2019 Impact factor 2.176
Hadrons and Nuclei
Eur. Phys. J. A 3, 197-199

Short note

Rotational bands in $^{\bf 181}$Ta

T.R. Saitoh1 - N. Hashimoto1,2 - G. Sletten1 - R.A. Bark1 - S. Törmänen1 - M. Bergström1 - K. Furuno2 - K. Furutaka3 - G.B. Hagemann1 - T. Hayakawa3 - T. Komatsubara2 - A. Maj4 - S. Mitarai5 - M. Oshima3 - J. Sampson6 - T. Shizuma2 - P.G. Varmette1

1 The Niels Bohr Institute, University of Copenhagen, Roskilde, Denmark
2 Department of Physics and Tandem Accelerator Center, University of Tsukuba, Ibaraki, Japan
3 The Japan Atomic Energy Research Institute, Tokai, Ibaraki, Japan
4 Henryk Niewodniczanski Inst. of Nucl. Phys., Krakow, Poland
5 Department of Physics, Kyushu University, Fukuoka, Japan
6 Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK

Received: 26 August 1998 Communicated by B. Herskind

Abstract
High-spin states in 181Ta have been studied via the 176Yb(11B,$\alpha $2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with $\alpha $-particle detection. The previously known, $K^{\pi }=\frac{7}{2}^+$ ground state band and $K^{\pi }=\frac{9}{2}^-$ band have been extended to spins $\frac{29}{2}^+$ and $\frac{31}{2}^-$, respectively. Two new one-quasiparticle bands, the $K^{\pi }=\frac{5}{2}^+$ band built on the known $\frac{5}{2}^+$isomer and a $K^{\pi }=(\frac{1}{2}^-)$ band have been observed. Two other rotational bands with three-quasiparticle structure, $K^{\pi
}=\frac{15}{2}^-$ and $(\frac{19}{2}^+)$ with $\pi \frac{7}{2}[404]\nu ^2
\frac{1}{2}[510]\frac{9}{2}[624]$ and $\pi \frac{9}{2}[514]\nu ^2
\frac{1}{2}[510]\frac{9}{2}[624]$ configurations, respectively, have been newly observed. The half-life of the $K^{\pi }=(\frac{19}{2}^+)$ bandhead which decays to the head of the $\frac{15}{2}^-$ band has been measured to be 140(36) ns. However, transitions from the $(\frac{19}{2}^+)$ state to the $\frac{15}{2}^-$ band have not been observed.

PACS
21.10.Re Collective levels - 21.10.Tg Lifetimes - 23.20.En Angular distribution and correlation measurements - 23.20.Lv Gamma transitions and level energies - 27.70.+q $150 \le A \le 189$


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