Level structure of 80Rb studied with the 79Br(α, 3n) reaction

doi:10.1016/0375-9474(77)90495-X

Nuclear Physics A

Volume 287, Issue 2, 5 September 1977, Pages 255-264

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Abstract

States of ⁸⁰Rb were excited through the ⁷⁹Br(α, 3n) reaction at bombarding energies between 30 and 55 MeV. Excitation functions, γ-ray angular distributions, γ-γ coincidences and γ-time distributions with respect to the beam bursts were determined. Levels with the following excitation energies (in keV) and spin-parity values are proposed: 175.6 2, 334.9 3⁽⁻⁾, 375.9 3⁺, 418.6 (4), 423.1 (4), 470.5, 472.5 4, 486.1 (5) and 496.4 (5). The 175.6, 375.9 and 472.5 keV levels together with the ground state exhibit a K^π = 1⁺ quasi-rotational structure, regarding the energy spacings and the mixing ratios of the γ-rays. It is shown that this structure is quite similar to bands known in ⁶⁸Ga and ⁶⁴Cu. A description of these bands in terms of the Nilsson model gives satisfactory results.

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Nuclear data sheets for A = 80
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Nuclear spectroscopic information for known nuclides of mass number 80 (Cu,Zn,Ga,Ge,As,Se,Br,Kr,Rb,Sr,Y,Zr) with Z = 29 to 40 and N = 51 to 40 have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No excited state data are yet available for ⁸⁰Cu and ⁸⁰Zn. In ⁸⁰Sr, four superdeformed bands have been reported. The half-life of fully-ionized ⁸⁰Y isomer at 228.5 keV has been measured as 6.8 s 5, as compared to 4.8 s 3 for the neutral atom. This evaluation supersedes previous full evaluations of A = 80 published by 1982Si20 and 1975Gr19, a midstream evaluation of A = 80 published in ‘up-date mode’ by 1992Si19, and an update of ⁸⁰Y nuclide for ENSDF by J.K. Tuli in August 2003.
Alignments and new band structures in the doubly odd nucleus 80Rb
1998, Nuclear Physics A
The high spin structure of ⁸⁰Rb has been investigated using the reaction ⁵¹V(³²S,2pn) at a beam energy 105 MeV. The level scheme was established from γ-γ and recoil-γ-γ coincidence measurements obtained using the Gamma Detector Array consisting of eight Compton suppressed Ge detectors coupled to the recoil mass separator HIRA. Rotational states upto an excitation energy 13 MeV and a spin 25ħ were studied. Band crossings at ħω = 0.63 and 0.73 MeV in the negative parity band, due to successive $g_{92}$ proton and neutron alignment, were observed for the first time. Evidence has also been found for a hitherto unknown sideband. The yrast positive parity bands in ⁷⁸Kr and ⁸⁰Rb have similar transition energies beyond a rotational frequency ħω ≈ 0.55 MeV. This is the only known example of identical bands in nuclei differing by two quasiparticles, in this mass region.
Nuclear data sheets update for A = 80
1992, Nuclear Data Sheets
Nuclear spectroscopic information for known nuclides of mass number 80 (Zn, Ga, Ge, As, Se, br, Kr, Rb, Sr, Y, Zr) have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No data are yet available for excited states in ⁸⁰Zn and ⁸⁰Y. This evaluation represents a revision of earlier ones (82Si20, 75Gr19). No data are available for ⁸⁰Ni, but calculations of %β⁻ n and T_1/2 (g.s.) using RPA method have been reported by 89Kr02.
A severe disagreement is noted in the systematics (85Wa02) and measured (82De36, 81Li12) Q(ɛ) of ⁸⁰Y decay. A remeasurement of this value is required to clarify the difference of about 2 Mev.
Nuclear Data Sheets for A = 80
1982, Nuclear Data Sheets
Level structure of 82Rb, studied through the 81Br(α, 3n) reaction
1980, Nuclear Physics, Section A
Nuclear states of ⁸²Rb were studied through the ⁸¹Br(α, 3n) reaction at various bombarding energies between 30 and 55 MeV. Excitation functions, γ-ray angular distributions, γ-γ coincidences and γ-time distributions with respect to the beam bursts were determined. Levels at 123.2, 187.7, 233.6, 796.3, 1214.1 keV and tentatively at 1835.5 keV were observed. It was not possible to establish whether the lowest state of the proposed level scheme corresponds to the ground state or to the $T_{12} = 6.2 h$ isomeric state. The 45.9 and 64.5 keV γ-rays do not exhibit any measurable lifetime and a limit $T_{12} ≦ 5 ns$ has been determined. The situation is similar for the 123.2 keV γ-ray, although in this case the presence of a long-lived component cannot be ruled out.
The mass and kinetic energy distributions in the fission of 237Np, 232Th, 238U, 235U and 209Bi induced by 110 MeV electrons
1979, Nuclear Physics, Section A
Fission of ²³²Th, ²³⁷Np, ²⁰⁹Bi, ²³⁵U and ²³⁸U induced by 110 MeV electrons has been studied by means of surface barrier detectors. The resulting mass and kinetic energy distributions are presented. Comparison with the liquid drop model predictions shows reasonable agreement in the case of ²⁰⁹Bi. The data are analysed in terms of a two component model of fission and the mean total kinetic energies of the components are shown to depend linearly on $Z_{1} Z_{2} (A_{1}^{13} + A_{2}^{13})$ . Interesting differences are found when the present results are compared with the recent photofission experiments of Areskoug et al. and features in both sets of data correlate with changes of fragment deformation implied by the calculations of Wilkins et al.

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^☆: Work partially supported by Fundación Sauberán.

^††: Fellow of the Consejo Nacional de Investigaciones Cientificas y Técnicas.

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Nuclear Physics A

Abstract

References (11)

Nucl. Phys.

Nucl. Data Tables

Nucl. Instr.

Nucl. Phys.

Phys. Rev.

Cited by (8)

Nuclear data sheets for A = 80

Alignments and new band structures in the doubly odd nucleus <sup>80</sup>Rb

Nuclear data sheets update for A = 80

Nuclear Data Sheets for A = 80

Level structure of <sup>82</sup>Rb, studied through the <sup>81</sup>Br(α, 3n) reaction

The mass and kinetic energy distributions in the fission of <sup>237</sup>Np, <sup>232</sup>Th, <sup>238</sup>U, <sup>235</sup>U and <sup>209</sup>Bi induced by 110 MeV electrons

Level structure of 80Rb studied with the 79Br(α, 3n) reaction☆

Abstract

Nucl. Phys.

Nucl. Data Tables

Nucl. Instr.

Nucl. Phys.

Phys. Rev.

Level structure of ⁸⁰Rb studied with the ⁷⁹Br(α, 3n) reaction☆