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Moller, W.-D.

Paper Title Page
TUPMS085 Photoemission Tests of a Pb/Nb Superconducting Photoinjector 1365
 
  • J. Smedley, T. Rao
    BNL, Upton, Long Island, New York
  • J. Iversen, D. Klinke, D. Kostin, W.-D. Moller, A. Muhs, J. S. Sekutowicz
    DESY, Hamburg
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • R. S. Lefferts, A. R. Lipski
    SBUNSL, Stony Brook, New York
  
  Funding: This work has been partially supported by the EU Commission, contract no. 011935 EUROFEL-DS5, US DOE under contract number DE-AC02-98CH10886.

We report recent progress in the development of a hybrid lead/niobium superconducting (SC) injector. The goal of this effort is to produce an all-SC injector with the SCRF properties of a niobium cavity along with the superior quantum efficiency (QE) of a lead photocathode. Two prototype hybrid injectors have been constructed, one utilizing a cavity with a removable cathode plug, and a second consisting of an all-niobium cavity arc-deposited with lead in the cathode region. We present the results of QE measurements on these cavities, along with tests of the effect of the laser on the cavity RF performance.

 
WEPMN111 3.9 GHz Superconducting Accelerating 9-cell Cavity Vertical Test Results 2295
 
  • T. N. Khabiboulline, C. A. Cooper, N. Dhanaraj, H. Edwards, M. Foley, E. R. Harms, D. V. Mitchell, A. M. Rowe, N. Solyak
    Fermilab, Batavia, Illinois
  • W.-D. Moller
    DESY, Hamburg
  
  The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve beam performances of the FLASH (TTF/DESY) facility. In the frame of collaboration Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first results of vertical tests of 9-cell Nb cavities didn?t reached the designed accelerating gradient. The main problem is multipactoring in HOM couplers, which leads to quenching and overheating of the HOM couplers. New HOM couplers with improved design integarated to next 9-cell cavities. In this paper we present all results of vertical tests.  
WEPMS013 High Power Tests of First Input Couplers for Cornell ERL Injector Cavities 2355
 
  • V. Veshcherevich, S. A. Belomestnykh, P. Quigley, J. J. Reilly, J. Sears
    CLASSE, Ithaca
  • W.-D. Moller
    DESY, Hamburg
  
  Funding: Work is supported by the National Science Foundation grant PHY 0131508

First RF power couplers for the ERL injector, currently under construction at Cornell University, have been fabricated. The couplers were assembled in pairs in the liquid nitrogen cryostat, built for their tests. A 15 kW CW IOT transmitter was available for coupler tests. A resonant ring was used for additional increase of the power. The couplers were successfully tested up to the goal power level of 50 kW CW. However, the first pair of couplers showed excessive temperature rise in some points. Therefore, minor changes in the design have been done to improve cooling.

 
TUPMN021 Status of Nb-Pb Superconducting RF-Gun Cavities 962
 
  • J. S. Sekutowicz, J. Iversen, D. Klinke, D. Kostin, W.-D. Moller, A. Muhs
    DESY, Hamburg
  • M. Ferrario
    INFN/LNF, Frascati (Roma)
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • K. Ko, Z. Li, L. Xiao
    SLAC, Menlo Park, California
  • R. S. Lefferts, A. R. Lipski
    SBUNSL, Stony Brook, New York
  • T. Rao, J. Smedley
    BNL, Upton, Long Island, New York
  • P. Strzyzewski
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  
  We report on the progress in the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead. Measured values of quantum efficiency for lead at 2K and the RF-performance of three half-cell niobium cavities with the lead spot exposed to high electric fields are reported in this contribution.