title: DAΦNE operation with electron-cloud-clearing electrodes.
abstract: The effects of an electron cloud (e-cloud) on beam dynamics are one of the major factors limiting performances of high intensity positron, proton, and ion storage rings. In the electron-positron collider DAΦNE, namely, a horizontal beam instability due to the electron-cloud effect has been identified as one of the main limitations on the maximum stored positron beam current and as a source of beam quality deterioration. During the last machine shutdown in order to mitigate such instability, special electrodes have been inserted in all dipole and wiggler magnets of the positron ring. It has been the first installation all over the world of this type since long metallic electrodes have been installed in all arcs of the collider positron ring and are currently used during the machine operation in collision. This has allowed a number of unprecedented measurements (e-cloud instabilities growth rate, transverse beam size variation, tune shifts along the bunch train) where the e-cloud contribution is clearly evidenced by turning the electrodes on and off. In this Letter we briefly describe a novel design of the electrodes, while the main focus is on experimental measurements. Here we report all results that clearly indicate the effectiveness of the electrodes for e-cloud suppression.
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Alesini
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Drago
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Gallo
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Guiducci
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Milardi
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Stella
authors.affiliation: LNF-INFN, Via E. Fermi 40, 00044 Frascati, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Zobov
authors.affiliation: Ernest Orlando Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: S
authors.initials: S
authors.lastname: De Santis
authors.affiliation: Laboratoire de l'Accélérateur Linéaire, CNRS-IN2P3, Université Paris-Sud 11, 91898 Orsay, France.
authors.forename: T
authors.initials: T
authors.lastname: Demma
authors.affiliation: European Synchrotron Radiation Facility (ESRF), BP 220, 38043 Grenoble Cedex 9, France.
authors.forename: P
authors.initials: P
authors.lastname: Raimondi