AVS 53rd International Symposium
    Vacuum Technology Tuesday Sessions
       Session VT-TuA

Invited Paper VT-TuA1
Extreme High Vacuum (XHV): The Need, Production and Measurement

Tuesday, November 14, 2006, 2:00 pm, Room 2000

Session: Extreme High Vacuum and Vacuum Metrology
Presenter: M.L. Stutzman, Thomas Jefferson National Accelerator Facility
Authors: M.L. Stutzman, Thomas Jefferson National Accelerator Facility
P.A. Adderley, Thomas Jefferson National Accelerator Facility
M. Poelker, Thomas Jefferson National Accelerator Facility
Correspondent: Click to Email
Extreme High Vacuum is defined to be pressures below 1x10@super -10@ Pa. The technology required to achieve XHV at room temperature involves careful consideration of vacuum chamber materials and preparation, pumping, and pressure measurement. Many vacuum applications find UHV pressure (1x10@super -7@ to 1x10@super -10@ Pa) adequate for their purposes and research focuses on rapid pumpdown times or control of specific process gasses. However, for applications such as particle storage rings and high current photoelectron guns, operational lifetime is inversely proportional to the total pressure, with XHV pressures beneficial or essential for operation. Literature regarding the materials, preparation and fabrication processes required to achieve XHV, and XHV pressure measurement will be discussed. The focus will be on work performed at JLab for photoelectron gun applications including high average current RF and DC high voltage electron guns.