Beam-cavity interactions in the rapid cycling synchrotron chain of the future muon collider

TL;DR

This paper investigates beam-cavity interactions in the rapid cycling synchrotrons of a future muon collider, focusing on beam loading effects and cavity voltage stability to optimize muon acceleration.

Contribution

It provides a detailed analysis of beam loading effects in the RCS chain and proposes optimal parameters to minimize cavity voltage transients for muon acceleration.

Findings

Beam loading significantly perturbs cavity voltage during acceleration.

Counter-rotating beam interactions influence cavity voltage stability.

Optimal parameters can reduce voltage transients and improve acceleration efficiency.

Abstract

The International Muon Collider Collaboration (IMCC) is engaged in a design study for a future facility intended to collide muons. Subsequent to the initial linear acceleration, the counter-rotating muons and anti-muons are accelerated in a chain of rapid cycling synchrotrons (RCS) up to the multi-TeV collision energy. To maximise the number of muons available in the collider, it is essential to exploit the time dilation of the muon lifetime by employing a large accelerating gradient. The 1.3 GHz TESLA cavity serves as the baseline for the RCS chain. Considering the high bunch population and the small aperture of the cavity, the resulting beam-induced voltage per bunch passage is considerable, resulting in a substantial perturbation of the cavity voltage for subsequent bunch passages. In this contribution, the effects of beam loading during the acceleration cycle on the muons are calculated with the objective of determining the optimum parameters for minimising the cavity voltage transients. The interaction of the induced voltages, considering the counter-rotating beams, is studied.