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@PHDTHESIS{Imgram:276718,
      author       = {Imgram, Phillip},
      title        = {{H}igh-precision laser spectroscopy of helium-like carbon
                      $^{12}${C}$^{4+}$},
      school       = {TU Darmstadt},
      type         = {Dissertation},
      address      = {Darmstadt},
      publisher    = {TU Darmstadt},
      reportid     = {GSI-2023-00327},
      pages        = {71},
      year         = {2023},
      note         = {Dissertation, TU Darmstadt, 2022},
      abstract     = {The size of an atomic nucleus is a fundamental observable
                      and defined by the distribution of the neutrons and protons
                      composing the nucleus and the respective mean-square radii.
                      The precise investigation of the nuclear size across the
                      chart of nuclides delivers important benchmarks for nuclear
                      structure theory and tests our fundamental knowledge of
                      matter. In contrast to matter and neutron radii, the nuclear
                      charge radius can be probed through the well-known
                      electromagnetic interaction. Different techniques have been
                      developed over time to measure nuclear charge radii such as
                      elastic electron scattering or muonic atom spectroscopy.
                      While these techniques are typically limited to stable
                      nuclei, collinear laser spectroscopy and resonant ionization
                      spectroscopy are used to determine nuclear charge radii of
                      short-lived radioactive isotopes relative to a reference
                      charge radius of a stable isotope. In some cases, this can
                      limit the uncertainty of the obtained charge radii of
                      radioactive nuclei to the uncertainty of the reference
                      measurements from elastic electron scattering or muonic atom
                      spectroscopy. To overcome this limit in light mass nuclei
                      like 10, 11B, an all-optical approach for the charge radius
                      determination purely from laser spectroscopy measurements
                      and non-relativistic QED calculations was tested in this
                      work with the well-known nucleus of 12C through laser
                      excitation of helium-like 12C4+ from the metastable 1s2s 3S1
                      state with a lifetime of 21 ms to the 1s2p 3PJ states. The
                      high-precision collinear laser spectroscopy was performed at
                      the Collinear Apparatus for Laser Spectroscopy and Applied
                      Science (COALA), situated at the Institute for Nuclear
                      Physics at the Technical University Darmstadt. In order to
                      produce the the highly charged C4+ ions, a new electron beam
                      ion source including a Wien filter for charge/mass
                      separation was installed and commissioned at COALA.
                      Additionally, a new switchyard and beam diagnostics were
                      designed, built and installed. The 1s2s 3S1 → 1s2p 3PJ
                      rest-frame transition frequencies were determined with less
                      than 2 MHz uncertainty through quasi-simultaneous collinear
                      and anticollinear laser spectroscopy. These transition
                      frequencies are in excellent agreement with state-of-the-art
                      ab initio atomic structure calculations and an all-optical
                      nuclear charge radius of 12C was extracted. Its accuracy is
                      limited by theory, which must be improved by two orders of
                      magnitude before the experimental uncertainty becomes
                      significant again. At that point, the accuracy of the
                      extracted charge radius would have already outperformed all
                      previous measurements of this observable. Furthermore, the
                      high precision of this work enabled the estimation of the
                      next missing order in the atomic structure calculations and
                      the transition frequencies from this work can be used
                      together with ongoing measurements in 13C4+ for a
                      conventional determination of the mean-square charge radius
                      difference δ⟨r2⟩12,13 between 12C and 13C which has not
                      been measured so far by laser spectroscopy.},
      cin          = {ATP},
      cid          = {I:(DE-Ds200)ATP-20051214OR020},
      pnm          = {631 - Matter – Dynamics, Mechanisms and Control
                      (POF4-631) / SFB 1245 A01 - Präzisionsmessungen zur
                      Struktur leichter Kerne (A01) (289442692)},
      pid          = {G:(DE-HGF)POF4-631 / G:(GEPRIS)289442692},
      experiment   = {$EXP:(DE-Ds200)no_experiment-20200803$},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:tuda-tuprints-230828},
      doi          = {10.26083/TUPRINTS-00023082},
      url          = {https://repository.gsi.de/record/276718},
}