アイテム詳細

要旨

The novel Penning-trap mass spectrometer Pentatrap aims for mass-ratio measurements of highly-charged ions with a relative precision of a few parts in 10¹². As the key part, an innovative trap assembly was designed. It consists of five cylindrical traps allowing for simultaneous measurements of two ion species and for continuous monitoring of the trapping conditions. This promises a substantial reduction of systematic errors. Moreover, in the course of this thesis a detection system was developed and characterized, which will enable fast and accurate measurements through its single-ion sensitivity and high signal-to-noise ratio. In neutrino physics, the detection of neutrinoless double-electron capture would unambiguously prove the Majorana nature of neutrinos. In search for a suitable nuclide for the observation of this process, precise information about the total decay energy (Q-value) is needed in order to find a transition with a resonant enhancement of the decay rate. The mass ratios of ¹⁵²Sm/ ¹⁵²Gd and ¹⁶⁴Dy/ ¹⁶⁴Er were measured to a relative uncertainty of ~ 10⁻⁹ at Shiptrap. This presents the first directly determined Q-values for the corresponding transitions.