AVS 50th International Symposium
    Vacuum Technology Wednesday Sessions
       Session VT-WeA

Paper VT-WeA8
Vacuum Analysis and Improvement for the Jefferson Lab Photo-Electron Guns

Wednesday, November 5, 2003, 4:20 pm, Room 323

Session: Outgassing and Large Vacuum Systems
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
G.R. Myneni, Thomas Jefferson National Accelerator Facility
B.M. Poelker, Thomas Jefferson National Accelerator Facility
Correspondent: Click to Email
The 100 keV photo-electron guns at Jefferson Lab have demanding vacuum requirements since the photo-cathode lifetime is decreased by residual gas ionization and photocathode ion back-bombardment. The gun vacuum in the vicinity of the cathode/anode gap is ~ 1x10@super -11@ Torr. Improved vacuum would enhance the operating lifetime of the photo-electron guns. Measurements on vacuum test stands have been undertaken to better understand the vacuum limitations of the Jefferson Lab photo-electron guns. The measurements include a comparison of vacuum chamber material outgassing rates, preliminary investigations into coatings to reduce outgassing rates, and NEG pump speed measurements under various activation conditions. The results of these studies will be presented together with recommendations for improving photo-electron gun vacuum. @FootnoteText@ This work was supported by U.S. Department of Energy Contract No. DE-AC05-84-ER40150.