Study of 0+ States at iThemba LABS

Abstract: Please refer to full text to view abstract

High resolution 148Nd(3He,nγ) two proton stripping reaction and the structure of the 02 + state in 150Sm

Abstract: Please refer to full text to view abstract

Octupole correlations in the structure of O2 bands in the N=88 nuclei150Sm Gd

Knowledge of the exact microscopic structure of the 01 + ground state and first excited 02 + state in 150Sm is required to understand the branching of double β decay to these states from 150Nd. The detailed spectroscopy of 150Sm and 152Gd has been studied using (α,xn) reactions and the γ -ray arrays AFRODITE and JUROGAM II. Consistently strong E1 transitions are observed between the excited Kπ = 02 + bands and the lowest negative parity bands in both nuclei. These results are discussed in terms of the possible permanent octupole deformation in the first excited Kπ = 02 + band and also in terms of the “tidal wave” model of Frauendorf.Web of Scienc

β and γ bands in N = 88 , 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory : vibrations, shape coexistence, and superdeformation

CITATION: Majola, S. N. T. et al. 2019. β and γ bands in N=88, 90, and 92 isotones investigated with a five-dimensional collective Hamiltonian based on covariant density functional theory: Vibrations, shape coexistence, and superdeformation. Physical Review C, 100(4). doi:10.1103/PhysRevC.100.044324.The original publication is available at https://journals.aps.org/prc/A comprehensive systematic study is made for the collective β and γ bands in even-even isotopes with neutron numbers N = 88 to 92 and proton numbers Z = 62 (Sm) to 70 (Yb). Data, including excitation energies, B(E0) and B(E2) values, and branching ratios from previously published experiments are collated with new data presented for the first time in this study. The experimental data are compared to calculations using a five-dimensional collective Hamiltonian (5DCH) based on the covariant density functional theory (CDFT). A realistic potential in the quadrupole shape parameters V (β,γ ) is determined from potential energy surfaces (PES) calculated using the CDFT. The parameters of the 5DCH are fixed and contained within the CDFT. Overall, a satisfactory agreement is found between the data and the calculations. In line with the energy staggering S(I) of the levels in the 2γ + bands, the potential energy surfaces of the CDFT calculations indicate γ -soft shapes in the N = 88 nuclides, which become γ rigid for N = 90 and N = 92. The nature of the 02 + bands changes with atomic number. In the isotopes of Sm to Dy, they can be understood as β vibrations, but in the Er and Yb isotopes the 02 + bands have wave functions with large components in a triaxial superdeformed minimum. In the vicinity of 152Sm, the present calculations predict a soft potential in the β direction but do not find two coexisting minima. This is reminiscent of 152Sm exhibiting an X(5) behavior. The model also predicts that the 03 + bands are of two-phonon nature, having an energy twice that of the 02 + band. This is in contradiction with the data and implies that other excitation modes must be invoked to explain their origin.https://journals.aps.org/prc/abstract/10.1103/PhysRevC.100.044324Publisher’s versio

High Resolution (<SUP>3</SUP>He, <I>n</I>) Two Proton Stripping Reaction to 0<SUP>+</SUP> States Populated in 2<I>B</I> Decay

Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.NatuurwetenskappeFisik

Dipole bands in <SUP>196</SUP>Hg

Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Congruent band structures in

We have used the ($\alpha$, 2n) and ($\alpha$, 4n) reactions and the AFRODITE $\gamma$ -ray spectrometer to make a comprehensive study of the nucleus 154Gd below \ensuremath 20\hbar . While the first excited 02 + state at 681 keV is usually considered to be the head of a \ensuremath K^{\pi}=0^{+} $\beta$ -vibrational band, we propose that the data are best described as two separate vacuum states, the ground state and the 681 keV level, each with its own $\gamma$ and octupole vibrations, pairing and alignments. The implications of this finding, for understanding the structure of transitional rare-earth nuclei, are discussed

New nanosecond isomers identified with the AFRODITE array

The Recoil Shadow Anisotropy Method for measuring nanosecond lifetimes is being implemented on the AFRODITE array and four new isomers were found in 198,200Bi, 164Ta and 162Lu

Characterization of quasiparticle states at and beyond stability in ytterbium isotopes: Spectroscopy of

Excited states in 175Yb, 176Yb and 177Yb were populated via the bombardment of a 176Yb target with a 750 MeV 136Xe beam. Gamma-ray decays from these states were measured with the AFRODITE multi-detector spectrometer. The rotational band previously assigned to the ground state of 177Yb has been reassigned to the first-excited state of 175Yb. A new rotational band based on the ground state of 177Yb is presented, and the band based on the K π = 4- two-quasiparticle state in 176Yb has been identified. Also a candidate for the rotational band based on the K π = 8-, T 1/2 = 11.4(3) s two-quasiparticle state in 176Yb has been found. Comparisons of gK values derived from in-band branching ratios are consistent with the ν9/2+[624] assignment to the ground state of 177Yb, the ν2{9/2+[624] ⊗ 1/2-[510]} assignment to the K π = 4- state and with the ν2{9/2+[624] ⊗ 7/2-[514]} assignment to the K π = 8- metastable excited state in 176Yb