# Wedge Absorbers In Final Cooling For A High-Energy High Luminosity Lepton Collider

## TL;DR

This paper explores the use of wedge absorbers in ionization cooling for muon colliders, demonstrating how they can effectively reduce transverse emittance while increasing longitudinal emittance, supported by simulation results.

## Contribution

It introduces a novel application of diamond wedge absorbers for final cooling in high-energy muon colliders, with simulation validation.

## Key findings

- Wedge absorbers can reduce transverse emittance to ~25 microns.
- Simulation confirms ionization cooling effectiveness with wedge absorbers.
- Longitudinal emittance increases by a factor of ~25 during cooling.

## Abstract

A high-energy muon collider scenario requires a final cooling system that reduces transverse emittance to ~25 microns (normalized) while allowing longitudinal emittance increase. Ionization cooling using high-field solenoids (or Li Lens) can reduce transverse emittances to ~100 microns in readily achievable configurations, confirmed by simulation. Passing these muon beams at ~100 MeV/c through cm-sized diamond wedges can reduce transverse emittances to ~25 microns, while increasing longitudinal emittances by a factor of ~25. Implementation will require optical matching of the exiting beam into downstream acceleration systems.

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Source: https://tomesphere.com/paper/1704.07889