% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Oelmann:873300,
      author       = {Oelmann, Jannis},
      title        = {{Q}uantitative {U}ntersuchung des {L}aserablationsprozesses
                      mittels {K}ombination von optischer {S}pektroskopie und
                      {M}assenspektrometrie},
      volume       = {486},
      school       = {Universität Bochum},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2020-00618},
      isbn         = {978-3-95806-453-9},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {X, 141 S.},
      year         = {2020},
      note         = {Universität Bochum, Diss., 2019},
      abstract     = {This dissertation assesses the process of laser-induced
                      ablation using picosecond laser pulses by applying it to
                      different materials. The introduction reviews the
                      theoretical background of the different ablation mechanisms,
                      which are classified according to the used laser parameters.
                      Following that, the ablation is characterized by employing
                      various experimental methods: the crater formation resulting
                      from successive ablation and the material-depending ablation
                      rates are determined by analyzing the crater structures.
                      Moreover, an experimental setup for the study of
                      laser-induced ablation in vacuum, which has been built in
                      the course of this work, is presented. This setup enables
                      the simultaneous appliance of mass spectrometry and
                      complementary optical spectroscopy. The analyses of a thin
                      film solar cell and a C/Ti/Mo-layer structure demonstrate
                      that depth-resolved sample characterization is possible with
                      laser-induced ablation using picosecond pulse durations.
                      Results show that the ablation rates within one sample layer
                      are proportional to the applied pulse energy. In spite of
                      the short pulse duration of τ$_{L}$ = 35 ps, thermal
                      effects are observed in the ablation process: the crater
                      size depends on the laser pulse energy and material is
                      redeposited around the crater in the laser-induced ablation
                      process. Laser parameters like pulse energy and diameter are
                      optimized for the determination of hydrogen content in
                      fusion-relevant materials via a residual gas analysis and a
                      simultaneously performed laser-induced breakdown
                      spectroscopy. An investigation of the laser-induced
                      fragmentation of an amorphous hydrogenated carbon layer
                      (a–C:H) shows that one third of the total hydrogen content
                      is found in hydrocarbons after ablation. This needs to be
                      included in a quantitative sample analysis. For the first
                      time, the depth-resolved hydrogen content in graphite tiles,
                      which were exposed in the fusion test facility Wendelstein
                      7-X, could be measured quantitatively in ex-situ analysis.
                      The integrated signals show good agreement with thermal
                      desorption spectroscopy measurements. Aiming at applying the
                      developed measurement technique in a future fusion reactor,
                      first results of deuterium retention analyses in graphite
                      and tungsten are presented. These show particle densities in
                      the order of 10$^{19}$ $^{D}$ $^{Atome/_{cm}}$ $^{3}$
                      vorgestellt.},
      cin          = {IEK-4},
      cid          = {I:(DE-Juel1)IEK-4-20101013},
      pnm          = {174 - Plasma-Wall-Interaction (POF3-174)},
      pid          = {G:(DE-HGF)POF3-174},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:0001-2020102057},
      url          = {https://juser.fz-juelich.de/record/873300},
}