Refine
Year of publication
Document Type
- Doctoral Thesis (373) (remove)
Language
- English (373) (remove)
Has Fulltext
- yes (373)
Is part of the Bibliography
- no (373)
Keywords
- Quark-Gluon-Plasma (8)
- Heavy Ion Collisions (5)
- LHC (5)
- Monte-Carlo-Simulation (5)
- Zeitprojektionskammer (5)
- ALICE (4)
- CERN (4)
- QCD (4)
- Quantenchromodynamik (4)
- Renormierungsgruppe (4)
- Schwerionenphysik (4)
- quantum chromodynamics (4)
- CBM (3)
- FAIR (3)
- Functional Renormalization Group (3)
- HADES (3)
- Hadron (3)
- Hadronenjet (3)
- Heisenberg-Modell (3)
- Neutron Star (3)
- Photon (3)
- Quantum chromodynamics (3)
- Quark <Physik> (3)
- Relativistische Hydrodynamik (3)
- Schwerionenkollisionen (3)
- Schwerionenstoß (3)
- Theoretische Physik (3)
- lattice (3)
- particle physics (3)
- ALICE <Teilchendetektor> (2)
- Anisotropie (2)
- Beschleuniger (2)
- Boltzmann-Gleichung (2)
- CBM Experiment (2)
- CBM experiment (2)
- CERN SPS (2)
- Control System (2)
- Correlations (2)
- Delaunay-Triangulierung (2)
- Dileptonen (2)
- Dissertation (2)
- EPICS (2)
- Feldtheorie (2)
- Flow (2)
- Fluktuation <Physik> (2)
- Funktionale Renormierungsgruppe (2)
- Gammaspektroskopie (2)
- Heavy-ion Collisions (2)
- Hochenergiephysik (2)
- Kalibrieren <Messtechnik> (2)
- MAPS (2)
- Multiplizität (2)
- Neutron star (2)
- Neutronenstern (2)
- Numerical Relativity (2)
- Phasenumwandlung (2)
- Physics (2)
- Poisson-Gleichung (2)
- Porin (2)
- Proteine (2)
- Proton (2)
- Quantenspinsystem (2)
- Quark-Gluon Plasma (2)
- Quarkconfinement (2)
- Radio Frequenz Quadrupol (2)
- Resonanzen (2)
- STAR <Teilchendetektor> (2)
- Schweres Ion (2)
- Schwerionen (2)
- Simulation (2)
- Spinwelle (2)
- Strangeness (2)
- Strangeness Enhancement (2)
- Teilchenerzeugung (2)
- Zustandsgleichung (2)
- detector (2)
- energy system design (2)
- equation of state (2)
- heavy-ion collision (2)
- heavy-ion physics (2)
- p-Kerne (2)
- photons (2)
- power transmission (2)
- quark gluon plasma (2)
- relativistic hydrodynamics (2)
- terahertz (2)
- thermal transition (2)
- 2D materials (1)
- ALICE <particle detector> (1)
- ALICE upgrade (1)
- ALICE, Teilchendetektor (1)
- ALTRO (1)
- ATR-Spektroskopie (1)
- Absorptionsspektroskopie (1)
- Accelerator (1)
- Activation (1)
- Activation experiment (1)
- Ageing (1)
- Aktivierungsmethode (1)
- Alignment parameter (1)
- Alignmentparameter (1)
- Anderson Impurity model (1)
- Anderson-Modell (1)
- Anisotropic flow (1)
- Anregung (1)
- Antenne (1)
- Antiproton (1)
- Artificial Intelligence (1)
- Arzneimitteldesingn (1)
- Arzneimittelentwicklung (1)
- Astrophysics (1)
- Auditory cortex (1)
- Azimuthal angular distributions (1)
- Azimuthale Winkelverteilung (1)
- BEDT-TTF (1)
- Beam dynamics (1)
- Beliaev Dämpfung (1)
- Beliaev damping (1)
- BetP (1)
- Betain (1)
- Bilderkennung (1)
- Bildladung (1)
- Binary (1)
- Binary Neutron Star Mergers (1)
- Binary encounter approximation (1)
- Biomembran (1)
- Black hole (1)
- Blei (1)
- Bleikern (1)
- Bohmian mechanics (1)
- Boltzmann equation (1)
- Bose Einstein condensation (1)
- Bose-Einstein-Kondensation (1)
- Bosonisierung (1)
- Brookhaven National Laboratory (1)
- Brownsche Bewegung (1)
- Bulk viscosity (1)
- CERN ; Bleitarget ; Blei-Reaktion ; Quark-Gluon-Plasma (1)
- CERN PSB (1)
- CO2 emission reduction targets (1)
- CPS (1)
- Chaostheorie (1)
- Charge-Ordering (1)
- Charge-Transfer Salts (1)
- Chiral Symmetry (1)
- Chirale Symmetrie (1)
- Chopper (1)
- Cluster Hadronization (1)
- Collective Flow (1)
- Color Glass Condensate (1)
- Color superconductivity (1)
- Colour (1)
- Complex networks (1)
- Compressed Baryonic Matter (1)
- Compton scattering (1)
- Computersimulation (1)
- Confinement (1)
- Conformational transitions (1)
- Correlated systems (1)
- Coulombdissoziation (1)
- Coulombspaltung (1)
- Cross section (1)
- Czochralski method (1)
- DNA Translocation (1)
- Datenanalyse (1)
- Deep Learning (1)
- Density functional theory (1)
- Detector (1)
- Dielectric Boundaries (1)
- Dielectron (1)
- Dileptons (1)
- Dipol-Dipol-Wechselwirkung (1)
- Dirac-Gleichung (1)
- Dirac-Operator (1)
- Dirac-Vakuum (1)
- Discontinous Galerkin methods for Numerical Relativity (1)
- Dotierter Halbleiter (1)
- Double-sided silicon microstrip detectors characterization readout quality assurance (1)
- Dynamical mean field theory (1)
- Dynamischer Strukturfaktor (1)
- Dünne Schicht (1)
- Dünnschichttransistor (1)
- Effective Field Theory (1)
- Eichtheorie (1)
- Eindimensionaler Leiter (1)
- Elektrische Ladung (1)
- Elektrodenarray (1)
- Elektromagnetische Strahlung (1)
- Elektron ; Impulsverteilung ; Heliumion (1)
- Elektronen-Korrelation (1)
- Elementarteilchenphysik (1)
- Emissionsspektroskopie (1)
- Energy system design (1)
- Ensemble Inequivalance (1)
- Entwicklungspsychologie (1)
- Evolutionäre Spieltheorie (1)
- Excitation (1)
- Exotic Hadrons (1)
- Exotic State (1)
- Exotische Hadronen (1)
- Exotischer Kern ; Quantenhadrodynamik (1)
- FT-IR-Spectroscopy (1)
- FT-IR-Spektroskopie (1)
- Farbsupraleitung (1)
- Feldeffekt (1)
- Feldeffekttransistor (1)
- Fermi-Fläche (1)
- Fermi-Flüssigkeit (1)
- Fermionensystem (1)
- Fermions (1)
- Ferromagnetische Spinkette (1)
- Festkörperphysik (1)
- Field-effect (1)
- Fluctuation (1)
- Fluctuations (1)
- Fluka (1)
- Formulations of Einstein Field Equations (1)
- Franck-Condon (1)
- Fullerene (1)
- GEANT (1)
- Gabor lens (1)
- Gammaspectroscopy (1)
- Gasionisationsdetektor (1)
- Gefangenendilemma (1)
- Gehirn (1)
- General relativistic hydrodynamics (1)
- Germanium detectors (1)
- Germaniumdetektor (1)
- Gesellschaft für Schwerionenforschung (1)
- Gittereichtheorie (1)
- Glimmentladung (1)
- Global polarization (1)
- Globale Optimierung (1)
- Gold-197-Reaktion (1)
- Gold-197-Target (1)
- Graphentheorie (1)
- Gravitational Waves (1)
- Gravitational wave (1)
- Großhirnrinde (1)
- H/D Austausch (1)
- HBT (1)
- HLT (1)
- Hades (1)
- Hadron Spectroscopy (1)
- Hadronisierung (1)
- Hagedorn Zustände (1)
- Hagedorn states (1)
- Halbleiter (1)
- Harte Röntgenstrahlung (1)
- Hartree-Näherung (1)
- Heavy Ion Physics (1)
- Heavy Ions (1)
- Heavy-Ion Collision (1)
- Heavy-ion collision (1)
- Heavy-ion collisions (1)
- Heavy-ions (1)
- Heisenberg model (1)
- Heisenberg modell (1)
- Herzberg-Teller (1)
- High Energy Heavy Ion Collisions (1)
- High-Level Trigger (1)
- High-energy photoabsorption (1)
- High-k dielectric (1)
- High-k-Dielektrikum (1)
- Hirnforschung (1)
- Hochfrequenzsputtern (1)
- Hochgeladene Ionen (1)
- Homeostasis (1)
- Hubbard model (1)
- Hydrodynamic (1)
- Image Charge (1)
- Impact parameter (1)
- Inclusive Reconstruction (1)
- Instabilität (1)
- Internet (1)
- Inverse Kinematics (1)
- Ion Beam (1)
- Ion Tail (1)
- Ionenimplantation (1)
- Ionenstrahl (1)
- Ionisationsdichte (1)
- Iron pnictides (1)
- Jet-Medium-Wechselwirkungen (1)
- Jitter-Effekt (1)
- K+ (1)
- K- (1)
- Kaon (1)
- Kaons (1)
- Katze ; Sehrinde ; Reizverarbeitung (1)
- Keldysh-Formalismus (1)
- Kern-Kern-Streuung (1)
- Kern-Kern-Stößen (1)
- Kernmaterie (1)
- Kernphysik (1)
- Kinetic Theory (1)
- Kinetische Theorie (1)
- Kitaev model (1)
- Kohlenstoff (1)
- Kohlenstoffion (1)
- Kollektive Anregung (1)
- Konformationsübergänge (1)
- Kooperativität (1)
- Korrelation (1)
- Kraftmikroskopie (1)
- LET (1)
- LINAC (1)
- Ladder-RFQ (1)
- Ladungstransfer (1)
- Lambda Hyperon (1)
- Lambverschiebung (1)
- Laser (1)
- Lattice Gauge Theory (1)
- Learning (1)
- Luttinger liquid (1)
- Luttinger-Flüssigkeit (1)
- Mach cone (1)
- Mach cones (1)
- Machkegel (1)
- Magnetic field (1)
- Magnetoelektronik (1)
- Magnons (1)
- Magon-Phonon-Wechselwirkung (1)
- Many-body physics (1)
- Mars (1)
- Master Equations (1)
- Mathematisches Modell (1)
- Mehrfach geladenes Ion (1)
- Membraneproteins (1)
- Membranproteine (1)
- Mesons (1)
- Metasurfaces (1)
- Micro Vertex Detector (1)
- Mikroelektrode (1)
- Molekulardynamik (1)
- Molekularstrahlepitaxie (1)
- Molybdän (1)
- Mott Metal-Insulator Transition (1)
- Mott Transition (1)
- Multigrid Poisson Solver (1)
- Multimessenger (1)
- Multiplicity Fluctuations (1)
- Multiplizitätsfluktuationen (1)
- NA61/SHINE (1)
- Nepomnyashchy theorem (1)
- Network model (1)
- Netzwerktopologie (1)
- Neural Networks (1)
- Neural net (1)
- Neuronales Netz (1)
- Nichtgleichgewicht (1)
- Nichtrelativistisches Potentialmodell (1)
- Niedrige Dimensionen (1)
- Non-dipole (1)
- Nuclear Astrophysics (1)
- Nucleus-Nucleus Collisions (1)
- Nukleare Astrophysik (1)
- Nukleosynthese (1)
- Nullter Schall (1)
- Numerical Renormalization Group (1)
- Numerisches Verfahren (1)
- O(4) conjecture (1)
- OmpF (1)
- OmpG (1)
- Ontogenie (1)
- Open Charm (1)
- Optimierung (1)
- Optisches Potenzial (1)
- Organic Conductors (1)
- Osmosensor (1)
- PHENIX <Teilchendetektor> (1)
- Paarerzeugung (1)
- Particle Accelerator (1)
- Particle Dynamic (1)
- Phase diagram (1)
- Phase transition (1)
- Phase transitions (1)
- Phasendiagramm (1)
- Phasenübergänge (1)
- Photon conversions (1)
- Photonen (1)
- Photonenspektrum (1)
- Photonkonversionen (1)
- Physik (1)
- Pi0 (1)
- Pion (1)
- Plasmadiagnostik (1)
- Plasticity (1)
- Polarimetrie (1)
- Polyfluorene ; Elektrolumineszenz ; Polarisiertes Licht (1)
- Polypeptide (1)
- Polypeptides (1)
- Population activity (1)
- Protein-Lipid Wechselwirkung (1)
- Proteins (1)
- Protonen Linac (1)
- Pulse Shape Analysis (1)
- QCD phase diagram (1)
- QGP (1)
- Quantencomputer (1)
- Quantenelektrodynamik (1)
- Quantenelektrodynamik (QED) (1)
- Quantenhadrodynamik (1)
- Quantenphysik (1)
- Quantum Impurity System (1)
- Quantum modified Gravity (1)
- Quark Model (1)
- Quark deconfinement (1)
- Quark-Gluon-Plasma ; Effektive Wirkung ; Supraleitung (1)
- Quark-Rekombination (1)
- Quark-gluon-plasma (1)
- Quarkonia (1)
- Quarkonium (1)
- Quasiteilchen (1)
- RBW (1)
- RFQ (1)
- RFQ-Accelerator (1)
- RFQ-Beschleuniger (1)
- RHIC (1)
- Radiation hardness (1)
- Rastersondenmikroskop (1)
- Ratengleichungen (1)
- Reaktions-Diffusionsgleichung (1)
- Recombination (1)
- Rekombination (1)
- Relativistische Quantenfeldtheorie (1)
- Representational drift (1)
- Resonances (1)
- Riccati equation (1)
- Rydberg (1)
- SIS (1)
- SPS (1)
- SYK model (1)
- Sarkoplasmatisches Retikulum ; Calcium ; ATP ; Wechselwirkung (1)
- Satz von Nepomnyashchy (1)
- Scanning Probes (1)
- Scattering-type Scanning Near-field Optical Microscopy (1)
- Schottky (1)
- Schwerionenbeschleuniger ; Energiereiches Teilchen ; Teilchendetektor (1)
- Schwerionenkollision (1)
- Schwerionenstrahl (1)
- Schwerionentherapie (1)
- Schwinger-Dyson equation (1)
- Schwinger-Dyson-Gleichung (1)
- Secondary Structure (1)
- Sehrinde (1)
- Sekundärstruktur (1)
- Selbstorganisation (1)
- Self-triggered front-end electronics (1)
- Seltsamkeitsüberhöhung (1)
- Septum (1)
- Shield (1)
- Shock Waves (1)
- Signalschweif (1)
- Silicon Tracking System (1)
- Silicon tracking system (1)
- Slavkovska (1)
- Solar power generation (1)
- Solid state theory (1)
- Spectators (1)
- Speicherring (1)
- Spektralfunktion (1)
- Spieltheorie (1)
- Spin Hall (1)
- Spin Hamiltonians (1)
- Spin chain models (1)
- Spin wave (1)
- Spin-Liquid (1)
- Spin-orbit coupling (1)
- Spinwaves (1)
- Spinwellen (1)
- Spurselektion (1)
- Sputtern (1)
- Stabilität (1)
- Starkes Feld (1)
- Statistische Mechanik (1)
- Statistische Physik (1)
- Storage Ring (1)
- Storage ring (1)
- Stoßwelle (1)
- Strahldynamik (1)
- Strahlentherapie (1)
- Strange hadrons (1)
- Streutheorie (1)
- Störungstheorie (1)
- Stößparameter (1)
- Supernova (1)
- Symmetriebrechung (1)
- Synaptic plasticity (1)
- Synchronisierung (1)
- Säugling (1)
- THz (1)
- THz imaging (1)
- TNSA (1)
- TPSC (1)
- Teilchen (1)
- Teilchenbeschleuniger (1)
- Teilchendynamik (1)
- Teilchenphysik (1)
- Teilchenspur (1)
- Temperaturbeständigkeit (1)
- TeraFET (1)
- Terahertz (1)
- Theoretical neuroscience (1)
- Theoretical physics (1)
- Thermal Expansion (1)
- Thermal Field Theory (1)
- Thermal Stability (1)
- Thermalisierung (1)
- Thermodynamik (1)
- Thermodynamische Eigenschaft (1)
- Thin film transistor (1)
- Time projection chamber (1)
- Topologische Zustände (1)
- Topology (1)
- Toroidal magnetic field (1)
- Toroidalen Magnetfeld (1)
- Transition Radiation Detector (1)
- Transport (1)
- Transport Approach (1)
- Transport Simulations (1)
- Transportmodellen (1)
- Ultrakalte Quantengase (1)
- UrQMD (1)
- Vakuumdeposition (1)
- Vakuumzerfall (1)
- Vertex Detector (1)
- Voronoi-Diagramm (1)
- Walecka model (1)
- Walecka-Modell (1)
- Wasserstoffmolekül ; Heliumion ; Ion-Molekül-Stoß ; Rückstoßimpulsspektroskopie (1)
- Weak Decays (1)
- Weiche Materie (1)
- Wellen (Physik) / shock waves in nuclear matter (1)
- Wigner function (1)
- Wind power generation (1)
- Xi-Hyperon (1)
- Yang-Mills-Theorie (1)
- YbNi4P2 (1)
- YbRh2Si2 (1)
- Yttrium-Eisengranat (1)
- accelerator physics (1)
- agent-based model (1)
- agentenbasierte Modelle (1)
- anisotropy (1)
- antennae (1)
- application (1)
- astrophysikalischer p-Prozess (1)
- atomare Strukturtheorie (1)
- atomic cluster deposition (1)
- atomic cluster on a suface (1)
- atomic physics (1)
- beam dynamics (1)
- bilinear model (1)
- bilineares Modell (1)
- brightness (1)
- bunch-to-bucket (1)
- calibration (1)
- cell internal structure (1)
- chaos (1)
- chiral effect (1)
- chiral symmetry (1)
- circadian rhythm (1)
- closed orbit feedback system (1)
- cognition (1)
- coherent state (1)
- color superconductivity (1)
- commissioning (1)
- communication networks (1)
- complex networks (1)
- compression (1)
- confinement (1)
- correlated electrons (1)
- correlation (1)
- critical systems (1)
- data traffic (1)
- deconfinement (1)
- density isomers (1)
- detector characterization (1)
- detectors (1)
- development (1)
- diagnostics (1)
- dileptons (1)
- dipole-dipole interaction (1)
- dynamical mean-field theory (1)
- electrical characterization (1)
- electrical tests (1)
- electromagnetic fields (1)
- electromagnetic radiation (1)
- electron tunneling (1)
- fermi surface (1)
- field-effect transistor (1)
- field-effect transistors (1)
- flow (1)
- fluctuations (1)
- frequency beating (1)
- fullerene (1)
- game theory (1)
- gasous detectors (1)
- generative model (1)
- generatives Modell (1)
- gitterfrei (1)
- graph theory (1)
- hadron jet (1)
- hadronic transport approach (1)
- haevy-ions (1)
- half-integer resonance (1)
- heavy fermions (1)
- heavy ion collisions (1)
- heavy ion physics (1)
- heavy ions (1)
- heavy-ions (1)
- high-Tc superconductivity (1)
- high-energy physics (1)
- hybrid approach (1)
- hydrodynamics (1)
- in-Medium Modifikation (1)
- infancy (1)
- infrared laser test (1)
- instability (1)
- interacting bosons (1)
- ion implantation (1)
- ionizing radiation (1)
- jet-medium interactions (1)
- kinetic theory (1)
- kritische Systeme (1)
- large-scale integration of renewable power generation (1)
- large-scale integration of variable renewable generation (1)
- laser (1)
- laser characterization (1)
- laser test (1)
- laser-ion acceleration (1)
- lattice-supersolid (1)
- liver, pancreas (1)
- low dimensions (1)
- low-mass dilepton (1)
- magnon condensation (1)
- magnon-phonon interaction (1)
- magnon-phonon interactions (1)
- many-body blockade (1)
- many-body method (1)
- mathematical model (1)
- model (1)
- molecular dynamics (1)
- monte carlo simulation (1)
- nano lithography (1)
- nano tools (1)
- nanocarbon (1)
- nanofractal formation (1)
- nanofractal fragmentation (1)
- nanolithographie (1)
- networks (1)
- nnp (1)
- non-Condon (1)
- non-equilibrium (1)
- non-invasive test (1)
- non-neutral plasma (1)
- nonequilibrium phase transitions (1)
- nonneutral plasma (1)
- nuclear fluid dynamics (1)
- nuclear physics (1)
- nuklear matter (1)
- nukleare Wirkungsquerschnitte (1)
- off-lattice (1)
- optimal wind/solar mix (1)
- optimization (1)
- optische Potentiale (1)
- organic semiconductor (1)
- organotypic slice culture (1)
- overcritical fields (1)
- p-Linac (1)
- phase diagram (1)
- phase shift (1)
- phase transition (1)
- phase transitions (1)
- photon (1)
- pion condensation (1)
- plasmonics (1)
- quality assurance (1)
- quantum criticality (1)
- quantum field theory (1)
- quantum hydrodynamics (1)
- quantum liquid (1)
- quantum mechanics (1)
- quantum spin system (1)
- quark matter (1)
- quark-gluon plasma (1)
- quark-gluon plasma temperature (1)
- quark-gluon-plasma (1)
- quasiparticle expansion (1)
- r-Prozess (1)
- radiation hard sensor (1)
- renormalization group (1)
- resonant (1)
- selbstkonsistent (1)
- semiconductors (1)
- shock waves (1)
- sign problem (1)
- silicon detector (1)
- silicon sensor (1)
- single crystal growth (1)
- slowness Lernen (1)
- slowness learning (1)
- space charge (1)
- sparse coding (1)
- spectral function (1)
- spin wave (1)
- stability analysis (1)
- stability matrix eigenvalues (1)
- storage ring (1)
- strong correlations (1)
- su(2) x u(2) (1)
- superconductivity (1)
- surface reconstruction (1)
- synchronization (1)
- synchronization two rings (1)
- temperature (1)
- theoretical biology (1)
- thermal field theory (1)
- thermalization (1)
- thermodynamics (1)
- thermoelectrics (1)
- thin film (1)
- thin films (1)
- topological states (1)
- track selection (1)
- transmission grid extensions (1)
- ultracold quantum gases (1)
- vacuum decay (1)
- vacuum deposition (1)
- van der Waals (1)
- vector mesons (1)
- vibronic (1)
- wechselwirkende Bosonen (1)
- yttrium-iron garnet (1)
- Äquivalenzprinzip <Physik> (1)
- überkritische Felder (1)
Institute
- Physik (373) (remove)
Construction and commissioning of a setup to study ageing phenomena in high rate gas detectors
(2014)
In high-rate heavy-ion experiments, gaseous detectors encounter big challenges in terms of degradation of their performance due to a phenomenon dubbed ageing. In this thesis, a setup for high precision ageing studies has been constructed and commissioned at the GSI detector laboratory. The main objective is the study of ageing phenomena evoked by materials used to build gaseous detectors for the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR).
The precision of the measurement, e.g., of the gain of a gaseous detector, is a key element in ageing studies: it allows to perform the measurement at realistic rates in an acceptable time span. It is well known the accelerating ageing employing high intensity sources might produce misleading results. The primary objective is to build an apparatus which allows very accurate measurements and is thus sensitive to minute degradations in detector performance. The construction and commissioning of the
setup has been carried out in two steps. During the first step of this work, a simpler setup which already existed in the detector laboratory of GSI had been utilised to define all conditions related to ageing studies. The outcome of these studies defined the properties and characteristics that must be met to build and operate a new, sophisticated and precise setup. The already existing setup consisted of two identical Multi Wire Proportional Chambers (MWPCs), a gas mixing station, an 55Fe source, an x-ray generator, an outgassing box and stainless steel tubing. In a first step, the gain and electric field configuration of the MWPCs were simulated by a combination of a gas simulation (Magboltz) and electric field simulation program (Garfield). The performance and operating conditions of the chambers have been thoroughly characterised before utilising them in first preparatory ageing test. The main diagnostic parameter in ageing studies is the detector gain, thus it is mandatory for precise ageing studies to minimise the systematic and statistical variation of the pressure and temperature corrected gain. To achieve the required accuracy, several improvements of the chamber design and the gas system have been implemented. In addition, the temperature measurement has been optimised. During the preparatory tests, several ageing studies have been carried out. The ageing effect of seven materials and gases have been carried out during these tests: RTV-3145, Ar/CO2 gas, Durostone flushed with Ar/Isobutane gas, Vetronit G11, Vetronit G11 contaminated with Micro 3000 and Gerband 705. The results of these studies went into the design of the new sophisticated ageing setup. For example some tests revealed that there was, even after cleaning, a certain level of contamination with "ageing agents" in the existing setup, which made it imperative to ensure a very high level cleanness of all components during the construction of the setup. The curing period of some testing samples like glues or the gas flow rate were found to be very important factors that must be taken into account to obtain comparable results. Very important changes in the chamber design have been made, i.e., the aluminium-Kapton cathodes used in MWPCs have been replaced with multi-wire planes and the fibreglass housing of the chamber has been changed to metal. The second step started with building the new setup which was designed based on the findings from the first step. The new ageing setup consists of three MWPCs, two moving platforms, an 55Fe source, a copper-anode x-ray generator, two outgassing boxes, both flexible and rigid stainless steel tubes. Before fabrication of the chambers, simulations of their electric field and the gain have been done using Magboltz and Garfield programs. After that, the chambers were installed and tested. A 0.3% peak-to-peak residual variation of the corrected gain has been achieved. Finally, the complete setup has been operated with full functionality in no-ageing conditions during one week. This test revealed very stable gain in all three chambers. After that two materials (Gerban 705 and RTV-3145) have been inserted in the two outgassing boxes and tested. They revealed an ageing rate of about 0.3%/mC/cm and 3%/mC/cm respectively. The final test proves the stability and accuracy of the ageing measurements carried out with the ageing setup at the detector laboratory at GSI which is ready to conduct the envisaged systematic ageing studies.
The high energy loss of heavy ions in matter as well as the small angular scattering makes heavy ion beams an excellent tool to produce almost cylindrical and homogeneously excited volumes in matter. This aspect can be used to pump short wavelength lasers. In an experiment performed at the GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) ion accelerator facility in December 2005 the well-known KrF* excimer laser was pumped with an intense high energy uranium beam. Pulses of an uranium beam with initial particle energy of 250 MeV per nucleon, provided by heavy-ion-synchrotron SIS-18, were delivered to the HHT-target station and then stopped inside a gas laser cell. The maximum beam intensity reached in the experiment was 2,5·109 particles per pulse, which resulted in 34 J/g specific energy deposited in the laser gas. By applying electron cooling and a bunch compression technique at SIS-18, the beam pulses were compressed down to 110 ns (FWHM). A mixture of an excimer laser premix gas (95,5% Kr + 0,5% F2) and a buffer gas (Ar 4.8) was used as the laser gas in proportions of 35/65 and 60/40, respectively. The gas pressure inside the laser cell was varied in the range of 1,2÷2 bar in continues flow mode. The experimental setup consisted of a 1 m long stainless steel tube with a number of diagnostic viewports and two mirror adjustment units. The optical cavity was formed by a flat, Alcoated mirror at the beam entrance and a second dielectrically coated, highly reflective mirror with 3 m radius of curvature at a distance of 1,3 m. A beam of heavy ions has been used to pump a short wavelength gas laser for the first time. Laser effect on the KrF* laser transition (λ = 248 nm) has been successfully demonstrated. Laser threshold for this specific setup was reached with a beam intensity of 1,2·109 particles per pulse. Laser action has been clearly proofed by the following methods: appearance of the laser line, spectral narrowing of the laser line, temporal narrowing of the laser signal, non-linear response of the laser output intensity on the pumping power, and cavity disalignment effect. An energy of the laser pulse of about 2 mJ was measured for an ion beam intensity of 2·109 particles per pulse. The time delay of the onset of the laser emission with respect to the pumping pulse was measured as a function of ion beam intensity. The dependence of spontaneous emission spectra on the gas pressure in a range of 1,3÷2 bar was observed and the optimal gas pressure for laser experiments in the sense of laser efficiency was concluded. As a next step in studying short wavelength lasers pumped with heavy ion beams it is planned to reduce the laser wavelength down to the VUV region of the spectrum, and to proceed to the excimer lasers of the pure rare gases: Xe2 * (λ = 172 nm), Kr2 * (λ = 146 nm), Ar2 * (λ = 126 nm), Ne2 * (λ = 83 nm) and He2 * (λ = 80 nm). We believe that the use of heavy ion beams as a pumping source may lead to new pumping schemes on the higher lying level transitions and considerably shorter wavelengths (XUV and X-ray spectral region), which rely on the high cross sections for multiple ionization of the target species.
Cold target recoil ion momentum spectroscopy (COLTRIM) has been employed to image the momentum distributions of continuum electrons liberated in the impact of slow He2+ on He and H2. The distributions were measured for fully determined motion of the nuclei that is as a function of the impact parameter and in a well de ned scattering plane The single ionization (SI) of H2 leading to H2+ recoil ions in nondissociative states (He2+ + H+ -> He2+ + H+ + e-) and the transfer ionization (TI) of H2 leading to H2 dissociation into two free protons (He2+ H2 -> He+ + H+ + H+ + e-) were investigated. Similar measurements have been carried out for He target, the corresponding atomic two electron system, i.e. the single ionization (SI) (He2+ + He -> He+ + He2+ e- and the transfer ionization (TI) (He2+ + He -> He+ + He2+ + e-). These measurements have been exploited to understand the results obtained for H target. In comparing the continuum electron momentum distributions for H2 with that for He, a high degree of similarity is observed. In the case of transfer ionization of H2, the electron momentum distributions generated for parallel and perpendicular molecular orientations revealed no orientation dependence. The in scattering plane electron momentum distributions for the transfer ionization of H2 by He2+ and for the transfer ionization of He by He2e showed that the salient feature of these distributions for both collisions systems consists in the appearance of two groups of electrons with difeerent structures. In addition to the group of the saddle electrons forming two jets separated by a valley along the projectile axis we nd a new group of electrons moving with a velocity higher than the projectile velocity These new fast forward electrons result from a narrow range of impact parameters and appear as image saddle in the projectile frame. In contrast to the transfer ionization of He, the fast forward electrons group disappears in the in scattering plane electron momentum distribution generated for the single ionization of He. Instead of this group another new group of electrons appear These electrons exhibit an amount of backscattering These backward elec trons appear as image saddle in the target frame The structures that the saddle electrons show are owing to the quasi molecular nature of the collision process For the TI of H2, the TI of He and the SI of He, a pi-orbital shape of the electron momentum distribution is observed This indicates the importance of the rotational coupling 2-p-theta -> 2p-pi in the initial promotion of the ground state followed by further promotions to the continuum The backward electrons as well as the fast forward electrons are not discussed in the theoretical literature at all. However, a number of obvious indications of the existence of the backward and fast forward electrons could be seen in the experimental works of Abdallah et al. as well as in the theoretical calculations of Sidky et al One might speculate that electrons which are promoted on the saddle for some time during the collision could finally swing around the He+ ion in the way out of the collision, i.e. either around the projectile in the forward direction as in the TI case forming the fast forward electrons or around the recoil ion in the backward direction as in the SI case forming the backward electrons. This might be a result of the strong gradient, and hence the large acceleration of the screened He+ potential.
Starting from the first observation of the halo phenomenon 20 years ago, more and more neutron-rich light nuclei were observed. The study of unstable nuclear systems beyond the dripline is a relatively new branch of nuclear physics. In the present work, the results of an experiment at GSI (Darmstadt) with relativistic beams of the halo nuclei 8He, 11Li and 14Be with energies of 240, 280 and 305 MeV/nucleon, respectively, impinging on a liquid hydrogen target are discussed. Neutron/proton knockout reactions lead to the formation of unbound systems, followed by their immediate decay. The experimental setup, consisting of the neutron detector LAND, the dipole spectrometer ALADIN and different types of tracking detectors, allows the reconstruction of the momentum vectors of all reaction products measured in coincidence. The properties of unbound nuclei are investigated by reconstructing the relative-energy spectra as well as by studying the angular correlations between the reaction products. The observed systems are 9He, 10He, 10Li, 12Li and 13Li. The isotopes 12Li and 13Li are observed for the first time. They are produced in the 1H(14Be, 2pn)12Li and 1H(14Be, 2p)13Li knockout reactions. The obtained relative-energy spectrum of 12Li is described as a single virtual s-state with a scattering length of as = -22;13.7(1.6) fm. The spectrum of 13Li is interpreted as a resonance at an energy of Er = 1.47(13) MeV and a width of Gamma ~ 2 MeV superimposed on a broad correlated background distribution. The isotope 10Li is observed after one-neutron knockout from the halo nucleus 11Li. The obtained relative-energy spectrum is described by a low-lying virtual s-state with a scattering length as = -22.4(4.8) fm and a p-wave resonance with Er = 0.566(14) MeV and Gamma = 0.548(30) MeV, in agreement with previous experiments. The observation of the nucleus 8He in coincidence with one or two neutrons, as a result of proton knockout from 11Li, allows to reconstruct the relative-energy spectra for the heavy helium isotopes, 9He and 10He. The low-energy part of the 9He spectrum is described by a virtual s-state with a scattering length as = -3.16(78) fm. In addition, two resonance states with l 6= 0 at energies of 1.33(8) and 2.4 MeV are observed. For the 10He spectrum, two interpretations are possible. It can be interpreted as a superposition of a narrow resonance at 1.42(10) MeV and a broad correlated background distribution. Alternatively, the spectrum is being well described by two resonances at energies of 1.54(11) and 3.99(26) MeV. Additionally, three-body energy and angular correlations in 10He and 13Li nuclei at the region of the ground state (0 < ECnn < 3 MeV) are studied, providing information about structure of these unbound nuclear systems.
This thesis is structured into 7 chapters:
• Chapter 2 gives an overview of the ultrashort high intensity laser interaction with matter. The laser interaction with an induced plasma is described, starting from the kinematics of single electron motion, followed by collective electron effects and the ponderamotive motion in the laser focus and the plasma transparency for the laser beam. The three different mechanisms prepared to accelerate and propagate electrons through matter are discussed. The following indirect acceleration of protons is explained by the Target Normal Sheath Acceleration (TNSA) mechanism. Finally some possible applications of laser accelerated protons are explained briefly.
• Chapter 3 deals with the modeling of geometry and field mapping of magnetic lens. Initial proton and electron distributions, fitted to PHELIX measured data are generated, a brief description of employed codes and used techniques in simulation is given, and the aberrations at the solenoid focal spot is studied.
• Chapter 4 presents a simulation study for suggested corrections to optimize the proton beam as a later beam source. Two tools have been employed in these suggested corrections, an aperture placed at the solenoid focal spot as energy selection tool, and a scattering foil placed in the proton beam to smooth the radial energy beam profile correlation at the focal spot due to chromatic aberrations. Another suggested correction has been investigated, to optimize the beam radius at the focal spot by lens geometry controlling.
• Chapter 5 presents a simulation study for the de-neutralization problem in TNSA caused by the fringing fields of pulsed magnetic solenoid and quadrupole. In this simulation, we followed an electrostatic model, wherethe evolution of both, self and mutual fields through the pulsed magnetic solenoid could be found, which is not the case in the quadrupole and only the growth of self fields could be found. The field mapping of magnetic elements is generated by the Matlab program, while the TraceWin code is employed to study the tracking through magnetic elements.
• Chapter 6 describes the PHELIX laser parameters at GSI with chirp pulse amplification technique (CPA), and Gafchromic Radiochromic film RCF) as a spatial energy resolver film detector. The results of experiments with laser proton acceleration, which were performed in two experimental areas at GSI (Z6 area and PHELIX Laser Hall (PLH)), are presented in section 6.3.
• Chapter 7 includes the main results of this work, conclusions and gives a perspective for future experimental activities.
Next-generation DIRC detectors, like the PANDA Barrel DIRC, with improved optical designs and better spatial and timing resolution, require correspondingly advanced reconstruction and PID methods. The investigation of the PID performance of two DIRC counters and the evaluation of the reconstruction and PID algorithms form the core of this thesis. Several reconstruction and PID approaches were developed, optimized, and tested using hadronic beam particles, experimental physics events, and Geant simulations. The near-final design of the PANDA Barrel DIRC was evaluated with a prototype in the T9 beamline at CERN in 2018. The analysis finds excellent agreement between the experimental data and the Geant simulations for all reconstruction algorithms. The best PID performance of up to $5.2 \pm 0.2$ s.d. $\pi$/K separation at 3.5 GeV/c, was obtained with a time imaging PID method. The PANDA Barrel DIRC simulation, as well as the reconstruction and PID algorithms, were evaluated using experimental data from the GlueX DIRC as part of the FAIR Phase-0 program. The performance validation was carried out using physics events of the GlueX experiment and simulations. The initial analysis results of the commissioning dataset show a $\pi$/K separation power of up to 3 s.d. at a momentum of 3.0-3.5 GeV/c, obtained using a geometric reconstruction algorithm.
The subject of this thesis is the experimental investigation of the neutron-capture cross sections of the neutron-rich, short-lived boron isotopes 13B and 14B, as they are thought to influence the rapid neutron-capture process (r process) nucleosynthesis in a neutrino-driven wind scenario.
The 13;14B(n,g)14;15B reactions were studied in inverse kinematics via Coulomb dissociation at the LAND/R3B setup (Reactions with Relativistic Radioactive Beams). A radioactive beam of 14;15B was produced via in-flight fragmentation and directed onto a lead-target at about 500 AMeV. The neutron breakup of the projectile within the electromagnetic field of the target nucleus was investigated in a kinematically complete measurement. All outgoing reaction products were detected and analyzed in order to reconstruct the excitation energy.
The differential Coulomb dissociation cross sections as a function of the excitation energy were obtained and first experimental constraints on the photoabsorption and the neutron-capture cross sections were deduced. The results were compared to theoretical approximations of the cross sections in question. The Coulomb dissociation cross section of 15B into 14B(g.s.) + n was determined to be s(15B;14B(g:s:)+n) CD = 81(8stat)(10syst) mb ; while the Coulomb dissociation cross section of 14B into a neutron and 13B in its ground state was found to be s(14B;13B(g:s:)+n) CD = 281(25stat)(43syst) mb: Furthermore, new information on the nuclear structure of 14B were achieved, as the spectral shape of the differential Coulomb dissociation cross section indicates a halolike structure of the nucleus.
Additionally, the Coulomb dissociation of 11Be was investigated and compared to previous measurements in order to verify the present analysis. The corresponding Coulomb dissociation cross section of 11Be into 10Be(g.s.) + n was found to be 450(40stat)(54syst ) mb, which is in good agreement with the results of Palit et al.
In der Experimentierhalle der Physik am Campus Riedberg der Goethe – Universität wird gegenwärtig die Beschleunigeranlage FRANZ aufgebaut. FRANZ steht für Frankfurter Neutronenquelle am Stern-Gerlach-Zentrum. Die Anlage bietet vielfältige Experimentiermöglichkeiten in der Untersuchung intensiver, gepulster Protonenstrahlen. Ein Forschungsschwerpunkt an den sekundären Neutronenstrahlen sind Messungen zur nuklearen
Astrophysik. Die Neutronen werden durch einen 2 MeV Protonenstrahl mittels der Reaktion 7Li (p, n) 7Be erzeugt. Die geplanten Experimente erfordern sowohl eine hier weltweit erstmals realisierte Pulsrepetitionsrate von bis zu 250 kHz bei Pulsströmen im 100 mA – Bereich als auch eine extreme Pulskompression auf eine Nanosekunde bei dann auftretenden Pulsströmen im Ampere – Bereich. Daneben ist auch ein Dauerstrich – Strahlbetrieb im mA – Strombereich möglich. Auch viele einzelne Beschleunigerkomponenten wie die Ionenquelle, der Chopper zur Pulsformung, die hochfrequent gekoppelte RFQ-IH-Kombination, der Rebuncher in Form einer CH – Struktur und der Bunchkompressor sind Neuentwicklungen. Mittlere Strahlleistungen von bis zu 24 kW treten im Niederenergiestrahltransportbereich auf, da die Ionenquelle grundsätzlich im Dauerstrich zu betreiben ist, auch bei Hochstrom mit hohen Pulsrepetitionsraten. Der Personen- und Geräteschutz spielt damit auch eine wesentliche Rolle bei der Auslegung des Kontrollsystems für FRANZ. Der Aufbau von FRANZ und seine wesentlichen Komponenten werden in Kapitel 2 erläutert. Die vielen unterschiedlichen Komponenten wie Hochspannungsbereich, Magneten, Hochfrequenzbauteile und Kavitäten, Vakuumbauteile, Strahldiagnose und Detektoren machen plausibel, dass auch das Kontrollsystem für eine solche Anlage speziell ausgelegt werden muss. In Kapitel 4 werden zum Vergleich die Konzepte zur Steuerung und Regelung aktueller, großer Beschleunigerprojekte aufgezeigt, nämlich für die „European Spallation Source ESS“ und für die „Facility for Antiproton and Ion Research FAIR“. In der vorliegenden Arbeit wurde die Ionenquelle als komplexe Beschleunigerkomponente ausgewählt, um Entwicklungen zur Steuerung und Regelung durchzuführen und zu testen. Zum Anfahren und Betreiben der Ionenquelle wurde ein Flussdiagramm (Abb. 5.15) entwickelt und realisiert. Im Detail wurden Untersuchungen zur Abhängigkeit der Heizkathodenparameter von der Betriebsdauer gemacht. Daraus konnte ein Algorithmus zur Vorhersage eines rechtzeitigen Filamentaustausches abgeleitet werden. Weiterhin konnte die Nachregelung des Kathodenheizstromes automatisiert werden, um damit die Bogenentladungsspannung innerhalb eines Intervalls von ± 0.5 V zu stabilisieren. Das Anfahren des Filamentstroms wurde ebenfalls automatisiert. Dazu wird die Vakuumdruckänderung in Abhängigkeit der Filamentstromerhöhung gemessen, ausgewertet und daraus der nächste erlaubte Stromerhöhungsschritt abgeleitet. Auf diese Weise wird der Betriebszustand schneller und kontrollierter erreicht als bei manuellem Hochfahren. Das Ziel eines unbemannten Ionenquellenbetriebs ist damit näher gerückt. In einem ersten Test zur Komponentensteuerung und zur Datenaufnahme wurde ein Ionenstrahl extrahiert und durch den ersten Fokussierungsmagneten – einen Solenoiden – transportiert. Es wurde der Erregungsstrom des Solenoiden sowie die Strahlenergie automatisch durchgefahren, die Daten abgespeichert und daraus ein Kontourplot zum gemessenen Strahlstrom hinter der Fokussierlinse erstellt (Abb. 5). Die vorliegende Arbeit beschäftigt sich nur mit den „langsamen“ Steuerungs- und Regelungsprozessen, während die schnellen Prozesse im Hochfrequenzregelungssystem unabhängig geregelt werden. Neben der Überwachung des Betriebszustandes aller Komponenten werden auch alle für den Service und die Personensicherheit benötigten Daten weggeschrieben. Das System basiert auf MNDACS (Mesh Networked Data Acquisition and Control System) und ist in JAVA geschrieben. MNDACS besteht aus einem Kernel, welcher die Komponententreiber-Software sowie den Netzwerkserver und das graphische Netzwerkinterface (GUI) betreibt. Weterhin gehört dazu das Driver Abstraction Layer (DAL), welches den Zugang zu weiteren Computern oder zu lokalen Treibern ermöglicht. CORBA stellt die Middleware für Netzwerkkommunikation dar. Dadurch wird Kommunikation mit externer Software geregelt, weiterhin wird die Umlegung von Kommunikation im Fall von Leitungsunterbrechungen oder einem lokalen Computerabsturz festgelegt. Es gibt bei FRANZ zwei Kontrollebenen: Über Ethernet läuft die „High Level Control“ und die Datenverarbeitung. Über die „Low Level Control“ läuft das Interlock – und Sicherheitssystem. Die Netzwerkverbindungen laufen über 1 Gb Ethernet Links, womit ein schneller Austausch auch bei lokalen Netzwerkstörungen noch möglich ist. Um bei Stromausfällen das Computersystem am Laufen zu halten, wurde im Rahmen dieser Arbeit ein „Uninterruptable Power Supply“ UPS beschafft und erfolgreich am Hochspannungsterminal getestet.
In this thesis we study strongly correlated electron systems within the Density Functional Theory (DFT) in combination with the Dynamical Mean-Field Theory (DMFT).
First, we give an introduction into the theoretical methods and then apply them to study realistic materials. We present results on the hole-doped 122-family of the iron-based superconductors and the transition-metal oxide SrVO3. Our investigations show that a proper treatment of strong electronic correlations is necessary to describe the experimental observations.