  We present a simulation study to characterize the stability region of the
Fermilab (FNAL) Recycler in the context of secondary emission yield (SEY).
Interactions between electrons and beam pipe material can produce electron
clouds that jeopardize beam stability in certain focusing configurations. Such
an instability was documented in the Recycler, and the work presented here
reflects improvements to better understand that finding. We incorporated the
Furman-Pivi Model into a PyECLOUD analysis, and we determined the instability
threshold given various bunch lengths, intensities, SEY magnitudes, and model
parameters.
