Reactions of 40Ar with 233U, 235U, and 238U at the barrier

Production cross sections for target-like transfer products in reactions of 40Ar with 233,235,238U at the barrier were determined using radiochemical techniques. The heaviest products dtected are isotopes of californium (Z=98). In addition to the quasi-elastic component of the isotopic distributions observed in the vicinity of uranium, there are also relaxed contributions of this component for fixed atomic number, after the transfer of >3 charges, approach closely the minimum of the potential energy surfaces (PES). The experimental results thus indicate the cold formation of the reaction products. A search for long-lived heavy actinides produced, by fusion-evaporation, via isotopes of element 110 and their subsequent decay through α-decay chains, remained unsuccessful at a cross section limit of 21 pb. (orig.)