data analysis,
• Motivation to work with large data sets and international collaborations.

Learning Outcomes

The student will gain experience in:

• Precision neutrino oscillation physics,
• PMNS unitarity tests,
• Sterile neutrino phenomenology,
• Reactor antineutrino data analysis,
• Treatment of detector and reactor systematic uncertainties,
• Statistical methods for parameter estimation and exclusion limits,
• Scientific work within JUNO, TAO, and potentially global neutrino-oscillation contexts.

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Background and Motivation

Plastic scintillators are widely used as radiation detection materials due to their fast signal response, mechanical robustness, and comparatively simple and cost-efficient production. However, their application in environments with high radiation exposure is limited by radiation-induced ageing processes. In particular, the formation of color centers, yellowing of the polymer matrix, and the resulting loss of optical transparency and scintillation light yield can significantly reduce detector performance and lifetime.

Within a joint research project between the Technical University of Munich (TUM) and BGZ Gesellschaft für Zwischenlagerung mbH, a new generation of radiation-hard, highly efficient polystyrene-based plastic scintillators is being developed for applications in nuclear facilities and hot-cell environments.

First highly transparent polystyrene-based scintillators have already been successfully produced at TUM. With optimized fluor combinations, these materials reach light yields of up to approximately 13,500 photons/MeV and fast scintillation decay times of approximately 2.2 ns, demonstrating performance comparable to or exceeding established commercial plastic scintillators.

Objective of the Thesis

The objective of this Bachelor’s thesis is the production and systematic characterization of polystyrene-based plastic scintillators and the investigation of the influence of material composition and radiation exposure on their optical and scintillation properties.

Different combinations and concentrations of primary scintillation molecules and wavelength shifters will be investigated and optimized with respect to light yield, optical transparency, emission spectrum, and material stability.

A particular focus will be placed on the radiation hardness of the developed materials and the identification of material formulations that retain their optical and scintillation performance after exposure to high gamma doses.

Tasks

Depending on the progress of the project, the thesis will include several of the following tasks:

• Production of polystyrene-based plastic scintillators using thermal polymerization and cell-casting techniques
• Optimization of selected fluor combinations and dopant concentrations
• Investigation of wavelength shifters for spectral matching to modern silicon photomultipliers (SiPMs)
• Characterization of optical transparency using UV/Vis spectroscopy
• Measurement and analysis of fluorescence and emission spectra
• Determination of the relative and/or absolute scintillation light yield
• Gamma irradiation of selected scintillator samples in collaboration with Radiochemistry Munich (RCM) at TUM
• Investigation of radiation-induced changes in optical transparency, emission spectra, and scintillation light yield
• Comparison of different material formulations with respect to radiation hardness
• Quantitative data analysis and scientific interpretation of the experimental results

Depending on the progress of the project, cross-linked and additively manufactured plastic scintillators may additionally be investigated and compared to conventionally produced samples.

Experimental Methods

The thesis has a strong experimental component and combines methods from polymer chemistry, optical spectroscopy, materials science, and radiation detection.

Experimental methods may include:

Polymerization and sample preparation · Cell casting · UV/Vis spectroscopy · Fluorescence spectroscopy · Scintillation measurements · Gamma irradiation · SiPM/PMT-based readout · Data analysis

Gamma-irradiation studies will be performed in close collaboration with Radiochemistry Munich (RCM) at TUM, providing access to irradiation facilities and expertise for studying material degradation under high radiation exposure.

Expected Results

The thesis will provide a quantitative comparison of different polystyrene-based scintillator formulations. The central goal is to identify material compositions that combine:

• high optical transparency,
• high scintillation light yield,
• fast scintillation response, and
• high stability under ionizing radiation.

The results will directly contribute to the development of a new generation of long-lived plastic scintillators for radiation detection systems in nuclear facilities and hot-cell environments.

Candidate Profile

We are looking for a motivated B.Sc. student from Physics, Chemistry, Chemical Engineering, Materials Science, or a related field.

An interest in experimental laboratory work, materials science, and radiation detection is expected. Previous experience in polymer chemistry, spectroscopy, radiation detection, or scientific programming is beneficial but not required.

Research Environment

The thesis is embedded in an interdisciplinary research project involving:

Technical University of Munich (TUM)
BGZ Gesellschaft für Zwischenlagerung mbH
Radiochemistry Munich (RCM), TUM

Location: Technical University of Munich, Garching Research Campus

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Background and Motivation

Reliable discrimination between neutron and gamma radiation is an important challenge in the characterization of radioactive materials and nuclear waste. This is particularly relevant for irradiated nuclear materials, where intense gamma-ray fields can occur simultaneously with significant neutron fluxes.

Organic scintillators can exhibit different temporal scintillation profiles for electron and proton recoils. These differences can be exploited using Pulse Shape Discrimination (PSD) to distinguish neutron-induced events from gamma-ray interactions on an event-by-event basis.

High-performance PSD detectors, however, are still frequently based on liquid organic scintillators or other materials with disadvantages regarding handling, mechanical robustness, and long-term stability.

Within a joint research project between the Technical University of Munich (TUM) and BGZ Gesellschaft für Zwischenlagerung mbH, novel polystyrene-based plastic scintillators with intrinsic neutron–gamma discrimination capabilities are therefore being developed.

The project combines material development at TUM with irradiation and radiation-hardness studies in collaboration with Radiochemistry Munich (RCM), TUM, as well as dedicated neutron-beam measurements at the Laboratori Nazionali di Legnaro (INFN-LNL), Italy.

Objective of the Thesis

The objective of this Master’s thesis is the development and quantitative characterization of PSD-capable polystyrene-based plastic scintillators.

The composition of the scintillation materials and fluor systems will be systematically modified in order to enhance differences between the temporal emission characteristics of electron and proton recoils.

The resulting scintillation kinetics will be experimentally characterized and quantitatively evaluated with respect to their capability for neutron–gamma discrimination.

A central part of the thesis will be the characterization of the temporal scintillation response and, depending on the schedule of the experimental campaign, the investigation of the developed materials in well-defined neutron fields at the BELINA beamline of INFN-LNL in Legnaro, Italy.

Tasks

The thesis will include several of the following research topics:

• Literature study on Pulse Shape Discrimination in organic and polymer-based scintillators
• Selection and production of suitable polystyrene-based scintillator formulations
• Systematic variation of fluor combinations and concentrations to modify scintillation kinetics
• Optical and scintillation characterization of the developed materials
• Development and/or adaptation of fast detector readout systems for measurements of temporal scintillation profiles
• Measurement and modeling of fast and slow scintillation components
• Development and application of algorithms for neutron–gamma Pulse Shape Discrimination
• Quantitative determination of PSD performance for different material formulations
• Investigation of the energy dependence of neutron–gamma discrimination
• Measurement and analysis of proton-recoil quenching
• Determination of material-specific quenching parameters, e.g. using the Birks model
• Comparison of newly developed materials with established reference scintillators
• Scientific interpretation and documentation of the experimental results

Selected materials may additionally undergo gamma irradiation in collaboration with Radiochemistry Munich (RCM), TUM, allowing the stability of their PSD and scintillation properties under high radiation exposure to be investigated.

Experimental Campaign at INFN-LNL

A major component of the project is the experimental characterization of the developed scintillator materials at the BELINA beamline of the Laboratori Nazionali di Legnaro (INFN-LNL), Italy.

Pulsed, quasi-monoenergetic neutron fields available at this facility allow the scintillation response of the materials to be investigated under well-defined irradiation conditions.

Neutron- and gamma-induced events can be separated using Time-of-Flight (ToF) measurements, providing high-purity datasets for studying the temporal scintillation response.

For high-precision measurements of the scintillation kinetics, a Time-Correlated Single Photon Counting (TCSPC) setup will be used. This technique allows the photon emission-time probability distribution to be reconstructed on the single-photon level and differences between proton- and electron-induced scintillation to be quantitatively investigated.

In addition, quasi-monoenergetic neutrons will be used to produce well-defined proton recoils in the plastic scintillators. The resulting proton-quenching curves can be used to determine Birks parameters and provide essential input parameters for realistic simulations of future neutron and gamma detector systems.

Possible Extensions

Depending on the progress of the thesis, the project can be extended towards multifunctional plastic scintillators.

One particularly interesting approach is the incorporation of neutron-capturing elements such as ⁶Li, ¹⁰B, or gadolinium into the polymer matrix.

Such materials could potentially combine PSD-based detection of fast neutrons with enhanced sensitivity to thermal neutrons, opening a pathway towards compact multi-purpose radiation detectors.

Expected Results

The thesis aims to provide a quantitative assessment of neutron–gamma discrimination in newly developed polystyrene-based plastic scintillators.

Key outcomes are expected to include:

• identification of promising material formulations for PSD,
• quantitative temporal scintillation profiles for neutron- and gamma-induced interactions,
• determination and optimization of neutron–gamma discrimination performance,
• characterization of proton-recoil quenching,
• determination of relevant Birks parameters,
• investigation of the radiation stability of selected PSD materials, and
• derivation of material parameters for future detector simulations and detector designs.

The results will provide a basis for the development of compact and robust neutron/gamma detection systems for radiation characterization in nuclear facilities and hot-cell environments.

Candidate Profile

We are looking for a motivated M.Sc. student from Physics, Nuclear Engineering, Engineering Physics, or a related scientific or engineering discipline.

Experience or interest in one or more of the following fields is beneficial:

Nuclear and particle physics · Radiation detectors · Scintillation detectors · Fast electronics · Pulse-shape analysis · Python/C++/ROOT · Statistical data analysis

The candidate should have a strong interest in experimental detector physics and in the quantitative analysis and physical modeling of scintillation processes.

Depending on the beam-time schedule, the thesis may include participation in a multi-week experimental campaign at INFN-LNL in Legnaro, Italy.

Research Environment and Partners

The thesis is embedded in an interdisciplinary research project involving:

Technical University of Munich (TUM)
BGZ Gesellschaft für Zwischenlagerung mbH
Radiochemistry Munich (RCM), TUM
Laboratori Nazionali di Legnaro (INFN-LNL), Italy

The combination of materials development, radiation-hardness studies, detector characterization, and dedicated accelerator-based neutron measurements provides the opportunity to work at the interface of materials science, nuclear physics, and radiation detector development.

Primary location: Technical University of Munich, Garching Research Campus

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Motivation

At the Technical University of Munich, a compact electrostatic storage ring for precision experiments with low-energy ion beams is currently being commissioned. The storage ring is designed for particle energies in the range of approximately 10–30 keV and is intended for fundamental-physics experiments, including searches for ultralight dark matter and electric dipole moments.

A key requirement for reliable operation of the storage ring is the controlled injection of short and well-defined ion bunches. The currently implemented injector produces ion bunches with a temporal length of approximately 2 µs. For efficient and precisely timed injection into the storage ring, these bunches need to be shortened to 500 ns or less.

The aim of this Bachelor’s thesis is therefore to develop, construct, and integrate a fast electrostatic beam chopper into the existing injector system.

Objective

The main objective of the thesis is to develop a beam chopper that allows the currently approximately 2 µs-long ion bunches to be temporally cut down to 500 ns or less.

In contrast to the existing buncher system, the beam chopper is not primarily intended to perform longitudinal compression of the ion bunch. Instead, the unwanted temporal parts of the ion beam shall be removed by means of a rapidly switched electric field.

One possible implementation consists of a pair of electrostatic deflection electrodes driven by a fast high-voltage switching system. Outside the desired transmission window, the ion beam is deflected away from the nominal beam trajectory and directed towards an aperture or beam dump. During a short and well-defined time interval, the electric field is switched such that the selected part of the ion bunch can pass through the chopper and continue towards the storage ring.

The electrode geometry, required deflection voltage, switching speed, and high-voltage pulser requirements shall be investigated and optimized as part of the thesis.

Integration into the Existing Injector and Timing System

A central aspect of the project is the integration of the beam chopper into the already implemented timing and injection architecture of the experiment.

The existing system consists of several synchronized components, including:

Master Clock → Laser Trigger Circuit →  Injection System / Injection Bender of the Storage Ring → Buncher System 

The new beam chopper shall be fully integrated into this trigger architecture.

The Master Clock provides the common timing reference for the complete injection cycle. Starting from the laser trigger used for ion generation and/or extraction, the subsequent components of the injector are activated with precisely defined delays.

The beam chopper shall be inserted into this timing sequence and generate an accurately adjustable transmission window. The injection bender of the storage ring must subsequently be switched at the appropriate time so that the selected short ion bunch can be injected into the closed orbit of the storage ring.

Particular attention shall be paid to the reproducible adjustment of the relative delays between the individual components, as well as to switching times, trigger jitter, and timing stability.

Work Packages

1. Characterization of the Existing Injector System

At the beginning of the project, the existing injector and trigger system shall be characterized and documented.

This includes, in particular, measurements of the temporal structure of the currently generated ion bunches as well as an analysis of the existing trigger signals for the laser, buncher system, and injection bender.

Based on these measurements, the technical requirements for the beam chopper shall be defined, including:

• required transmission window,
• maximum acceptable switching time,
• required trigger levels,
• timing accuracy,
• trigger jitter,
• and synchronization requirements.

2. Development of the Beam-Chopper Concept

A suitable concept for the fast electrostatic beam chopper shall then be developed.

Relevant questions include:

• Which electrode geometry provides sufficient deflection of the ion beam?
• What deflection voltage is required?
• What electrode length and electrode spacing are suitable?
• What switching times are required to reliably generate bunch lengths of 500 ns or less?
• How does the chopper affect the trajectory and emittance of the transmitted ion beam?
• Should the beam be deflected by default and only transmitted during a short time window, or should the opposite switching scheme be used?
• How can an appropriate aperture or beam dump for the rejected part of the bunch be implemented?

The design may be supported by analytical calculations as well as electrostatic-field and particle-trajectory simulations.

3. Development and Characterization of the Fast Switching System

A fast high-voltage pulser is required to drive the chopper electrodes.

The switching system must allow the generation of a well-defined transmission window of approximately 500 ns or less. In particular, the rise and fall times of the high-voltage pulse must be sufficiently short compared with the desired bunch duration.

Suitable switching and pulser concepts shall be investigated, implemented, and experimentally characterized.

Important parameters include:

• pulse width,
• rise time,
• fall time,
• voltage amplitude,
• trigger jitter,
• shot-to-shot reproducibility,
• maximum repetition rate,
• and long-term stability.

4. Integration into the Master Clock and Trigger System

The developed beam chopper shall subsequently be integrated into the existing timing architecture of the experiment.

A suitable trigger logic shall be implemented that allows precise control of:

• the delay relative to the laser trigger,
• the opening time of the beam chopper,
• the width of the chopper transmission window,
• the synchronization with the buncher system,
• and the timing relative to the injection bender.

The goal is to obtain a fully reproducible injection sequence controlled by the central Master Clock of the experiment.

5. Mechanical and Electrical Integration into the Beamline

The developed chopper shall be mechanically and electrically integrated into the existing injector beamline.

The design must take into account the constraints imposed by:

• the existing vacuum system,
• available beamline space,
• electrical insulation,
• high-voltage stability,
• electrode mounting,
• vacuum compatibility,
• and the existing ion-beam geometry.

Where appropriate, the system may first be tested in a dedicated setup before final installation into the injector beamline.

6. Experimental Characterization with the Ion Beam

Following integration, the performance of the beam chopper shall be experimentally characterized using the ion beam.

In particular, the temporal beam profile before and after the chopper shall be measured.

The primary experimental goal is to demonstrate that the initially approximately 2 µs-long ion bunches can reproducibly be cut down to 500 ns or less.

Furthermore, the influence of different chopper pulse widths and timing delays on beam transmission and subsequent injection into the storage ring shall be investigated.

Expected Results

At the end of the Bachelor’s thesis, a functional concept and, ideally, an experimentally tested prototype of a fast beam chopper for the electrostatic storage-ring injector shall be available.

The expected results include:

• development and design of a suitable electrostatic chopper geometry,
• determination of the required deflection voltages,
• implementation or selection of a suitable fast high-voltage pulser,
• generation of an adjustable transmission window of 500 ns or less,
• synchronization with the existing Master Clock,
• integration into the existing laser trigger circuit,
• synchronization with the existing buncher system,
• synchronization with the injection bender of the storage ring,
• integration of the chopper into the injector beamline,
• and experimental characterization of the resulting bunch duration and beam transmission.

The overall goal is to establish a fully synchronized injection chain that allows short and precisely defined ion bunches to be injected into the electrostatic storage ring.

Requirements

The project is suitable for students interested in experimental physics, accelerator and beam physics, electronics, and instrumentation.

Previous experience in areas such as

• electronics,
• high-voltage technology,
• CAD,
• programming,
• vacuum technology,
• or charged-particle simulations

is helpful but not mandatory.

The thesis provides the opportunity to work directly on an active experimental setup and to gain practical experience in ion-beam physics, fast high-voltage electronics, precision timing systems, vacuum technology, beam diagnostics, and experimental instrumentation.

Contact:

Dr. Hans Th. J. Steiger
Hans.Steiger@tum.de

Our group is actively developing optical atomic magnetometers, a type of sensors using light-atom interactions to detect magnetic fields.This approach, sitting on the junction of laser-optics, quantum-optics and atom-physics, offer a wide range of possibilities for undergraduate and graduate students, from theoretical approaches to practical experiments.
Possible student trainee positions and thesis projects are:

• Characterization of a non-magnetic Optical Atomic Magnetometer Array
• Development of a non-magnetic Free Space Cesium Magnetometer
• Development of an Optical Earth Field Cesium Magnetometer
• Manufacturing and Characterisation of Cesium Vapour Cells
• Building an Multivoxel Magnetometer

If you are interested or want learn more on this topic - feel free to contact maximiliandominik.huber@tum.de and philipp.roessner@tum.de!

Several possibilities for Bachelor and Master theses are available, please contact peter.fierlinger@tum.de or hans.steiger@tum.de .

Many topics for Bachelor and Master thesis are currently available! If yor are interested contact peter.fierlinger@tum.de

We contribute to international neutrino experiments focused on detector development, with a special focus on innovative scintillation detectors, but also data analysis. We are supporting projects such as JUNO, ANNIE, EOS, and Liquid Scintillator R&D, which investigate neutrino properties and interactions across different energy ranges.

If you are interested or want to learn more on this topic - feel free to contact: Dr. Hans Th. J. Steiger (hans.steiger@tum.de).

Student trainee positions and thesis projects are available on all aspects of the project:

• Passive magnetic shielding from mumetal
• Active magnetic compensation
• Detection of magnetic signatures with optically pumped magnetometers
• Analysis of existing data
• Simulation of bio-magnetic signals
• Ongoing work with patients in fMCG acquisition

Please contact lena.wunderl@tum.de if you are interested!

Several possibilities for Bachelor and Master theses are available, please contact florian.kuchler@tum.de

Several possibilities for Bachelor and Master theses are available, please contact peter.fierlinger@tum.de

Several possibilities for Bachelor and Master theses are available, please contact florian.kuchler@tum.de