Precision mass measurements using the Phase-Imaging Ion-Cyclotron-Resonance detection technique

This thesis presents the implementation and improvement of the Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) detection technique at the ISOLTRAP experiment, located at the ISOLDE / CERN, with the purpose of on-line high-precision and high-resolution mass spectrometry. Extensive simulation studies were performed with the aim of improving the phase-imaging resolution and finding the optimal position for detector placement. Following the outcome of these simulations, the detector was moved out of a region of electric-field distortion and closer to the center of the Penning trap, showing a dramatic improvement in the quality and reproducibility of the phase-imaging measurements. A new image reconstitution and analysis software for the MCP-PS detector was written in Python and ROOT and introduced in the framework of PI-ICR mass measurements. The state of the art in the field of time-of-flight ion-cyclotron-resonance measurements is illustrated through an analysis of on-line measurements of the mirror nuclei $^{21}$Na/Ne and $^{23}$Mg/Na using the Ramsey excitation pattern. The $Q$-values determined from this analysis play an important role for verifying the Conserved-Vector-Current hypothesis and for testing the unitarity of the CKM quark-mixing matrix. Finally, the results of a first high-precision, on-line measurement using the PI-ICR technique are presented, addressing the $Q$-value of the $^{88}$Rb-$^{88}$Sr $\beta$-decay.