Estimating the mass variance in neutron multiplicity counting - A comparison of approaches

Year
2016
Author(s)
A. Favalli - Los Alamos National Laboratory
C. Dubi - Nuclear Research Center of the Negev, Physics Department
Stephen Croft - Oak Ridge National Laboratory
A. Ocherasvili - Nuclear Research Center of the Negev
B. Pedersen - Nuclear Security Unit, JRC
Abstract
In standard practice of Neutron Multiplicity Counting (NMC), the first three fac- torial moments of the event triggered neutron count distribution are sampled. Then they are used to quantify the three main neutron source terms: the spontaneous fissile material, the (a, n) source and the induced fission source. In the study, we compare between three different methods to quantify the statistical uncertainty of the estimated mass: the Bootstrap method, propagation of variance through moments method and statistical analysis of cycle data method. Each of the three methods was implemented on a set of four different NMC measurements, held at the JRC- laboratory in Ispra, Italy, sampling four different Pu samples in a standard PSMC well counter.