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Abstract

This thesis presents the implementation and improvement of the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) detection technique at the ISOLTRAP experiment, located at the ISOLDE / CERN, with the purpose of on-line high-precision and high-resolution mass spectrometry. Extensive simulation studies were performed with the aim of improving the phase imaging resolution and finding the optimal position for detector placement. Following the outcome of these simulations, the detector was moved out of a region of electric-field distortion and closer to the center of the Penning trap, showing a dramatic improvement in the quality and reproducibility of the phase-imaging measurements. A new image reconstitution and analysis software for the MCP-PS detector was written in Python and ROOT and introduced in the framework of PI-ICR mass measurements. The state of the art in the field of time-of-flight ion-cyclotron-resonance measurements is illustrated through an analysis of on-line measurements of the mirror nuclei ²¹Na/Ne and ²³Mg/Na using the Ramsey excitation pattern. The Q-values determined from this analysis play an important role for verifying the Conserved-Vector-Current hypothesis and for testing the unitarity of the CKM quark-mixing matrix. Finally, the results of a first high-precision, on-line measurement using the PI-ICR technique are presented, addressing the Q-value of the ⁸⁸Rb- ⁸⁸Sr ß-decay.