  The Proton Improvement Plan phase II (PIP-II) project currently under
construction at FNAL will replace the existing 400 MeV normal conducting linac
with a new 800 MeV superconducting linac. The beam power in the downstream
rapid-cycling Booster synchrotron will be doubled by raising the machine cycle
frequency from 15 to 20 Hz and by increasing the injected beam intensity by a
factor 1.5. This has to be accomplished without raising uncontrolled losses
beyond the administrative limit of 500 W. In addition, slip-stacking efficiency
in the Recycler, the next machine in the accelerator chain, sets an upper limit
on the longitudinal emittance of the beam delivered by the Booster. As part of
an effort to better understand potential losses and emittance blow-up in the
Booster, we have been conducting full cycle 6D simulations using the code
PyORBIT. The simulations include space charge, wall impedance effects and
transition crossing. In this paper, we discuss our experience with the code and
present representative results for possible operational scenarios.
