Lawrence Berkeley National Laboratory

The AP2 beamline transports anti-protons from the production target to the Debuncher ring. The observed aperture is smaller than that estimated from linear, on-energy optics. We have investigated possible reasons for the aperture limitation and have identified possible sources, including residual vertical dispersion from alignment errors and chromatic effects due to very large chromatic lattice functions. Some experiments have already been performed to study these effects. We present results of the experimental and theoretical studies and possible remedies.