14 research outputs found

    Properties of very n-rich He isotopes

    No full text
    International audienceLow-energy spectra of the 8,10He nuclei were investigated in the (t, p)-type reactions at small centre-of-mass angles using ∼ 25AMeV beams of 6He and 8He nuclei. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6-3.9MeV and (1+) at 5.3-5.5MeV, were populated with cross-sections of 200, 100-250, and 90-125 μb/sr, respectively. To account for a near-threshold anomaly observed in the 8He spectrum the population of a 1− continuum (soft dipole excitation) was considered. The lowest-energy group of events in the 10He spectrum was observed at ∼ 3MeV with a cross-section of ∼ 140 μb/sr. This result is consistent with the previously reported observation of 10He providing a new g.s. position for 10He at about 3MeV

    The 8^{8}He and 10^{10}He spectra studied in the (t, p) reaction

    Get PDF
    JINR U-400M cyclotron, separator ACCULINNAThe low-lying spectra of 8He and 10He nuclei were studied in the 3H(6He, p)8He and 3H(8He, p)10He transfer reactions. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6–3.9 MeV and (1+) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μb/sr, respectively. Some evidence for a 8He state at about 7.5 MeV was obtained. We discuss a possible nature of the nearthreshold anomaly above 2.14 MeV in 8He and relate it to the population of a 1− continuum (soft dipole excitation) with a peak value at about 3 MeV. The lowest energy group of events in the 10He spectrum was observed at ∼ 3 MeV with a cross section of ∼ 140 μb/sr. We argue that this result is consistent with the previously reported observation of 10He providing the new 10He g.s. position at about 3 Me

    Soft dipole mode in 8He

    No full text
    The low-lying spectrum of 8He was studied in the 3H(6He, p)8He transfer reaction for small center of mass angles. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6-3.9 MeV and (1+) at 5.3-5.5 MeV, were populated with cross sections of 200, 100-250, and 90-125 μb/sr. Some evidence for the excited state at about 7.5 MeV can be found in the data. The possible nature of the near-threshold anomaly above 2.14 MeV in 8He is related to the population of a 1- continuum (soft dipole excitation) with a peak energy value at about 3 MeV. This assumption can probably resolve the problem of a large uncertainty existing in the experimental data on the 8He 2+ state energy. © Pleiades Publishing, Ltd. 2009.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Soft Dipole Mode in 8^{8}He

    No full text
    The low-lying spectrum of 8 He was studied in the 3 H( 6 He, p ) 8 He transfer reaction for small center of mass angles. The 0 + ground state (g.s.) of 8 He and excited states, 2 + at 3.6–3.9 MeV and (1 + ) at 5.3–5.5 MeV, were populated with cross sections of 200, 100–250, and 90–125 μ b/sr. Some evidence for the excited state at about 7.5 MeV can be found in the data. The possible nature of the near-threshold anomaly above 2.14 MeV in 8 He is related to the population of a 1 – continuum (soft dipole excitation) with a peak energy value at about 3 MeV. This assumption can probably resolve the problem of a large uncertainty existing in the experimental data on the 8 He 2 + state energy
    corecore