The ${}^{138}\mathrm{Te}$ and ${}^{140}\mathrm{Xe}$ nuclei have been reinvestigated using prompt $\gamma$-ray data from spontaneous fission of ${}^{248}\mathrm{Cm}$, collected with the EUROGAM2 Ge array. $\gamma$ bands have been identified in both nuclei. The $\gamma$ band observed in ${}^{138}\mathrm{Te}$, a nucleus with only six valence nucleons, indicates the presence of collectivity very close to the doubly magic ${}^{132}\mathrm{Sn}$ core. Such band is even more pronounced in ${}^{140}\mathrm{Xe}$, the $N$ = 86 isotone of ${}^{138}\mathrm{Te}$. The newly observed bands are interpreted within the shell model, which reproduce well the $\gamma$ collectivity at $N$ = 86.

• Received 7 December 2015

DOI:https://doi.org/10.1103/PhysRevC.93.034326