The Radioactivity of Potassium

Abstract

The radioactivity of K was measured with a Geiger counter by placing a thick layer of the salt under a thin Al window. The results agree with those of Mühlhoff and give for the radioactive constants when corrected for the relative abundance of ${\mathrm{K}}^{40}$ the following values: $\lambda =(1.56\mathrm{}\pm 0.6)\times {10}^{-17\mathrm{}}$ ${\sec .\mathrm{}}^{-1\mathrm{}}$, and $T=(14.2\mathrm{}\pm 3.0)\times {10}^{+8\mathrm{}}$ yr.