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The 61 30Zn31 isotope has been produced at the Oak Ridge National Laboratory in the fusion-evaporation reaction 40Ca(24Mg, 2pn)61Zn at 104MeV. The experimental set-up allowed γ-rays to be detected in the CLARION Ge detector array in coincidence with the detection of recoiling nuclei in the focal plane at the end of the recoil mass spectrometer. This provides a unique identification of γ-rays belonging to 61Zn. The excited states have been explored by means of recoil- γγ coincidences, and the resulting decay scheme comprises almost 70 transitions. The data reveal numerous non-yrast states and suggest a revised spin and parity assignment for a previously observed superdeformed band. The resulting decay scheme is compared to predictions from different sets of large-scale shell model calculations. [ABSTRACT FROM AUTHOR]

Presents a table of contents of articles of the August 2, 2005 issue of the "European Physical Journal".

Following Coulomb excitation of the radioactive ion beam (RIB) 132Te at HRIBF, we report the first use of the recoil-in-vacuum (RIV) method to determine the g-factor of the 2+1 state to be (+)0.35(5). The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed. [ABSTRACT FROM AUTHOR]

Single-neutron transfer reactions have been measured on two N = 50 isotones at the Holifield Radioactive Ion Beam Facility (HRIBF). The single-particle-like states of 83Ge and 85Se have been populated using radioactive ion beams of 82Ge and 84Se and the ( d, p) reaction in inverse kinematics. The properties of the lowest-lying states --including excitation energies, orbital angular momenta, and spectroscopic factors-- have been determined for these N = 51 nuclei. [ABSTRACT FROM AUTHOR]

We describe an experiment optimized to determine the transition probabilities for excitation of the first excited 2+ state in 132Sn. The large excitation energy (4.04MeV) and consequent small excitation cross-section, together with the modest beam intensity available makes this a challenging experiment. The preliminary result is B( E2;0+ → 2+) = 0.11±0.03 e2 b2. The high efficiency and generalized nature of the setup enabled us to also measure the first 2+ state in the two-neutron nucleus 134Sn. We have determined a value of B( E2;0+ → 2+) = 0.029±0.005 e2 b2 which shows no sign of the asymmetry with respect to the N = 82 shell closure exhibited by the Te isotopes. [ABSTRACT FROM AUTHOR]

Neutron-rich radioactive ion beams available from the HRIBF allow a variety of measurements around the 132Sn region, including Coulomb excitation and single-nucleon transfer. The B( E2;0+ → 2+) values for first 2+ excited states of even-even neutron-rich 132-136Te and 126-130Sn have been measured by Coulomb excitation in inverse kinematics. Neutron transfer onto a 134Te beam from 9Be and 13C targets, to populate single-particle states in 135Te, has also been studied. Gamma rays from the 13C(134Te, 12C) reaction were used to identify the ν i13/2 state in 135Te, at an energy of 2109 keV. These and other results, and plans for future experiments with these neutron-rich beams, are presented. [ABSTRACT FROM AUTHOR]

Proton-nucleus elastic scattering at intermediate energies, a well-established method for probing nuclear-matter density distributions of stable nuclei, was applied for the first time to exotic nuclei. This method is demonstrated to be an effective means for obtaining accurate and detailed information on the size and radial shape of halo nuclei. Absolute differential cross-sections for small-angle scattering were measured at energies near 700 MeV/u for the neutron-rich helium isotopes 6He and 8He, and more recently for the lithium isotopes 6Li, 8Li, 9Li and 11Li, using He and Li beams provided by the fragment separator FRS at GSI Darmstadt. Experiments were performed in inverse kinematics using the hydrogen-filled ionization chamber IKAR which served simultaneously as target and recoil-proton detector. For deducing nuclear-matter distributions, differential cross-sections calculated with the aid of the Glauber multiple-scattering theory, using various parametrizations for the nucleon density distributions as input, were fitted to the experimental cross-sections. The results on nuclear-matter radii and matter distributions are presented, and the significance of the data for a halo structure is discussed. Nuclear-matter distributions obtained for 6He and 8He conform with the concept that both nuclei compose of α-particle like cores and significant neutron halos. The matter distribution in 11Li exhibits, as expected from previous reaction cross-section studies with nuclear targets, the by far most extended halo component of all nuclei being investigated. In addition the present data allow a quantitative comparison of the structure of the He and Li isobares of either the mass number A = 6 or A = 8. The measured differential cross-sections have also been used for probing density distributions as predicted from various microscopic calculations. A few examples are presented. [ABSTRACT FROM AUTHOR]

The evolution of the π h11/2ν h11/2 and π h11/2ν s1/2 isomeric configurations was studied for the N = 77 isotones near the proton drip line. The decays of metastable levels in 140Eu, 142Tb , and 144Ho were measured by means of X-, gamma- and conversion electron spectroscopy at the Recoil Mass Spectrometer at Oak Ridge. The sequence of isomeric levels in 140Eu was experimentally determined. The half-life of the π h11/2ν h11/2 state in 142Tb was remeasured to be 25(1) μs. The spins and parities of 5- and 8+ for the π h11/2ν s1/2 and π h11/2ν h11/2142Tb isomers, respectively, were established from measured multipolarities. No evidence for the expected 1+ ground state was found in the 144Ho decay data. [ABSTRACT FROM AUTHOR]

Evidence for the proton decay of 144Tm was found in an experiment at the Recoil Mass Spectrometer at Oak Ridge National Laboratory. The 144Tm events were found in the weak p5n channel of the fusion reaction using a 58Ni beam at 340 MeV on a 92Mo target. The observed proton decay energies are 1.70 MeV and 1.43 MeV and the half-life ∼ 1.9μs. The decay properties suggest proton emission from the dominant π h11/2 part of the wave function and from the small π f7/2 admixture coupled to a quadrupole vibration. [ABSTRACT FROM AUTHOR]

A technique to enhance the purity of accelerated radioactive ion beams for decay studies is presented. The technique requires a 3MeV/nucleon beam and a transmission ionization chamber. The gas pressure in the multi-anode ionization chamber is adjusted so that high- Z components of the beam are ranged out in the gas transmitting the more exotic, low- Z components to the measuring station. Initial tests with a radioactive 120Ag and 120In mixed beam indicate at least a factor of 5 relative enhancement of the 120Ag decay transitions. [ABSTRACT FROM AUTHOR]

Measurement of fine structure in proton emission allows one to deduce the composition of the parent and daughter state’s wavefunction populated by proton emission. This paper presents new experimental data on the fine-structure decay of 146Tm, and a new interpretation of its decay properties. [ABSTRACT FROM AUTHOR]

132Te has been studied through β- decay of 132Sb radioactive beam at HRIBF leading to a significantly revised level scheme. A number of newly identified, likely 2+ states allows for a test of recent quasiparticle random phase approximation calculations with a density-dependent pairing force. In addition, the removal of a previously proposed 3- state allows for a simple shell model interpretation of the low-lying negative-parity states. [ABSTRACT FROM AUTHOR]

A test experiment was carried out at the Holifield Radioactive Beam Facility to extend Coulomb excitation studies of heavy neutron-rich radioactive isotopes from even-even to odd- A nuclei. The experiment identified 10 and 4 gamma rays in 129Te and 129Sb, respectively. The B( E2) value of one transition in 129Sb was tentatively established. More B( E2) values in 129Te and 129Sb will be extracted upon completion of the data analysis. [ABSTRACT FROM AUTHOR]

Evaporation residue cross-sections measured with short-lived 132Sn on 64Ni at energies near and below the Coulomb barrier were found to be enhanced as compared to those measured with stable Sn isotopes on 64Ni. Subsequent measurements of fission following fusion of 132Sn with 64Ni and extending the measurement of evaporation residues to higher energies were carried out. [ABSTRACT FROM AUTHOR]

Evaporation residue cross sections for 132Sn, 134Te and 124Sn with 64Ni were measured. A compact system to measure these cross sections to values as low as 1 mb is described and a sample of data acquired with this system is shown. [ABSTRACT FROM AUTHOR]

The 61 30Zn31 isotope has been produced at the Oak Ridge National Laboratory in the fusion-evaporation reaction 40Ca(24Mg, 2pn)61Zn at 104MeV. The experimental set-up allowed γ-rays to be detected in the CLARION Ge detector array in coincidence with the detection of recoiling nuclei in the focal plane at the end of the recoil mass spectrometer. This provides a unique identification of γ-rays belonging to 61Zn. The excited states have been explored by means of recoil- γγ coincidences, and the resulting decay scheme comprises almost 70 transitions. The data reveal numerous non-yrast states and suggest a revised spin and parity assignment for a previously observed superdeformed band. The resulting decay scheme is compared to predictions from different sets of large-scale shell model calculations. [ABSTRACT FROM AUTHOR]