Level lifetimes and the structure of ${}^{134}\mathrm{Xe}$ from inelastic neutron scattering

The level structure of ${}^{134}\mathrm{Xe}$ was studied with the inelastic neutron scattering reaction followed by $\gamma$-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a $0^{+}$ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The $3^{-}$ octupole phonon has been confirmed, and the complete negative-parity multiplet resulting from the $\nu \left(1h_{11/2}2d_{3/2}\right)$ configuration has also been tentatively identified for the first time in the $N=80$ isotones.

Figure 1

Portion of the excitation function spectra for incident neutron energies of 1.6, 1.7, and 1.8 MeV showing the 766.7 keV $\gamma$ ray from the 1613.8 keV $2_2^{+}$ state and the 789.1 keV $\gamma$ from the 1636.2 keV $0_2^{+}$ state. The $\gamma$-ray excitation functions are shown as insets.

Figure 2

$\gamma$-ray angular distributions measured at $E_n=2.7$ MeV for (a) the 351.0 keV $5_1^{-}\to 4_1^{+}$ transition from the 2082.2 keV state, (b) the 789.1 keV $0_2^{+}\to 2_1^{+}$ transition from the 1636.2 keV state, and (c) the 1072.7 keV $4_2^{+}\to 2_1^{+}$ transition from the 1919.8 keV state. The experimental data are shown as points with error bars and Legendre polynomial fits to the data are shown as solid lines.

Figure 3

Doppler-shift attenuation data for the determination of the lifetime of the 1947.2 keV level from the 1100.1 keV $\gamma$ ray.

Figure 4

Transitions and $B\left(E2\right)\mathrm{s}$ in W.u. relevant to a potential vibrational description of ${}^{134}\mathrm{Xe}$. The values for the $2_1^{+}\to 0_1^{+}$ and $4_1^{+}\to 2_1^{+}$ transitions are taken from Ref. [6].

Figure 5

Systematics of the $N=80$ isotones in the vicinity of ${}^{134}\mathrm{Xe}$ [9, 10, 27].