In-beam study of 106Te and 107Te using the recoil decay tagging technique

Sammanfattning: Atomic nuclei are complex many-body systems and exhibit an interplay between single-particle and collective degrees of freedom. In order to describe and predict the “behavior” of nucleons inside the nuclei a variety of theoretical models have been created, each applicable to their own domain of nuclear phenomena. Experimental information is needed in order to test and improve the various theoretical models with the ultimate goal of creating unified theory of nuclear structure. In-beam γ-ray spectroscopy is one way of probing the inner structure of nuclei and it is the subject of this thesis, which describes the first identification of excited states in the extremely neutron deficient nuclei 106Te and 107Te. The experiments were performed at the Accelerator Laboratory of the University of Jyväskylä, Finland, using the recoil-decay tagging technique. Prompt γ rays emitted following fusion evaporation reactions were detected by the Jurogam detector array and the selection of the γ rays of interest was based on the recoil identification provided by the RITU gas-filled recoil separator and the GREAT focal plane spectrometer. The production cross sections were estimated to be 25nb and 1μb for 106Te and 107Te, respectively. In case of the nucleus 106Te, several γ rays have been observed. A vibrational-like yrast band has been suggested. For 107Te a number of γ rays have been assigned and a tentative partial level scheme has been suggested. The experimental data have been compared to shell model calculations.