Heavy nuclei far from stability in the N < 126, Z > 82 region

There are long-standing calculations suggesting that nuclei in the N < 126, Z > 82 region far from stability exhibit deformation effects. Away from stability an observable permanent quadrupole deformation should be achieved but, as yet, there is no experimental evidence for such an effect. A series of experiments was performed to assess the production of nuclei in this region and to study their structure. These experiments were performed using gamma-ray spectroscopy to investigate the low-lying level schemes and alpha-particle spectroscopy in order to isolate fine structure in the decay. The low-lying level structure of the neutron-deficient isotope 202Rn was studied, for the first time, using the 181Ta(27Al,6n) and 192Pt(16O,6n) reactions. Gamma-ray transitions between excited states in 202Rn were identified by mass tagging the Fragment Mass Analyzer and by observation of coincident X rays. Transitions in 203Rn were also identified. The level scheme deduced from these data is consistent with the systematics of light radon isotopes below the N = 126 shell closure and with theoretical calculations indicating that the ground-state shape should not be strongly deformed at N = 116