First measurement of the partial widths of $^{209}$Bi decay to the ground and to the first excited states

TL;DR

This paper reports the first direct measurement of the alpha decay partial widths of bismuth-209 to its ground and first excited states using a BGO scintillating bolometer, providing new precise decay data.

Contribution

It presents the first observation and measurement of $^{209}$Bi alpha decay to both ground and excited states with precise half-life and branching ratio values.

Findings

Half-life of $^{209}$Bi decay is (2.01±0.08)×10^{19} years.

Branching ratio to ground state is (98.8±0.3)%.

Abstract

$^{209}$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)%.