title: A high-current electron gun for the electron beam ion trap at the National Superconducting Cyclotron Laboratory.
abstract: The Electron Beam Ion Trap (EBIT) in NSCL's reaccelerator ReA uses continuous ion injection and accumulation. In order to maximize capture efficiency and minimize breeding time into high charge states, the EBIT requires a high-current/high current-density electron beam. A new electron gun insert based on a concave Ba-dispenser cathode has been designed and built to increase the current transmitted through the EBIT's superconducting magnet. With the new insert, stable EBIT operating conditions with 0.8 A of electron beam have been established. The design of the electron gun is presented together with calculated and measured perveance data. In order to assess the experimental compression of the electron beam, a pinhole CCD camera has been set up to measure the electron beam radius. The camera observes X-rays emitted from highly charged ions, excited by the electron beam. Initial tests with this camera setup will be presented. They indicate that a current density of 640 A/cm(2) has been reached when the EBIT magnet was operated at 4 T.
authors.affiliation: National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: S
authors.initials: S
authors.lastname: Schwarz
authors.affiliation: National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Baumann
authors.affiliation: National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kittimanapun
authors.affiliation: National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: A
authors.initials: A
authors.lastname: Lapierre
authors.affiliation: National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, Michigan 48824, USA.
authors.forename: A
authors.initials: A
authors.lastname: Snyder