Author: Xiang, R.
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.