A stochastic transport theory of neutron and photon coupled fields: neutron and photon counting statistics in nuclear assemblies

The behavior of neutrons and gamma rays in a nuclear reactor or con®guration of ®ssile material can be represented as a stochastic process. The observation of this stochastic process is usually achieved by measuring the ¯uctuations of the neutron and gamma ray population on the system. The general theory of the stochastic neutron ®eld has been developed to a high degree. However, the theory of the stochastic nature of the gamma rays and neutrons couples the two processes. The generalized probability balances are developed from which the ®rst and higher moments of the neutron and gamma rays ®elds are obtained. The paper also provides a descrip- tion of the probability generating functions for both photon and neutron detectors that are the foundations for measurements of the ¯uctuations. The formalism developed in this paper for the representation of the statistical descriptors of the neutron-photon coupled ®eld is applicable for many neutron noise analysis measurements