α-decay spectroscopy of light odd-odd Bi isotopes: I: 188,190Bi nuclei

Detailed fine-structure α-decay studies of 188,190 Bi were performed using the complete-fusion reactions of 50,52 Cr ions with a 142 Nd target at the velocity filter SHIP. The evaporation residues were separated in-flight and subsequently identified on the basis of recoil-α, recoil-α-γ/X-ray and excitation function measurements. Improved data on the α-decay of 188,190 Bi were obtained and a number of new low-lying excited states in the daughters 184,186 Tl were observed. An intruder, presumably 10- state was identified in 184 Tl extending the systematics of such states in the odd-odd Tl nuclei beyond the neutron mid-shell at N = 104. Some technical aspects of experiment at recoil separators are also discussed.