  We study theoretically the current-noise energy dependence for a N-N'-S
structure, where N and S stand for bulk normal metal and superconductor,
respectively, and N' for a short diffusive normal metal. Using quasiclassical
theory of current fluctuations we obtain explicit expressions for the noise
valid for arbitrary distributions of channel transparencies on both junctions.
The differential Fano factor turns out to depend on both junction
transparencies and the ratio of the two conductances. We conclude that
measurement of differential conductance and noise can be used to probe the
channel distribution of the interfaces.
