Rotational level structure of sodium isotopes inside the "island of inversion"

The neutron-rich nuclei 33,34,35Na were studied via in-beam γ-ray spectroscopy following nucleon removal reactions from a 36Mg secondary beam at ~220 MeV/u. Excited states of 34,35Na are reported for the first time. A third transition was observed for 33Na in addition to the known 7/2+ 1 → 5/2+ 1 → 3/2+ g.s. cascade and is suggested to be the 9/2+ 1 → 7/2+ 1 transition. Similarly, a 7/2+ 1 → 5/2+ 1 → 3/2+ g.s. cascade is proposed for the decay pattern observed for 35Na. The transition energy ratios are close to expectation values for K = 3/2 rotational bands in the strong coupling limit. Comparisons to large-scale shell model calculations in the sd-p f model space support the spin-parity assignments. © The Author(s) 2014.published_or_final_versio

Structure of 136Sn and the Z = 50 magicity

The first 2+ excited state in the neutron-rich tin isotope 136Sn has been identified at 682(13) keV by measuring γ -rays in coincidence with the one proton removal channel from 137Sb. This value is higher than those known for heavier even-even N = 86 isotones, indicating the Z = 50 shell closure. It compares well to the first 2+ excited state of the lighter tin isotope 134Sn, which may suggest that the seniority scheme also holds for 136Sn. Our result confirms the trend of lower 2+ excitation energies of even-even tin isotopes beyond N = 82 compared to the known values in between the two doubly magic nuclei 100Sn and 132Sn. © The Author(s) 2014.published_or_final_versio

Investigating nuclear shell structure in the vicinity of 78Ni: Low-lying excited states in the neutron-rich isotopes 80,82Zn

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Single-particle and collective excitations in neutron-rich sd- and fp-shell nuclei

Yrast and near-yrast structures in neutron-rich sd- and fp-shell nuclei have been deduced from four separate heavy-ion fusion-evaporation reactions performed at Argonne National Laboratory by exploiting different combinations of neutron-rich beams and targets.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Observation of new isotope 131Ag via the two-step fragmentation technique

We report on the first observation of the neutron-rich nucleus 131Ag. This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams, including 134,135Sn. The secondary beams were produced from induced fission reactions from a stable 238U beam at 345 MeV/nucleon. Secondary reaction residues were selected by the ZeroDegree spectrometer and identified by measuring their magnetic rigidity, time of flight, energy loss, and total kinetic energy. © 2013 Chinese Physical Society and IOP Publishing Ltd.link_to_subscribed_fulltex

Investigating the strength of the N = 34 subshell closure in 54Ca

Excited states in the exotic N = 34 isotope 54Ca have been measured for the first time via in-beam γ-ray spectroscopy with proton-knockout reactions from 55Sc and 56Ti radioactive beams on a Be reaction target at the Radioactive Isotope Beam Factory, Japan. A strong candidate for the transition from the first 2+ state to the 0+ ground state has been identified, in addition to several other weaker transitions. The structure of the N = 33 isotope 53Ca has also been investigated from the same data. Preliminary γ-ray energy spectra for 54Ca and 53Ca will be presented and the significance of the N = 34 subshell closure will be examined. Predictions of several shell-model interactions performed in the fp model space will be discussed in light of the new results.link_to_subscribed_fulltex