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Abstract

During the last years, high precision mass measurements with relative uncertainties of δm/m ~ 10¹¹ were peformed by using Penning-traps to measure the mass of light and medium heavy ions in low charge states. The PENTATRAP-experiment will use highly charged ions to perform mass measurements on medium heavy and heavy ions within relative uncertainties on the order of 10¹¹ or better. The necessary highly sensitive cryogenic detections system consists of resonators with high quality factors followed by cryogenic amplifiers. An active feedback loop allows for the manipulation of the quality factor of the used resonators or the effective temperature of the system. A phaseshifter as part of the feedback loop was developed to utilisability and characterized within this thesis. By applying positive feedback the quality factor of the resonator was improved more than one order of magnitude. Using neagtive feedback the system was tuned to a state which corresponds to an effective ion-temperature of 210 mK. Furthermore, simualtions and first measurements were carried out for a planned sideband-suppression of the mixers for the cyclotron detection system of PENTATRAP. In addition, a prototype of a phaseshifter, adapted to the requirements of another Penning-trap experiment, was designed and successfully tested.