Quantum-state Selective Nuclear Decay Spectroscopy

Abstract: This thesis focusses on the results of two experiments employing Penning traps to prepare pure beams of the 213Ra ground state and 127Cd, which were then studied with the decay-spectroscopy setup TASISpec. The experiments were conducted with SHIPTRAP at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany, and JYFLTRAP at the IGISOL Accelerator Facility at the University of Jyväskylä, Finland.The α-decay branching ratios of the 213Ra ground state have been revised based on comprehensive Geant4 simulations, i.e. ‘virtual experiments’, which were confronted with the experimental results. These findings are supported by theoretical calculations. This work is published in Papers I and II. Using the same method, the proton-decay branch of the 53Co 3174 keV isomer has been studied, which is the content of Paper IV. In Paper III the results of the 127Cd experiment are presented. There the decay scheme of 127In populated by the β decay of 127Cd was considerably extended and the β feeding into the individual states deduced. Extensive shell-model calculations have been conducted to calculate the energy levels and γ-ray branching ratios of 127In as well as the Gamow-Teller strength distributions of the β decay of the 3/2+ and 11/2− states in 127Cd. Based on these calculations the experimentally observed decay-scheme of 127In could be reproduced remarkably well. The order of the 3/2+ and 11/2− state in 127Cd has been established, identifying the 3/2+ state as the ground state and the 11/2− state as the 283 keV isomer. Furthermore, the phase-depended cleaning method was employed for the first time in an attempt to study the β decay of the 127Cd isomer individually.