Half-Life ofMn53

The half-life of ${\mathrm{Mn}}^{53}$ has been calculated from the measured ${\mathrm{Mn}}^{53}$ activity in a manganese sample extracted from a fragment of the Canyon Diablo iron meteorite and from the manganese sample's measured isotopic ratio ${\mathrm{Mn}}^{53}$/${\mathrm{Mn}}^{55}$. The half-life of ${\mathrm{Mn}}^{53}$ determined in this work, 10.8±4.5 million years ($3\sigma$ error), and the measured manganese sample activity are compared with theoretically and experimentally determined ${\mathrm{Mn}}^{53}$ half-lives and ${\mathrm{Mn}}^{53}$ activities measured in other meteorites.