  $^{209}$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)%.

Nuclear Experiment