[en] The binding of at least six additional neutrons of fluorine compared to oxygen is linked to the emergence of the N = 16 shell close to the dripline. Single proton knock-out reactions from neutron-rich fluorine isotopes on a ¹²C target were measured at energies of ∼50 MeV/nucleon. Oxygen isotopes of A = 19 - 24 were observed. The particle instability of ²⁵O was confirmed

[en] Very neutron-deficient fragments were produced by projectile fragmentation of a 140 MeV/ nucleon ⁷⁸Kr primary beam on a beryllium target. The secondary fragments were unambiguously identified after separation in the A1900 fragment separator. Three events of ⁶⁰Ge and four events of ⁶⁴Se have been observed for the first time, making ⁶⁰Ge the heaviest known isotone of the N=28 neutron shell. No events of ⁵⁹Ga and ⁶³As have been observed providing very strong evidence that these nuclei are unbound with respect to proton emission. (orig.)

[en] The knockout of protons from ⁸B and ⁹C on a carbon target has been studied at average energies of 76 and 78 MeV/nucleon, respectively, with beams from the A1900 fragment separator incident on a stack of silicon detectors. The following cross sections were obtained: σ_-1p(⁸B→⁷Be)=130(11) mb, σ_-1p(⁹C→⁸B)=54(4) mb, and σ_-2p(⁹C→⁷Be)=98(7) mb. The results are discussed within the framework of an eikonal approach and compared with measurements performed at higher energies. From this analysis, a consistent picture emerges that gives evidence for the validity of the eikonal approach at energies below 100 MeV/nucleon. Knockout reactions at intermediate energy can thus be used to deduce absolute shell occupancies. We find the spectroscopic factors to be reduced by R_s of 0.86(7) and 0.82(6) for ⁸B and ⁹C, respectively, relative to shell-model predictions. The ⁹C result provides an accurate measurement of the asymptotic normalization coefficient of 1.27(10) fm^-1. A new technique is reported for determining separately the contributions from stripping and diffractive breakup

No abstract available

[en] A new experimental approach was developed that can reduce the uncertainties in astrophysical rapid proton capture (rp) process calculations due to nuclear data. This approach utilizes neutron removal from a radioactive ion beam to populate the nuclear states of interest. Excited states were deduced by the γ-decay spectra measured in a semiconductor Ge-detector array. In the first case studied, Ar³³, excited states were measured with uncertainties of several keV. The 2 orders of magnitude improvement in the uncertainty of the level energies resulted in a 3 orders of magnitude improvement in the uncertainty of the calculated Cl³²(p,γ)Ar³³ rate that is critical to the modeling of the rp process. This approach has the potential to measure key properties of almost all interesting nuclei on the rp-process path

[en] The measurement of the single proton knock-out reaction from ²⁴F on a ¹²C target at 46.7 MeV/nucleon yielded a ²³O ground state population of (6.6+/-1.0) mb. The data were compared to calculations based on the many-body shell model and the eikonal theory. The results are consistent with a [0d5/26]-bar 1s1/2 configuration of ²³O

[en] Two new neutron-deficient isotopes, ⁶⁰Ge and ⁶⁴Se, were observed for the first time. They were produced by projectile fragmentation of a 140-MeV/nucleon ⁷⁸Kr primary beam on a beryllium target. The secondary fragments were unambiguously identified after separation in the A1900 fragment separator. The nucleus ⁶⁰Ge corresponds to the heaviest isotone of the N=28 neutron shell and it is most likely the last isotone to be observed. Lower limits of 110 and 180 ns were extracted for the half-life of ⁶⁰Ge and ⁶⁴Se, respectively. No events of ⁵⁹Ga or ⁶³As have been observed, providing very strong evidence that these nuclei are unbound with respect to proton emission. This non-observation implies an upper limit for the half-life of 43 ns for ⁵⁹Ga and ⁶³As