Development of compact electron accelerators and free-electron lasers requires novel acceleration schemes at shorter driving wavelengths. The Axsis project seeks to developterahertz based electron acceleration as well as the high energy terahertz sources required. [...]

This thesis shows the first synchrotron-based Mössbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of x-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. [...]

Galaktische und extra-galaktische Objekte sind in der Lage geladene Teilchen (die kosmische Strahlung) zu sehr hohen Energien zu beschleunigen. Allerdings sind noch viele Fragen bezüglich dieser Objekte und der Beschleunigungsmechanismen offen. [...]

In this thesis mainly two topics in the field of coherent X-ray magnetic scattering are addressed. The first topic deals with the determination of spatial coherence properties of synchrotron radiation in the soft X-ray range by means of magnetic speckle patterns. [...]

A good understanding of the strong interaction is crucial for every experiment at a hadron collider. Events with photons provide a direct access to study processes of the strong interaction. [...]

Ultrashort laser pulses are used in physical analysis techniques as well as in materials processing and are generated in passively mode-locked oscillators. However, those oscillators produce low pulse energies, but can be used as seeding sources for regenerative amplifiers. [...]

Ultrashort laser pulses are used in physical analysis techniques as well as in materials processing and are generated in passively mode-locked oscillators. However, those oscillators produce low pulse energies, but can be used as seeding sources for regenerative amplifiers. [...]

Der 3D-IPM vereinigt zwei Geräte. Er zeigtdas horizontale und vertikale Projektionsabbild einesElektronen-oder Photonenstrahls an. [...]

Transition metal (TM) complexes are ubiquitous in both technological and biological catalytic systems. For a detailed understanding of their reactivity, a knowledge of the fundamental processes during chemical reactions is crucial. [...]

During neuron development, the precise wiring of neuronal network is mainly secured by molecular probes that prevent synapse formation with sister dendrites, generating repulsive signals. At the same time, cell surface receptors dictate the axon orientation and growth, in response to signaling sources (guidance cues) through attractive or repulsive mechanisms [...]

In this thesis, we present detailed studies of top-pair production with($t \bar t H$) and without association of a Higgs boson ($t \bar t$) in$e^+e^-$ collisions.These processes are of utmost interest for the top physics programof future lepton colliders.They allow in particular a precise measurement of the top quark mass andthe Yukawa coupling.For this purpose, we present predictions for off-shell $t \bar t$ and$t \bar t H$ production including non-resonant and interferencecontributions up to next-to-leading order (NLO) in perturbative quantum chromodynamics (QCD).This allows for top-quark phenomenology in the continuum at anunprecedented level of accuracy.We show that off-shell effects and NLO QCD corrections forthese processes do not factorize in general.In particular, we present the Yukawa coupling dependence of the crosssection, which receives negative corrections due to sizable interferenceterms.We also add a discussion of $\p_T$ resummation in the form ofcombining the NLO prediction via \textsc{Powheg} matching with the partonshower and the associated uncertainties.To handle large Coulomb singularities at threshold, we include thenext-to-leading log (NLL) threshold resummation derived in nonrelativistic QCD (NRQCD) for $t \bar t$ production.This results in a form factor that we incorporate in a fullyrelativistic cross section, which is factorized within an extendeddouble-pole approximation.Fixed-order QCD corrections are included, hereby, for the top decay.We combine this calculation with the full fixed-order QCD results at NLO for $W^+b W^-\bar b$ production to obtain a computation that is not onlyvalid at threshold but smoothly interpolates to the continuum.This allows us to present the first prediction for exclusive $W^+b W^-\bar b$production at a lepton collider with a consistent matching between thetop-antitop threshold and continuum regions.This computation is not only required to describe the intermediateenergy region but also allows to study threshold resummation effects infully differential distributions and incorporates important electroweakand relativistic corrections.All computations are implemented within the automated NLO MonteCarlo event generator \textsc{Whizard}.Thus, we review the important aspects of the program and variousnew features that we have implemented..

The motivation behind this Ph.D. project is to determine the structural modification of solids by ultra-short X-ray laser pulses. [...]

In this thesis we investigate various aspects of ux compactications in six-dimensionalquantum eld theories. After introducing the internal geometries, i.e. [...]

Non Ionizing Energy Loss (NIEL) in the sensor bulk is a limiting factor for the lifetime of silicon detectors. In this work, the proton-energy dependent bulk-damage is studied in n- and p-type silicon pad diodes. [...]

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. [...]

Imaging techniques are of paramount importance for our understanding of the universe. From galaxies and stars explored by huge telescopes down to micro and nanostructures studied by microscopes, imaging systems provide invaluable scientific information. [...]

After the discovery of a Standard-Model-like Higgs boson at the LHCa central aspect of the LHC physics program is to studythe Higgs boson's couplings to Standard Model particles in detailin order to elucidate the nature of the Higgs mechanismand to search for hints of physics beyond the Standard Model.This requires precise theory predictions for both inclusiveand differential Higgs cross sections.In this thesis we focus on the application of resummation techniquesin the framework of Soft-Collinear Effective Theory (SCET)to obtain accurate predictions with reliable theory uncertaintiesfor various observables.We first consider transverse momentum distributions,where the resummation of large logarithms in momentum (or distribution) spacehas been a long-standing open question.We show that its two-dimensional nature leads to additional difficultiesnot observed in one-dimensional observables such as thrust,and solving the associated renormalization group equations (RGEs)in momentum space thus requires a very careful scale setting.This is achieved using distributional scale setting,a new technique to solve differential equations such as RGEs directly in distribution space,as it allows one to treat logarithmic plus distributions like ordinary logarithms.We show that the momentum space solution fundamentally differs from the standard resummationin Fourier space by different boundary terms to all orders in perturbation theoryand hence provides an interesting and complementary approach to obtain new insightinto the all-order perturbative and nonperturbative structure oftransverse momentum distributions.Our work lays the ground for a detailed numerical study of themomentum space resummation.We then show that in the case of a discovery of a new heavy color-singlet resonancesuch as a heavy Higgs boson, one can reliably and model-independently inferits production mechanism by dividing the data into two mutually exclusive jet bins.The method is based on a resummation framework that preciselypredicts the jet cut dependence and systematically incorporates theory uncertaintiesand their correlations among the jet bins. The technique is demonstratedfor an example scalar resonance of mass $m_X = 750~\mathrm{GeV}$.It can also be applied to and tested in diphoton productionwhich receives contributions from both quark annihilation and gluon fusion.Here, the presence of final state photons requires photon isolation cutswhich yield unresummed nonglobal logarithms.As a first step towards the full analysis, we show that these are numerically smalland can be incorporated in fixed-order perturbation theory.Vice versa, we find that the jet veto renders contributions from fragmentation photons power suppressed,and thus is a particularly clean channel to study direct diphoton production at the LHC.Lastly, we discuss the resummation of timelike logarithms $\ln^2(-1)=-\pi^2$in Higgs production, arising in the form factor at timelike momentum transfer.Their resummation is well understood in exclusive cross sections known to factorize.We show how to consistently incorporate the resummation into inclusive cross sections,discussing in detail the validity of the technique and associated uncertainties.The method is first applied to the total cross section in gluon fusion Higgs productionat N$^3$LO$+$N$^3$LL$^\prime$, where it significantly improves perturbative convergenceand reduces perturbative uncertainties by about a factor of two.We also obtain the currently most precise Higgs rapidity spectrum at NNLO$+$NNLL$^\prime$with a similar reduction of uncertainties.The effect is less pronounced in bottom-quark annihilation,but still shows that the resummation of timelike logarithmsis a beneficial and viable tool for Higgs production..

The idea of spontaneous symmetry breaking as the mechanism through which elementaryparticles gain mass has been confirmed by the discovery of the Higgs boson at the CERNLarge Hadron Collider. Studying the Higgs boson properties are of great importance toverify the Standard Model predictions [...]

Technology is able to provide solutions for the challenges that the modern world needs, and one of the great new ideas is the development of a network of small autonomous, communicating sensors. A combination of microtechnology and energy harvesting is needed for such a network to operate. [...]

Staphylococcus epidermidis is a nosocomial pathogen, which infects biotic and abiotic surfaces by forming adherent biofilms. Biofilm is a multilayered microbial community formed by the production of an extracellular matrix. [...]

The edge Transient Current Technique (TCT) is a method for the investigation of silicon sensors. This method requires infrared light from a sub-ns pulsed laser to be focused to aμm-size spot and scanned across the polished cut edge of a sensor. [...]

Structural studies of liquid interfaces were performed using X-ray diffraction and X-ray reflectivity methods.The kinetics of the potential dependent growth of a crystalline PbBrF structure at the interface between a liquid mercury electrode and an aqueous electrolyte solution containing Br-, F- and Pb2+ were studied in situ by a combination of time-resolved X-ray diffraction and electrochemical methods.These measurements confirm the known reversible formation of a PbBrF monolayer at potentials positive of the lead (de)amalgamation equilibrium potential. The formation of PbBrF is driven by the oversaturation of the solution close to the interface due to a high Pb2+ concentration, which is a result of the lead deamalgamation.The rate of the monolayer formation increases with more positive potentials.The monolayer formation is followed by the quasi-epitaxial growth of a three-dimensional PbBrF phase. [...]

Silicon tracking detectors employed in high-energy physics are located very close to the interactionpoints of the colliding particle beams. The high energetic radiation emerging from the interactioninduces defects into the silicon, downgrading the efficiency to collect the charges created by passingparticles and increasing the noise while data taking. [...]

Das Energiespektrum der kosmischen Strahlung bietet wichtige Hinweise auf ihren Ursprung und ihre Ausbreitung. Verschiedene Messtechniken müssen kombiniert werden, um den ganzen Energiebereich abdecken zu können: Direkte Messungen mit Teilchendetektoren bei niedrigen Energien sowie indirekte Messungen von Luftschauern bei hohen Energien. [...]

Diese Arbeit umfasst die Konzeptentwicklung und Konstruktion einerlebensdaueroptimierten UHV Schaltspiegelkammer. Die Kammer wird am Ende einesLinearbeschleunigers genutzt, um einen Laserstrahl situationsbedingt abzulenken oderdurchzulassen (statischer Fall). [...]

Graphene on Ir(111) forms a moire structure with well defined nucleation centres. Therefore it can be utilized to create hexagonal metal cluster lattices with outstanding structural quality. [...]

Diese Bachelorarbeit wurde unter der Leitung von Prof. Dr. [...]

A microfluidic evanescent field optical tweezer system was tested and developed for sample delivery of micro- and nanocrystals in serial crystallography. The fluid line was enforced, and the setup changed from vacuum pump-driven to syringe pump-driven. [...]

Das Fermi Large Area Telescope (LAT) ist ein satellitengestütztes Gammastrahlungs-Teleskop zur Messung von Gammastrahlung im Energiebereich zwischen ∼ 30 MeV und mehreren hundert GeV. Der Nachweis extraterrestrischer Gammastrahlung in diesem Energiebereich erlaubt Rückschlüsse auf die astrophysikalischen Quellen der Gammastrahlung und Beschleunigungsmechanismen kosmischer Strahlung mit Energien zwischen 1 GeV und ∼ 10 TeV. [...]

X-ray radiation has been used to study structural properties of materials for morethan a hundred years. Construction of extremely coherent and bright X-ray radiationsources such as free electron lasers (FELs) and latest generation storage rings led torapid development of experimental methods relying on high radiation coherence.These methods allow to perform revolutionary studies in a wide range of fields fromsolid state physics to biology. [...]

In this thesis, measurements of different charged-particle distributions performed with the CMS detector in proton-proton collisions at a centre-of-mass energy √s = 13TeV are presented.In particular, the charged-particle pseudorapidity distributions, also referred to as charged-particle pseudorapidity densities, the multiplicity distributions of charged particlesper event, and different transverse-momentum distributions corresponding to all chargedparticles, the leading charged-particle, and the integrated spectrum of the latter are presented.The charged-particles are selected with transverse momenta pT > 0.5 GeV in the range |η| < 2.4. The data are corrected for the different detector effects such as resolution andefficiency [...]

<p>Permanent magnets (PMs) are indispensable constituents of electronic devices, consumer appliances, transportation components, military hardware, etc. They are also integral part of clean energy technologies, such as wind turbine generators or hybrid vehicle regenerative motors, as well as basis of several state-of-the-art biomedical applications.[1] Despite rare-earth (RE) magnets offering the best known magnetic performance, RE metals are critical raw materials, subject to worldwide market fluctuations and intermittent shortage [...]

This thesis describes quantum optical experiments with x-rays with the aim of reaching the strong-coupling regime of light and matter. We make use of the interaction which arisesbetween resonant matter and x-rays in specially designed thin-film nanostructures which form x-ray cavities. [...]

Die Röntgenfluoreszenz-Mikroskopie ist ein präzises, zerstörungsfreies und bildgebendes Verfahren zur Bestimmung der Elementverteilungen einer Probe mit einer räumlichen Auflösung im Submikrometerbereich. Röntgenstrahlung wird dafür auf einen möglichst kleinen Bereich in der Probenebene fokussiert und schrittweise oder kontinuierlich verfahren. [...]

All images are flawed, no matter how good your lenses, mirrors etc. are [...]

This work covers two important aspects in the field of high-energy physics; detector development and physics data analysis.The first part of this thesis is devoted to the detector development activities for the Phase-II upgrade of the Compact Muon Solenoid (CMS) experiment's outer tracking detector. To cope with the increased luminosity during the high-luminosity era of the Large Hadron Collider (LHC), it is foreseen to replace the existing tracking system of CMS with an entirely new system. [...]

FLASH and the European XFEL are linear accelerator driven SASE-FELs, operating in a pulsed mode with long bunch-trains. Multi-bunch FEL operation requires longitudinal and transverse stability within the bunch-train. [...]

The Large Hadron Collider (LHC) is the largest particle accelerator and storage ring in the world, used to investigate fundamentals of particle physics and to develop at the same time the technology of accelerators and detectors. Four main experiments, located around the LHC ring, provide insight into the nature of particles and search for answers to as yet unexplained phenomena in the universe. [...]

Modern x-ray sources and analysis techniques such as lens less imaging combined with phase retrieval algorithms allow for resolving structure sizes in the nanometerrange. For this purpose optics have to be employed, ensuring small focal spot dimensions simultaneously with high photon densities [...]

This thesis discusses a series of advances toward - and resulting in -the demonstration of the first ultrafast THz-driven electron gun, a technology with the potential to deliver unprecedented electron beam quality to scientists studying matter at the ultrafast and ultrasmall scale via electron diffraction or x-ray imaging. In Part 1, we discuss various advances in generation of high energy pulsed THz radiation, a spectral regime uniquely effective at accelerating electrons but historically lacking in effcient sources. [...]

Die vorliegende Arbeit beschreibt einen semi-analytischen Ansatz zur Modellierung der Dichteverteilung von DM im Galaktischen Halo. Aus den verschiedenen Substrukturmodellen wird die γ-Strahlungsintensität, welche die Erde erreicht, berechnet. [...]

Liquid Jets finden heute Verwendung in vielen Bereichen der Wissenschaft und der Technik. In dieser Arbeit werden Liquid Jets für Röntgenstreuexperimente im Vakuum charakterisiert [...]

Luminosity is a key quantity of any collider, since it allows for the determination of the absolute cross sections from the observed rates in a detector. Since theHiggs boson discovery in 2012, the highest priority at the Large Hadron Collider (LHC) has been given to an accurate understanding of the electroweak scale anda search for new physics. [...]

Folding, isomerization, and dissociation of molecules, i.e., bond breaking and bond formation, is happening on ultrafast time scales. Femtoseconds (1 fs = 10$^{−15}$ s) are the time scale on which atoms move. [...]

Die Ptychographie ist ein neues und in vielfältiger Weise genutztes bildgebendes Verfahrender Röntgenmikroskopie. Bei diesem kohärenten Scanverfahren wird im Fernfeld anjedem Scanpunkt einer Probe ein Beugungsbild aufgenommen. [...]

Silicon detectors in Photon Science and Particle Physics require silicon sensors with very demanding specifications. New accelerators like the European X-ray Free Electron Laser (EuXFEL) and the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), pose new challenges for silicon sensors, especially with respect to radiation hardness. [...]

Teilchenschauer können sowohl durch Photonen als auch durch geladene Teilchen erzeugt werden. Letztere kommen etwa 1000-mal häufiger vor als die durch Photonen erzeugten Teilchenschauer. [...]

This work is a systematic study of the enhancement of soft-X-ray high-harmonic generation (HHG) driven by two-color (&#969; + 3&#969;) waveforms in argon at different pressures. The observed enhancement due to the two-color driver reaches factors over one order of magnitude when compared to single-color driven HHG. [...]

The invention of a femtosecond stable Laser-to-RF phase detector allows to measure with femtosecond precision the relative phase between a phase stable optical reference and an RF signal. Thereby one can stabilize RF reference signals in modern FELs on a femtosecond scale. [...]

The radial seismic structure of the earth is marked by a sharp transition about 200 km above the core-mantle boundary. This defines the top of the region called the D'' layer [...]

In this thesis, the interfacial melting phenomenon of ice in nanocomposite materials is studied by high energy X-ray diffraction (HEXRD) and quasi elastic neutron scattering (QENS) technologies. In order to conduct experiments under hydrostatic pressure, a new high-pressure cell which can sustain pressures up to 5 kbar was designed. [...]

Following the example of L. Dinu et al. [...]

Development of high power/energy ultrafast fiber lasers for scientific research and industrial applications is one of the most exciting fields in ultrafast optics. This thesis demonstrated newmeans to improve two essential properties—which are indispensable for novel applications such as high-harmonic generation (HHG) and multiphoton microscopy (MPM)—of anultrafast fiber laser system: energy scaling capability and wavelength tunability. [...]

The central question addressed in this thesis is how to make the free-electron laser (FEL) more efficient. In recent years, coherent diffraction imaging provides an important motivation for efficiency enhancement. [...]

This thesis seeks to further explore the origin of cosmic electrons and positrons. The unexpected excess of very-high-energy electrons above 100 GeV has been established and is now considered proof of a new class of electron sources. [...]

In this thesis two automatic methods for the reduction of large fluorescence data sets are presented.The first method is proposed in the framework of BioXAS experiments. The challenge of this experiment is to deal with samples in ultra dilute concentrations where the signal-to-background ratio is low. [...]

This thesis presents two searches for physics beyond the Standard Model (SM). A searchfor pair production of third-generation leptoquarks decaying into a top quark and a taulepton using pp collision data recorded at a center-of-mass energy of 8TeV with theCMS experiment is presented. [...]

Differential measurements in the LHC precision era require precise theoretical predictions to match.One class of important observables are transverse momentum ($q_T$) distributions of color-singlet final states such as the Higgs boson or Drell-Yan lepton pairs.Related observables are color-singlet production cross sections with a jet veto, e.g. a cut $p_T^\mathrm{jet} < p_T^\mathrm{cut}$ on the transverse momentum of the leading jet.For both cases, well-known factorization theorems exist to describe the cross section at central rapidity or, equivalently, integrated in rapidity.These factorization theorems enable the all-order resummation of Sudakov logarithms induced by initial-state radiation.We show how to systematically extend the known factorization theorems to the region of forward rapidities,where the kinematic constraint induces additional single logarithms of the distance from kinematic endpoint.We identify three different kinematic regimes that lead to distinct factorization theorems,compute all new ingredients at one-loop order, and discuss RG consistency relations in detail.We analyze the matching between regimes and give a novel argument why one set of power corrections vanishes to all orders in the strong coupling, for both $q_T$ and $p_T^\mathrm{cut}$.This provides all ingredients for a NNLL'$+$NNLO $q_T$ ($p_T^\mathrm{cut}$) resummation analysis fully differential in rapidity. [...]

Increasing world population and living standards results in increasing energyconsumption. Unfortunately, >80% of our energy comes from fossil fuels. [...]

YFe2O4-The main part of this thesis is dedicated to the determination of the charge order crystallographicstructures of YFe2O4- at 160K and 200 K. YFe2O4- is above the charge orderingtransition isostructural to LuFe2O4- with the space group R¯3m. [...]

Over the past decade, development of high-energy ultrafast laser sources hasled to important breakthroughs in attoscience and strong-field physicsstudy of atoms and molecules. Coherent pulse synthesis of a few-cyclehigh-energy laser pulse is a promising tool to generate isolated attosecond pulsesvia high harmonics generation (HHG). [...]

A combination of the inclusive lepton-proton cross sections from the ZEUS and H1 experiments is presented. The data are combined taking into account correlations of the systematic uncertainties of the measurements. [...]

This work presents the measurements of the charge asymmetry and top quark spin observables in ttbar events based on 20.3 fb$^{-1}$ of $\sqrt{s}$ = 8 TeV proton--proton collisions recorded with the ATLAS detector at the LHC. These analyses are performed in the dilepton final state, characterized by the presence of two isolated leptons (electrons or muons). [...]

In this thesis, a search for pair produced vector-like $T$ quarks in $pp$ collision data from the LHC at $\sqrt{s} = 13\,\text{Te}\kern-0.06667em\text{V}$ is presented. The data were collected with the CMS detector and correspond to an integrated luminosity of up to $2.6\,\mathrm{fb}^{-1}$. [...]

KurzfassungIm Forschungsumfeld der Elektronenspeicherring-Anlagen übernehmen rechnergestütz-te Simulationen eine wichtige Rolle. Die Auslegung von optischen Komponenten für An-lagen zur Erzeugung von Synchrotronstrahlung (Synchrotron Radiation, SR) erforderteine präzise Beurteilung der thermischen Lasten, die durch absorbierte Synchrotron-strahlung in den Bauteilen auftreten können. [...]

Supersymmetric (SUSY) theories such as the Minimal Supersymmetric Standard Model(MSSM) predict a new particle spectrum, including an extended Higgs sector, in orderto address fundamental questions that remain unanswered with the results obtained atthe Large Hadron Collider (LHC) so far. Despite an extensive programme to searchfor additional Higgs bosons at the LHC, no new Higgs-like particles have been observedbeyond the discovered signal at 125 GeV. [...]

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. [...]

As part of the ATLAS phase-II upgrade a new, all-silicon tracker will be built. The newtracker will consist of silicon pixel sensors and silicon microstrip sensors. [...]

The mitogen-activated protein kinase (MAPK) cascade is an essential member of the cell defense system against stressors. The capability and efficiency of the cell reactions to different stress signals depend on signal transduction pathway, where signals from MAPK kinase kinase (MAP3K) are transferred through phosphorylation to downstream MAPK kinase (MAP2K) and finally to MAPK [...]

For the detailed investigation of biological, chemical or physical processes on the nano scale, high-resolution imaging techniques are essential. For this purpose, the coherentimaging technique – X-ray ptychography – has been established in recent years. [...]

With B meson decays it is possible to probe the Standard Model of particle physics without thenecessity to investigate high energy scales. In previous analyses, the quark transition $b \to s\ell^{+}\ell^{-}$ showed signs of New Physics in kinematic observables that deviated from the Standard Modelpredictions [...]

Photoabsorption spectra of gaseous hydrides of 3p elements (PH$_3$, H$_2$S, HCl) are measured in the energy region of photoexcitations pertaining to K edge. The analysis is extended to hydrides of 4p series (GeH$_4$, AsH$_3$, H$_2$Se, HBr) from an earlier experiment, and to noble gases Ar and Kr as well as the published spectrum of SiH$_4$, inaccessible to our measurement. [...]

In the framework of this thesis, a new method for high-speed fixed-target serial crystallography experiments and its applicability to biomacromolecular crystallography at both synchrotron light sources and X-ray free electron lasers (XFELs) is presented. The method is based on a sample holder, which can carry up to 20,000 microcrystals and which is made of single-crystalline silicon. [...]

Ionic liquids (ILs) have received considerable interest in various fields of research and promise a vast range of applications; among others, they are promising stabilizers for nanoparticles. ILs consist of a large organic cation and a small inorganic anion. [...]

This thesis investigates the simulation of nonlinear effects and the propagation of optical diffractive light pulses. On this account, two simulation programs were considered.Firstly, distributed by the company Oxalis, the program Commod Pro, which follows the classical approach by coupling three differential equations. [...]

A search for a heavy neutral Higgs boson as postulated by the Minimal Supersymmetric StandardModel is performed. The data used in the search was taken by the CMS experiment atthe LHC in 2016 at a center-of-mass energy of 13 TeV and amounts to an integrated luminosityof 36.3fb$^{-1}$1. [...]

In this thesis a search for direct pair production of supersymmetric top-quark partners as well as work on the upgrade of the front-end readout controller of the Hadron Calorimeter (HCAL) of the Compact Muon Solenoid (CMS) experiment are presented. The most appealing extension of the Standard Model (SM) is supersymmetry (SUSY), relating the integer spin (bosons) and half-integer spin elementary particles (fermions). [...]

This thesis investigates structural properties and the underlying microscopic dynamicsof suspensions of $\alpha$-FeOOH goethite platelets in water under the influence of magneticfields. Goethite particles show unusual physical properties and a rich phase diagram,which makes their suspensions an object of high interest for research in the area of”smart nanoparticles”. [...]

This work presents an implementation and optimization of a pulse characterization technique for ultrashort laser pulses. Namely the technique of two-dimensional spectral shearinginterferometry (2DSI) is set up with the development a full automatic MATLAB code to acquire, store and reconstruct the complex pulse in frequency and time domain. [...]

In the framework of this thesis several candidate molecules were tested with regard to their feasibility for benchmark electron diffraction experiments on controlled gaseous samples. Electron diffraction serves as a tool for structure determination of molecules in the gas phase without the need for crystalline samples. [...]

Although the Standard Model of particle physics is well established by many experimentssome phenomena are observed that cannot be explained by the Standard Model alone. Furthermorerecent evaluations of experimental data yield results deviating from the Standard Model'spredictions with a significance of up to 4$\sigma$5$\sigma$ [...]

Am DESY (Deutsches Elektronen Synchrotron), Standort Zeuthen wird ein linearer Elek-tronenbeschleuniger betrieben. Dabei werden Komponenten, welche sich im Beschleuniger-raum befinden aktiviert [...]

Due to their high secondary electron yield, copper-beryllium alloys with a beryllium molefraction of approximately 14 % (Cu 0.86 Be 0.14 ) are commercially available materials fordynodes of charged particle detectors. By using multiple layers of dynodes, even singleparticles can be detected. [...]

Low-noise transfer of time and frequency standards over large distances provides high temporal resolution for ambitious scientific explorations such as sensitive imaging of astronomical objects using multi-telescope arrays, comparison of distant optical clocks or gravitational-wave detection using large laser interferometers. In particular, rapidly expanding photon science facilities such as X-ray free-electron lasers (FELs) and attoscience centers have the most challenging synchronization requirements of sub-fs timing precision to generate ultrashort X-ray pulses for the benefit of creating super-microscopes with sub-atomic spatiotemporal resolution. [...]

The most essential compounds in biomembranes are lipoids and proteins. Herein, the proteins are usually considered to be the key players by actively carrying out the essential functions in a living active membrane. [...]

This thesis is logically divided into two main parts. The first part present a ZEUS analysis which was performed on the data obtained from electron-proton collisions measured by theZEUS detector for the 2003-2007 running period. [...]

The European XFEL and the International Linear Collider are based on superconductingrf cavities. In order to reach the theoretical gradient limits of the superconducting cavitiesit is necessary to increase the mechanical quality and chemical composition of the innersurface as well as to understand the reason for performance limitations. [...]

Phase tomography based on hard X-ray double-grating interferometry (XDGI) is a well-established imaging technique for the three-dimensional visualization of soft tissues, providing tomograms with superior contrast. The experimental setup contains a beam-splitter grating and an analyzer grating. [...]

The presented work is a search for single production of vector-like T quarks.Vector-like quarks are common among non-SUSY theories that strive to solve the hierarchy problem.The search is undertaken with 2.3$\,$fb of proton-proton collisions at a centre of mass energy of $\sqrt s=13\,$TeV, recorded with the CMS experiment at the CERN LHC in 2015.The T quark decay channel into a top quark and a Higgs boson is considered.A mass-range from 700$\,$GeV up to 1800$\,$GeV is scanned, where the top quark and Higgs boson acquire a significant Lorentz boost.An electron or muon in the final state is required, as well as a collimated pair of b quarks from the decay of the boosted Higgs boson.The search is performed as a shape analysis with a signal plus background model, fitted to the data.The shape of the background is extracted from a signal-depleted control region in the data.The background shape describes the observed data well and no excess of events is seen.Exclusion limits are derived for the single T quark production cross section times the branching fraction of the T quark decay into a Higgs boson and a top quark.A Bayesian statistical method is applied.At 95\% confidence level, values of 0.49$\,$pb and 0.18$\,$pb (0.42$\,$pb and 0.14$\,$pb) for T quark masses of 1200$\,$GeV and 1700$\,$GeV, respectively, are excluded for T quark production in association with b (top) quarks.These are the first results on singly produced vector-like quarks published by the CMS Collaboration and the first results from the LHC at $\sqrt s=13\,$TeV..

Laser wakefield acceleration (LWFA) is a novel technique to accelerate charged particles. Acceleration is achieved by a high-power laser pulse transmitting a gas target where electrons and ions form a strong wakefield with gradients up to 100 GV/m. [...]

A combination is presented of all previously published deep inelastic neutral and charged current $e^{\pm}p$ scattering measurements at HERA for zero beam polarisation.The ZEUS and H1 collaborations have collected data at electron beam energy of $27.5$ GeV and proton beam energies of $920$, $820$, $575$ and $460$ GeV.The combined data correspond to an integrated luminosity of about $1$ fb$^{-1}$ and cover a kinematic range in the negative four-momentum-transfer squared from $Q^{2} = 0.045$ GeV$^{2}$ to $Q^{2} = 50000$ GeV$^{2}$ and in Bjorken $x$ from $x_{\rm Bj} = 6 \times 10^{-7}$ to $x_{\rm Bj} = 0.65$.The correlations of systematic uncertainties between different sets of data were taken into account, resulting in significantly improved precision.The combined $e^{\pm}p$ cross sections were used in a QCD analysis at next-to-leading order, providing a set of parton distribution functions, called ZCIPDF.The combined measurements were also used in an analysis beyond the Standard Model using a new approach, performing simultaneous fits on large sets of Monte Carlo replicas of parton distribution functions, PDFs, together with the parameters of "new physics" processes.A simplified approach to reduce the calculation time was developed and extensively tested.It allowed the calculation time to be reduced by about a factor of 50.The resulting $95\,\%$ C.L. upper limit on the effective quark radius is $0.43 \cdot 10^{-16}$ cm and the limits on the mass scales for different contact interaction scenarios extend up to $10$ TeV.The analyses have shown that taking into account the possible influence of processes beyond the Standard Model on the PDF parameters is necessary, since the limits that would be obtained using PDFs from QCD analysis within the Standard Model are too strong by about $10\,\%$.Studies of the surface quality of 28 Niobium superconducting radio frequency, SRF, cavities and development of a controllable cooling system for Niobium samples are also reported.The SRF cavities are the core of the accelerating technology for the future International Linear Collider, ILC; the reported studies are part of an ongoing research and development program..

While the Standard Model is very successful in describing subnuclear phenomena, it is not a complete theory of particle physics. Several new theories have been developed to address its issues. [...]

The present work concentrates on prototypical studies of light-induced correlated manybodydynamics in complex systems. In its course a reflective split-and-delay unit (SDU)for phase-resolved one-color pump-probe experiments with gas phase samples using VUV–XUV laser pulses was built. [...]

In this thesis, a search for lepton-flavour violating (LFV) decays of the Higgs boson to an electron and a tau lepton is presented. LFV decays of the Higgs boson are forbidden in the Standard Model of particle physics (SM). [...]

A detailed study of three solid oxide fuel cells (SOFCs) related model systems is presented in this work with the aim of the better understanding of the structural changes in cell components associated with their operation. The first model system is an La$_{0.6}$Sr$_{0.4}$CoO$_{3−δ}$ (LSC) on yttria-stabilized zirconia (YSZ). [...]

The discovery of the Higgs boson in July 2012 by the ATLAS and CMS collaborations opened new doors for the search for physics beyond the Standard Model. In particular, the presence of new particles and interactions might be deduced indirectly via precision measurements [...]

A Time Projection Chamber (TPC) is foreseen as the main tracking detector in theInternational Large Detector (ILD) - one detector concept for the planned InternationalLinear Collider (ILC). This TPC will use Micro Pattern Gaseous Detectors (MPGDs) foramplification, of which Gas Electron Multipliers (GEMs) are one possibility. [...]

The goal of this work was the realisation of a setup for spectral broadening andsubsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire basedCPA laser system by means of the hollow core ?bre chirped mirror compressor technique.For the spectral broadening a vessel containing the hollow waveguide ?lled with a noble gasserving as the nonlinear medium was set up and an alignment procedure was developed.Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses.With this setup spectral broadening, su?cient for supporting sub 5 fs pulses, was observed.The spectra at di?erent input energies and neon gas pressures were measured and thestability of these and their respective Fourier transform-limited pulses determined in orderto ?nd an operating point. For the compression of the self-phase modulated pulses achirped mirror compressor was designed and set up, but not tested yet. [...]

Für die plasmabasierte Teilchenbeschleunigung ist es wichtig zu wissen, wie sich die Plasmaelektronen- dichte, sowie indirekt auch die Plasmaelektronentemperatur, während des Beschleunigungsprozesses verhalten. Im Rahmen der vorliegenden Bachelorarbeit sollten diese beiden Parameter spektroskopisch an einer Gasentladungsplasmazelle für Plasmabeschleunigungsexperimente bei PITZ, am DESY in Zeuthen,gemessen werden [...]

Experiments in high energy physics have reached an unprecedented accuracy. Thisaccuracy has to be matched by the theoretical predictions used to search for new physics.For this purpose, sophisticated computer programs are necessary, both for the calculationof matrix elements (tree-level and loop) and in the field of Monte-Carlo event generation.The hadronic initial state at the LHC poses signifcant challenges for measurement andsimulation. [...]

Ultrashort pulse laser sources have been greatly developed over the past few decades. The available pulse duration has been reduced to the single-cycle pulse regime. [...]

In this thesis, the collected charge and the Lorentz angle on non-irradiated and the irradiatedminiature of the current test silicon micro-strip sensors (ATLAS12) of the future ATLAS innertracker are measured. The samples are irradiated up to 51015 1MeV neq=cm2 and some of themalso measured after short-term annealing (80 min at 60 C). [...]

In the present study, the microstructure, tensile deformation behavior and mechanical property of X60Mn18 steel were investigated by means of light optical microscopy (LOM), ex-situ synchrotron-XRD and ex-situ small angle neutron scattering (SANS) as a function of the various recrystallization annealing durations (2 min and 30 min) and tensile deformation levels (0%, 25% and 50%). The ex-situ synchrotron-XRD analysis was conducted via MAUD software to reveal the microstructural properties including the phase fractions, lattice parameters, microstrain, crystallite size, stacking fault probability and dislocation density..

Modern light sources like synchrotron and free electron laser facilities provide highbrilliant, monochromatic and high coherent X–ray beam with tunable photon energiescovering almost the whole electromagnetic spectrum. These unique properties ofthe light sources enable to implement novel experimental methods for investigatingdynamical chemical processes.The atomic components of chemically relevant systems and solvents essentially consistof light elements. [...]

Laser Wakefield Acceleration (LWFA) has the potential to become the next-generation accelerationtechnique for electrons. In particular, the large field gradients provided by these plasma-based acceleratorsare an appealing property, promising a significant reduction of size for future machines and user facilities.Despite the unique advantages of these sources, however, as of today, the produced electron bunches cannotyet compete in all beam quality criteria compared to conventional acceleration methods. [...]

The aim of this thesis is to demonstrate that x-ray waveguide optics can be gen- eralized from a single guiding film to an array of planar waveguides, enabling more complex and controllable phenomena of field propagation both in partic- ular in the near-field in the vicinity of objects to be probed by coherent imaging. Two advanced x-ray multilayer waveguides (MWGs) structures, i.e [...]

In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. [...]

The SINBAD (Short INnovative Bunches and Accelerators at DESY) project is adedicated, long-term accelerator research and development (R&D) facility currentlyunder construction at the DESY Hamburg campus, aiming to provide an infrastructurefor developing several types of novel high-gradient accelerators. The research presented in this thesis addresses the design of the magnetic lattice as well as the modeling and simulations of ultra-short electron bunch generation at the ARES (Accelerator Research Experiment at SINBAD) linac, which is the core of the SINBAD facility. [...]

In the scope of the EndoTOFPET-US project, a novel multimodal device for ultrasound(US) endoscopy and positron emission tomography (PET) is being developed. The projectaims at detecting and quantifying morphologic and functional biomarkers and developingnew biomarkers for pancreas and prostate oncology. [...]