The electron-capture-delayed fission (ECDF) process allows us to study structure in very neutron-deficient nuclei that could not be directly produced in a fusion reaction. This decay mode may be important in the production of heavy elements in the r-process. The ECDF nuclide 232Am was produced at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron in the 237Np(3He,8n) reaction using a stack of 10 thin (124-197 mu-g/cm2 each) targets at a beam energy of 75 MeV incident on the first target. Recoiling activities were collected and transported to a specially designed "Sample Changer" that moved samples into Gammasphere for analysis. The latest results on ECDF in this nuclide and rotational structure in the electron capture daughter 232Pu will be discussed. These experiments show the promise of using Gammasphere to study nuclei that would otherwise be inaccessible due to the need for radioactive targets or pre-separation in the Berkeley Gas-Filled Separator.

The excitation function for the 208Pb(55Mn,n)262Bh reaction has been measured for the first time. Using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron, a total of 33 decay chains attributable to 262Bh were observed at three different projectile energies. The existence of a previously reported alpha-decaying isomeric state was confirmed, although the production of the ground state was favored at all three energies. Additionally, 2 decay chains attributable to 261Bh were observed. The observed cross sections are much larger than those reported for the analogous 209Bi(54Cr, n)262Bh reaction, suggesting that in the latter case the projectile energies used were too high for optimum production of the 1n product. These results will be compared with predictions for the location of the excitation function maximum and the maximum cross section using the "Fusion by Diffusion" theory proposed by Swiatecki, Siwek-Wilczynska, and Wilczynski.

The production of neutron-deficient transactinide isotopes using cold fusion reactions has been studied in recent experiments with the Berkeley Gas-filled Separator (BGS). These experiments were part of a systematic study of using odd-Z projectile reactions for heavy element synthesis. Targets of 208Pb were bombarded with projectiles of 64Ni, 65Cu, and 55Mn to produce 271Ds, 272-111, and isomers of 262Bh, respectively. The excitation function of the 208Pb(64Ni,n)271Ds reaction was measured and seven atoms of 271Ds were produced. This result was used to estimate the optimum beam energy for the 208Pb(65Cu,n) reaction, and one decay chain of 272-111 was observed. Lastly, the excitation function of the 208Pb(55Mn,n)262Bh reaction was measured and preliminary results will be presented. These results will be characterized in terms of the performance and use of the BGS for heavy element production.

New level schemes of $^{141}$Ba and $^{139}$Xe are proposed from the analyses of spontaneous-fission gamma data from our $^{252}$Cf spontaneous fission Gammasphere runs of 1995 and 2000. By analogy with the N = 85 even-odd isotones $^{149}$Gd, $^{147}$Sm, and $^{145}$Nd, spins and parities were assigned to the observed excited states in $^{141}$Ba and $^{139}$Xe. It appears that spherical shell model neutron excitations plus octupolephonons are an appropriate basis at the lower end of the bands. Going to higher spins it is clear that the soft rotor involving valence protons as well as neutrons becomes increasingly important in the configurations. Level systematics in the N = 85 even-odd isotones from Gd(Z=64) through Te(Z=52), are discussed. The excitation systematics and smooth trends of the analogous levels support the spin and parity assignment for excited levels observed in $^{141}$Ba and $^{139}$Xe. The level systematics and the comparison with neighboring even-even isotopes indicate that quadrupole and octupole collectivity play roles in $^{141}$Ba and $^{139}$Xe. From Gd(Z=64) through Te(Z=52), increasing excitation energies of the 13/2$^{+}$ states and lowering relative intensities of the positive parity bands in the N = 85 even-odd isotones may indicate that the octupole strength is becoming weaker for the isotones when approaching the Z = 50 closed shell.

Using Gammasphere data on prompt gamma rays from spontaneous fission of 252Cf, we propose energy-level schemes for 110,111,112, & 113Rh (Z=45). The fission-gamma data complement earlier studies of others on beta decay of fission products in that prompt fission gammas mainly populate yrast or near-yrast levels, while beta decay populates lower-spin levels. For the odd-A rhodium nuclei studied here, their ground bands and collective sidebands are compared with model calculations using triaxial-shaped nucleus with one odd quasi-proton. The energies and E2 transition rates are best fit by a shape slightly to the prolate side of maximum triaxiality, namely, gamma = 28 deg. The model calculations also show a K=1/2+ band with energies not in good agreement with a corresponding exerimental band. The experimental 1/2+ band is regarded as an intruder band from a prolate-driving proton orbital 1/2[431] above the Z=50 closed shell. This intruder band, seen in other odd-A Rh isotopes, is probably more deformed and prolate and would not be expected to be fit at the same triaxial shape parameter as the 7/2+ ground band. We observe a band-crossing (backbending) in the odd-A ground bands above spins of about 21/2. The odd-odd nuclei 110 and 112 Rh show mainly a single band with no backbending up to higherfrequency than the backbend in the odd-A isotopes. It is concluded that the backbend is due to alignment of a pair of h11/2 neutrons.