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Abstract

Astronomical observations of elements heavier than iron in stars are very crucial to understand
stellar nucleosynthesis. Elements produced by the slow neutron-capture process, commonly
known as the s-process, are particularly interesting in that respect because they provide information
on the time-scales involved in the process. Ruthenium is among these elements.
However, a direct identification of such elements is still not possible since wavelength positions
cannot be computed precisely. Therefore, laboratory measurements are crucial to overcome this
problem. In this thesis, measurements using an electron beam ion trap device were carried out.
Using very low electron beam energies ruthenium ions in the charge states from Ru⁺³+ to Ru⁺⁷
were produced. The fluorescent emitted by these excited ions was recorded using a flat-field
grazing incidence spectrometer in a wavelength range of 15nm to 24 nm. The experimental
data unveiled a number of fluorescent lines from ruthenium ions. The line positions and relative
intensities were accurately extracted. These data may help to benchmark various theories
which further may help to build precise astrophysical models to identify trans-irons lines from
the stars.