Revised level structure of ${}^{120}\mathrm{Te}$

The level scheme of the nucleus ${}^{120}\mathrm{Te}$, populated in the reaction ${}^{80}\mathrm{Se}({}^{48}\mathrm{Ca},\alpha 4n)$, was reinvestigated using $\gamma$-ray coincidence data measured with the Gammasphere spectrometer. Previously, five high-spin rotational bands were discovered in this nucleus. The present reinvestigation revealed that the decay of band $b1$ is more complex than suggested in the earlier work and that it cannot be uniquely determined. Furthermore, a number of new transitions are added to the level scheme. The implications for the spin assignments and excitation energies of the five bands and for comparisons with cranked Nilsson-Strutinsky calculations are discussed.

Figure 1

Summed triple-gated $\gamma$-ray coincidence spectra of bands $b1$ and $b3$. (a) and (b): Spectrum of band $b1$ generated with a double gate from the list of $b1$ transitions from 1471 to 2209 keV and a single gate from the list of the 184-, 648-, and 693-keV transitions. (c) Spectrum of band $b3$ generated with a double gate from the list of $b3$ transitions, except for 1305 keV, together with a single gate on the list with transitions of 560, 601, 425, 1039, 325, 693, and 483 keV. The hash mark points to the 1305-keV transition which exists also in band $b1$.

Figure 2

Summed triple-gated $\gamma$-ray coincidence spectra demonstrating revisions in the level scheme in the medium-spin range. (a) Spectrum produced by gating on one $\gamma$ ray from the list of 648-, 693-, and 184-keV transitions and on the 1397- and 505-keV lines. The asterisks point to the missing 483- and 950-keV transitions. (b) Spectrum created with gates on the 482-, 1598-, and 663-keV transitions. The asterisks mark the absence of the 746- and 852-keV $\gamma$ rays. (c) Spectrum created with a gate on the 505-, 472- and 1732-keV $\gamma$ rays. The asterisks point to the missing 663-, 746-, and 872-keV transitions. (d) Spectrum produced with a gate on the 950-, 505-, and 1541-keV lines. The asterisks indicate the positions of the missing transitions with energies of 746, 852, and 872 keV.

Figure 3

Level scheme of ${}^{120}\mathrm{Te}$ based on previous work [1] and on the present results.

Figure 4

Energies, relative to a rotating liquid-drop reference, as a function of spin for excited states in ${}^{120}\mathrm{Te}$. For bands $b1$–$b5$, energies and spins are estimates.

Figure 5

(a) Calculated energies relative to a rotating liquid-drop reference for low-energy configurations. (b) Differences between the observed and calculated energies.