A Mass-Spectrographic Study of the Isotopes of Argon, Potassium, Rubidium, Zinc and Cadmium

Abstract

A mass spectrograph is described with which a study of the isotopic constitution of argon, potassium, rubidium, zinc and cadmium has been made. A calculation is carried out which indicates that the radioactivity of potassium and rubidium can best be explained by assuming that it is ${\mathrm{K}}^{40}$ in the case of potassium and ${\mathrm{Rb}}^{87}$ in the case of rubidium which is undergoing decay.