Radiative depolarization of high-energy electron beams in wakefield accelerators

TL;DR

This paper investigates how radiative effects, specifically spin-flips during betatron oscillations, impact the polarization preservation of high-energy electron beams in wakefield accelerators using advanced simulations.

Contribution

It introduces a simulation approach combining particle-in-cell and Monte-Carlo methods to analyze radiative spin-flips at high energies in wakefield accelerators.

Findings

Radiative effects significantly influence beam polarization at high energies.

Alignment of the witness beam with the wakefield affects radiative depolarization.

Monte-Carlo simulations reveal the importance of radiative spin-flips during betatron oscillations.

Abstract

The preservation of witness beam polarization in wakefield accelerators will be crucial for future collider applications. While extensive theoretical studies on the injection and initial acceleration of polarized electrons exist, a study concerning higher-energy regimes has been neglected thus far. Besides the spin precession usually considered in wakefield-related research, radiative effects could become increasingly relevant at higher energies as the witness electrons perform betatron oscillations during which they will emit photons. In the present study, we use particle-in-cell simulations extended with Monte-Carlo routines to study the influence of radiative spin-flips on beam polarization. We find that at high energies, the importance of radiative effects on beam polarization mainly comes down to the alignment of the witness beam with respect to the wakefield.