Heavy neutron-rich nuclei close to
N
=
126
were produced by fragmentation of a
1
A
GeV
208
Pb
beam at the FRS at GSI. The
β-decay half-lives of 8 nuclides have been determined using a novel ...numerical analysis method. The comparison of the data with model calculations provides indications on the importance of first-forbidden transitions around
A
=
195
. The measured data indicate that the matter flow in the r-process to heavier fissioning nuclei may be faster than previously expected.
Approaching r-process nuclei at N = 126 Benlliure, J; Alvarez-Pol, H; Kurtukian-Nieto, T ...
Journal of physics. Conference series,
01/2012, Letnik:
337, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The production of heavy neutron-rich nuclei approaching the r-process waiting point at N≈126 has been investigated in fragmentation reactions of relativistic 238U and 208Pb projectiles. Using this ...technique we were able to identify 73 new heavy neutron-rich nuclei expanding considerably the north-west frontier of the chart of nuclide. Moreover, we were able to determine the half lives of 13 of those nuclides. The measured values are significantly shorter than the predictions used for r-process model calculations. These shorter half lives are understood as due to the role of first-forbidden transitions in the decays of these nuclei. The confirmation of these results for r-process nuclei at N≈126 would indicate that the r-process at this point is faster than expected, leading to a larger production of the heaviest nuclei.
The presence of a neutron halo in 15C has been demonstrated in several reaction experiments at intermediate energies. In the present study, the dynamical effects of this structure are observed for ...the first time at Coulomb barrier energies in the 15C + 208Pb quasi-elastic scattering at Elab=65 MeV, measured at the HIE-ISOLDE facility, CERN using the high-granularity detector array GLORIA. A combined continuum discretised coupled channels and coupled reaction channels calculation describes the data well and significant coupling effects due both to breakup and single-neutron stripping are identified.
Background: Nuclear structure of the neutron-rich isotopes beyond 132 Sn is investigated. Purpose: The level scheme of 137 I is obtained after decay of 137 Te. Transitions in 136 I are detected after ...delayed neutron emission of 137 Te. The half life of 137 Te is measured. Methods:-delayed-ray spectroscopy is employed for neutron-rich 137 Sb and 137 Te isotopes, produced at the ILL after neutron-induced fission to populate excited states in 137 I. Results: The new decay level scheme of 137 I is established. The half lives of 137 Sb and 137 Te are determined as 0.57(26) s and 2.46(5) s, respectively. The-delayed neutron emission probability P limiting value of 137 Te is deduced to be 2.17(66)%. Conclusions: The experimental results are an important input to the theoretical description of nuclei in the region, being well interpreted within LSSM calculations and provide essential information on the firstforbidden transitions beyond > 82 and > 50.
The two protons emitted in the decay of 54Zn have been individually observed for the rst time in a Time Projection Chamber. The total decay energy and the half-life measured in this work agree with ...the results obtained in a previous experiment. Angular and energy correlations between the two protons are determined and compared to theoretical distributions of a three-body model. Within the shell model framework, the relative decay probabilities show a strong contribution of the p2 con guration for the two-proton emission. After 45Fe, the present result on 54Zn constitutes only the second case of a direct observation of the ground state two-proton decay of a long-lived isotope.
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