A carbon jet beam profile monitor for LEAR

CERN´s Low Energy Antiproton Ring (LEAR) is now equipped with a non-destructive beam profile monitor. A pulsed carbon jet of 0.8 ms is used to minimize the disruption of the low-energy beam. The jet is produced by a laser beam impinging on a solid carbon target. The atomic jet is collimated to form a thin curtain, which traverses the coasting antiproton beam. The electrons produced by the ionization of the jet are accelerated by electrodes before they hit a phosphorous screen. The image of the profile is acquired by a charge coupled device (CCD) camera and digitized for display on a workstation. The authors describe the techniques used, from generation of the carbon jet, to the analysis of the digitized image. Preliminary results and future improvements are discussed.<>