Measurements of Electron Cloud Growth and Mitigation in Dipole, Quadrupole, and Wiggler Magnets

TL;DR

This paper reports on measurements of electron cloud growth in various magnetic environments at CESR using RFAs, evaluating mitigation techniques like coatings, grooves, and electrodes.

Contribution

It introduces RFA designs tailored for different magnetic regions and provides the first comprehensive assessment of mitigation effectiveness in these environments.

Findings

Electron cloud growth varies with magnetic field type.

Mitigation techniques reduce electron cloud density.

RFA measurements confirm effectiveness of coatings, grooves, and electrodes.

Abstract

Retarding field analyzers (RFAs), which provide a localized measurement of the electron cloud, have been installed throughout the Cornell Electron Storage Ring (CESR), in different magnetic field environments. This paper describes the RFA designs developed for dipole, quadrupole, and wiggler field regions, and provides an overview of measurements made in each environment. The effectiveness of electron cloud mitigations, including coatings, grooves, and clearing electrodes, are assessed with the RFA measurements.