Effect of Compton Scattering on the Electron Beam Dynamics at the ATF Damping Ring

TL;DR

This paper investigates how Compton scattering affects electron beam dynamics at the ATF damping ring, focusing on energy spread and bunch length, using a Monte Carlo simulation to analyze potential observable effects.

Contribution

It introduces a Monte Carlo-based 2D tracking simulation to study Compton scattering effects on electron beam dynamics at ATF, a novel approach for this context.

Findings

Compton scattering influences energy spread and bunch length.

Simulation results show measurable effects on beam parameters.

Proposed methods for experimental observation of these effects.

Abstract

Compton scattering provides one of the most promising scheme to obtain polarized positrons for the next generation of $e^-$ -- $e^+$ colliders. Moreover it is an attractive method to produce monochromatic high energy polarized gammas for nuclear applications and X-rays for compact light sources. In this framework a four-mirror Fabry-P\'erot cavity has been installed at the Accelerator Test Facility (ATF - KEK, Tsukuba, Japan) and is used to produce an intense flux of polarized gamma rays by Compton scattering \cite{ipac-mightylaser}. For electrons at the ATF energy (1.28 GeV) Compton scattering may result in a shorter lifetime due to the limited bucket acceptance. We have implemented the effect of Compton scattering on a 2D tracking code with a Monte-Carlo method. This code has been used to study the longitudinal dynamics of the electron beam at the ATF damping ring, in particular the evolution of the energy spread and the bunch length under Compton scattering. The results obtained are presented and discussed. Possible methods to observe the effect of Compton scattering on the ATF beam are proposed.