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Abstract

- In the framework of this thesis, a measurement campaign on the
atomic mass of the deuteron, the nucleus of deuterium, was conducted at the
Penning-trap experiment Liontrap (Light-Ion TRAP). For this purpose, major
parts of the original experimental facility were rebuilt and improved.
The measurement principle at Liontrap is based on a comparison of the cyclotron
frequency of the ion to of interest and the cyclotron frequency of a
carbon ion. From this, the mass in atomic mass units is deduced. Liontrap
is optimized on the special requirements of light ions, as inconsistencies in the
combination of different measurements hamper the use of their mass values for
applications for example in neutrino physics.
In the measurement campaign, it was possible to measure the atomic mass
of deuteron with a relative precision of 8.5 · 10⁻¹². This is the most precise
measurement in atomic mass units to date. The value is a factor 2.4 more
precise than the previously most precise measurement and shows a discrepancy
of 5 standard deviations. Additionally, a measurement of the molecular ion HD⁺
was conducted. The mass of this molecular ion can be derived from the masses
of the deuteron and the proton, previously also measured at Liontrap. The
atomic mass of the electron and the molecular binding energy are sufficiently
known to not add an additional uncertainty. Both values for the atomic mass
of HD⁺ agree, giving a strong confidence check of the measurement methods
used at Liontrap.