  The Fermilab Booster uses multi-turn beam injection with all its cavities
phased such that beam sees a net zero RF voltage even when each station is at
the same maxi-mum voltage. During beam capture the RF voltage is increased
slowly by using its paraphase system. At the end of the capture the feedback is
turned on for beam acceleration. It is vital for present operations as well as
during the PIP-II era that both the HLRF and LLRF systems provide the proper
intended phase and RF voltage to preserve the longitudinal emittance from
injection to extraction. In this paper, we describe the original architecture
of the cavity phase distribution, our recent beam-based RF phase measurements,
observed significant deviation in the relative phases between cavities and
correction effort. Results from the improved capture for high intensity beam
are also presented.
