Author: Kuriki, M.
Paper Title Page
MOPC014 RF Processing of L-band RF Gun for KEK-STF 92
 
  • M. Kuriki, H. Iijima, Y.M. Masumoto
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Hayano, H. Sugiyama, J. Urakawa, K. Watanabe
    KEK, Ibaraki, Japan
  • G. Isoyama, R. Kato
    ISIR, Osaka, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • Y. Takahashi
    Sokendai, Ibaraki, Japan
 
  Funding: This work is supported by MEXT Quantum Beam Technology Program, KEK Promotion of collaborative research programs in universitie.
KEK STF (Superconducting Test Facility) is established for developing super-conducting accelerator technology for ILC (International Linear Collider). At KEK-STF, accelerator operation with a beam loading is planned in 2013. An electron injector based on L-band Photo-cathode RF gun is now being developed. A L-band RF gun designed by DESY and fabricated by FNAL has been placed in KEK-STF and RF processing was carried out. The results of the RF processing and status of STF injector will be presented.
 
 
THPC116 Surface Analysis of a Degraded NEA-GaAs Photocathode by Temperature Programmed Desorption Technique 3158
 
  • H. Iijima, M. Kuriki, Y.M. Masumoto
    HU/AdSM, Higashi-Hiroshima, Japan
 
  A GaAs photocathode activated the surface to negative electron affinity (NEA) is an important device for high-average-current electron accelerators, such as a next-generation light source based on an energy recovery linac. It is well known that the quantum efficiency of the NEA-GaAs photocathode is decaying with time elapsing, even if the electron beam is not extracted. The degradation is mainly caused by adsorption of residual gases in a vacuum chamber. Previously a few investigators reported that the quantum efficiency of the photocathode was rapidly degraded by water or carbon dioxide vapor. In order to analyze such surface states, we have measured desorption of gases from the degraded NEA-GaAs photocathode by using of temperature programmed desorption (TPD) technique with a quadrupole mass spectrometer. The desorption peaks of hydrogen, carbon oxide and carbon dioxide from the degraded NEA surface were observed, while that of water was not observed.  
 
THPC117 Analysis Quantum Efficiency Spectrum of NEA-GaAs Photocathode 3161
 
  • Y.M. Masumoto, H. Iijima, M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
 
  ERL is a future project of synchrotron light source with high brightness and partial coherence. ERL is based on super conducting linear accelerator providing the high brightness electron beam to insertion devices continuously. One of the most difficult technical challenge is the electron source for ERL. A photo-cathode DC biased gun is assumed, but several issues should be solved. One of the issue is the operational lifetime of cathode material, NEA GaAs. NEA stands for Negative electron affinity made by artificial treatment on clean GaAs surface. Emission from the cathode is decreased in time and extracted beam current. In order to research the phenomena, the surface potential is studied by measuring the QE (Quantum Efficiency) spectrum. Observing temporal evolution of QE, we found that the photon energy threshold did not change during the decay. The spectrum shape was changed suggesting that the surface potential barrier becomes thicker.