Excited states in ${}^{180}$Hg were populated using the ${}^{147}$Sm(${}^{36}$Ar,3n)${}^{180}$Hg reaction and studied by in-beam conversion-electron spectroscopy. Conversion electrons emitted at the target position were measured using the Silicon Array for Conversion Electron Detection (SACRED) spectrometer and tagged through the characteristic $\alpha$ decays of ${}^{180}$Hg detected in a position-sensitive silicon strip detector located at the focal plane of the gas-filled recoil separator Recoil Ion Transport Unit (RITU). Electron conversion of transitions previously assigned to ${}^{180}$Hg through in-beam $\gamma$-ray spectroscopy studies was identified up to the 10${}^{+}\to 8^{+}$ transition and the intensities of the conversion-electron transitions were found to be consistent with the previous multipolarity assignments. Evidence was also found for two highly converted transitions in ${}^{180}$Hg: a 167 keV transition is interpreted as the transition from the newly identified 2${}_2^{+}$ state at 601 keV to the 2${}_1^{+}$ state at 434 keV, while a 420 keV transition is assigned as the $E0$ decay from the 0${}^{+}$ bandhead of the prolate-deformed configuration to the weakly deformed ground state.

• Received 23 June 2011

DOI:https://doi.org/10.1103/PhysRevC.84.034308