Low-lying positive parity bands in 162Yb

Mdletshe, L.; Ntshangase, S. S.; Sharpey‐Schafer, J. F.; Majola, S. N. T.; Dinoko, T. S.; Khumalo, N. A.; Lawrie, E. A.; Bark, R. A.; Bucher, T. D.; Erasmus, N.; Jones, P.; Jongile, S.; Kheswa, B. V.; Lawrie, J. J.; Makhathini, L.; Malatji, K. L.; Maqabuka, B.; Ndayishimye, J.; Noncolela, S. P.; Shirinda, O.; Sithole, M. A.

doi:10.1140/epja/i2018-12613-4

Cited by 8 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…examples of reflection asymmetry have been reported for some of the odd-mass nuclei in the N ≈ 90 region, namely, the N = 91 isotones-153 Sm and 155 Gd [27,64]. Due to the structural similarities between the N ≈ 90 isotones in the A ≈ 150-160 mass region [65][66][67][68][69][70][71], it is reasonable to expect the presence of octupole correlations in 157 Dy, which is also an N = 91 isotone.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopy of low-spin states in Dy157 : Search for evidence of enhanced octupole correlations

Majola¹,

Bark²,

Bianco³

et al. 2019

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

Low-spin states of 157 Dy have been studied using the JUROGAM II array, following the 155 Gd (α, 2n) reaction at a beam energy of 25 MeV. The level scheme of 157 Dy has been expanded with four new bands. Rotational structures built on the [523]5/2and [402]3/2 + neutron orbitals constitute new additions to the level scheme as do many of the inter-and intra-band transitions. This manuscript also reports the observation of cross I + → (I-1)and I -→ (I-1) + E1 dipole transitions inter-linking structures built on the [523]5/2 -(band 5) and [402]3/2 + (band 7) neutron orbitals. These interlacing band structures are interpreted as the bands of parity doublets with simplex quantum number s = -i related to possible octupole correlations.Two previous experiments conducted with large Ge detector arrays used heavy-ion induced reactions 150 Nd( 12 C,5n) and 124 Sc( 36 S,3n) [71,72,97] to study the medium to high-spin states of 157 Dy. These experiments reported rotational bands built on the h9/2[521]3/2 -, i13/2[651]3/2 + and h11/2[505]11/2neutrons configurations but reported no transitions linking these structures. To this end we have performed in-beam measurements using the JUROGAM II array to study the rotational bands of 157 Dy and to search for evidence of octupole correlations. We report on four new bands as well as many new linking transitions relative to the previously observed structures.The rotational behaviour of the new bands is described in terms of quasi-particle assignments, and the observed alignment properties are analyzed within the framework of the cranked shell model. II. Experimental details and analysisExcited states of 157 Dy were populated using the 155 Gd (α, 2n) reaction at a beam energy of 25 MeV. The 155 Gd target was 0.98 mg/cm 2 thick with a purity of 91%. Gamma-rays following the fusion evaporation reaction were detected with the JUROGAM II multi-detector array [73] in JYFL, Jyväskylä, Finland. The spectrometer setup comprised 39 high-purity germanium detectors, all with BGO escape suppression shields; 15 EUROGAM coaxial detectors (Phase 1 [75] and GASP [74] type) and 24 EUROGAM Phase II clover detectors [76]. Approximately 14 x 10 9 γ-γ events were unfolded from the data in the off-line analysis and replayed into γ-γ Radware [77, 78] coincidence matrices, which were used to construct the level scheme of 157 Dy. The spins and parities for the new rotational structures were successfully assigned using the Directional Correlation from Oriented States (DCO ratios/RDCO) [79, 80] and linear polarization anisotropy (Ap) methods [81]. While Ap is given as used in [82], the DCO matrices were constructed using data from detectors in the rings at 158° and 86°+94°, thus the RDCO for the JUROGAM II array in this work is; RDCO = I γ1(at 158º : gated on γ2 near 90 º) / I γ1(near 90º : gated on γ2 at 158º)

show abstract

Section: Introductionmentioning

confidence: 99%

“…mass region[64][65][66][67][68][69][70], it is reasonable to expect the presence of octupole correlations in 157 Dy, which is also an N = 91 isotone.…”

mentioning

confidence: 99%

Spectroscopy of low-spin states in Dy157 : Search for evidence of enhanced octupole correlations

Majola¹,

Bark²,

Bianco³

et al. 2019

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

show abstract

“…The 150 Sm( 16 O, 4n) 162 Yb reaction was recently performed at iThemba LABS, using the AFRODITE array. Though partial results of 162 Yb are shown in this work, the complete spectroscopy pertaining to the low-lying positiveparity bands of this nucleus will be published elsewhere [58].…”

Section: N = 92 Isotonesmentioning

confidence: 95%

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 superdeforma

Majola¹,

Shi²,

Song³

et al. 2019

Phys. Rev. C

Self Cite

View full text Add to dashboard Cite

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(E 0) and B(E 2) 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 2 γ + 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 0 2 + 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 0 2 + bands have wave functions with large components in a triaxial superdeformed minimum. In the vicinity of 152 Sm, the present calculations predict a soft potential in the β direction but do not find two coexisting minima. This is reminiscent of 152 Sm exhibiting an X (5) behavior. The model also predicts that the 0 3 + bands are of two-phonon nature, having an energy twice that of the 0 2 + band. This is in contradiction with the data and implies that other excitation modes must be invoked to explain their origin.

show abstract

Nuclear Data Sheets for A=162

Nica

2024

Nuclear Data Sheets

View full text Add to dashboard Cite

Low-lying positive parity bands in 162Yb

Cited by 8 publications

References 29 publications

Spectroscopy of low-spin states in Dy157 : Search for evidence of enhanced octupole correlations

Spectroscopy of low-spin states in Dy157 : Search for evidence of enhanced octupole correlations

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 superdeforma

Nuclear Data Sheets for A=162

Contact Info

Product

Resources

About