[en] An essential component of modern nuclear physics is the description of the composition of the atomic nucleus through experimental and theoretical applications. With only two components, the protons and neutrons, it carries a lot of information which is accessible via its structure. One of these parameters, which can provide information about the structure, is the mass of the atomic nucleus, with which on the basis of the binding energy of the individual constituents, shell-closures, and thus the stability and probabilities of such structures can be explained. Among other things, this information provides the explanation on how elements such as copper, silver and gold can be formed in the first place in a double neutron star merger or in a supernova. This dissertation gives first insights into the new phase-imaging ion-cyclotron-resonance technique at ISOLTRAP, which enables an even higher resolving power of isomeric- and ground-states in a shorter measuring period than with previously used techniques. Thus, this new technique allows to measure more short-lived isotopes than before. The installation as well as the characterization in direct comparison of the old time-of-flight measurement method are evaluated. Furthermore, studies of the electron capture, of the pair ${}^{202}$Pb-${}^{202}$Tl, are presented, with which it is shown whether they can serve the more precise upper neutrino mass limit determination. The high-precision measured masses along the neutron-rich copper isotopes ${}^{75-<!--\; ???\; -->79}$Cu, which reach the neutron shell-closure N = 50, are used with their nucleon structure in comparison to a calculation of a shell model to interpret the behavior of the important waiting point nuclide ${}^{78}$Ni. Finally, the first mass measurements of the isotopes ${}^{123g,m}$Cd and ${}^{127g,m}$Cd are presented using the phase imaging method, which were measured at ISOLTRAP and validated with existing values of other facilities. The dissertation concludes with a summary and an outlook on further improvement possibilities of the new phase imaging technique as well as a brief overview of further relevant candidates with respect to mass spectroscopy.

No abstract available

[en] ISOLTRAP mass measurements of neutron rich copper isotopes are presented. ⁷⁹Cu could be addressed by the first time using a Multi-Reflection Time-of-Flight Mass Spectrometer (MR-ToF MS). With only one proton above the Z=28 core, the binding energies of the copper isotopes are sensitive to the evolution of nuclear shell structure close to the doubly-magic ⁷⁸Ni isotope. Preliminary results in combination with a shell-model theory will be shown. To reach even more exotic nuclides and to improve ISOLTRAP's mass precision limit, a position-sensitive ion detector was installed upstream the precision Penning-trap. It will allow the application of the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) detection method developed at SHIPTRAP/GSI. This new method offers compared to the presently used Time-Of-Flight Ion-Cyclotron-Resonance detection technique higher precision and resolution in shorter measurement time, and thus the ability to resolve low-lying isomers. The current status, first measurements, and an outlook on the implementation of the PI-ICR technique at ISOLTRAP are presented.

[en] In near-spherical nuclei, the two most fundamental quadrupole-collective excitations can be understood as a mixture of the collective 2⁺ proton and 2⁺ neutron excitations: the fully symmetric 2⁺₁ state and the so-called mixed-symmetric 2⁺₁, ms state. Based on the evolution of these states in the N=80 isotonic chain, it has been suggested that the properties of the mixed-symmetry states are sensitive to the underlying subshell structure. In particular, the observed fragmentation of the 2⁺₁, ms of ¹³⁸Ce has been explained as due to the absence of a mechanism dubbed shell stabilization. In order to examine further the effect of shell stabilization of the MSSs, it is necessary to identify and study the properties of these states in the next heavy N=80 isotones beyond Z=58: ¹⁴⁰Nd and ¹⁴²Sm. This Coulomb excitation experiment was performed at the RIB facility ISOLDE at CERN using the MINIBALL HPGe-array. Preliminary results from the experiment are shown.