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

Paper VT-TuP11
Measurement of the Photon Stimulated Desorption for the Aluminum Chambers with Ti-Zr-V NEG-coating

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Vacuum Technology Poster Session
Presenter: G.Y. Hsiung, NSRRC, Taiwan
Authors: G.Y. Hsiung, NSRRC, Taiwan
C.Y. Yang, NSRRC, Taiwan
C.M. Cheng, NSRRC, Taiwan
C.L. Chen, NSRRC, Taiwan
C.K. Chan, NSRRC, Taiwan
J.R. Chen, NSRRC and NTHU, Taiwan
Correspondent: Click to Email
Several NEG-coated aluminum chambers have been considered for the injection section of the 1.5 GeV Taiwan Light Source (TLS) for improving the effective pumping speed. The performances of the NEG chambers including the pumping capabilities, the outgassing behaviors, the electron yield, the dusts, the reliabilities after activations and the long term photon exposures by synchrotron radiation, etc. will be inspected prior to the installation. The tests for the NEG chambers are performed at the 19B1 white light beam line of TLS, 2.14 keV of the critical photon energy, for the photon exposure experiments. A residual gas analyzer has been installed for measuring the outgassing rate and the yield of the photon stimulated desorption (PSD) for the chambers coated with the NEG film of Ti-Zr-V at 0.5 ~ 1 micron in thickness. Activations of the NEG film at both 180 °C for 24 hours and 200 °C for 2 hours have been made for the test. The behaviors of the outgas including the hydrogen, methane, krypton, and carbon monoxide, desorbed during the activations and PSD exposures are interesting throughout the experiments. The measured yields of PSD are lower than 1.0E-4 molecules/photon and reduced to 100 times lower after the exposure with > 100 Ah of the accumulated beam dose. The residual gases are mostly the hydrogen rather than methane or others. More measurements on the desorption of methane and krypton, the photoelectron yield, the dust, for the Al NEG-chambers are inspected and the results will be discussed.