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Abstract

In neutrino physics, a variety of experiments aim for the determination of the neutrino mass by means of the beta-decay and electron-capture spectra, while a detection of the neutrinoless double-electron capture would reveal the Majorana nature of neutrinos. However, a lack of knowledge on the total decay energy (Q-value) of these processes constrains present neutrino experiments. To this end, high-precision measurements of the Q-values are obligatory. In order to find suitable nuclides for neutrinoless double-electron capture experiments, a determination of the Q-values by direct Penning-trap mass-ratio measurements on ¹⁰⁶Pd/ ¹⁰²Ru, ¹⁰⁶Cd/ ¹⁰⁶Pd, ¹⁴⁴Sm/ ¹⁴⁴Nd and ¹⁵⁶Dy/ ¹⁵⁶Gd with a relative precision of a few 10⁻⁹ were performed for the first time at SHIPTRAP using the Time-of-Flight Ion-Cyclotron- Resonance (ToF-ICR) detection technique and the multiresonance phenomenon in ¹⁵⁶Dy was discovered. A novel Phase Imaging Ion-Cyclotron-Resonance detection technique was developed being substantially faster and providing ca. 40-fold gain in resolving power in comparison with the presently used ToF-ICR technique. The novel Penning-trap mass spectrometer PENTATRAP aims for direct mass-ratio measurements with a relative precision better than 10⁻¹¹, which is required for the betadecay and electron-capture experiments. In this context, the PENTATRAP Control System was developed in order to maximize the efficiency of the measurement process.