High-spin States In ¹⁹⁴Au And ¹⁹³Os And Preparation Of The Bound-state β^- Decay Of Bare ²⁰⁵TI⁸¹⁺ Experiment

This doctorial thesis is devided into two parts as follows:In the first part,High-spin states in the odd-odd ¹⁹⁴Au nucleus have been inves-tigated by means of conventional in-beam γ ray spectroscopy using the¹⁹²Os（⁷Li,5n） reaction at a beam energy of 44 MeV.An array consisted of 12 Compton-suppressed HPGe detectors and 2 planar HPGe detectors has been used to perform γ—γ—t and γ—X—t coincidence measurements.Approximately 10⁸ two fold coincidence events has been recorded during the experiment.Based on the coincidence relation-ships between γ rays, the previously known structures built on the πh11/2-1⊕vi13/2-1 and πh11/2-1⊕vi13/2-2 vj configurations have been extended to high-spin states,and a new Iπ=（20+）state associated with the πh11/2-1（?）vi13/2-2vh9/2-1 configuration is identified.The πh11/2-1（?）vi13/2-1 band is found to exhibit normal signature splitting in ¹⁹⁴Au while signature inversions have been previously observed in the analogic bands in lighter odd-odd Au isotopes.Possible reasons for the absence of signature inversion in ¹⁹⁴Au have been discussed through total Routhian surface and cranked shell model calculations.Moreover,by comparing the experimental results with predictions from total Routhian surface and cranked shell model calculations,nonaxial shapes for the πh11/2-1（?）vi13/2-1 and πh11/2-（?）vi13/2-2vh9/2-1 configurations are proposed.In the same experiment,the high-spin states of neutron rich nucleus ¹⁹³Os have also been populated via the ¹⁹²Os（⁷Li,6li）¹⁹³Os reaction.An isomeric state with half-life of T1／2=110（28）ns has been identified.The configuration of it has been proposed to be the 9／2 ˉ「505（?） Nilsson orbital.The half-life and configuration of the isomeric state nas been aiscussea in terms of R—forbidden γ transitions. The high-spin states level scheme based on this isomeric state has been established and cross-checked by another experimental data from the ⁸²Se+¹⁹²Os collision system.In the second part, we give a brief introduction to the bound-state β^-decay of bare ²⁰⁵T1⁸¹⁺ experiment which is to be carried out in GSI Helmholtzzentrum fur Schwerionenforschung. Bound-state β^-decay was predicted by Daudel et al. in ¹⁹⁴Os and first observed in GSI in 1992. Due to experimental restraints, GSI is still the only place where bound-state β^-decay can be studied. In this thesis, the physics cases of the measurement of bound-state β^-decay of ²⁰⁵Pb⁸¹⁺ are explained. It can help to address the problem of solar neutrino flux in the past 4 million years and nucleonsynthesis processes in stars involving the short lived radioactive nucleus ²⁰⁵Pb. The techniques to be used in this experiment and the detailed preparation of this experiment based on the GSI accelerator complex is presented at the end of this thesis.