Author: Huang, W.-H.
Paper Title Page
THPO116 Space-Charge Dominated Photoemission in High Gradient Photocathode RF Guns 941
THOP11   use link to see paper's listing under its alternate paper code  
 
  • Y. Chen, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • H. Chen, Y. C. Du, W.-H. Huang, C.-X. Tang, Q.L. Tian, L.X. Yan
    TUB, Beijing, People’s Republic of China
  • H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Dohlus
    DESY, Hamburg, Germany
  • S. A. Schmid
    Institut Theorie Elektromagnetischer Felder, TU Darmstadt, Darmstadt, Germany
  
  The cath­ode emis­sion physics plays a cru­cial role in the over­all beam dy­nam­ics in the gun. In­ter­plays be­tween in­tri­cate emis­sion mech­a­nisms in the cath­ode vicin­ity strongly in­flu­ence the cath­ode quan­tum ef­fi­ciency (QE) and the in­trin­sic emit­tance. The pres­ence of strong space-charge ef­fects in high gra­di­ent RF guns fur­ther com­pli­cates the emis­sion process. A proper mod­el­ing of pho­toe­mis­sion and a care­ful treat­ment of the space-charge con­tri­bu­tion is thus of great ne­ces­sity to un­der­stand­ing the for­ma­tion of the beam slice emit­tance. In this ar­ti­cle, emis­sion mea­sure­ments are car­ried out using the L-band ce­sium-tel­luride pho­to­cath­ode RF gun at the Photo In­jec­tor Test Fa­cil­ity at DESY in Zeuthen (PITZ) and the S-band cop­per pho­to­cath­ode RF gun at Ts­inghua Uni­ver­sity. Fol­low­ing the Dow­ell model a sim­ple so-called space-charge it­er­a­tion ap­proach is de­vel­oped and used to de­ter­mine the QE through tem­po­ral and spa­tial-de­pen­dent elec­tro­mag­netic fields. An im­pact of the space-charge cool­ing on the ther­mal emit­tance is pre­sented. Mea­sure­ment data are shown and dis­cussed in com­par­isons to pre­lim­i­nary sim­u­la­tion re­sults.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO116  
About • paper received ※ 11 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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