Simulations of merging and squeezing bunches in booster and AGS
During the 2012 RHIC run, uranium, gold, and copper ions from EBIS were accelerated in Booster and AGS and delivered to RHIC for the physics program. In order to achieve the desired number of ions per bunch in RHIC, it was necessary to merge bunches in both Booster and AGS. After the bunches are merged in AGS, they need to be squeezed into harmonic 12 buckets for subsequent acceleration. In this note we carry out simulations of bunch merging and squeezing in Booster and AGS. These are meant to
... These are meant to serve as benchmarks for what can be achieved in practice. In Booster the total longitudinal emittance of the 4 bunches to be merged is taken to be 0.15 eV s per nucleon. In AGS the total for each group of 4 bunches to be merged is taken to be 0.60 eV s per nucleon. The simulations show that the RF voltages currently available in Booster and AGS are sufficient for merging and holding the merged bunches in RF buckets. The voltages available in AGS are not sufficient for completely squeezing the merged bunches into harmonic 12 buckets. The merging of bunches is treated in sections 9 through 12. The required squeezing into harmonic 12 buckets is treated in sections 13 and 14. Debunching and rebunching beam as an alternative to merging bunches in Booster is treated in section 15. For completeness, sections 1 through 8 give a derivation of the turn-by-turn equations of longitudinal motion at constant magnetic field. The derivation is based on the work of MacLachlan . The reader may wish to skip over these sections and start with section 9.