An Application of Probabilities to the Counting of Alpha-Particles

Abstract

The Poisson law of probability is directly applicable to radioactive emissions only in certain simple cases. In general, when a radioactive series such as the thorium series is present the probability function is complex. It can be found readily, however, if the interval of time for which probabilities are calculated is chosen so as to be either very short or very long compared with the mean life of each radioactive substance involved. The probability function for $\alpha$-particles from the thorium series is determined on the basis of an interval of five minutes and is illustrated graphically in a special case.