A Helical Cooling Channel System for Muon Colliders

TL;DR

This paper presents a novel helical cooling channel system that enables rapid six-dimensional muon beam cooling, crucial for muon collider feasibility, through innovative magnetic and RF cavity design optimized by simulations.

Contribution

It introduces a new helical cooling channel design with optimized segments for effective 6D muon beam cooling, including hardware concepts and prototype status.

Findings

Achieved 10^5 emittance reduction in 300 m

Optimized HCC segments with smaller aperture and higher magnetic field

Demonstrated progress in RF and magnet prototype development

Abstract

Fast muon beam six dimensional (6D) phase space cooling is essential for muon colliders. The Helical Cooling Channel (HCC) uses hydrogen-pressurized RF cavities imbedded in a magnet system with solenoid, helical dipole, and helical quadrupole components that provide the continuous dispersion needed for emittance exchange and effective 6D beam cooling. A series of HCC segments, each with sequentially smaller aperture, higher magnetic field, and higher RF frequency to match the beam size as it is cooled, has been optimized by numerical simulation to achieve a factor of 105 emittance reduction in a 300 m long channel with only a 40% loss of beam. Conceptual designs of the hardware required for this HCC system and the status of the RF studies and HTS helical solenoid magnet prototypes are described.