# Master Theses

 2018-10-1414:27 [PUBDB-2018-03781] Master Thesis Schippers, S. Construction and Characterization of a Cs-Sputter Ion Source for theGeneration of Intense Beams of Negatively Charged Atomic Ions 148 pp. (2017) = Masterarbeit, Justus-Liebig-University Giessen, 2017 In this thesis the construction and a first characterization of a new cesium-sputterion source for the generation of intense beams of negatively charged atomic ions ispresented. Such an ion source was manufactured by the mechanical workshop of thephysics department at Justus-Liebig-University Giessen. [...] 2018-09-1621:23 [PUBDB-2018-03516] Master Thesis Moortgat-Pick, G. Precise predictions for same-sign Vector Boson Scattering at the LHC 1-100 (2018) = Masterarbeit, University of Hamburg, 2018 The scattering of two vector bosons is a crucial class of processes for the electroweak theory and has only recently been observed at the Large Hadron Collider.This thesis presents detailed predictions for cross sections and differential observables at leading order for the scattering of two positively charged vector bosons at a hadron-hadron collider with a centre-of-mass energy of $\sqrt{s} = 13 \text{ TeV}$.This involves predictions at parton level as well as predictions matched to parton shower.Two cases are studied: We provide predictions for vector boson scattering derived with fixed renormalisation scale and factorisation scale and for dynamically assigned scales.All results are computed with the Monte Carlo event generator WHIZARD and are validated in the course of an international collaboration.. Restricted: PDF PDF (PDFA); 2018-09-1108:59 [PUBDB-2018-03426] Master Thesis Kärtner, F. Characterization of laser to RF ynthesis and synchronization techniques Hamburg 100 pp. (2018) = Masterarbeit, Technische Universität Hamburg-Harburg, 2018 High-precision and low noise time transfer between a master clock and slave sources has become essential for numerous scientific applications in the latest decades. This is, from the comparison of different optical clocks around the world, to high sensitivity imaging of astronomical objects using multi-telescope arrays and to next generation photon science facilities such as X-ray free-electron lasers (FELs). [...] 2018-09-0414:26 [PUBDB-2018-03366] Master Thesis Heinze, J. Cosmogenic neutrinos as secondary messengers of Ultra-High Energy Cosmic Rays x (2016) = Masterarbeit, Humboldt-Universität zu Berlin, 2016 2018-09-0414:20 [PUBDB-2018-03365] Master Thesis Rudolph, A. Implications of collision dynamics in Gamma-Ray Burst internal shocks on the production of multiple astrophysical messengers x (2017) = Masterarbeit, KIT Karlruhe, 2017 2018-08-1517:10 [PUBDB-2018-02967] Master Thesis Laarmann, T. Electron - Ion Coincidence Spectroscopy on Small Quantum Systems 81 pp. (2018) [10.3204/PUBDB-2018-02967] = Masterarbeit, University of Hamburg, 2018   OpenAccess: PDF PDF (PDFA); 2018-07-3117:23 [PUBDB-2018-02731] Master Thesis Lindemann, H. Entwicklung eines Positioniersystems für ein Absorptionselement im Hochvakuum 129 pp. (2018) [10.3204/PUBDB-2018-02731] = Masterarbeit, Hochschule für Angewandte Wissenschaften Hamburg, 2018   As part of the reconstruction of an experiment at the synchrotron PETRA III, a new positioning system for the far field X-ray detector has been developed. With this new positioning system, the detector is now running in a high vacuum environment. [...] OpenAccess: PDF PDF (PDFA); 2018-07-2619:20 [PUBDB-2018-02704] Book/Report/Master Thesis Moortgat-Pick, G. Vlasov Simulation of Exotic Phase-Space Densities via Tree-Based Domain-Decomposition [DESY-THESIS-2018-022] Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-THESIS 77 pp. (2018) [10.3204/PUBDB-2018-02704] = Masterarbeit, Universität Hamburg, 2018   Magnetic bunch compression is used to produce the high-brightness electron bunches needed for the operation of a free-electron laser. A longitudinal energy chirp -- imprinted on the bunch via off-crest acceleration -- results in the compression of the bunch in a subsequent dispersive section of the accelerator in form of a magnetic chicane.Such a setup sets the stage for the self-interaction of charge-density in homogeneities via the space-charge fields they generate within the bunch.This can potentially lead to an enhancement of initially present charge-densitymodulations; an effect known as microbunching amplification.Numerical simulation of this dynamics is encumbered by the fact that phase-space densities of electron bunches encountered at free-electron lasers typically exhibit an exotic'' structure, as they form a thin, hair-like bandmeandering through phase-space.In this thesis, a Vlasov-simulation approach based on tree domain-decomposition is presented, that allows for the efficient simulation of these phase-space densities despite their exoticness.Further, a beam-dynamics model is presented, which most notably enables the time-discrete treatment of collective space-charge effects in drift regions of the accelerator.Based on this model an arbitrary-order perturbation theory for the microbunching gain in a bunch-compressor is conceived and applied to the case of a long bunch with monochromatic density modulation.Finally, the results from theory and simulation are compared as part of thebenchmarking of the simulation code.. OpenAccess: mthesis_amstutz - PDF PDF (PDFA); desy-thesis-18-022-title - PDF PDF (PDFA); 2018-07-0510:36 [PUBDB-2018-02530] Master Thesis Dose, D. Einfluss des Laser-Shock-Peening auf die Eigenspannungsverteilung in Laser-Schweißnähten 1-82 (2017) = Masterarbeit, Christian-Albrechts-Universität, 2017 Eigenspannungen sind mechanische Spannungen, die in einem Körper vorhanden sind, andem keine externen Kräfte angreifen und der sich im thermischen Gleichgewicht befindet.Bei der Bearbeitung von Materialien und technischen Bauteilen können stets auch Eigenspannungenin diesen Materialien entstehen. Die entstehenden Eigenspannungen sind dabeihäufig charakteristisch für die jeweiligen Bearbeitungsprozesse. [...] Restricted: PDF PDF (PDFA); 2018-05-0816:04 [PUBDB-2018-01927] Master Thesis Küpper, J. Stark effect influenced rotational coherence spectroscopy 90 pp. (2018) [10.3204/PUBDB-2018-01927] = Masterarbeit, University of Hamburg, 2018   Rotationally cooled molecules offer versatile applications. However, many of thoseexperiments rely on a knowledge about the occupation of rotational states $g_J$ withdistinct rotational angular momentum quantum numbers J in the molecular probe. [...] Fulltext: GIF; OpenAccess: PDF PDF (PDFA);