German Title: Hochpräzise Bestimmung der Massen und Massenverhältnisse von Neon- und Ytterbiumisotopen zur Überprüfung grundlegender physikalischer Prinzipien

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Abstract

During the research for this thesis, several mass ratios were measured with a relative uncertainty of a few parts per trillion using the cryogenic Penning trap mass spectrometer Pentatrap. The determination of the mass ratio of the 20Ne isotope against the 12C isotope reached a relative uncertainty of 4×10−12 and, with a deviation of 4 standard deviations to the former literature value, results in the most precise mass measurement in atomic mass units to date and an improvement of this mass value by a factor of nineteen. This precision mass determination is used in a test of the theory of quantum electrodynamics (QED), especially confirming one- and two-loop corrections of bound-state QED at highest precision. The determination of mass ratios between the five stable even ytterbium isotopes reached a precision of also 4×10−12. These mass ratios are used in a King plot analysis of isotope shifts in atomic transitions to exclude the existence of a proposed new boson mediating a new 5th force. The measurements improve the respective mass ratios determined from literature masses by one to two orders of magnitude. Lastly, the binding energies of the valence electrons in 172Yb41+ and 172Yb42+ are determined to sub-eV precision as a cross-check of the measurement accuracy and a test of the theoretical models and methods used to calculate these binding energies.

The presented cyclotron frequency determinations show an improvement of at least a factor of two compared to previous measurements of isotope mass ratios at Pentatrap and an improvement of a factor of six in the determination of binding energies of highly charged ions, made possible by an upgrade of the experiments detection system within this thesis. The measurement of the mass of 20Ne was the first measurement of light ions and the first measurement against the atomic mass unit reference 12C at this experiment, and, with the precision demonstrated, paves the way for further high-precision mass determinations in atomic mass units in this experiment. The presented accuracy of binding energy determinations will enable stringent tests of QED-theory in the future by determining the binding energies of electrons in heavier atoms and higher charge states.