Radioactivity of Potassium

Abstract

KLEMPEKER¹ has recently shown that postulation of the existence of a radioactive isotope, ₁₉K⁴⁰, with a large nuclear spin, affords the most likely explanation of the radioactivity of potassium. He appears, however, to have over-estimated the value of the nuclear spin (i = 4 or 5 units) necessary to obtain a sufficiently high half-value period for the isotope. Klemperer made use of a statement due to Gamow², which was based on theoretical reasoning. The latter author reached the conclusion that, if two radio-active elements possess the same upper velocity limit in their -ray spectra, and if one of them suffers unit change in nuclear spin during decay while the other preserves its spin unchanged, then the ratio of their half-value periods is about 100.