First measurement of the partial widths of $^{209}$Bi decay to the   ground and to the first excited states
  $^{209}$Bi alpha decay to the ground and to the first excited state have been contemporary observed for the first time with a large BGO scintillating bolometer. The half-life of $^{209}$Bi is determined to be $\tau_{1/2}$=(2.01$\pm$0.08)$\cdot10^{19}$ years while the branching ratio for the ground-state to ground-state transition is (98.8$\pm$0.3)%. 
J.W.Beeman, M.Biassoni, C.Brofferio, C.Bucci, S.Capelli, L.Cardani,   M.Carrettoni, M.Clemenza, O.Cremonesi, E.Ferri, A.Giac...
nucl-ex