The 159Tb(t, α)158Gd reaction with 17 MeV polarized tritons

doi:10.1016/0375-9474(81)90284-0

Nuclear Physics A

Volume 366, Issue 2, 17 August 1981, Pages 202-220

https://doi.org/10.1016/0375-9474(81)90284-0 Get rights and content

Abstract

The ¹⁵⁹Tb( $t$ , α)¹⁵⁸Gd reaction has been studied using 17 MeV polarized tritons from the Los Alamos Scientific Laboratory Tandem Van de Graaff accelerator. The α -spectra were analyzed with a Q3D magnetic spectrometer. The observed analyzing powers for most of the strong transitions have large magnitudes similar to those observed for ( $t$ , α ) studies with neighbouring even-even targets. This is consistent with a Nilsson model description of the two quasiparticle states populated in ¹⁵⁸Gd, in which most of the strong transitions would be expected to be dominated by a single j-value. The present results provide strong confirmation of the previously suggested assignments of the 1380 keV (K^π = 4⁺) and 1930 keV (K^π = 1⁺) band heads as $52^{+} [413] ± 32^{+} [411]$ configurations. Several rotational members of the K^π = 1⁻ octupole band were populated via the $52^{−} [532]- 32^{+} [411]$ component of this vibration, and from the observed strengths it is estimated that this two-quasiparticle admixture makes up ∼45% of the octupole vibration. Strong transitions to several levels above 2 MeV excitation are dominated by $l = 5, j = 112$ transfers, and these are ascribed to pickup of a $52^{−} [532]$ proton. The spin 5, 6 and 7 members of the $K^{π} = 4^{−}, 52^{−} [532] + 32^{+} [411]$ band have been assigned at 2176 keV, 2282 keV and 2418 keV, respectively. Whereas previous studies have shown that the (t, α) reaction with polarized tritons is a very useful specroscopic technique when used with even-even target nuclei, the present results extend the proven effectiveness to cases of odd-mass deformed targets.

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Nuclear Data Sheets for A=158
2017, Nuclear Data Sheets
The experimental results published before February 2017 from the various reaction and decay studies leading to nuclides ¹⁵⁸Nd, ¹⁵⁸Pm, ¹⁵⁸Sm, ¹⁵⁸Eu, ¹⁵⁸Gd, ¹⁵⁸Tb, ¹⁵⁸Dy, ¹⁵⁸Ho, ¹⁵⁸Er, ¹⁵⁸Tm, ¹⁵⁸Yb, ¹⁵⁸Lu, ¹⁵⁸Hf, ¹⁵⁸Ta, ¹⁵⁸W in the A=158 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties. Large sections of the mass chain are almost identical to the ones in the previous 2004He05 NDS publication by R.G. Helmer.
Nuclear data sheets for A = 158
2004, Nuclear Data Sheets
(3He, d) and ( α, t) reaction studies of 154Gd: Nature of Kπ=4+ bands in heavy deformed nuclei
2001, Nuclear Physics A
Levels in ¹⁵⁴Gd have been studied with (³He, d) and (α, t) reactions using beams of 24 MeV ³He and 27 MeV α particles. Particle spectra were measured with a magnetic spectrograph at θ=30° and 60° for the (³He, d) and at θ=45° and 60° for the (α, t) reaction. Cross sections were compared with predictions based on Distorted Wave Born Approximation and Nilsson model calculations. The γ-vibrational band has an admixture of ∼15% of the 5/2⁺[413]−1/2⁺[411] two-quasiproton state, in good agreement with predictions of the Quasiparticle-Phonon Model. The K^π=4⁺ band at 1646 keV is very strongly populated, with a pattern of cross sections indicating its dominant component is an ∼80% admixture of the 5/2⁺[413]+3/2⁺[411] two-quasiproton state. Bands with similar structures have previously been found at 1510 keV in ¹⁵⁶Gd and 1380 keV in ¹⁵⁸Gd. Although there were earlier double-γ-phonon claims for the bands in ¹⁵⁴Gd and ¹⁵⁶Gd, quantitative analyses show that all the data (including the E2 strengths) agree better with a predominantly g boson, or single hexadecapole phonon, character. Some insights are provided which assist in understanding how microscopic structures of the K^π=4⁺ and γ bands help produce the relatively large E2 strengths coupling these bands. Two closely-spaced K^π=1⁺ bands based at 2175 keV and 2186 keV share the single-proton stripping strengths for the 5/2⁺[413]−3/2⁺[411] configuration, and a level at 2569 keV is proposed as the 7⁻ member of a Coriolis-mixed band formed by transfer of a proton to h_11/2 orbitals.
Nuclear data sheets for A = 158
1996, Nuclear Data Sheets
Abstract:The experimental results from the various reaction and decay studies leading to nuclides in the A=158 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties.Cutoff Date:Data available prior to October 1995 have been evaluated.General Policies and Organization of Material:See the January issue of Nuclear Data Sheets.Acknowledgments:The evaluator wishes to thank the reviewer and the editors for helpful discussions.
Description of low-lying vibrational states and gamma-ray transitions between excited states in 156Gd and 158Gd
1994, Nuclear Physics, Section A
The energies and wave functions of the nonrotational states below 2.3 MeV in ¹⁵⁶Gd and ¹⁵⁸Gd are calculated within the quasiparticle-phonon nuclear model. It is shown that the wave functions have the dominating one-phonon component. The contribution of the two-phonon configurations to the wave function of the excited states is less than 10%. The calculated excitation energies and B(E; λ = 2, 3, 4) values for transition from the ground state are found to be in agreement with experimental data. High intensities of the one-nucleon transfer reactions are explained by the corresponding large two-quasiparticle components of the one-phonon terms of the wave functions. The calculated intensities and reduced probabilities of the E1, E2, and M1 transitions between excited states are in reasonably good overall agreement with experimental data.
Nuclear data sheets for A = 158
1989, Nuclear Data Sheets

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^†: Financial support provided by the Natural Sciences and Engineering Research Council of Canada.

^∗: Permanent address: Department of Physics, University of Jyväskylä, SF-40720, Jyväskylä, Finland.

^††: Work performed under the auspices of the US Department of Energy.

^∗∗: Present address: Wright Nuclear Structure Laboratory, Yale University, New Haven, CT 06511.

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Nuclear Physics A

Abstract

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Cited by (14)

Nuclear Data Sheets for A=158

Nuclear data sheets for A = 158

(<sup>3</sup>He, d) and ( α, t) reaction studies of <sup>154</sup>Gd: Nature of K<sup>π</sup>=4<sup>+</sup> bands in heavy deformed nuclei

Nuclear data sheets for A = 158

Description of low-lying vibrational states and gamma-ray transitions between excited states in <sup>156</sup>Gd and <sup>158</sup>Gd

Nuclear data sheets for A = 158