Heavy isotope production by multinucleon transfer reactions with 254Es

Fast automated on-line and quasi-on-line radiochemical techniques were applied to search for new isotopes, to measure their decay characteristics, and to study the cross sections of the heaviest, most neutron-rich actinide isotopes in reactions of /sup 16,18/O and 22Ne projectiles with 254Es as a target. The measured yields for isotopes up to Lr-260 are three or more orders of magnitude higher than in any other reaction used so far. A comparison with data for similar transfers from 248Cm targets is made. Transfer cross sections are extrapolated for the production of unknown, neutron-rich isotopes of elements 101 through 105, and the unique potential of 254Es as a target to make these exoctic nuclei accessible is demonstrated. 18 refs., 2 figs., 1 tab