Iso-Adiabatic Merging of PBAR Stacks in the Fermilab Recycler

Considerable longitudinal emittance (LE) dilution is seen during merging of two stacks of pbars in the Fermilab Recycler. The emittance dilution results from the sequence of RF manipulations used for merging. Here I present a new scheme for merging two stacks adiabatically. This involves energy matching of the two stacks before merging. An analytical expression is derived for energy matching condition. The scheme is illustrated with multi-particle beam dynamics simulations and beam measurements. The beam experiments have shown that one can preserve the emittance to better than 15%.