Yazar "Darby I.G." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    ? decay of Re159 and proton emission from Ta155
    (2007) Page R.D.; Bianco L.; Darby I.G.; Uusitalo J.; Joss D.T.; Grahn T.; Juutinen S.
    The ? decay of Re159 has been observed for the first time in reactions of 300 MeV Ni58 ions with an isotopically enriched Cd106 target. The Re159 ions were separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The ? decay emanates from the proton-emitting ?h11/2 state in Re159 with an energy of E?=6776±26 keV and a branching ratio of 7.5 ± 3.5%. This ? decay populates a state in the closed neutron shell nucleus Ta155, which decays by emitting 1444 ± 15 keV protons with a half-life of 2.9-1.1+1.5 ms. These values are consistent with the emission of the proton from a ?h11/2 orbital. These results fit in with the systematics of proton and ?-particle separation energies in the region, but disagree with the previously reported decay properties of Ta155. © 2007 The American Physical Society.
  • Küçük Resim Yok
    Öğe
    Decays of new nuclides and isomers beyond the proton drip line - The influence of neutron configurations
    (American Institute of Physics Inc., 2008) Page R.D.; Bianco L.; Darby I.G.; Joss D.T.; Simpson J.; Al-Khalili J.S.; Hadinia B.
    The energy of the vh 9/2 orbital in nuclei above N = 82 drops rapidly in energy relative to the vf 7/2 orbital as the occupancy of the ?h 11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161 Os and 157 W, and studied the decays of the proton emitter 160 Re in detail. The 161 Os and 160 Re nuclei were produced in reactions of 290, 300 and 310 MeV 58 Ni ions with an isotopically enriched 106 Cd target, separated in-flight using the RITU separator and implanted into the GREAT spectrometer. The 161 Os a decays populated the new nuclide 157 W, which decayed by ß-particle emission. The ß decay fed the known ?-decaying l/2 + and 11/2 - states in 157 Ta, which is consistent with a vf 7/2 ground state in 157 W. The measured a-decay energy and half-life for 161 Os correspond to a reduced ?-decay width that is compatible with s-wave ?-particle emission, implying that its ground state is also a vf 7/2 state. Over 7000 160 Re nuclei were produced and the y decays of a new isomeric state feeding the ?d 3/2 level in 160 Re were discovered, but no evidence for the proton or a decay of the expected ?h 11/2 state could be found. The isomer decays offer a natural explanation for this non-observation and provides a striking example of the influence of the near degeneracy of the vh 9/2 and vf 7/2 orbitals on the properties of nuclei in this region. © 2008 American Institute of Physics.
  • Küçük Resim Yok
    Öğe
    Discovery of the proton emitting nucleus 159Re
    (2007) Joss D.T.; Darby I.G.; Page R.D.; Uusitalo J.; Eeckhaudt S.; Grahn T.; Nyman M.
    The observation of the new nuclide 159Re provides important insights into the evolution of single-particle structure in heavy nuclei beyond the proton drip line. The nuclide 159Re was synthesised in the reaction 106Cd(58Ni, p4n) and identified via its proton radioactivity using the RITU gas-filled separator and the GREAT focal-plane spectrometer. Comparisons of the measured proton energy (Ep = 1805±20 keV) and decay half-life (t1/2 = 21±4 µs) with values calculated using the WKB method indicate that the proton is emitted from an h11/2 state. The implications of these results for future experimental investigations into even more proton unbound Re isotopes using in-flight separation techniques are considered. © 2007 American Institute of Physics.