The Branching Ratio of Potassium 40

Abstract

The branching ratio of potassium 40 has been measured by determining the argon and potassium content of potassium feldspars of accurately known ages. The results obtained for five samples differing in age by more than a factor of five are all consistent within the limits of error with a branching ratio of 0.060±0.006 when a total decay constant of 0.54×${10}^{-9\mathrm{}}$ ${\mathrm{year}}^{-1\mathrm{}}$ is assumed. The authors feel that the results obtained indicate that loss of argon from these samples during geological time is unlikely.