Search for the Production of Element 112 in the 48Ca + 238U Reaction

We have searched for the production of element 112 in the reaction of 231 MeV 48Ca with 238U. We have not observed any events with a "one event" upper limit cross section of 1.6 pb for EVR-fission events and 1.8 pb for EVR-alpha events.Comment: 6 pages, 3 figures, submitted to Phys. Rev.

Have Superheavy Elements been Produced in Nature?

We discuss the possibility whether superheavy elements can be produced in Nature by the astrophysical rapid neutron capture process. To this end we have performed fully dynamical network r-process calculations assuming an environment with neutron-to-seed ratio large enough to produce superheavy nuclei. Our calculations include two sets of nuclear masses and fission barriers and include all possible fission channels and the associated fission yield distributions. Our calculations produce superheavy nuclei with A ~ 300 that however decay on timescales of days.Comment: 12 pages, 11 figure

Observation of rotational bands in the neutron-rich 107Ru nucleus

Levels in the neutron-rich, odd-mass 107Ru nucleus have been reinvestigated with Gammasphere by measuring high-fold, prompt coincidence events following spontaneous fission of 252Cf. The ground state band has been extended up to 27/2ℏ. The structure associated with the h11/2 excitation has been confirmed and extended to higher spin. The h11/2 band head has been established to lie at 301.8 keV. These results clear up differences between our earlier work and results from another experiment published recently. A new collective band based on a 9/2- level has been identified for the first time. Some distinct features of the level scheme are discussed