High-resolution Ge(Li) study of the decay of 129gTe and 128mTe

doi:10.1016/0375-9474(69)90998-1

Nuclear Physics A

Volume 123, Issue 3, 27 January 1969, Pages 481-496

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Abstract

The decay of ^129mTe and ^129gTe to levels in ¹²⁹I has been studied using Ge(Li) detectors for high-resolution γ-ray spectroscopy with some supporting data from NaI(Tl) detectors in coincidence. A total of 46 gamma rays is accounted for by 16 excited states (one tentative) in ¹²⁹I up to 1401.6 keV. These include ten new gamma rays not previously reported, a new level in ¹²⁹I at 1282.1 keV ( $52^{+}$ ) and a probable new level at 1204.2 keV ( $32^{+}, 52^{+}$ ) (values of J^π in parentheses). The decay scheme was arrived at primarily on the basis of precise γ-ray energy determinations (to ±50 eV in many cases and never worse than ±200 eV). Beta-decay log $ƒt$ values were determined from our γ-ray intensity balances coupled with published β-branchings. Most-probable spins and parities were deduced based on the γ-ray branching, the log $ƒt$ value and published angular correlations of other workers. The $J^{π} = 12^{+}$ state predicted by Kisslinger and Sorensen in the region of 200 eV and observed in ¹²⁵I and ¹²⁷I is not seen; we find log $ƒt$ $≧10.6$ for the allowed β-decay from ^129gTe to such a level. We likewise find no evidence for the $112^{−}$ state at ≈ 930 keV as predicted by Kisslinger and Sorensen; the allowed β-decay to this state would have log $ƒt ≧ 11.0$ .

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Nuclear Data Sheets for A = 129
2014, Nuclear Data Sheets
The experimental nuclear spectroscopic data for known nuclides of mass number 129 (Ag, Cd, In, Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm) have been evaluated and presented together with adopted properties for levels and γ rays. This evaluation represents a revision of the previous one 18 years ago by Y. Tendow (1996Te01). Extensive new data have become available for many nuclides in the intervening years, although, no data are available for excited states in ¹²⁹Pm and ¹²⁹Sm, and for ¹²⁹Ag and ¹²⁹Cd, only limited information is available for the g.s. and isomers. The decay schemes of ¹²⁹Ag, ¹²⁹Pm and ¹²⁹Sm are unknown, and those for ¹²⁹Cd, ¹²⁹In, ¹²⁹Ce, ¹²⁹Pr and ¹²⁹Nd are incomplete. Many γ rays and extended level schemes have been reported for the ground state and isomer decays of ¹²⁹Ba to ¹²⁹Cs, yet the adopted set of intensities in this evaluation originate from a brief paper in an annual laboratory report. There remain several unplaced gamma rays, coupled with ambiguity about division of intensities amongst the two activities of ¹²⁹Ba with nearly the same half-lives. Isomerism is expected in ¹²⁹Pr, but there is no confirmed identification. Low-lying level structure in ¹²⁹Nd, including identification of a possible third long-lived isomer in this nuclide, remains uncertain.
The spin-parity assignments of (5/2+) for the ground state and (7/2−) for an isomer at 107.6 keV in ¹²⁹Ce are assigned based on strong support from systematics and band configurations, yet this result is in contradiction with the quadrupole interaction hyperfine structure measurement which favors 9/2− over 7/2− for the isomer, consequently 7/2+ for the ground state. Direct measurements of spins of ground state and isomer of ¹²⁹Ce are needed to settle this issue. Confirmed spins and parities of the ground state and isomer of ¹²⁹La are also lacking. Assignments in this work are mainly based on systematics of $h_{11 / 2}$ decoupled structures. A direct measurement of ground state spin of ¹²⁹La will also be desirable.
Recommended data presented in this work supersede those in previous NDS evaluations of A=129 nuclides published by 1996Te01, 1983Ha46 and 1972Ho55.
Nuclear data sheets for A=129
1996, Nuclear Data Sheets
Abstract:The 1983 evaluation of A = 129 (83Ha46) has been updated using experimental decay and reaction data received by the cutoff date noted below.
Cutoff Date:All data available before December 31, 1995, have been considered for inclusion in this evaluation.
General Policies and Organization of Material:See the January issue of Nuclear Data Sheets.
Acknowledgments:The author would like to thank the staff of the Nuclear Data Center, Japan Atomic Energy Research Institute, for their support. The many useful comments and suggetions by the reviewer and Editor-in-Chief, are gratefully appreciated. I also thank T. Tamura for his helpful comments, and Y. Kidachi for her aid in the preparation of this evaluation.
Nuclear Data Sheets for A = 129
1983, Nuclear Data Sheets
Nuclear orientation study of the excited states of 129I populated in the decay of 129gTe and 129mTe
1973, Nuclear Physics, Section A
From the angular distributions of γ-rays emitted by oriented ^129gTe and ^129mTe nuclei implanted in iron by isotope separator, unique spin assignments could be made for the excited states of ¹²⁹I at 487.4 keV $(52^{+})$ , 696.0 keV $(112^{+})$ , 729.6 keV $(92^{+})$ , 768.9 keV $(72^{+})$ , 1050.4 keV $(72^{+})$ and 1111.8 keV $(52^{+})$ . In addition, E2/M1 amplitude ratios for the following ¹²⁹I γ-rays (energies are in keV) are derived: δ(459.6) = −(0.076^+0.037_−0.148); δ(487.4) = 0.50^+0.17_−0.10 or δ⁻ = 0.35^+0.15_−0.09; δ(556.7) = 0.06±0.02 or δ⁻ = −(0.10±0.02); δ(624.4) = 0.10±0.26 or δ⁻ > 0.4; the 696.0 keV γ-ray is pure E2; δ(729.6) = −(0.34±0.06) or δ⁻¹ = 0.55±0.05; δ(741.1) = −(0.27±0.10) or δ⁻¹ = −(0.43±0.12); δ(817.2) = 0.46±0.04 or δ⁻¹ =0.20±0.03 if $I^{π} (845 keV) = 72^{+}$ ; δ(1022.6) = −(0.02 ±0.02) or δ⁻¹ = −(0.23±0.02); $δ(1084) = 0.56^{+0.04}_{−0.14}$ ; δ(1111.8) = 0.06±0.05 or δ⁻¹ = −(0.08±0.05). The anisotropy of the 531.8 keV γ-ray excludes $12^{+}$ as a possible spin assignment for the 559.6 keV level, so that no $12^{+}$ level is fed in the decay from ¹²⁹Te. Anisotropies for the 209, 250.7, 278.4 and 281.1 keV γ-rays are also measured. Comparison of the level scheme is made with theoretical predictions from both the pairing-plus-quadrupole model and the intermediate coupling unified model.
A Mössbauer parity experiment on 61Ni and the determination of the 61Co ground state spin
1973, Nuclear Physics, Section A
In a β-γ coincidence experiment the resulting polarization of the daughter nucleus can be detected by Mössbauer spectroscopy. Using this polarization, an experiment to test parity violation in the allowed Gamow-Teller β-decay of ⁶¹Co has been performed, which yields $0.7 $ ̌ = c_{A′} /c_{A} $ ̌ = 1.5$ . From the sign of the asymmetry of the β-γ coincidence Mössbauer spectrum the spin of the ⁶¹Co gound state is measured to be $j = 72$ .
Magnetic moments of 127gTe and 129gTe
1973, Nuclear Physics, Section A
Anisotropies of several γ-rays in the decay of ^127gTe and ^129gTe implanted in iron, have been observed in nuclear orientation experiments. The magnetic moments of both ground states were derived: μ( $32$ ⁺) = 0.66 ± 0.05 n.m. for ^127gTe and μ( $32$ ⁺) = 0.66 ± 0.05 n.m. for ^129gTe. These results, compared to predictions from pairing-plus-quadrupole theory, suggest a pure single-quasiparticle character for these states.

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^†: This work was performed under the auspices of the U.S. Atomic Energy Commission.

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Nuclear Physics A

Abstract

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Cited by (16)

Nuclear Data Sheets for A = 129

Nuclear data sheets for A=129

Nuclear Data Sheets for A = 129

Nuclear orientation study of the excited states of <sup>129</sup>I populated in the decay of <sup>129g</sup>Te and <sup>129m</sup>Te

A Mössbauer parity experiment on <sup>61</sup>Ni and the determination of the <sup>61</sup>Co ground state spin

Magnetic moments of <sup>127g</sup>Te and <sup>129g</sup>Te