Cavity beam position monitor system for the Accelerator Test Facility 2

TL;DR

This paper presents a high-resolution cavity beam position monitor system for ATF2, achieving nanometer-scale precision with C-band cavities and millimeter-scale with S-band, enhancing beam diagnostics for collider research.

Contribution

Introduction of a high-resolution cavity BPM system for ATF2, detailing cavity design, electronics, and digital processing, with significant improvements in measurement resolution.

Findings

C-band cavity BPM achieved 27 nm resolution without attenuation.

S-band cavity BPM achieved 1 mm resolution with attenuation.

The system enhances beam position measurement accuracy for collider applications.

Abstract

The Accelerator Test Facility 2 (ATF2) is a scaled demonstrator system for final focus beam lines of linear high energy colliders. This paper describes the high resolution cavity beam position monitor (BPM) system, which is a part of the ATF2 diagnostics. Two types of cavity BPMs are used, C-band operating at 6.423 GHz, and S-band at 2.888 GHz with an increased beam aperture. The cavities, electronics, and digital processing are described. The resolution of the C-band system with attenuators was determined to be approximately 250 nm and 1 m for the S-band system. Without attenuation the best recorded C-band cavity resolution was 27 nm.