Recent Improvements in the Beam Capture at Fermilab Booster for High Intensity Operation

TL;DR

This paper discusses recent enhancements in Fermilab Booster's beam capture process, focusing on RF phase measurements, corrections, and improved high-intensity beam capture performance to support current and future operations.

Contribution

It introduces updated RF phase measurement techniques, identifies phase deviations, and demonstrates improved beam capture efficiency at high intensities.

Findings

Significant phase deviations between cavities were observed.

Corrective measures improved high-intensity beam capture.

Enhanced RF control supports PIP-II era operations.

Abstract

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.