Entwicklung des kryogenen Nachweissystems für ALPHATRAP und THe-Trap

The Penning trap experiments ALPHATRAP and THe-Trap are currently being set up at the Max-Planck-Institut für Kernphysik in Heidelberg. The ALPHATRAP pro ject is the follow-up to the Mainz g-factor experiment which has recently suc- ceeded in the most stringent test of quantum electro dynamics in the regime of strong fields on hydrogen-like ²⁸Si¹³⁺:The THe-Trap experiment is a precision Penning trap mass sp ectrometer. By measuring the mass ratio between tritium an helium it will contribute to the determination of the electron antineutrino mass in the Karlsruhe Tritium Neutrino experiment (KATRIN). The ion detection metho d in b oth exp er- iments is based on the non-destructive measurement of image-currents which are induced into the trap electro des by the ion. In order to convert these currents into a measurable voltage a cryogenic detection system is used. It consists of the combina- tion of a tank circuit (resonator) with a high quality factor and a cryogenic amplifier with very low-noise characteristics. One ma jor part of this work is the development, construction and characterization of the sup erconducting resonators with extremely high quality factors which are essential for the axial ion detection in the ALPHA- TRAP exp eriment. The other part is the implementation and characterization of the cryogenic ALPHATRAP amplifier in the THe-Trap experiment