Pulse-to-pulse Orbit Jitter Propagation in Multi-bunch Operation at the KEK Accelerator Test Facility 2 (ATF2)

TL;DR

This paper presents simulation studies on pulse-to-pulse orbit jitter propagation in the ATF2 at KEK, analyzing how vertical jitter affects beam stability at the interaction point and evaluating feedback correction methods.

Contribution

It introduces a simulation framework for vertical jitter propagation in multi-bunch operation at ATF2, including the impact of intra-train feedback correction.

Findings

Jitter propagation can be effectively modeled through the extraction line and final focus system.

Intra-train feedback correction improves orbit stability at the interaction point.

Simulations show potential to achieve the required stabilization for future linear colliders.

Abstract

Pulse-to-pulse orbit jitter, if not controlled, can drastically degrade the luminosity in future linear colliders. The second goal of the ATF2 project at the KEK accelerator test facility is to stabilise the vertical beam position down to approximately 5% of the nominal rms vertical beam size at the virtual Interaction Point (IP). This will require control of the orbit to better than 1 micrometre at the entrance of the ATF2 final focus system. In this report simulation studies are presented for vertical jitter propagation through the ATF2 extraction line and final focus system, and the jitter is evaluated at the IP. For these studies pulse-to-pulse vertical jitter measurements using three stripline beam position monitors are used as initial inputs. These studies are performed for the case of a bunch-train with three bunches, but could easily be extended for a larger number of bunches. The cases with and without intra-train orbit feedback correction in the extraction line of ATF2 are compared.