A Quantitative Analysis of the Feynman- and Rossi-Alpha Formulas with Multiple Emission Sources

Recently, analytical formulas have been derived for the Feynman- and Rossi-Alpha measurements in accelerator-driven systems. In such systems, due to the multiplicity of the sources, the Feynman- and Rossi-Alpha formulas contain additional terms as compared with the traditional cases. A numerical evaluation of these formulas for systems with such sources is given. An assessment of the contribution of the terms that are novel as compared to the traditional formula is made. These include the terms arising from the source multiplicity, and the prompt-delayed and delayed-delayed correlations. Further, the consequences of averaging the delayed-neutron families are analyzed. Finally, a comparison is made, assuming traditional core material and one possible type of future accelerator-driven system.