Ph.D. Theses

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 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. [...]

Monolithic Active Pixel Sensors (MAPS) are candidates to serve as vertex and tracking detectors in the future lepton colliders. This is due to the many advantages they provide compared to hybrid sensors, such as a reduced material budget and lower power consumption. [...]

The quest to understand the chemical processes that govern natural phenomena hasbeen a central theme in scientific research throughout the history of humanity. Fromthe large scales studied in astronomy and atmospheric sciences to the intrincate systemsin biochemistry, all such processes ultimately trace back to the dynamics of molecules atatomic and subatomic levels. [...]

In dieser Arbeit werden Multiwellenlängen-(MWL)-Daten zur Untersuchung der Emissionsprozesse von Gamma-Ray Bursts (GRBs) verwendet. Dabei kommen Beobachtungen des High Energy Stereoscopic System (H.E.S.S.) zum Einsatz, das für sehr hochenergetische (VHE) Gamma-Strahlung sensitiv ist [...]