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Abstract

The precise determination of the 3H-3He mass ratio, and hence the tritium Q-value, is of relevance for the measurement of the electron anti-neutrino mass performed by the Karlsruhe Tritium Neutrino experiment (KATRIN). By determining this ratio to an uncertainty of better than 1 part in 1010, systematic errors of the endpoint energy in the b-decay of 3H to 3He can be checked in the data analysis of KATRIN. To reach this precision, a Penning Trap Mass Spectrometer (MPIK/UW-PTMS) was constructed at the University of Washington, which has been transferred to the Max-Planck-Institute for Nuclear Physics in Heidelberg. Here, a dedicated tritium laboratory was set up. Special care was taken to stabilize several environmental parameters, such as the magnetic field or the temperature. The experiment was commissioned and extensive measurements with the test ion 12C4+ were carried out in order to characterize the spectrometer and to optimize the experimental procedures. Finally, the first mass measurements with the spectrometer were performed on 1H+ and 16O6+, yielding an uncertainty of some parts in 108, but also showing the potential of the spectrometer to reach a precision below 1 part in 1010 in the near future.