Bachelor’s Thesis in Physics

The DEAP dark matter detector has been taking physics data for 3 years, searching for interactions between galactic dark matter particles and the argon target material. This unique dataset spanning hundreds of TB offers many opportunities to study liquid argon scintillation physics, optical processes, and background suppression techniques. MSc and BSc topics related to background suppression through pulse shape analysis, Dark Matter signal modelling, and the study of rare coincidences, are available. Students work within an international collaboration of over 100 physicists and might have the opportunity to visit the detector site at SNOLAB in Canada. Students will acquire skills in data analysis and statistics, C++ and/or python programming, Linux/Unix command line operation, Monte Carlo simulation, and in working with large datasets on high performance computing systems. Students have the chance to practice communicating physics results to other students and experts from many different institutions by presenting their work in bi-weekly project-wide analysis phone-conferences.

Our group at the Technische Universität München (TUM) (https://www.denseandstrange.ph.tum.de/) studies the properties of hadronic interactions and their implications for astro-particle physics by means of accelerator experiments. The studies are connected to indirect searches for Dark Matter annihilation or decay products, such as stable Standard Model (anti-)particles in final state: p, anti-p, e+, e-, d, anti-d and others. These searches are currently being performed by several satellite- or balloon-based experiments. In particular, low-energy anti-deuterons are very promising probe for such searches, since cosmic ray-induced background is expected to be low. However, these studies suffer from the lack of our poor current knowledge of inelastic interaction cross-sections of anti-deuterons with matter, which are needed for precise calculation of primary and secondary anti-deuteron fluxes expected near the Earth.

The goal of the here advertised project is to study the inelastic interaction of (anti-)deuterons with matter using the ALICE detector at the CERN LHC. In ultra-relativistic collisions at the LHC, (anti-)deuterons are produced in large amounts, which, together with unique ALICE tracking and PID capabilities, allows one to investigate the inelastic interaction of (anti-)deuterons with the detector material. The idea of the project is to use the ALICE TPC and TOF sub-detectors for (anti-)deuteron identification and the material of the TRD sub-detector located between them as a passive absorption target. As a result, an effective anti-d + A inelastic interaction cross-section can be calculated, where A represents the properties of an averaged TRD material element.

Outline, calculation and design of a purification cryostat to produce isotopically pure He-4 out of natural helium in a continuous manner based on the superfluid heat flush principle.

The FRM II is presently testing and will subsequently install a source to produce ultra-cold neutrons (UCN) in the reactor. In the central section of this UCN source, helium is used for cooling. By passing through, the cooling agent helium will be irradiated by neutrons, which create radioactive tritium out of the He-3 portion. This negative side effect can be avoided respectively reduced to a permissible level if isotopically purified He-4 with no traceable He-3 content is used.

Sources for isotopically pure He-4 are scarce and availability varies with market demand. In order to ensure continuous operation of the UCN source the availability must be secured. For this reason such an isotopic purifier shall be build.

In this thesis a small illustrator shall be build up, and its cool down characteristics shall be measured.

Contact / Supervisor:

Dr. Andreas Frei, Tel. 089 289 14260, andreas.frei@tum.de

Mit Hilfe von Moleküldynamiksimulationen sollen freie Energien der Bindung von einem Liganden an ein Enzymmolekül berechnet werden. Der Ligand hemmt die Aktivität des Enzyms durch Bindung an die aktive Tasche des Enzyms. Durch Simulationsstudien kann der Einfluss einzelner chemischer Gruppen auf die Bindeaffinität (=Stärke der Bindung) des Liganden untersucht werden. Ziel der Simulationsstudien ist es, die Bedeutung einzelner chemischer Gruppen für die Bindeaffinität zu analysieren und mögliche Wege zu Erhöhung der Affinität aufzuzeigen.

Infrarotstrahlen. Kern der Funktionsweise dieser Membran ist, dass in der Membran aufgenommene Wärme über das darunterlegende Adernetzwerk schnell abgeleitet werden kann. Welche Netzwerkeigenschaften ermöglichen den schnellen Wärmetransport? Sie simulieren den Wärmetransport in Adernetzwerken der Grubenmembran von Klapperschlangen in Matlab. Variation der physikalischen Parameter der Strömung zeigen Ihnen auf wie robust der Wärmetransport ist und welche Netzwerkeigenschaften hierzu wichtig sind. Die Hoffnung ist, von der Klapperschlange neue Design Prinzipien für den Wärmetransport in Solarkollektoren zu finden.

Rattlesnakes orient themselves via a highly sensitive membrane for measuring infrared radiation. The core of the functioning of this membrane is that heat absorbed in the membrane can be quickly dissipated via the underlying vascular network. Which network properties enable the rapid heat transport? You will simulate the heat transport in the vascular networks of the sensory organ of rattlesnakes in Matlab. Variation of the physical parameters of the flow show you how robust the heat transport is and which network properties are important for this. The hope is to find new design principles for the heat transport in solar collectors from the rattlesnake.

Lithium ion microbattery is the type of battery where all components (electrodes, membrane, and packaging) are in the thin film format. The need for such types of batteries is to provide light-weight and shape flexible solid-state energy sources for some miniature medical devices, such as implantable pumps, biosensors, and wireless capsule endoscopes. Membrane based on mixing both lithium slat and polyelectrolyte block copolymers will be prepared and investigated using small-angle X-ray scattering and impedance spectroscopy. The effect of a third component such as inorganic SiO₂ nanoparticles on the morphology and conductivity of the prepared thin film membranes will be studied. The best performing membrane will be assembled between two electrodes to probe the performance of a complete assembly of a solid-state lithium battery. The project will involve a literature review, sample preparation, x-ray scattering and impedance spectroscopy.

The measurement of concentration profiles of elements as function of depth is important in many fields of materials science and physics. An important and often employed class of depth profiling methods uses sputter depth profiling, i.e. a beam of (typically heavy) energetic ions ejects particles from the sample and proceeds into depth by removal of material. The ejected particles can be detected by various methods, for example by secondary ion mass spectrometry (SIMS) or glow discharge optical emission spectroscopy (GDOES). While these methods are well established for smooth surfaces, their applicability on rough surfaces or multi-phase materials is more questionable and matter of debate since years. The increase of computing power during the last years enables the dynamic simulation of sputter depth profiling methods on three-dimensional surfaces using the existing code SDTrimSP-3D. This code will be used to model depth profiling on rough surfaces. The modeled results will be compared to existing experimental data.

Contact: Dr. Matej Mayer

The CRESST (Cryogenic Rare-Event Search with Superconducting Thermometers) experiment operated at the Gran Sasso underground laboratory employs highly sensitive cryogenic detectors to the search for signals of the elusive dark matter particles, a main ingredient of the Universe whose nature is still unknown. 

The energy thresholds reached in CRESST-III are the lowest in the field, making CRESST the most sensitive experiment to light dark matter. Optimisation of the tungsten thin-film thermometers and of the techniques for data analysis promise still improvement in energy threshold, which could significantly boost the physics reach of the experiment.

Scientific topics

A student can contribute to:

- design, production and prototyping of new CRESST detectors in Munich 

- development of high purity crystals 

- development of new software tools for data analysis

- dark matter data analysis

and, if interested, can participate in the operation of the main experiment at Gran Sasso. 

Thesis can be carried out at the Chair for astroparticle physics of the Physics Department and/or at the Max-Planck-Institute for Physics (MPP). Supervision at the Physics Deptartment by Prof. Schönert / Dr. Strauss and at the MPP by Prof. Schönert /  Dr. Federica Petricca. Please contact schoenert@ph.tum.de, raimund.strauss@ph.tum.de and petricca@mpp.mpg.de for further information. 

The QCD phase state diagram is object of study both in theory and in
experiments. A particular interesting phase is the one of high chemical potential.
Scope of this thesis is to study a recent paper on this subject in which
a version of QCD with two colors and two flavors of fermions has been studied on the
lattice as a function of the chemical potential mu and the temperature T.
In particular it is found that the quarkyonic region, where the behaviour of the quark number density and the
diquark condensate are described by a Fermi sphere of almost free quarks distorted by a BCS
gap, extends to larger chemical potentials with decreasing lattice spacing or quark mass. In both
cases, the quark number density also approaches its non-interacting value. The pressure at low
temperature is found to approach the Stefan–Boltzmann limit from below.

Our group is developing nuclear magnetic resonance imaging scanners, reminiscent of the MRI machines found in hospitals. In contrast to clinical machines our devices can access much smaller samples, down to single molecules. Imaging of these tiny objects requires strong magnetic field gradients, which we typically create by nano-fabricated conductors serving as electro-magnets. 

One important issue in these devices is heating and thermal expansion of the conductors, which degrades the quality of the MRI imaging. So far we have been relying on trial-and-error to assess the impact of this effect. 

Your task will be to put this research on a more solid foundation, by developing numerical models for current and thermal flows in nanoscale conductors. If things work out well, you might also be able to validate the results of your models by measurements on a real chip-scale MRI device. 

Organic solar cells have gained significant improvements via novel organic synthesis methods and optimized fabrication routes, especially with respect to their potential roll-to-roll processing for large-area device manufacturing. Printing technique, such as slot-die printing, allows for up-scaling to industrial-oriented scale which is not the case for laboratory deposition techniques like spin coating. This experimental bachelor thesis aims at understanding organic solar cell working principle and the corresponding fabrication process of solar cell via advanced slot-die printing technique. Besides, the relationship between its efficiency and morphology will be investigated by different measuring technique, such as AFM and small angle x-ray scattering. The project will involve a literature review, sample preparation process, data analysis and result exhibition.

The extreme environment in a fusion plasma reactor, especially the heavy load with hydrogen, leads to various unexpected effects. The Plasma Component Interaction research group at the Max Planck Institute for Plasma Physics (IPP) investigates these effects. One material system of interest is the Fe-W system, which exhibits tungsten enrichment on the surface under hydrogen bombardment. In order to separate the underlying mechanisms and their contribution, well-characterised model samples will be prepared and treated (annealed, ion beam bombarded) and their response to these treatments will be analysed by ion beam analyses and scanning electron microscopy. This thesis should contribute to answering the question: Does ion- and/or hydrogen-enhanced segregation exist in the system Fe-W?

Contact: Dr. Martin Balden

Neutronsterne sind die dichteste Objekte in unserem Universum und  keiner weiss noch was drin ist.

Es  könnte  nur Neutronen geben oder andere Hadronen,  wie  Hyperonen  ( Baryonen mit mindest  einem Strange  quark), oder man  könnte  sogar ein  Quark GLuon Plasma  dadrin finden.

Diese sehr untescheidlichen Szenarios kann man nur testen, wenn man die Wechselwirkungen zwischen den verschiedenen Konstituenten bestimmt. Wechselwirkungen zwischen  Hyperonen sind bisher nicht genau bekannt und das Themas diese Arbeit ist die Untersuchung der Korrelationen zwischen Lambda und Xi HYperonen.

Es werden Daten benutzt, die von mit dem ALICE Detektor am LHC aufgenommen worden sind und die Aufgabe besteht eine neue Analyse zu entwickeln, die uns erlauben wird verschiedene theoretische Vorhersage zu testen.

 Die Analyse wird in C++ geschrieben und es werden auch Simulationen durchgeführt werden.

Eine Vorkenntis in C++ is willkommen aber nicht notwendig. Experte im Bereiche der Analyse und Simulationen werden die direkte Betreuung der Arbeit übernehmen.

Die Kandidatin/ der kandidat werden die Möglichkeit haben, in Kontakt mit der internationalen ALICE COllaboration am CERN zu kommen.

NEPOMUC provides the world’s most intense positron beam. The positron is a applied as unique probe for material defect studies, surface investigation and fundamental research in quantum physics.
For the experiments we typically use electrostatic acceleration to implant the positrons in the material, with the sample holder being charged to tens of kilovolts with respect to ground. In these conditions it is extremely difficult to subject the sample to electric currents or potentials during the measurement, which limits the use of e+ for novel in-operando studies relevant for the construction of batteries, solar panels and integrated electronics.
At NEPOMUC we are now developing an active sample holder which makes use of light to
both power its onboard instrumentation and to communicate with the control system.
As an applicant you will be tasked, with the support of the NEPOMUC team and the TUM
facilities, to build a prototype of such sample holder, test it and program its onboard MCU.
The work will involve the following tasks:

1. Progressive assembling of the sample holder, performing electrical tests to ensure functionality after every assembling step.
2. Programing the onboard MCU and running all of the subsystems of the sample holder in a test environment.
3. Designing a control protocol to be run over an IRDA optical bridge and implement it.
4. esting the autonomous functioning of the sample holder, with the system being powered through light and communicating through an optical bridge.
5. Testing the system in UHV conditions with a 30 kV bias applied.

As an applicant you will be given the opportunity to experience first hand the development of
highly specialized scientific equipment. We attach particular importance to the training aspect
during the internship; as such you are not required to be able to carry out the entire task by
yourself, but you will be helped and tutored by our team. This said a certain level of autonomy
is expected from you.

Hast Du Dich schonmal gefragt, was passieren würde wenn man einen Lichtpuls zwischen zwei Spiegeln einfängt? Genau das wollen wir versuchen und damit die Grenzen der Physik im Bereich der hohen Laserleistungen austesten. Für den benötigten Versuchsaufbau müssten Spiegelaufbauten simuliert und konstruiert werden. Alles weitere erfährst Du bei einem persönlichen Gespräch.

Have you ever asked yourself what would happen if you trap a pulse of light in between two mirrors? This is exactly what we are planning to do and thereby determine the boundaries of high-power laserphysics. For the experimental setup, simulation and design studies have to be performed. If you are interested, feel free to get in touch.

Neutrinos were discovered in 1956, but only at the turn of the millennium was it experimentally proven that the three known neutrino types can convert into one another. These flavor oscillations are possible only if neutrinos have nonzero mass, which is currently the only established contradiction to the standard model (SM) of particle physics. From tritium beta  decay experiments and cosmological observations, we know that their masses are very small—less than 10^-5  of the electron mass. Neutrinos are the only fundamental spin-1/2 particles (fermions) without electric charge. As a consequence, they might be Majorana fermions, articles identical to their antiparticles. This is a key ingredient of some explanations for why matter is so much more abundant than antimatter in today’s Universe and why neutrinos are so much lighter than the other elementary particles. Majorana neutrinos would lead to nuclear decays that violate lepton number conservation and are therefore forbidden in theSMof particle physics. The so-called neutrinoless double-b (0nbb) decay simultaneously transforms two neutrons inside a nucleus into two protons with an emission of two electrons. The GERDA experiment and future LEGEND-200 experiment are located in the Italian Gran Sasso underground laboratory and are leading experiments in the world-wide competion. 

We offer the opportunity to carry out exciting experimental BSc and MSc theses with focus on liquid argon detector developments, germanium detector developments, data analysis and/or Monte Carlo simulations. You would be fully integrated in the research team and work closely together with our international partners. 

Pattern formation in cell layers is experimentally studied in both biological and synthetic systems. For instance, in developmental biology, the correct relative positioning of different cell types is essential to ensure that the organism functions correctly. This project will explore some of the underlying physical concepts with a theoretical approach. Whilst many models for pattern formation exist, the focus here is on cellularized systems with interactions only between neighboring cells. This form of communication has previously received less attention from theoretical research than e.g. long-range diffusible signals as a means of communication. Our goal is to explore fundamental limits and patterning concepts with a simple top-down model based on cellular automata. Building on previous work, the project will concentrate on investigating how the interaction range between cells can influence the ability to realiably create typical biological patterns such as a heterogeneous stripe-pattern. Successful work on this project requires some background in the concepts and methods of statistical physics, as well as skills in computational problem solving.

Thermoelectric (TE) materials can be used in TE generators to convert a temperature gradient directly into electrical energy. Therefore they are of great interest in terms of waste heat recovery or the use of solar thermal energy. To be qualified as good TE materials, polymers should have a high Seebeck coefficient S and electrical conductivity σ. In this bachelor thesis polymer films will be post-treated with different methods in order to increase S and σ, leading to a novel efficient TE generator. This project will involve a literature review, polymer film preparation/treatment and TE measurements of the fabricated films.

Find the best strategy to measure the width difference ΔΓ between even and odd CP eigenstates of the B⁰_d comparing various analyses methods, e.g. :

Two component fit, weighting, moments, multi-parameter log-likelihood fit, etc.

The detection of gravitational waves was one of the biggest scientific
breakthroughs of the past decade. Yet, little is known about the
polarization of these waves. In this thesis, the student should learn the
basic theory of gravitional waves in General Relativity drawing on
analogies with electromagnetic waves. Based on these properties, it will
be analyzed which interferometer configurations and which type bineary
black hole/neutron star merger events are optimal for an accurate
measurement of polarization. The present observational status is reviewed.
Using the available data of the advanced Virgo and LIGO detectors, the
student is expected to perform numerical studies of a few binary-BH events
with respect to their polarization signature.

No prior knowledge of general relativity is required. Learning the basics
of the theory is part of the thesis work.

Am Positronenexperimente zur Defektsusheilung in Kristallen bei hohen Temperaturen mittels eines neuartigen LED-Heizers FRM II existiert mit NEPOMUC(Neutron-induced Positron source Munich) die Anlage mit dem weltweit intensivsten Positronenstrahl. Um mit diesem Strahl insbesondere Kristalldefekte und deren Ausheilung zu untersuchen  ist ein heizbarer Probenhalter notwendig. Da mittlerweile kostengünstige LEDs mit hoher Lichtstrom (> 1.1 × 10
4lm bei 100 W Leistungsaufnahme) verfügbar sind, soll ein neuer Probenhalter gebaut werden, um Temperaturen von mehr als 1300 K zu ermöglichen. Nach erfolgreichem Aufbau soll das Ausheilverhalten verschiedener Metallproben mit in-situ Positronenannihilationsspektroskopie gemessen werden.

Die Arbeit gliedert sich in folgende Abschnitte:

1. Konstruktion eines Hochvakuums-, Hochspannungs- und Hochtemperaturfähigen Aufbaus
   
2. Einbau und Inbetriebnahme am Spektrometer vor Ort
3. Messung des Ausheilverhalten von Kristalldefekten in Metalleinkristallen

Perovskite solar cells have dramatically progressed within the last 2 years. Meanwhile championship perovskite solar cells have demonstrated efficiencies above 25%. The general intent of this work is to optimize printed perovskite thin-films for high-quality photovoltaic devices. This will include material and solution preparation, optimizing the printing process and analysis of printed films and/or devices. Analytical methods will focus on film morphology, spectroscopic material properties, crystal structure analysis and current-voltage measurements of self-built solar cells. The thesis also includes a brief literature review.

Amphiphilic block copolymers having a permanently hydrophobic block and a thermo-responsive block form nanoparticles, or rather core-shell micelles, in aqueous solution. The structure of these micelles is controllable by changing the temperature or the ratio between the hydrophobic and the hydrophilic block. These properties enable amphiphilic block copolymers as candidates for a wide variety of applications, such as drug delivery. The main goal of this thesis is to investigate above which polymer concentration micelles form and to characterize the size of the micelles by fluorescence correlation spectroscopy.  For more information, please contact Prof. Christine Papadakis, papadakis@tum.de.

Poly(2-ethyl-2-oxazoline) (PEtOx) in aqueous solution is a responsive polymer which suddenly dehydrates, becomes water-insoluble and collapses, when the sample is heated through the lower critical solution temperature (LCST). We investigate molecular brushes, in which PEtOx chains are densely-grafted on a polymer backbone. The compact architecture has an influence on the dehydration and collapse behavior, and the entire brush changes structure when the side chains collapse.

In the suggested bachelor project, the influence of the architecture on the collapse behavior shall be investigated using Fourier-transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). After a literature research, samples will be prepared and measured, and data analysis will be carried out. For more information, please contact Prof. Christine Papadakis, papadakis@tum.de.

In nature, quarks and gluons cannot exist as free particles. They are always confined into hadrons. Unfortunately, the equations of the strong interaction that governs the behavior of quarks and gluons cannot be directly solved at energy scales where hadrons form. Hence theoretical predictions of hadron properties such as their masses and decay modes are very difficult. This is in particular true for hadrons that are made of the three lightest quarks: „up“, „down“, and „strange“. Also on the experimental side much confusion exists on what concerns masses, decay widths, and the assignment of quantum numbers of some observed hadrons, let alone the interpretation of their internal structure.

Our group participates in the COMPASS experiment at CERN, where we study the production of mesons (hadrons with integer spin) in the scattering of a 190 GeV pion beam off a stationary proton target. The produced highly excited mesons have extremely short life times of the order of 10^-24 seconds and can hence be measured only via their decay products. Our group employs and develops mathematically involved statistical analysis tools in order to identify the produced mesons with high sensitivity and to measure their properties with high precision. We have recently found a new meson with surprising properties and also did groundbreaking work on precision measurements of the properties of the pion. This science addresses one of the last open questions of the Standard Model of particle physics, which is the understanding of the strong force at large distances and low energies.

We offer thesis topics, which cover a wide range of subjects in strong-interaction physics, statistics, and/or computer science. The thesis work can start at different levels within the analysis chain: from the selection of a reaction process itself up to the final fitting process leading to scientific publications. The topic can be chosen according to personal preference and interest.

Experience in computer programming is helpful, but not required.

Contact: Boris Grube bgrube@tum.de, room PH1 3574, Tel. 089 289 12588

Rare event searches looking for neutrino and dark matter interactions are performed with highly sensitive detector systems, often relying on scintillators, especially liquid noble gases, to detect particle interactions. Detectors consist of structural materials that are assumed to be optically passive, and wavelength-shifting materials that absorb photons and re-emit them at wavelengths where their detection is more easy or efficient. MSc theses are available related to measuring the wavelength shifting efficiency of a number of materials that might be used in future detectors. Furthermore, measurements to ensure that presumably passive materials do not re-emit photons, at the low level relevant to the detectors, can be done. Part of the thesis work can include Monte Carlo simulations and data analysis for current and upcoming dark matter detectors, to study the effect of different levels of desired and nuisance wavelength shifting. In this project, students will acquire skills in photon detection, wavelength shifting technologies, vacuum systems, UV and extreme-UV optics, detector design, and optionally in C++ programming, data analysis, and Monte Carlo techniques.
The work will be done in the context of the DarkSide-20k/DEAP-3600 and LEGEND nternational collaborations. This work is done in close collaboration with institutions in Canada, Poland and in Italy with the option of visiting the collaborating institutions. Students have the chance to practice communicating physics results to other students and experts from many different institutions by presenting their work in bi-weekly project-wide phone-conferences.

Outline, calculation and design of a purification cryostat to produce isotopically pure He-4 out of natural helium in a continuous manner based on the superfluid heat flush principle.

The FRM II is presently testing and will subsequently install a source to produce ultra-cold neutrons (UCN) in the reactor. In the central section of this UCN source, helium is used for cooling. By passing through, the cooling agent helium will be irradiated by neutrons, which create radioactive tritium out of the He-3 portion. This negative side effect can be avoided respectively reduced to a permissible level if isotopically purified He-4 with no traceable He-3 content is used.

Sources for isotopically pure He-4 are scarce and availability varies with market demand. In order to ensure continuous operation of the UCN source the availability must be secured. For this reason such an isotopic purifier shall be build.

In this thesis the thermodynamical properties of the purifier shall be simulated with COMSOL.

Contact / Supervisor:

Dr. Andreas Frei, Tel. 089 289 14260, andreas.frei@tum.de

Das COMPASS-Experiment am CERN zeichnet für Reaktionen hochenergetischer Teilchenstrahlen große Mengen komplexer Daten auf. Um den physikalischen Inhalt genau zu verstehen, ist sorgfältige Datenanalyse notwendig, die ein genaues Verständnis des Detektors voraussetzt, das teilweise aus den Daten selbst gewonnen wird. Durch Verfeinerung der Kalibration der Detektorsignale unter Ausnutzung von Korrelationen ziwschen verschiedenen Detektorbereichen lässt sich die Präzision erheblich steigern.

Die Arbeit setzt Programmierkenntnisse (z.B. C++), bzw. zumindest großes Interesse daran voraus.

Disorder has a drastic influence on transport properties. In the presence of a random potential, a system of electrons can become insulating; a phenomenon known as many-body localization (MBL) that has been envisioned by the Nobel laureate Phil Anderson. However, even beyond the vanishing transport such systems have very intriguing properties. For example, many-body localization describes an exotic state of matter, in which fundamental concepts of statistical mechanics break down. In this project we will explore these exciting aspects of many-body localization.

Thermoresponsive block copolymer thin films can be applied in vapor sensors detecting water and organic cosolvents. As sensitive layers, they exhibit characteristic swelling kinetics steered by cosolvent mediated effective interactions between individual polymer chains. This bachelor thesis will cover the fundamentals of responsive polymers and the cononsolvency effect. The experimental part revolves around thin film preparation and swelling behavior analysis in our vapor chamber. The project will include a brief literature review.

PEN ist ein industriell hergestelltes Plastikmaterial, das das Interesse als Szintillator für Experimente der Teilchenphysik auf sich gezogen hat. PEN szintilliert im blauen Regime, ideal für viele Photosensoren. Zusätzlich hat PEN exzellente mechanische Eigenschaften. Ausserdem konnte eine sehr extrem niedrige Belastung surch natürliche Radiositope nachgewiesen werden. Dies macht PEN als strukturelles, szintillierendes Material für Experimente zur Suche nach extrem seltenen Ereignissen interessant. In diesem Zusammenhang wurden PEN Platten für das LEGEND200 Experiment zur Suche nach neutrinolosem Doppelbetazerfall hergestellt. Im Rahmen dieser Arbeit sollen die optischen Eigenschaften diser Platten vermessen werden. Es sollen verschiedene PEN Samples mit einem existierenden Messaufbau auf Emissions- und Absorbtionsspektrum, sowie Lichtausbeute und Attenuierungslänge untersucht werden.

PEN is an industrial plastic that  has drawn the interest as a new type of plastic scintillator material. PEN scintillates in the blue regime, which is ideal for most photosensor devices. In addition, PEN has excellent mechanical properties and very good radiopurity has been achieved, which makes it an ideal candidate as an active structural scintillator material in low-background physics experiments. In this context, PEN plates have been produced for use in the LEGEND200 experiment for the search of neutrinoless double beta decay. The goal of this thesis will be the measurement of the main optical properties of PEN. The emission and absorption spectrum, attenuation length, and light output will be measured for several PEN samples using existing setups.

In 2011, a new solid lithium electrolyte was reported, featuring liquid-like Li-ion conduction in a crystalline solid matrix. The ultrafast room temperature transport of tetragonal Li10GeP2S12 (LGPS) with a conductivity of several mS/cm exceeds the values of most crystalline Li conductors by one order of magnitude. Accordingly, there has been a strong search in realizing LGPS-type materials based on the homologous elements Si and Sn. LXPS (X=Ge,Sn,Si) electrolytes appear in a tetragonal and orthorhombic modification. While the orthorhombic phase is an undesired inpurity in the LGPS electrolyte, orthorhombic LSPS leads to an enhancement of the conductivity. A possible explanation of the increased conductivity,
is an interplay of orthorombic and tetragonal LSPS, which distorts tetragonal LSPS. This distortion may lead to a favorable opening of Li-channels. The aim of this work is to investigate the effect of distortion on the materials conductivity for tetragonal LSPS. To do so a machine-learned force-field will be provided. The project will start with the construction of distorted LSPS structures and will then focus on Molecular Dynamics (MD) calculations for appropriate LSPS ensembles at finite temperatures. Finally, the conductivities will be calculated via the Nernst-Einstein relation.

Das LEGEND Experiment wird z.Zt. zur Suche nach nutrinolosem
Doppelbetazerfall mit Hilfe von Germaniumdetektoren augfgebaut.
Die LEGEND Gruppe am MPI untersucht in Muenchen zur Vorbereitung
der Analysen in speziell konzipierten Teststaenden
die fundamentalen Eigenschaften der Ladungstraeger in Germanium.
Zur Simulation von Halbleiterdetektoren hat die Gruppe u.a.
das open-source Programmpaket SSD.jl entwickelt.
Bachelorarbeiten koennen vergeben werden fuer
 -- spezialisierte Datennahme und Qualitaetskontrolle,
 -- Simulation von bestimmten Detektorkonfigurationen,
 -- Arbeiten am SSD.jl Paket [incl. Einarbeitung in die Sprache Julia],
 -- Simulationen fuer die Physik von LEGEND.
Interessenten moechten bitte Dr. Iris Abt [isa"at"mpp.mpg.de] und
Dr. Oliver Schulz[oschulz"at"mpp.mpg.de] kontaktieren.

The combination of quantum mechanical calculations and machine-learning techniques has led to massive advances in the high-throughput computational screening of materials and molecules. Here, it is frequently stated that training data obtained from quantum mechanical simulations (e.g. using density functional theory) is 'noise-free', because the calculations can be numerically converged to very high precision. However, this assumes that the self-consistent algorithm used to calculate the Kohn-Sham determinant always converges to the correct ground-state solution, which is by no means guaranteed. The goal of this project is to quantify the noise introduced into DFT data by different choices of intital guess and convergence acceleration. To this end, the true ground-state solutions for a representative set of molecules will be determined using wavefunction stability analysis. This benchmark will allow the development of an effective 'black-box' method for obtaining well-converged training data. Furthermore, the effect of noise on quantum mechanical machine-learning applications will be studied.

The candidate should be interested learning the fundamentals of density functional theory and supervised machine learning. The project will require the development of automated workflows for high-throughput electronic structure calculations and data analysis. Experience with a scripting language (e.g. Python) and UNIX operating systems is advantageous but not mandatory.

Questions about the project can be directed to johannes.margraf@ch.tum.de.

Amphiphilic block copolymers having a permanently hydrophobic block and a responsive block form core-shell micelles in aqueous solution. The structure of these micelles is controllable by changing the temperature or pH value. These properties enable amphiphilic block copolymers as candidates for a wide variety of applications, such as drug delivery. The main goal of this thesis is to investigate the effect of the pH value on the transition temperature and the micellar size. At this, differential scanning calorimetry (DSC) and dynamic light scattering will be used. For more information, please contact Prof. Christine Papadakis, papadakis@tum.de.