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@PHDTHESIS{Sasidharan:347258,
      author       = {Sasidharan, Sangeetha},
      title        = {{H}igh-precision atomic mass measurement of helium-4},
      school       = {Ruprecht-Karls-Universität Heidelberg},
      type         = {Dissertation},
      address      = {Heidelberg},
      publisher    = {Heidelberg University Library},
      reportid     = {GSI-2023-00967},
      pages        = {154},
      year         = {2023},
      note         = {Dissertation, Ruprecht-Karls-Universität Heidelberg, 2023},
      abstract     = {Penning-trap mass spectrometry enables a precise
                      determination of atomic masses, supporting sensitive tests
                      of fundamental physics. LIONTRAP (Light Ion TRAP) is a
                      specialized mass spectrometer focused on precise mass
                      measurements of light ions. In this experiment, we currently
                      reach a relative resolution of 10 parts-per-trillion (ppt)
                      and beyond for atomic masses. The measurement principle
                      involves comparing the cyclotron frequencies of the ions
                      under investigation and a carbon ion, which are inversely
                      proportional to their masses. In the scope of this thesis, a
                      high-precision mass measurement of 4He2+ was performed. To
                      this end, a source for gaseous species was developed, and an
                      extensive investigation of the systematics affecting the
                      mass measurements, including image charge shift, lineshape
                      systematics, and others, was conducted. The mass determined
                      herein has a relative precision of 12 ppt. Based on this,
                      the atomic mass of the neutral atom is determined from the
                      binding energies and the electron mass without loss of
                      precision. The mass value exhibits a precision that is 1.3
                      times greater than the current literature value but deviates
                      from it by 6.6 combined standard deviations. This result
                      contributes to fundamental physics by potentially supporting
                      the improvement of the electron mass via a g-factor
                      determination of 4He+. Towards the end of the thesis, new
                      developments are presented, including a test of the two-ion
                      balance technique to improve the precision of the upcoming
                      mass measurement.},
      keywords     = {530 Physics (Other)},
      cin          = {ATP},
      cid          = {I:(DE-Ds200)ATP-20051214OR020},
      pnm          = {631 - Matter – Dynamics, Mechanisms and Control
                      (POF4-631)},
      pid          = {G:(DE-HGF)POF4-631},
      experiment   = {$EXP:(DE-Ds200)no_experiment-20200803$},
      typ          = {PUB:(DE-HGF)11},
      urn          = { urn:nbn:de:bsz:16-heidok-339389},
      urn          = {urn:nbn:de:bsz:16-heidok-339389},
      doi          = {10.11588/HEIDOK.00033938},
      url          = {https://repository.gsi.de/record/347258},
}