Ph.D. Theses

Vector-like quarks are predicted in various scenarios in beyond the Standard Model (SM) theories. This work presents a search for a single vector-like top quark (T) decaying into a top quark and a SM Higgs boson (T!tH), in the T mass range from 600 GeV to 1200 GeV. [...]

The high global warming potential of CH4 makes the catalytic conversion of residual CH4 in exhaust gases vital for applications such as CH4 combus tion engines and turbines, power-to-gas or biomass plants. The most active heterogeneous catalyst system for complete CH4 oxidation at low temper atures (< 650K) in lean reaction gas mixtures (overstoichiometric oxygen content) is the class of Pd-based catalysts supported by (mixed) metal oxide supports. [...]

The past decades saw the development of X-ray induced Coulomb ex-plosion imaging as one of several methods to perform single-particlemolecular imaging on a femtosecond timescale. It has been enabledby the advent of x-ray free electron lasers. [...]

Recent advances in laser technologies such as x-ray free-electron lasers and high harmonic generation have led to ever-shorter light pulses that enable us to probe ultrafastnuclear and electronic dynamics in atoms and molecules. Theoretical quantum dynamics simulations are indispensable in gaining deeper insights into these ultrafastprocesses. [...]

Highest resolution X-ray microscopy requires high numerical aperture (NA) optics ofexcellent quality which allow to focus X-ray beams to small focal points. MultilayerLaue lenses (MLLs) are a new type of diffractive optic with the capability to focushard X-rays with high efficiency to nanometer spots. [...]

Particle accelerators are sophisticated scientific facilities that require precise but time-consuming optimisation to achieve optimal performance. Considering benchmark tasks at the ARES and LCLS facilities, this dissertation proposes methods to deploy simulation-trained reinforcement learning (RL) policies for accelerator tuning zero-shot to the real world and novel tuning tasks, while comparing their performance to traditional methods. [...]

Attosecond and few-femtosecond light pulses provide the time resolution required to track and control the very first instants of electron dynamics in molecules and condensed matter. Since its first demonstration, High-order Harmonic Generation (HHG) sources have been at the core of experimental schemes aiming at unravelling ultrafast electron motion. [...]

This thesis presents a novel method for studying capillary imbibition and vapor sorption in mesoporous silicon (PSi) with white light spectroscopy. By Fast-Fourier-Transformation of thin film interference and parallel analysis of an optical microcavity within the porous layer, it achieves high precision in monitoring fluid dynamics. [...]

This thesis presents two research works carried out within the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC): the system validation of the scintillator section of the High Granularity Calorimeter (HGCAL), and a search for a heavy resonance coupling to top quarks and produced in association with top quark pairs in proton–proton collisions at center-of-mass energies of 13 and 13.6 TeV. For the High-Luminosity LHC (HL-LHC) phase, the endcap calorimeters of CMS will be replaced by the HGCAL, a high-precision sampling calorimeter designed to cope with the extreme radiation and pileup conditions expected at the HL-LHC. [...]

The field of semiconductor manufacturing is heavily dependent on the process of photolithography. Photoresists undergo chemical changes when exposed to light, allowing for patterning of the silicon before other processing steps such as etching and ion implantation are performed. [...]