Synthesis of260Ku in the irradiation of249Bk by15N ions

1. In the249Bk(15N, 4n)260Ku reaction an isotope of kurchatovium (element 104) is obtained which decays by spontaneous fission with a half-life of ∼0.1 sec. This result is in complete agreement with conclusions of earlier works [1, 3, 5] in which260Ku was synthesized in other combinations of target and particle:242Pu+22Ne,246Cm+18O. 2. The failure to observe260Ku with T1/2≈0.1 sec at Berkeley [10, 11] resulted from improper experimental arrangements and data processing. 3. The detection of the spontaneous fission of nuclei of an unknown isotope when background is properly considered and suppressed permits the identification of the Z and A of the nuclei under study.