Beam Induced Electron Cloud Resonances in Dipole Magnetic Fields

TL;DR

This paper investigates how electron cloud resonances, specifically multipacting and cyclotron resonances, can develop in dipole magnetic fields within accelerators, affecting performance, supported by measurements, models, and simulations.

Contribution

It provides the first direct measurements and analysis of electron cloud resonances in dipole magnetic fields using advanced diagnostics, models, and simulations.

Findings

Identification of multipacting and cyclotron resonances in dipole fields.

Correlation of measurements with analytical models and simulations.

Insights into electron cloud buildup mechanisms in accelerators.

Abstract

The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring (CESR). These measurements are supported by both analytical models and computer simulations.