Higher moments of the distribution of detector counts in a subcritical reactor

Neutron noise methods are well established and known techniques for the experimental analysis and surveillance of nuclear reactors. One of these methods, the variance to mean ratio or α-Feynman, is based on the measurement of the histogram of the number of counts of a detector in a subcritical reactor driven by a external neutron source. The method uses the first and second moments of the distribution of counts. As a further step in the full characterization of the distribution we compute, in addition, third and fourth moments showing the limitations of approximated counts distributions.