Momentum spread reduction at beam extraction from the fermilab Booster at slipstacking injection to the Main Injector

In order to reduce the momentum spread of the beam at extraction from the booster to the main injector with slip stacking injection, the bunch rotation at the end of the cycle is applied. However, the fast RF voltage reduction often causes beam loading issues to booster RF cavities, and the reliability of extracted beam becomes a problem. An alternative solution is investigated - modulating the RF voltage with twice of the synchrotron frequency introduces bunch length oscillation, and the beam is extracted at the time when the bunch length reaches maximum and the momentum spread becomes minimal.