Counting statistic experiment

Abstract Radioactive decay has a statistical nature, which implies that the radioactive decay law can be deduced from statistical considerations alone. More precisely, the number of disintegrations for a given interval of time builds up towards a Poisson distribution. However, it can sometimes be difficult to distinguish between Poisson and Gaussian distributions, especially when the mean values are large. On the other hand, it is well known that a Poisson distribution for the number of events occurring during a certain time implies an Erlang distribution for the number of time intervals between two given events. We thus present an experimental method that allows measuring this time interval distribution, and we show that this result follows with a huge precision (up to 10 orders of magnitude) an Erlang distribution. In particular, this experimental method is addressed to Master physics students to evidence the Poisson behaviour of nuclear processes as radiation emissions.