R. Boscaino et al., FLUCTUATIONS IN RADIOACTIVE DECAYS .2. EXPERIMENTAL RESULTS, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 49(1), 1994, pp. 341-346
We experimentally investigate the decay statistics of a gamma source o
f Sn-119m(50). We find that, for counting periods of the order of 10 h
, the variance is higher than the Poissonian value by more than one or
der of magnitude. A careful study of the relative Allan variance and t
he measurement of the generalized Allan variance demonstrates that the
observed anomaly is not caused by 1/f noise. Rather, even if counting
periods are much shorter than the nucleus lifetime, the variance exce
ss is a consequence of the nonequilibrium nature of the decay process.
This conclusion is supported by the quantitative agreement between ou
r experimental data and the theoretical formulas derived in the preced
ing paper.