Author: Rice, D.H.
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]  
 
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.