% 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{Flenner:471334,
      author       = {Flenner, Silja},
      othercontributors = {Mueller, Martin and Salditt, Tim},
      title        = {{I}mplementation of {P}hase {C}ontrast {M}ethods at the
                      {P}05 {N}anotomography {E}ndstation at {PETRA} {III}:
                      {E}nabling in situ experiments},
      school       = {CAU Kiel},
      type         = {Dissertation},
      reportid     = {PUBDB-2021-04377},
      pages        = {139},
      year         = {2021},
      note         = {Dissertation, CAU Kiel, 2021},
      abstract     = {Hard X-ray full-field nanotomography is an ideal technique
                      to study the inner structureof materials non-destructively
                      at high spatial resolution, covering research areas suchas
                      material science, biology and medical research. In
                      particular, in situ experiments areof high importance to
                      study dynamics and processes in materials. High X-ray
                      energieshave the advantage to reduce the dose at the sample
                      and in the case of a transmissionX-ray microscope (TXM), to
                      increase the focal depth. One disadvantage of higherphoton
                      energies however is the low absorption contrast for many
                      materials, not onlyfor biological or biomedical specimen.
                      One approach to enhance the contrast is givenby phase
                      contrast methods.The main aim of this thesis is the
                      implementation of full-field phase contrast methods atthe
                      nanotomography endstation of the imaging beamline P05 at the
                      PETRA III storagering. In this context, the temporal
                      resolution is an important point in order to furtherreduce
                      the dose as well as enable in situ nanotomography
                      experiments. These two pointsare tackled by combining the
                      unique geometry of the presented beamline with
                      optimizedexperimental parameters and the development of new
                      tomographic techniques, as wellas integrating additional
                      post-processing steps using machine learning algorithms.One
                      approach to improve the contrast in a TXM is realized by
                      implementing Zernikephase contrast (ZPC). In addition, a new
                      denoising approach based on machine learningwas developed,
                      eliminating noise from nanotomographic data, in particular
                      when usingfast scanning modes. Utilizing these methods at
                      high temporal resolutions is key toperform the first in situ
                      nanotomography experiments at P05: A spider attachmenthair
                      is attached to a surface under force control and scanned at
                      different states ofattachment. An interesting aspect is here
                      also the orientation distribution of singleattachment
                      elements, which is linked to previously recorded diffraction
                      data.Another phase contrast approach utilizing the high
                      coherence of 3rd generation sources,is near-field
                      holotomography (NFH) based on propagation phase contrast. In
                      the frame-work of this thesis the worldwide first hard X-ray
                      holotomography setup using Fresnelzone plates has been
                      developed and realized at the P05 imaging beamline. In
                      contrastto ZPC, it offers a scalable field of view and
                      magnification, the quantitative analysis ofthe phase signal
                      and sufficient space for extended sample environments.The
                      developed and implemented phase contrast methods at the P05
                      nanotomographystation will enable the analysis of materials
                      with high resolution in 3D at high temporalresolutions.
                      Altogether this will open doors to in situ experiments and
                      offer greatopportunities to study dynamical processes.},
      cin          = {Hereon},
      cid          = {I:(DE-H253)Hereon-20210428},
      pnm          = {6G3 - PETRA III (DESY) (POF4-6G3)},
      pid          = {G:(DE-HGF)POF4-6G3},
      experiment   = {EXP:(DE-H253)P-P05-20150101},
      typ          = {PUB:(DE-HGF)11},
      url          = {https://bib-pubdb1.desy.de/record/471334},
}