Status of heavy element research using GARIS at RIKEN

A gas-filled recoil separator GARIS was installed at the RIKEN Linear Accelerator facility. Using the separator, two reactions, Pb-208(Ni-64,1n), and Bi-209(Ni-64,1n) were investigated. In the first reaction we observed fourteen a-decay chains which were assigned to be the decays starting from the isotope (271)Ds(Z=110). The alpha-decay energies as well as the decay times coincided well with the values reported by GSI group. Existence of an isomeric state in (271)Ds became clear from the present work. In the second reaction we have observed 44 a-decay chains that can be assigned to subsequent decays from (272) 111. The present result is the first clear confirmation for the discovery of (272)111 and its alpha-decay products, (264)Bh and (268)Mt, reported previously by a GSI group. New information on their half lives and decay energies is presented.