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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Harcourt Algeranoff to Mrs Porter, 20 February 1943

8TH CHINA-JAPAN JOINT NUCLEAR PHYSICS SYMPOSIUM: (CJJNPS2012)15–19 October 201

Numerical simulation using a Hamiltonian particle method for effective elastic properties in cracked media

We apply a Hamiltonian particle method, one of the particle methods, to simulate seismic wave propagation in a cracked medium. In the particle method, traction free boundaries can be readily implemented and the spatial resolution can be chosen in an arbitrary manner. Utilisation of the method enables us to simulate seismic wave propagation in a cracked medium and to estimate effective elastic properties derived from the wave phenomena. These features of the particle method bring some advantages of numerical efficiencies (e.g. calculation time, computational memory) and the reduction of time for pre-processing. We describe first our strategy for the introduction of free surfaces inside a rock mass, i.e. cracks, and to refine the spatial resolution in an efficient way. We then model a 2D cracked medium which contains randomly distributed, randomly oriented, rectilinear, dry and non-intersecting cracks, and simulate the seismic wave propagation of P- and SV-plane waves through the region. We change the crack density in the cracked region and determine the effective velocity in the region. Our results show good agreement with the modified self-consistent theory, one of the effective medium theories. Finally, we investigate the influence of the ratio of crack length to particle spacing on the calculated effective velocities. The effective velocity obtained becomes almost constant when the ratio of crack length to particle spacing is more than ~20. Based on this result, we propose to use more than 20 particles per crack length