ABSTRACT Using the stochastic transport theory formalism developed by Muñoz-Cobo for a radioactive source and for a spallation source, we derive an expression for the Cross Power Spectral Density (CPSD) for a subcritical system driven by an external pulsed neutron source. The derivation of this expression has been done in a rigorous and general way including the energy and spatial dependency. The CPSD shows some peaks at the source frequency together with its harmonics. The final expression containing some approximations (fundamental mode analysis; Dirac delta pulses for the source) is compared with calculations using a Monte Carlo code. In the future, comparisons with measurements in the MUSE project are planned
