 In 1950, for the first time the double beta decay half-life of was measured by geochemical methods to be 1.4 years, reasonably close to the modern value.This involved detecting the concentration in minerals of the xenon produced by the decay.In 1956, after the V-A nature of weak interactions was established, it became clear that the half-life of neutrinoless double beta decay would significantly exceed that of ordinary double beta decay.