Stochastic transport theory analysis of the 252Cf noise technique

The Mihalczo 252Cf-Source-Driven Noise Analysis Technique is an experimental method for determining the reactivity of subcritical systems. The technique employs three detectors: detector 1 contains a 252Cf spontaneous fission source and responds to 252Cf fissions, and detectors 2 and 3 respond to neutron absorption reactions in their active volumes. The detector signals are used to form the ratio of power spectral densities (PSDs) r(ω) = (G12*G13)/(G11G23), where the subscripts denote detector number. To determine the reactivity, one must know how it is related to the measured r(ω). The authors outline a derivation of this relationship. The relationship obtained differs from others that have appeared in the literature. The causes of these differences are discussed