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Abstract

Highly charged ions (HCI) are important for precision measurements in fundamental
physics, for example, they increase the precision of Penning-trap mass spectrometry
(PTMS) since the relative uncertainty scales with the charge of the ion. The production
of HCI without the need of large scale facilities is realized by electron beam ion
traps (EBITs) [1]. This thesis reports on the optimization of a novel, highly-efficient
loading scheme for rare isotopes in EBITs, namely in-trap laser desorption in a Heidelberg
compact EBIT (HC-EBIT) [2], the Tip-EBIT. The production and subsequent
extraction of HCI of ¹⁶⁵Ho, using sample sizes as small as 10¹² atoms (about 270 pg),
is demonstrated for charge states up to 47+. The target could be used for several ten
thousand laser shots with an overall production of more than 10⁷ ions of a single charge
state. Additionally, hydrogen-like calcium (⁴⁰Ca¹⁹⁺) has been produced and extracted,
demonstrating the applicability of the loading technique for lighter elements. In the
course of this thesis, the Tip-EBIT was attached to the Pentatrap PTMS experiment,
as a source for HCI of rare isotopes. The first measurement will be the mass-ratio
determination of ¹⁶³Ho and ¹⁶³Dy, for which FAC calculations were carried out within
this thesis to avoid charge states with low-lying metastable atomic states. This will
contribute an independent value of the energy available for the electron capture decay
(QEC-value) of this rare holmium isotope to the ECHo collaboration. The aim of the
collaboration is the determination of the electron neutrino mass on the sub-eV level
[3].