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@PHDTHESIS{Mller:348999,
      author       = {Müller, Patrick Matthias},
      title        = {{L}aserspectroscopic determination of the nuclear charge
                      radius of ¹³{C}},
      school       = {Technische Universität Darmstadt},
      type         = {Dissertation},
      address      = {Darmstadt},
      publisher    = {ULB Darmstadt},
      reportid     = {GSI-2024-00460},
      pages        = {118, xix Seiten},
      year         = {2024},
      note         = {Dissertation, Technische Universität Darmstadt, 2023},
      abstract     = {Light nuclei, that consist of only a few nucleons, are
                      exciting testing grounds for our understanding of
                      fundamental interactions. Bound by the residual strong
                      interaction acting between the quarks inside the protons and
                      neutrons, these nuclei form interesting structures such as
                      condensed α clusters or halo nuclei that are challenging to
                      describe by nuclear theory. Over the last decades, ab initio
                      nuclear structure calculations, that are rooted in quantum
                      chromodynamics, were improved significantly. Providing
                      precise benchmark values for these theories is essential to
                      improve the precision of predictions on how nuclear matter
                      emerges. The isotopes of the light element carbon (C) are
                      highly interesting cases to study as they exhibit pronounced
                      α clustering and are important contributors to the
                      nucleosynthesis process in stars. Additionally, C is at the
                      limit of what is computationally possible using higher-order
                      nuclear structure calculations, and due to its unfavorable
                      spectral properties, no experimental high-precision
                      spectroscopy data is available so far. In this work, the
                      differential nuclear charge radius of ¹²⸴¹³C is
                      determined purely from results of ab initio nonrelativistic
                      quantum electrodynamics atomic structure calculations and
                      highprecision collinear laser spectroscopy measurements
                      carried out at the Collinear Apparatus for Laser
                      Spectroscopy and Applied Science (COALA), located at the
                      Institute for Nuclear Physics at the Technical University
                      Darmstadt. For this, first high-accuracy measurements of the
                      1s2s ³S₁ → 1s2p ³P₀,₁,₂ transitions in He-like
                      ¹³C⁴⁺ were carried out and combined with measurements
                      in ¹²C⁴⁺ from preceding work. The C⁴⁺ isotopes in
                      the metastable ³S₁ state are produced in an electron beam
                      ion source and are accessible with lasers operated at a
                      wavelength of 227.6 nm. The fluorescence detection region
                      (FDR) of COALA at these deep-UV wavelengths was improved
                      with a new lens-based FDR designed and built within this
                      work. The new segment provides an improved signal-to-noise
                      ratio compared to the previous mirror-based design. This
                      considerably facilitated spectroscopy of the weakest
                      transitions in ¹³C⁴⁺, which split into hyperfine
                      structure (HFS). The effect of hyperfine-induced mixing on
                      the transition frequencies is investigated and benchmark
                      values for atomic structure calculations are provided. The
                      new model independent δ⟨r²⟩¹²⸴¹³ = −0.1245(66)
                      fm² is compared to results from elastic electron
                      scattering, muonic atom spectroscopy and ab initio nuclear
                      structure calculations. In combination with the existing
                      experimental results for ¹²C, the absolute nuclear charge
                      radius of ¹³C is determined. An elaborate analysis of the
                      fluorescence spectra and potential systematic uncertainties
                      is presented that is enabled by the new Python package
                      qspec, developed within this work for simulations and data
                      analysis surrounding laser spectroscopy. The package was
                      extensively tested during beamtimes at GSI, CERN/ISOLDE and
                      ANL where it significantly contributed to decision-making
                      processes by enabling a detailed live data analysis and
                      simulations. In addition to the analysis of ¹³C⁴⁺, an
                      investigation of quantum interference effects and
                      optical-population transfer in the HFS of ⁸⁷Sr⁺ is
                      presented in the appendix.},
      cin          = {ATP / DEC / SPARC@FAIR},
      cid          = {I:(DE-Ds200)ATP-20051214OR020 /
                      I:(DE-Ds200)DEC-20121002OR240 / I:(DE-Ds200)Coll-FAIR-SPARC},
      pnm          = {631 - Matter – Dynamics, Mechanisms and Control
                      (POF4-631) / DFG project 279384907 - SFB 1245: Atomkerne:
                      Von fundamentalen Wechselwirkungen zu Struktur und Sternen
                      (279384907)},
      pid          = {G:(DE-HGF)POF4-631 / G:(GEPRIS)279384907},
      experiment   = {$EXP:(DE-Ds200)no_experiment-20200803$},
      typ          = {PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:tuda-tuprints-267460},
      doi          = {10.26083/TUPRINTS-00026746},
      url          = {https://repository.gsi.de/record/348999},
}