[en] A kinematically complete measurement was made of the Coulomb dissociation of ⁸B nuclei on a Pb target at 83MeV/nucleon. The cross section was measured at low relative energies in order to infer the astrophysical S factor for the ⁷Be( p,γ)⁸B reaction. A first-order perturbation theory analysis including E1 , E2 , and M1 transitions was employed to extract the E1 strength relevant to neutrino-producing reactions in the solar interior. By fitting the measured cross section from E_rel=130 to 400keV, we find S₁₇(0)=17.8^+1.4_-1.2 eV b

[en] The results of the first spectroscopic studies of delayed neutron and γ emission following the β decay of ¹⁹N and ²⁰N are reported. Nuclides were produced by fragmenting an 80 MeV/nucleon ²²Ne beam in a 546 mg/cm² thick Be target and were separated at high velocities with the A1200 fragment separator. The nuclides were implanted in a thin plastic scintillator at the center of an array of neutron scintillators to determine the neutron time-of-flight spectrum. Two hyperpure germanium detectors were used to observe coincident γ events. The β-γ,β-n, and β-n-γ coincidence spectra were analyzed to obtain the energies of the states populated in ¹⁸O, ¹⁹O, and ²⁰O following the β decay. Eight new neutron energies with a total neutron emission probability of 41.8(9)%, six γ transitions among the excited states of ¹⁹O, and four γ transitions among the excited states of ¹⁸O were identified in the ¹⁹N β decay. Seven new neutron energies with a total neutron emission probability of 42.9(14)%, ten γ transitions among the excited states of ²⁰O, and two γ transitions among the exited states of ¹⁹O were observed from the ²⁰N β decay. Half-lives of 336(3) and 136(3) ms were determined for the ¹⁹N and ²⁰N decays, respectively. The branching ratios of both decays were deduced and compared with USD (universal sd-shell) shell model calculations. The β decay schemes for ¹⁹N and ²⁰N were deduced

[en] The ground state magnetic dipole moment of ⁹C has been remeasured using the β-NMR technique and our new value of 1.396(3)μ_N is in agreement with the previously measured value for this nuclide. The quenched magnetic moment of ⁹C and the anomalously large isoscalar spin expectation value for the ⁹C-⁹Li T=3/2 mirror pair compare favorably with the results of shell model calculations employing isospin nonconserving (INC) interactions. The ground state magnetic moment of ²¹Mg was also investigated to determine the significance of INC effects in the heavier A=21 T=3/2 mirror system

[en] Neutron-rich nuclides in the vicinity of the semi-magic nucleus ⁶⁸Ni have been produced by fragmentation of a 70 MeV/nucleon ⁷⁶Ge beam in a Be target. Beta-delayed γ ray studies were performed for these nuclides using a collection wheel apparatus, two thin plastic scintillators, and two large volume Ge detectors. A 195-keV isomeric transition was identified in ⁷³Zn having T_1/2=13.0(2) ms. A 1296-keV γ-ray transition with T_1/2=3.4(7) s has also been identified. The half-life of this transition is not consistent with the known beta-decay half-lives of nuclides in this region and may be evidence for a new β-decaying isomeric state in ⁶⁹Ni or ⁷¹Cu

[en] A state of the art Penning trap is being developed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University to make precision mass measurements of rare isotopes. The system relies on thermalizing nuclear reaction products in a helium-filled cell and then extracting them from the gas through ion-manipulation and differential pumping. Atomic ions and clusters are needed to calibrate various aspects of the entire system such as transport efficiency and the main magnetic field. High-power laser ablation has proven to be a successful method for producing a wide range of ions under various conditions, including atmospheric pressure. We have developed a laser ablation system to explore the production of test beams using a variety of targets. Laser ablation studies of C, Al, Au, Ag, Cu, Fe, and Zn were carried out in a test chamber with the second harmonic, 532 nm, from a Q-switched Nd:YAG laser. Many studies were carried out under vacuum using an ion-drift system and mass analysis in a quadrupole mass filter. The ablation target and laser optics were moved to the gas cell used to collect the nuclear reaction products and several ablation studies were performed. An overview of the laser-ablation system as well as some of the results of this work will be presented

[en] The low-energy level structure of ⁵⁸ Cr has been studied following the beta decay of '5⁸ V. This parent nuclide, along with eight additional neutron-rich nuclei, was produced by projectile fragmentation of a ⁷⁰ Zn beam and implanted into a double-sided silicon strip detector (DSSD). Implants were identified based on ΔE-TOF information and correlated to beta decays in the DSSD. Beta-delayed gamma rays were monitored by an array of three Ge clover detectors and two high purity Ge detectors. The results from these observations will be discussed in light of the development of quadrupole collectivity in the even-even chromium isotopes toward the N = 40 subshell closure. (authors)