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Photocathode publications

Since 1992, the CLIC Test Facility (CTF) has used photocathodes (illuminated by laser) as intense sources of electrons. These cathodes are mounted in an RF gun at 3 GHz and subjected to high electric fields, greater than 100 MV/m, in order to produce a beam charge of more than 10 nC in less than 10 ps. Traditional photocathodes developed for photo-multipliers have been shown to be unsuitable for our application. After having tested several types of photocathode, metallic, semi-conductor or impregnated, we have selected cesium telluride material because of its compatibility with the specifications of the photoinjectors and, at the same time, with the technical performance of our laser installations, but it must be transferred under vacuum from the production laboratory to the RF gun.

A photocathode is characterized by:


The photoemission threshold - defines the wavelength range of the laser (IR, visible, UV) ;


The quantum efficiency ( the ratio of the emitted electrons over the incident photons) - defines the power of the laser ;


The lifetime - defines the working time and the photocathode production frequency ;


Working conditions - defines the robustness of the photocathode.

Different kind of photocathodes are used :

bullet Metallic photocathodes
bullet Alkaline photocathodes
bullet Photocathodes to produce Polarized electrons

Photocathodes are developed and produced at the Photoemission laboratory, transported under UHV to the CTF, then used in the drive beam RF gun.


Photocathodes used in the CTF2

Photocathodes foreseen for CTF3 et CLIC


Publications with contribution of the Lasers & Photocathodes section members

  1. Production of a High Average Current Electron Beam with Cs-Te Photocathodes ,
    E.Chevallay, G. Suberlucq, H.Trautner, CERN CTF3 Note 020 (tech. photocathodes), 07/09/01 Publication
  2. Polarized RF Guns for Linear Colliders, An ICFA Workshop.  
    D. Edwards editor, Fermilab April 18-20, 2001.  Publication
  3. Studies and Production of Photocathodes for High Intensity Electron Beams,
    E. Chevallay, S. Hutchins, P. Legros, G. Suberlucq, H. Trautner, CERN CLIC Note 449, proceedings of Linac 2000 : Publication  , Poster page 1Poster page 2
  4. Photocathodes pour le Drive Beam du CTF3 et du CLIC, Préparation du test "mC" dans le canon DC,
    G. Suberlucq, H. Trautner, CERN CTF3 Tech-Note 2000-03/Injector, 3 avril 2000  :   Publication
  5. Spectral Response of Cesium Telluride and Rubidium Telluride Photocathodes for the Production of Highly Charged Electron Bunches ,
    H. Trautner, CERN CLIC Note 428, (21/3/00)  (Doctoral Thesis) : Publication
  6. Photo-cathodes for the CERN CLIC Test Facility,
    E. Chevallay, J. Durand, S. Hutchins, G. Suberlucq, H. Trautner, CERN CLIC Note 373 (27/8/98) , proceedings of Linac 1998 : PublicationPoster
  7. Gallium Arsenide photocathodes used in high electric fields ,
    G. Suberlucq editor, CERN CTF Note 98-13 (6/5/98) : Publication
  8. Development and Production of Photo Cathodes for the CLIC Test Facility ,
    G. Suberlucq, proceedings of FEL  1996 : Publication , Presentation
  9. Auger and X-ray photoemission spectroscopy study on Cs2Te photocathodes ,
    A. di Bona, F. Sabary, S. Valery, P. Michelato, D, Sertore, G. Suberlucq, J. Appl. Phys, 80 (5), 1 september 1996 : Publication
  10. Développements et production de photocathodes pour le CLIC Test Facility ,
    G. Suberlucq, CERN CLIC Note 299 (15/5/1996) : Publication
  11. RF Guns and the Production of Polarized Electrons,
    K. Aulenbacher, R. Bossart, H.H. Braun, J.P. Delahaye, J.H.B. Madsen, G.Suberlucq - CERN, J. Clendenin, G. Mulhollant, J. Sheppard, H. Tang (SLAC) CERN CLIC Note 303, SLAC NLC-Note 20, (1/5/1996) : Publication
  12. Photocathodes tested in the dc gun of the CERN photoemission laboratory,
    E. Chevallay, J. Durand, S. Hutchins, G. Suberlucq, M. Wurgel, CERN CLIC Note 203 (7/6/93), NIM Section A 340 (1994) : Publication
  13. Photocathodes en iodure de césium utilisées à fort courant,
    G. Suberlucq, CERN CLIC Note 162 (5/92) : Publication
  14. Experimental Results at the CERN Photoemission Laboratory with Co-deposition Photocathodes in the frame of the CLIC Studies,
    E. Chevallay CERN CTF3 Note 104 (5/2012) : : Publication