Speaker
Description
Capturing the high-intensity proton beams in the HL-LHC era will be challenging for the RF system. The increase of the bunch intensity to $2.3 \times 10^{11}$ protons per bunch will require significantly more RF power for beam-loading compensation. At the same time, a higher RF voltage must be provided to capture and retain the beam at the injection plateau. Together, these two factors will push the peak RF power beyond the limit of the present klystrons. Capture of equidistant bunches from the injectors currently relies on forcing a constant RF voltage in amplitude and phase, for which only the half-detuning compensation scheme is applicable. This detuning leaves the beam-induced voltage only partially compensated. However, by modulating the RF phase along the turn, one can fully counteract the detuning caused by beam loading. We propose a novel technique that applies RF phase modulation at the bunch-to-bucket transfer to reduce the RF power during the injection process by up to a factor of two. We present simulations combining longitudinal beam dynamics and detailed time-domain models of the SPS and LHC RF feedback systems. Results from first beam tests in the LHC will also be shown.
| Abstract Classification | Control Loop Modeling, Tuning and Optimization |
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