Multiple superdeformed bands in 81Sr

doi:10.1016/0370-2693(95)00918-B

Physics Letters B

Volume 357, Issue 3, 7 September 1995, Pages 281-286

https://doi.org/10.1016/0370-2693(95)00918-B Get rights and content

Abstract

Four superdeformed bands extending over five to twelve transitions have been identified in ⁸¹Sr from a study with the Gammasphere array and the Microball charged-particle array. One of the bands shows an upbend in the dynamic moment of inertia at a rotational frequency of 1.2 MeV and all bands exhibit a nearly constant moment of inertia below that frequency.

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Cited by (22)

Nuclear Data Sheets for A = 81
2008, Nuclear Data Sheets
Nuclear structure data pertaining to all nuclei with mass number A = 81 (Zn, Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb) have been compiled and evaluated and incorporated into the ENSDF data file. This publication for A = 81 supersedes the previous publication (Coral M. Baglin, Nuclear Data Sheets 79, 447 (1996), literature cutoff 1 November 1996) and the subsequent updates by C. Baglin for ⁸¹Y (literature cutoff 8 October 1998) and ⁸¹Zr (literature cutoff 24 March 2000). All literature available prior to 15 August 2008 has been considered. Subsequent to previous A = 81 evaluations, excited states have been reported for the first time in ⁸¹Ga, and knowledge of excited state properties for ⁸¹Y and ⁸¹Zr has been significantly expanded. However, the expected $ɛ + β^{+}$ decay of ⁸¹Zr has yet to be studied.
Termination of rotational bands: Disappearance of quantum many-body collectivity
1999, Physics Report
One of the most interesting features of nuclei is the process by which specific configurations, manifest as collective rotational bands at intermediate spin values, gradually lose their collectivity and terminate in a non-collective state at the maximum spin which can be built within the configuration. Recent advances in both experiment and theory allow the study of this nuclear structure feature in detail. The bands, which show such a continuous transition from high collectivity to a pure particle–hole (terminating) state, are generally called terminating bands or to underline their continuous character, smooth terminating bands. The best examples of such bands known at present are in the neutron-deficient A∼110 mass region, where terminating configurations involving proton particle–hole excitations across the Z=50 gap can be observed over their entire spin range. The main features of band termination as a specific high-spin phenomenon inherent to finite many-fermion strongly interacting systems are overviewed, based mainly on the configuration-dependent cranked Nilsson–Strutinsky approach. The extensive experimental results on smooth terminating bands in the A∼110 mass region, which have been addressed by these theoretical calculations, are presented along with the theoretical comparisons in a systematic way. In addition, specific features of band termination in other parts of the periodic chart and other possible theoretical approaches are briefly reviewed.
Superdeformed bands in 80Sr and the evolution of deformation in Sr isotopes
1997, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Four superdeformed bands are reported in ⁸⁰Sr, extending known superdeformation in the ₃₈Sr series down to N = 42. The characteristics of these bands are discussed. Residual Doppler shifts were measured and average transition quadrupole moments (Q_t) inferred for these new bands. These Q_t values are compared to Q_t values obtained for previously identified superdeformed bands in ^81–83Sr. The low Q_t of 2.7 ^+0.7_−0.6 eb obtained for the yrast band in ⁸⁰Sr indicates a reduction in the deformation of yrast superdeformed bands in the series ^80–83Sr with decreasing N, and possibly the onset of triaxiality in superdeformed shapes.
Physics with GAMMASPHERE and beyond
1997, Progress in Particle and Nuclear Physics
Forking and unusual decay out of superdeformed bands in 83Zr
1996, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Two superdeformed (SD) bands extending over eight to eleven transitions have been identified in ⁸³Zr. The quadrupole moment of the more intense band was determined by the Residual Doppler Shift Method and is consistent with a quadrupole deformation of β₂ ≈ 0.5. The large quadrupole moment and population intensity of the yrast SD band (≈ 5%) in Zr isotopes relative to their isotones in Sr and Y nuclei suggest the presence of a large SD shell gap at proton number Z = 40. At the decay-out points, the Routhians of the SD bands reapproach that of the positive parity normally-deformed states which may be the reason why both of these bands feed mainly (≈ 85%) into the positive-parity yrast band.
Gamma-ray spectroscopy of 79Rb and 81Sr
1996, Nuclear Physics A
High spin states in ⁷⁹Rb and ⁸¹Sr were populated through the bombardment of a ⁵⁸Ni target with a ³⁰Si beam at 134 MeV. Gamma rays depopulating the excited states were detected using the EUROGAM phase-2 array. A band of nine transitions has been observed in ⁸¹Sr decaying to the $α = − 12$ sequence built on the $[303] 52^{−}$ Nilsson orbit. The decay schemes of several bands in both ⁷⁹Rb and ⁸¹Sr have been extended to higher spin with angular correlation measurements providing firm spin assignments for a number of states. A fork is observed in ⁷⁹Rb after a band crossing at $h ̷ ω ⋍ 0.72 MeV$ in the $α = + 12$ sequence built on the $[312] 32^{−}$ Nilsson orbit. A previously observed cascade of three γ-rays in ⁷⁹Rb has been extended by the addition of ten transitions up to 16 MeV. This has been assigned as a positive parity band built on the $[440] 12^{+}$ Nilsson orbit.

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Physics Letters B

Abstract

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Cited by (22)

Nuclear Data Sheets for A = 81

Termination of rotational bands: Disappearance of quantum many-body collectivity

Superdeformed bands in <sup>80</sup>Sr and the evolution of deformation in Sr isotopes

Physics with GAMMASPHERE and beyond

Forking and unusual decay out of superdeformed bands in <sup>83</sup>Zr

Gamma-ray spectroscopy of <sup>79</sup>Rb and <sup>81</sup>Sr