The general backward theory of neutron fluctuations in subcritical systemswith multiple emission sources

The Feynman-alpha and Rossi-alpha formulae are derived analytically for sub critical systems driven by a multiple emission source, i.e. one that emits several neutrons on each source emission event. The prime example of such s ources is a spallation source, which will be used in future accelerator dri ven subcritical systems (ADS) such as the energy amplifier. Such formulae f or ADS have been derived recently but in simpler neutronic models. In this paper six groups of delayed neutron precursors are taken into account, and the full joint statistics of the prompt and all delayed groups is included. Thus the present results are generalisations of earlier ones. The involved problems that are encountered are solved with a combination of effective a nalytical techniques and symbolic algebra codes.