title: Absolute measurement of electron-cloud density in a positively charged particle beam.
abstract: Clouds of stray electrons are ubiquitous in particle accelerators and frequently limit the performance of storage rings. Earlier measurements of electron energy distribution and flux to the walls provided only a relative electron-cloud density. We have measured electron accumulation using ions expelled by the beam. The ion energy distribution maps the depressed beam potential and gives the dynamic cloud density. Clearing electrode current reveals the static background cloud density, allowing the first absolute measurement of the time-dependent electron-cloud density during the beam pulse.
authors.affiliation: Heavy-Ion Fusion Science Virtual National Laboratory, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: Michel
authors.initials: M
authors.lastname: Kireeff Covo
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Molvik
authors.forename: Alex
authors.initials: A
authors.lastname: Friedman
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Vay
authors.forename: Peter A
authors.initials: PA
authors.lastname: Seidl
authors.forename: Grant
authors.initials: G
authors.lastname: Logan
authors.forename: David
authors.initials: D
authors.lastname: Baca
authors.forename: Jasmina L
authors.initials: JL
authors.lastname: Vujic