Tests for randomness of spontaneous quantum decay - art. no. 042106

Analyses of the runs (i.e., uninterrupted sequences of identical outcomes) were made of the temporal succession of decays from three nuclear processes : (1) beta decay of Cs-137, (2) electron capture decay of Mn-54, and (3) be ta decay of Bi-214 followed by alpha decay of Po-214. Sample half lives var y widely from about 30 yr (Cs-137) to 20 min (Bi-214). For each process, th e numbers of runs of length k (1 less than or equal to k less than or equal to 20) were determined from three distinct types of generating procedures: (a) runs with respect to a target value, (b) runs with respect to parity, and (c) runs with respect to sequential differences. Comparison of experime ntal results with those predicted by the theory of runs ton the assumption that every distinguishable arrangement of a temporal sequence of disintegra tions is equally likely) provides comprehensive support of the hypothesis t hat the spontaneous decay of a nucleus is a random occurrence unaffected by past history.