IOTA Experiment for Proton Pulse Compression at Extreme Space-Charge

TL;DR

This paper proposes an experiment at Fermilab's IOTA ring to study proton bunch compression under extreme space-charge conditions, aiming to improve future proton-driven muon collider performance.

Contribution

It introduces a novel experimental setup and simulation approach to optimize proton bunch compression in high space-charge regimes at IOTA.

Findings

Bunch length can be halved without degrading transverse quality.

Simulations show effective compression is possible despite space-charge effects.

Longitudinal defocusing remains a key challenge in the process.

Abstract

The longitudinal compression of high-intensity, space-charge-dominated proton bunches is a critical requirement for future proton-driven muon colliders. We propose a proton bunch compression experiment at the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab to investigate optimal radio-frequency (RF) cavity parameters and lattice configurations. IOTA is a compact, fixed-energy storage ring dedicated to beam physics Research and Development and capable of circulating a 2.5 MeV proton beam under extreme space-charge conditions. Using the ImpactX code with its 3D space-charge solver, simulations indicate that the bunch length can be rapidly reduced by at least a factor of two without appreciable degradation of transverse beam quality--even in the strong space-charge regime. However, longitudinal defocusing due to the space-charge remains a significant challenge in short-pulsed intense proton bunches, and the optimization of compression under these conditions is discussed.