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Abstract

An improvement of the upper limit of the electron neutrino mass to a sub eV/c2 level is the goal of the ECHo collaboration. The upper limit of the neutrino mass will be determined with cryogenic microcalorimetry from the analysis of the atomic de-excitation spectrum of 163Dy after the EC in 163Ho. To check for systematic errors an independent measurement of the Q-value of the EC in 163Ho is required. For the first phase of ECHo the issue with the discrepancy between the latest microcalorimetry measurements of the Q-value and its literature value needed to be fixed. For this, a first direct measurement of the Q-value of the EC in 163Ho with the Penning-trap mass spectrometer SHIPTRAP was accomplished in the context of this thesis using the novel PI-ICR technique. Within the uncertainty, it agrees with the latest microcalorimetry measurements. Furthermore, the achieved precision is sufficient for ECHo-1k to be able to improve the upper limit of the electron neutrino mass to 10 eV/c2 (95% C.L.). For further improvements on the neutrino mass, the Q-value needs to be improved, too. For this, the novel high precision Penning-trap mass spectrometer PENTATRAP has been developed and commissioned. PENTATRAP will utilize five Penning traps to test new measurement schemes, which could make it possible to reach unv certainties in the 10^12 regime. Currently, first mass-ratio measurements of the nuclei pair 132Xe and 131Xe with known masses were carried out to test the performance of PENTATRAP.