Author: Arnold, A.
Paper Title Page
THP047 Photoemission Studies of Niobium and Lead Photocathodes Using Picosecond UV Laser 836
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J. Teichert, H. Vennekate
    HZDR, Dresden, Germany
  • R. Barday
    HZB, Berlin, Germany
  
  Funding: We acknowledge the support of Enhanced European Coordination for Accelerator Research & Development (EuCARD2, WP12), and the support of German Federal Ministry of Education and Research grant 05K12CR1.
We pre­sent the re­sults of our in­ves­ti­ga­tions on su­per­con­duct­ing pho­to­cath­odes for su­per­cond­cut­ing rf in­jec­tors. Bulk nio­bium and lead film on nio­bium have been con­sid­ered as the best can­di­dates. The quan­tum ef­fi­ciency (QE) at room tem­per­a­ture has been mea­sured with 258 nm UV laser pulses of 14 ps du­ra­tion. A QE of 10-4 has been ob­tained for the lead film. In order to im­prove the pho­toe­mis­sion yield of nio­bium, new treat­ment meth­ods, like Cs-ac­ti­va­tion and im­plan­ta­tion with al­kali met­als, have been ap­plied and the re­sults are re­ported. 		 
 
THP061 Commissioning of an Improved Superconducting RF Photo Injector at ELBE 881
 
  • J. Teichert, A. Arnold, M. Freitag, P.N. Lu, P. Michel, P. Murcek, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • P. Kneisel
    JLab, Newport News, Virginia, USA
  • I. Will
    MBI, Berlin, Germany
  
  In order to pro­duce high-bright­ness elec­tron beams in a su­per­con­duct­ing RF photo in­jec­tor, the most im­por­tant point is to reach a high ac­cel­er­a­tion field in the cav­ity. For this rea­son two new 3.5-cell nio­bium cav­i­ties were fab­ri­cated, chem­i­cally treated and cleaned in col­lab­o­ra­tion with Jlab. The first of these two cav­i­ties was shipped to HZDR and as­sem­bled in a new cry­omod­ule. This new gun (SRF Gun II) was in­stalled in the ELBE ac­cel­er­a­tor hall in May 2014 and re­places the pre­vi­ous SRF Gun I. Be­side the new cav­ity the ELBE SRF gun II dif­fers from the pre­vi­ous gun by the in­te­gra­tion of a su­per­con­duct­ing so­le­noid. The paper pre­sents the re­sults of the first test run with a Cu pho­to­cath­ode.