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The (d, p) reaction was measured with the radioactive ion beams of 126Sn and 128Sn in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, utilizing the Super ORRUBA silicon detector array. Angular distributions of reaction protons were measured for several states in 127Sn and 129Sn to determine angular momentum transfers and deduce spectroscopic factors. Such information is critical for calculating direct (n,γ) cross sections for the r-process as well as for constraining shell model parameters in the A≈130 region. Combined with previous experiments on 130Sn and 132Sn, these results will provide a complete set of (d, p) reaction data on even tin isotopes between stable 124Sn and doubly-magic 132Sn.

Neutron transfer (d, p) reactions have been measured with neutron‐rich fission fragment beams of 130,132Sn and 134Te populating l = 1 and l = 3 excitations above the N = 82 shell gap. Preliminary results and future prospects are discussed.

The systematics of the πh11/2⊗νh11/2 and πh11/2⊗νs1/2 isomeric configurations were studied for the odd‐Z N = 77 isotones near the proton dripline. The spin and parity of Iπ = 8+ and 5− were deduced for the isomers in 140Eu and 142Tb. No evidence for the expected 1+ ground‐state was found in the 144Ho decay data. The proton emission from 146Tm was restudied and the spin and parity values of Iπ = 10+ and 5− were established for 146mTm and 146gsTm, respectively. The interpretation of the observed decay properties and structure of the proton‐emitting states was made by accounting for deformation and proton and neutron coupling to the core excitations.

Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of β‐stability, and as a direct input into astrophysical models. In the case of astrophysical processes involving neutron rich nuclei, such as nucleosynthesis during the r‐process and the evolution of matter in the crust of an accreting neutron star, we are mostly limited to using theoretical mass models. The time of flight (TOF) mass measurement technique allows measuring very short‐lived nuclei. It has been effectively applied using the fast fragment beams produced at the A1900 fragment separator at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. We describe a recent mass measurement experiment in the neutron rich Fe region performed at the NSCL, and present preliminary results.

Evaporation residue (ER) production from several isotopes of Sn and Te bombarding Ni targets at energies near and below the Coulomb barrier was measured. Measured ER data were compared with the predictions of sub‐barrier fusion calculated in a WKB approximation. These comparisons are used to study effects of neutron excess and neutron transfer on the sub‐barrier fusion cross sections for reactions induced by heavy nuclei.

Two N=51 isotones have been measured using (d,p) reactions in inverse kinematics at the Holifield Radioactive Beam Facility (HRIBF) of Oak Ridge National Laboratory. Additionally, we have performed a test measurement using a stable 124Sn beam in preparation for measurements of the 2H(130,132Sn,p)131,133Sn reactions. Preliminary results for 83Ge and 85Se suggest a 5/2+ ground state and a 1/2+ first excited state for both isotopes, in agreement with systematics for the N=51 isotones. The excitation energy of the first excited state is shown to drop as the proton number is reduced. Proton angular distributions following the 2H(124Sn,p)125Sn reaction show sensitivity to the l‐value of the transfered nucleon and spectroscopic factors are in agreement with previous measurements in normal kinematics.

The d(82Ge,p) reaction has been measured in inverse kinematics at the Holifield Radioactive Ion Beam facility, enabling a study of the evolution of single‐particle structure above the N=50 shell gap for neutron‐rich nuclei.

Radioactive ion beams of 55 MeV 11C from the BEARS project at LBNL and a thick‐target technique were used to study resonant states in 12N. With a reaction in inverse kinematics an excitation function of elastic scattering cross section was measured in a single exposure covering the center of mass energy range between 300 keV to 1100 keV. The elastic scattering reaction 11C(p,p)11C is related to the reaction 11C(p,γ)12N, an important branch point in the hot pp chains and a determinant of the evolution of supermassive stars. The data was analyzed using the R‐matrix code MULTI. Preliminary results suggests that the first excited state in 12N (0.96 MeV) might play a more important role in determining the 11C(p,γ)12N reaction rate than previously believed.

The mass A = 140 products of the 54Fe (315 MeV) + 92Mo reaction were selected by a recoil mass spectrometer and studied in a recoil ‐ delayed γ‐γ coincidence experiment. A new 7 μs isomer was identified in the drip line nucleus 140Dy. Five cascading γ transitions were assigned to the decay of the Iπ = 8− {v9/2−[514] ⊗ v7/2+[404]} K isomer via the ground state band transitions. The established structure of 140Dy is discussed with reference to the fine structure in proton decay of 141Ho.

The new neutron‐rich radioactive ion beams available from the HRIBF allow an exciting variety of measurements around the 132Sn region, including Coulomb excitation, fusion‐evaporation, and neutron transfer. Experiments using these beams also provide an excellent training ground for developing techniques to be used at the future RIA facility. The B(E2;0+ → 2+) value for first 2+ excited states of neutron‐rich 132,134,136Te and 126,128Sn have been measured by inverse‐kinematics Coulomb excitation. The B(E2) values obtained for 132,134Te are in excellent agreement with expectations based on the systematics of heavy stable Te isotopes, while that for 136Te is unexpectedly small. These results are discussed in terms of the shell model and the quasiparticle random phase approximation. Neutron transfer onto a 134Te beam, from 9Be and 13C targets to populate single‐particle states in 135Te, has also been studied. Results, and plans for future experiments with these neutron‐rich beams, are presented.

Radioactive Nuclear Beams (RNBs) are opening new regions of the nuclear landscape to nuclear structure studies. Early experiments with RNBs rely on reactions with large cross sections, inverse kinematics, and very efficient detector geometries in order to measure observables that are very sensitive to structural features. A Coulomb excitation experiment extracted the B(E2;01+ → 21+) values of the neutron rich RNBs 132,134Te at the HRIBF with the GRAFIK through‐well NaI(Tl) detector. In addition, other experiments with RNBs, such as Coulomb excitation of octupole states and reorientation experiments, inelastic scattering, and single‐particle transfer, will be discussed.

Excited states in the N = Z+1 nucleus Y-79 Were identified using the reaction Si-28(Fe-54, p2n)Y-79 at a 200 MeV beam energy and an experimental set up consisting of an array of Ge detectors and the Recoil Mass Spectrometer at Oak Ridge National Laboratory. With the help of additional gamma-gamma coincidence data obtained with Gammasphere, these gamma-rays were found to form a strongly-coupled rotational band with rigid-rotor-like behavior. Results of conventional Nilsson-Strutinsky cranked shell model calculations, which predict a deformation of beta(2)similar to 0.4, are in excellent agreement with the properties of this band. Similar calculations for the neighboring N = Z and N = Z + 1 nuclei are also in good agreement with experimental data. This suggests that the presence of the putative T = 0 neutron-proton pairing does not significantly affect such simple observables as the moments of inertia of these bands at low spins. (Less)

Monitors of this type are mostly intended for the lowest intensity beams at the HRIBF at ORNL. They are used to aid the accelerator operator in focusing and steering the beam and by the experimenters at the focal plane of the spectrometers.

The recoil mass spectrometer at the Holifield Radioactive Ion Beam Facility is currently undergoing commissioning tests. This new spectrometer is designed to transmit ions with rigidities of K = 100 resulting from fusion-evaporation reactions using inverse-kinematics. The device consists of two sections: a momentum separator to provide beam rejection and a mass separator for product identification. Using normal-kinematic and symmetric reactions, the commissioning tests have shown that the A/Q acceptance is almost {+-}5%, the energy acceptance is approximately {+-}12%, and there has been little, if any, primary beam observed on the focal plane. Commissioning tests are presently underway with reactions using inverse-kinematics.