$\ensuremath{\beta}$ decay of $^{81}\mathrm{Zn}$ and migrations of states observed near the $N=50$ closed shell

$β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell

S. Padgett, M. Madurga, R. Grzywacz, I. G. Darby, S. N. Liddick, S. V. Paulauskas, L. Cartegni, C. R. Bingham, C. J. Gross, K. Rykaczewski, D. Shapira, D. W. Stracener, A. J. Mendez, II, J. A. Winger, S. V. Ilyushkin, A. Korgul, W. Królas, E. Zganjar, C. Mazzocchi, S. Liu, J. H. Hamilton, J. C. Batchelder, and M. M. Rajabali

Phys. Rev. C 82, 064314 – Published 23 December 2010; Erratum Phys. Rev. C 83, 019903 (2011)

Abstract

The $β$ decay of the $N = 51$ nucleus ${}^{81}{Zn}$ was studied by means of $β$ - $γ$ spectroscopy and from isotopically pure beams produced at the Holifield Radioactive Ion Beam Facility (HRIBF). We observe several competing $β$ transitions populating ${}^{81}{Ga}$ that are interpreted as allowed Gamow-Teller decays to positive parity, core excited states, and first-forbidden decays to negative parity states. The measured $β$ -decay pattern suggests an assignment of $I^{π} = 5 / 2^{+}$ for the ${}^{81}{Zn}$ ground state. The systematics of core excited states in $N = 50$ isotones indicate a strengthening of the $N = 40$ subshell gap near ${}^{78}{Ni}$ .

Received 5 October 2010

DOI:https://doi.org/10.1103/PhysRevC.82.064314

Erratum

Erratum: $β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell [Phys. Rev. C 82, 064314 (2010)]

S. Padgett, M. Madurga, R. Grzywacz, I. G. Darby, S. N. Liddick, S. V. Paulauskas, L. Cartegni, C. R. Bingham, C. J. Gross, K. Rykaczewski, D. Shapira, D. W. Stracener, A. J. Mendez, II, J. A. Winger, S. V. Ilyushkin, A. Korgul, W. Królas, E. Zganjar, C. Mazzocchi, S. Liu, J. H. Hamilton, J. C. Batchelder, and M. M. Rajabali

Phys. Rev. C 83, 019903 (2011)

Authors & Affiliations

S. Padgett¹, M. Madurga¹, R. Grzywacz¹, I. G. Darby¹, S. N. Liddick¹, S. V. Paulauskas¹, L. Cartegni¹, C. R. Bingham¹, C. J. Gross², K. Rykaczewski², D. Shapira², D. W. Stracener², A. J. Mendez, II², J. A. Winger³, S. V. Ilyushkin³, A. Korgul⁴, W. Królas⁵, E. Zganjar⁶, C. Mazzocchi^4,7, S. Liu⁸, J. H. Hamilton⁸, J. C. Batchelder⁹, and M. M. Rajabali¹

¹Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
²Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
³Department of Physics and Astronomy, Mississippi State University, Mississippi 39762, USA
⁴Faculty of Physics, University of Warsaw, Warszawa PL 00-681, Poland
⁵Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, PL 31-342, Poland
⁶Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
⁷Università degli Studi di Milano and INFN, Sez. di Milano, I-Milano I20133, Italy
⁸Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA
⁹UNIRIB, Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA

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Vol. 82, Iss. 6 — December 2010

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Figure 1
The $γ$ spectrum for ${}^{81}{Zn}$ decay observed in this work. The two upper panels show the spectrum in coincidence with $β$ decays. The lower panel corresponds to the singles $γ$ spectrum in add-back mode, for increased photo-peak efficiency at high energy. The transitions assigned to the decay of ${}^{81}{Zn}$ are marked by numbers, with the single escape peak (SE) and double escape peak (DE) marked where appropriate. The black triangles indicate decays of ${}^{81}{Ga}$ . The stars indicate transitions from background contamination. The open triangles mark transitions in ${}^{80}{Ge}$ . The 4880-keV single escape area contains 40(10)% of intensity that may be attributed to ${}^{81}{Zn}$ or ${}^{81}{Ga}$ . This would correspond to $1.3 %$ branching ratio and because of the uncertainty it was not added to the level scheme.Reuse & Permissions
Figure 2
Level scheme of ${}^{81}{Ga}$ , populated in the $β$ decay of ${}^{81}{Zn}$ . The placement of $γ$ transitions in this level scheme are supported by both coincidence data and half-life measurements. Relative intensities of each $γ$ transition, shown above each arrow, are normalized to the 351-keV transition. Solid circles mark transitions with observed coincidences. There is weak evidence of a state at 4368 keV of $1.3 %$ branching ratio and because of the uncertainty it was not added to the level scheme. See Fig. 1 for more details.Reuse & Permissions
Figure 3
(Top) Growth and decay curve of the ${}^{81}{Zn}$ $β$ -decay 351-keV transition with the fit to the Bateman equations superimposed in red. (Bottom) Growth and decay curve of the ${}^{81}{Ga}$ $β$ -decay 216-keV transition with the fit to the Bateman equations superimposed in red. The Bateman equations were fitted to include direct implantation rate from the beam. The best fit was obtained for zero ${}^{81}{Ga}$ implantation rate, with a maximum of $5 %$ of the ${}^{81}{Zn}$ implantation rate at three standard deviations.Reuse & Permissions
Figure 4
The red triangles show the observed energies of the 1/ $2^{+}$ first excited state in $N$ $=$ $51$ isotones [5, 6, 19]. The black squares correspond to our shell-model calculation using the full $π f_{5 / 2} p_{3 / 2} p_{1 / 2} g_{9 / 2}$ and $ν d_{5 / 2} s_{1 / 2} g_{7 / 2} d_{3 / 2} h_{11 / 2}$ shells. The overall behavior of the calculation matches well the experimental trend except for ${}^{83}{Ge}$ and ${}^{85}{Se}$ , and predicts increased 1/ $2^{+}$ energy for $Z < 34$ isotones. To investigate the effect of configuration mixing in the proton valence shell we performed a shell-model calculation where the proton valence shell was truncated to the $f_{5 / 2}$ orbital. Then the shell model correctly predicts the minimum at $Z$ $=$ $32$ . The green points represent the 5/ $2^{+}$ ground state in the $N = 51$ isotones.Reuse & Permissions
Figure 5
Distribution of the core excited states in $N = 50$ isotones. The systematics for the odd-Z isotones have been obtained in $β$ -decay studies. The states populated with the largest B(GT) values are shown in black lines. The circles show the evolution of the centroid of the B(GT) distribution. The systematics for even-Z isotopes are taken from [9] and shows excitations of the $6^{+}$ states (green). The red dot is a linear extrapolation for the core excitation of ${}^{79}{Cu}$ .Reuse & Permissions

Physical Review C

covering nuclear physics

$β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell

Phys. Rev. C 82, 064314 – Published 23 December 2010; Erratum Phys. Rev. C 83, 019903 (2011)

Abstract

Erratum

Erratum: $β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell [Phys. Rev. C 82, 064314 (2010)]

Phys. Rev. C 83, 019903 (2011)

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Physical Review C

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β decay of Zn81 and migrations of states observed near the N=50 closed shell

Phys. Rev. C 82, 064314 – Published 23 December 2010; Erratum Phys. Rev. C 83, 019903 (2011)

Abstract

Erratum

Erratum: β decay of Zn81 and migrations of states observed near the N=50 closed shell [Phys. Rev. C 82, 064314 (2010)]

Phys. Rev. C 83, 019903 (2011)

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$β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell

Erratum: $β$ decay of ${}^{81}{Zn}$ and migrations of states observed near the $N = 50$ closed shell [Phys. Rev. C 82, 064314 (2010)]