AVS 46th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuP

Paper VT-TuP9
A Vacuum Gauge System with a Self-compensator for Photoelectrons Produced in the SPring-8 Storage Ring

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H. Saeki, Japan Synchrotron Radiation Research Institute, Japan
Authors: H. Saeki, Japan Synchrotron Radiation Research Institute, Japan
T. Momose, Miyagi National College of Technology, Japan
H. Yonehara, Japan Synchrotron Radiation Research Institute, Japan
Correspondent: Click to Email
Some of the Bayard-Alpert gauges mounted on crotch chambers in the SPring-8 storage ring have indicated negative pressures at stored electron beam currents more than 5 mA. Simple measurements determined that negative and lower pressure indications of the vacuum gauges were caused by an influx of photoelectrons to the collectors. Therefore, to measure pressure more accurately in such a hot-vacuum environment, we proposed a vacuum gauge system with a self-compensator for photoelectrons from the environment. The gauge has a correcting electrode which only detects photoelectron current from the environment and obtains the actual pressure by compensating the current detected in the primary collector of the gauge. The estimated actual pressure of the gauge system with a self-compensator is adequate, compared with the apparent pressure detected with Extractor gauges. To make sure of the estimation, the new gauge system will be evaluated with an experimental vacuum chamber which makes such a hot-vacuum environment using an electron gun.