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Pagani, C.

Paper Title Page
WEPPH048 XPS Studies of Cs2Te Photocathodes 457
 
  • H. A. Duerr, R. Ovsyannikov, M. Sperling, A. Vollmer
    BESSY GmbH, Berlin
  • J. H. Han, S. Schreiber, S. Lederer
    DESY, Hamburg
  • P. Michelato, L. Monaco, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  • F. Stephan
    DESY Zeuthen, Zeuthen
 
  Cesium Telluride (Cs2Te) photocathodes are used as sources for electron beams because of their high quantum efficiency (QE) and their ability to release high peak current electron bunches in a high gradient RF-gun. Starting from a high QE level of about 10% the quantum efficiency of these cathodes decreases during operation in a photo-injector to below 0.5%. To understand this behaviour, XPS investigations on the chemical composition were performed at BESSY. In this contribution we compare two fresh cathodes from INFN with one used under normal operation at FLASH and one used at PITZ at a higher than usual RF-gradient of 60 MV/m.