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

摘要

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.