Gamma-ray and conversion-electron spectroscopy at CERN-ISOLDE facility

The topic of this thesis is the systematic study of the shape coexistence in odd-mass Au isotopes in the vicinity of N=104 mid-shell point. Experimental part of the thesis was performed at ISOLDE facility, within the scope of the IS521 experiment. Excited states of $^{181,183}$Au isotopes were populated by $\beta^+$/EC decay of $^{181,183}$Hg precursors produced by ISOLDE. Nuclear structure of $^{181,183}$Au isotopes was investigated by means of simultaneous spectroscopy of conversion electrons and $\gamma$ rays. A unique tape transportation system TATRA, based on rapidly quenched metallic tape, was designed and successfully commissioned. For the first time in the fundamental nuclear structure experiment, novel Broad Energy Germanium (BEGe) detector was used. Its supreme energy resolution, together with almost ideally Gaussian peak shape allowed peak recognitions in many multiplets and the determination of peak energies with 30 eV precision. It was so precise, that Rydberg-Ritz combination principle was used for level scheme constructions. An enormous complexity of measured spectra emerges in the case of odd-mass nuclei study. Therefore, innovative method was developed. Results of the study are significantly improved level scheme of the $^{183}$Au in comparison with previous work and the level scheme of the $^{181}$Au was constructed for the first time. Systematics of particular states of odd-Au isotopes were extended and slight change in shape based on PTRM calculations was observed. The key result is observation of a parabolic trend in the systematics of intruder states with its minimum in neutron midshell point N= 104 ($^{183}$Au).