Author: Quigley, P.
Paper Title Page
MOOAA01 Performance of the Cornell High-Brightness, High-Power Electron Injector 20
  • B.M. Dunham, A.C. Bartnik, I.V. Bazarov, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, X. Liu, F. Löhl, P. Quigley, D.H. Rice, E.N. Smith, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
    CLASSE, Ithaca, New York, USA
  • S.S. Karkare, H. Li, J.M. Maxson
    Cornell University, Ithaca, New York, USA
  Funding: NSF DMR-0807731
The last year has seen significant progress in demonstrating the feasibility of a high current, high brightness photoinjector as required for the Energy Recovery Linac driven X-ray source at Cornell University. Both low emittances (0.4 mm-mrad rms normalized for 100% of the beam at 20 pC per bunch and 0.15 mm-mrad rms core emittance with 70% of the beam, and twice these values at 80 pC per bunch) and high average currents with a good lifetime well in excess of 1000 Coulombs at 5 MeV, 20 mA have been demonstrated. If these beams can be accelerated to 5 GeV without diluting the phase space, it would already provide a beam brightness higher than any existing storage ring. Operational experience, results, and the outlook for the future will be presented.
slides icon Slides MOOAA01 [1.424 MB]  
WEPPC072 High Current Operation of the Cornell ERL Superconducting RF Injector Cryomodule 2378
  • M. Liepe, G.H. Hoffstaetter, S. Posen, P. Quigley, V. Veshcherevich
    CLASSE, Ithaca, New York, USA
  Cornell University has developed a SCRF injector cryomodule for the acceleration of high current, low emittance beams in continuous wave operation. This cryomodule is based on superconducting RF technology, and is currently under extensive testing in the Cornell ERL injector prototype with CW beam currents exceeding 25 mA. Strong damping of Higher-Order-Modes in the cavities is essential for high beam current operation, and is achieved by beamline RF absorber located at cryogenic temperatures in the beam pipe sections between the cavities. This paper gives an overview of the experience gained during the high beam current operation of the cryomodule.  
WEPPC075 Testing of the Main-Linac Prototype Cavity in a Horizontal Test Cryomodule for the Cornell ERL 2387
  • N.R.A. Valles, F. Furuta, G.M. Ge, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, S. Posen, P. Quigley, J. Sears, M. Tigner, V. Veshcherevich
    CLASSE, Ithaca, New York, USA
  Cornell has recently finished producing and testing the first prototype 7-cell main linac cavity for the Cornell Energy Recovery Linac (ERL). The cavity construction met all necessary fabrication constraints. After a bulk BCP, 650C outgassing, final BCP, and 120C bake the cavity was vertically tested. The cavity met quality factor and gradient specifications (2·1010 at 16.2 MV/m) in the vertical test. Progressing with the ERL linac development, the cavity was installed in a horizontal test cryomodule and the quality factor versus accelerating gradient was again measured. This baseline measurement is the first test in a sequence of tests of the main linac cavity in the test cryomodule. Subsequent tests will be with increased complexity of the beam line, e.g. with HOM beamline loads installed, to study potential sources of reducing the cavity’s quality factor.  
WEPPC031 Completed Assembly of the Daresbury International ERL Cryomodule and its Implementation on ALICE 2272
  • P.A. McIntosh, M.A. Cordwell, P.A. Corlett, P. Davies, E. Frangleton, P. Goudket, K.J. Middleman, S.M. Pattalwar, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S.A. Belomestnykh
    BNL, Upton, Long Island, New York, USA
  • A. Büchner, F.G. Gabriel, P. Michel
    HZDR, Dresden, Germany
  • J.N. Corlett, D. Li, S.M. Lidia
    LBNL, Berkeley, California, USA
  • G.H. Hoffstaetter, M. Liepe, H. Padamsee, P. Quigley, J. Sears, V.D. Shemelin, V. Veshcherevich
    CLASSE, Ithaca, New York, USA
  • T.J. Jones, J. Strachan
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • R.E. Laxdal
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  • D. Proch, J.K. Sekutowicz
    DESY, Hamburg, Germany
  • T.I. Smith
    Stanford University, Stanford, California, USA
  The completion of an optimised SRF cryomodule for application on ERL accelerators has now culminated with the successful assembly of an integrated cryomodule, following an intensive 5 years of development evolution. The cryomodule, which incorporates 2 x 7-cell 1.3 GHz accelerating structures, 3 separate layers of magnetic shielding, fully adjustable & high power input couplers and fast piezo tuners, has been installed on the ALICE ERL facility at Daresbury Laboratory. It is intended that this will permit operational optimisation for maximised efficiency demonstration, through increased Qext adjustment whilst retaining both effective energy recovery and IR-FEL lasing. The collaborative design processes employed in completing this new cryomodule development are explained, along with the assembly and implementation procedures used to facilitate its successful installation on the ALICE ERL facility.  
WEPPD082 Characterization of Photocathode Damage during High Current Operation of the Cornell ERL Photoinjector 2717
  • J.M. Maxson, S.S. Karkare
    Cornell University, Ithaca, New York, USA
  • I.V. Bazarov, S.A. Belomestnykh, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, K. Finkelstein, R.P.K. Kaplan, V.O. Kostroun, Y. Li, X. Liu, F. Löhl, B. Pichler, P. Quigley, D.H. Rice, K.W. Smolenski, M. Tigner, V. Veshcherevich, Z. Zhao
    CLASSE, Ithaca, New York, USA
  The Cornell ERL Photoinjector prototype has recently demonstrated successful operation at 20 mA for 8 hours using a bi-alkali photocathode grown on a Si substrate. The photocathode film was grown off center, and remained relatively undamaged; however, upon removal from the gun, the substrate at the gun electrostatic center displayed significant visible damage. Here we will describe not only the parameters of that particular high current run, but a suite of post-operation surface morphology and crystallographic measurements, including X-ray fluorescence, X-ray diffraction, contact profilometry, scanning electron microscopy, performed about the damage site and photocathode film. The data indicate violent topological changes to the substrate surface, as well as significant induced crystallographic strain. Ion back-bombardment is proposed as a possible mechanism for damage, and a simple model for induced crystal strain is proposed (as opposed to ion induced sputtering), and is shown to have good qualitative agreement with the spatial distribution of damage.