Electromagnetic properties through two band crossings in 165Lu
Abstract
The two signatures of a band built on a shell model state have been established to high spin in 165Lu. An observed second band crossing at ℏ ω ∼ 0.40 MeV is interpreted as the alignment of a second pair of neutrons. M1 transitions are observed through both crossing and the data utilized in connection with the observed signature splitting of energies and alignments to interpret the measured values of . Alignment effects and shape changes are discussed.
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Nuclear Structure and Decay Data for A=165 Isobars
2024, Nuclear Data SheetsExperimental nuclear spectroscopic data are compiled and evaluated for 18 known nuclides of mass 165 (Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt). Detailed information is presented for each reaction and decay experiment. Combining all the available data, recommended values are provided for energies, spins and parities, and half-lives of levels, with energies, branching ratios and multipolarities of γ radiations, and characteristics of β and α radiations in radioactive decays. 165Dy, 165Ho, 165Er, 165Tm, 165Yb, 165Lu and 165Hf are among the most extensively studied nuclides via decay and high-spin gamma-ray spectroscopy measurements, followed by limited data for 165Tb, 165Ta, 165W, 165Re, and 165Os. No excited states have yet been identified in 165Sm, 165Gd, and 165Pt, while for 165Eu and 165Ir, information is available for only the g.s. and an isomer, but with no γ rays. This work supersedes earlier evaluation of A=165 nuclides by 2006Ja09.
Nuclear Data Sheets for A = 165
2006, Nuclear Data SheetsNuclear spectroscopic information for known nuclides of mass number 165 (Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Hf,Ta,W,Re,Os,Ir) with Z = 63 to 77 and N = 102 to 88 have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No excited state data are yet available for 165Eu, 165Gd and 165Tb. In 165Re an isomer is known at about 50 keV; in 165Os, about 15 gamma rays are known but no level scheme has been proposed; and in 165Ir, the the ground state has not yet been identified, but an isomeric state at about 180 keV has been established. Fairly rich structures are known for all the other A = 165 nuclides. Triaxial Superdeformed structures are known in 165Lu (five SD bands). This evaluation supersedes previous full evaluations of A = 165 by 1987Pe01 and 1974Bu29, a midstream evaluation (in update mode) by 1992Pe04 with literature cutoff date of November 1990, and evaluation of 165Lu nuclide by 1999Si16. Extensive new data have since become available for most of the nuclides of A = 165 and have been included in the current evaluation.
Nuclear data sheets for <sup>165</sup> Lu
1999, Nuclear Data SheetsThe experimental nuclear structure data for 165Lu have been compiled and evaluated. Extensive revisions to all the data sets for this nuclide have been made, based on the new high-spin study of 1995Sc39. From the interconnections of different rotational bands in 1995Sc39, the assignment of the ground state and its spin have been revised. There does not seem any evidence to support isomerism in 165Lu has proposed earlier in the 1987 Nuclear Data Sheets (and the 1992 update) of A = 165, the Wall Chart of Nuclides and by 1997Au04. The assignment of 1/2;pl to the ground state is also supported by the recent (1998Ge13) laser-spectroscopic measurements of hyperfine structure. A superdeformed (triaxial) structure is reported by 1995Sc39. This revision supersedes earlier 165Lu data contained in the A = 165 update published by L. K. Peker, Nuclear Data Sheets 65, 439 (1992) with literature coverage up to Nov. 1, 1990. The transitions connecting the low lying states to the ground state are expected to be in the low-energy region of 5 to 24 keV for which experiments to measure conversion electrons are needed.
High-spin states in odd-odd <sup>164</sup>Lu
1996, Nuclear Physics AHigh-spin states in odd-odd 164Lu have been studied using 19F and 23Na induced fusion-evaporation reactions. Three strongly coupled rotational bands have been established and three decoupled bands were tentatively assigned to 164Lu. The band crossing frequencies, energy sig-nature splittings, and relative transition probabilities were deduced from experimental data and compared with neighboring even-even and odd-A nuclei. An anomalously large band crossing frequency was observed in the excited band, and a pronounced signature inversion was observed in the yrast band of 164Lu. These anomalies may be associated with residual neutron-proton interactions.
Electromagnetic properties of <sup>161</sup>Tm at high spin
1995, Nuclear Physics, Section AThe decay of the yrast and near-yrast high-spin states in 161Tm has been observed following the reaction 128Te(37Cl,4n). Extension of the known level scheme reveals previously unobserved crossings in the bands built on the , and Nilsson states. The use of both gold- and terbium-backed targets has enabled the measurement by the Doppler shift attenuation method of lifetimes of states in the yrast band in the spin range . The results show little evidence for change in the nuclear deformation over this interval in spin (Qt ≈ 6 eb). From lifetime measurements and values in the band, absolute B(M1) values for five transitions (for states with ) were determined. These results provide some evidence for a reduction in the proton spin projection on the deformation axis relative to its value at low rotational frequency. The signature splitting in the Routhians and values for the band is discussed in terms of the inclusion of non-axially-symmetric (γ-deformed) components in the nuclear wavefunction.
Shapes, electromagnetic properties and enhanced E1 strength in <sup>169</sup>Lu
1993, Nuclear Physics, Section ARotational bands in 169Lu previously observed via (p, 3n) and (α, 4n) reactions were extended by 8–14 units of angular momentum using the 154Sm(19F, 4n) reaction and the Nordball detector array. By analysis of γγ coincidence relations and γ-ray angular correlations we have established the , band to , the bands to > the [404]+ bands to and the [411], to . The bands belonging to the and configurations with appear to be rather mixed in the low spin region. One of these bands is established to units of spin. The transitions interconnecting the signature partners, in the bands based on the and [404] Nilsson orbitais, as well as in and between the strongly mixed and bands are compared to particle-rotor model calculations. By DSAM analysis, lifetimes and thereby transition quadrupole moments for the band built on the configuration , could be extracted. The abnormal alignment pattern at the crossing for the ban analysed in terms of a difference in both deformation and neutron pairing compared to the other less polarizing configurations. The influence of octupole modes on the strength of observed transitions as well as on observed spin-flip, , E1 transitions is investigated theoretically and compared to the experimental data.