Author: Rao, T.
Paper Title Page
MOPFI005 XPS and UHV-AFM Analysis of the K2CsSb Photocathodes Growth 291
  • S.G. Schubert
    HZB, Berlin, Germany
  • I. Ben-Zvi, M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  • X. Liang
    SBU, Stony Brook, New York, USA
  • H.A. Padmore, T. Vecchione
    LBNL, Berkeley, California, USA
  • T. Rao, J. Smedley
    BNL, Upton, Long Island, New York, USA
  Funding: This work is funded by the Department of Energy, under Contract No. KC0407-ALSJNT-I0013, DE-SC0005713, the Bundesministerium für Bildung und Forschung (BMBF) and the state of Berlin, Germany.
Next generation light sources, based on Energy Recovery Linac and Free Electron Laser technology will rely on photoinjector based electron sources. Successful operation of such sources requires reliable photocathodes with long operational life, uniform and high quantum efficiency, low thermal emittance and low dark current. The goal of this project is to construct a cathode which meets these requirements. Advances in photocathode research must take a combined effort. The materials have to be analyzed by means of chemical composition, surface structure and these findings have to be correlated to the quantum efficiency and performance in the injector. The presented work focuses on the chemical composition and surface structure of K2CsSb photocathodes. The XPS and AFM measurements were performed at the Center of Functional Nanomaterials at BNL. K2CsSb photocathodes were grown under UHV conditions. The components were adsorbed one at a time and after each growth step the corresponding XPS spectra was taken. During growth the quantum efficiency was recorded. As last step the sample was moved into the AFM without exposure to air to determine the surface roughness.
MOPFI080 Fabrication, Transport and Characterization of Cesium Potassium Antimonide Cathode in Electron Guns 461
  • T. Rao, S.A. Belomestnykh, I. Ben-Zvi, X. Liang, I. Pinayev, B. Sheehy, J. Skaritka, J. Smedley, E. Wang, T. Xin
    BNL, Upton, Long Island, New York, USA
  • R.R. Mammei, J.L. McCarter, M. Poelker
    JLAB, Newport News, Virginia, USA
  • M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  a number of accelerator applications need high current, low emittance and high brightness electron beams. Recent studies have shown cesium potassium antimonide to be a robust photocathode capable of producing high peak and average currents. However, for some applications, the UHV conditions required for producing these cathodes necessitate their fabrication site to be physically removed from the gun location and the cathode to be transferred between the two sites in UHV load-lock chambers. We have fabricated two cathodes at BNL, transported and tested them in DC gun at JLab at 100 kV and 200 kV. These cathodes have delivered up to 8A/cm2 without significant degradation. Localized changes in the QE have been attributed to heating due to laser, increasing the QE at lower laser power, but damaging the cathode at higher power. Two more load-lock chambers have been built to transport and insert similar cathodes in SRF guns operating at 700 MHz and 112 MHz for the first time. In this paper, we will describe the design of the load-lock chambers, transfer mechanisms, transport of the cathodes over ~ 1000 km and the cathode performance in gun environment.  
TUPFI081 Progress with Coherent Electron Cooling Proof-Of-Principle Experiment 1535
  • I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, K.A. Brown, J.C. Brutus, L. DeSanto, A. Elizarov, C. Folz, D.M. Gassner, Y. Hao, R.L. Hulsart, Y.C. Jing, D. Kayran, R.F. Lambiase, V. Litvinenko, G.J. Mahler, M. Mapes, W. Meng, R.J. Michnoff, T.A. Miller, M.G. Minty, P. Orfin, A. Pendzick, F. Randazzo, T. Rao, T. Roser, J. Sandberg, B. Sheehy, J. Skaritka, K.S. Smith, L. Snydstrup, R. Than, R.J. Todd, J.E. Tuozzolo, G. Wang, D. Weiss, M. Wilinski, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • G.I. Bell, J.R. Cary, K. Paul, B.T. Schwartz, S.D. Webb
    Tech-X, Boulder, Colorado, USA
  • C.H. Boulware, T.L. Grimm, R. Jecks, N. Miller
    Niowave, Inc., Lansing, Michigan, USA
  • M.A. Kholopov, P. Vobly
    BINP SB RAS, Novosibirsk, Russia
  • M. Poelker
    JLAB, Newport News, Virginia, USA
  We conduct proof-of-the-principle experiment of coherent electron cooling (CEC), which has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. In this paper, we present the progress with experimental equipment including the first tests of the electron gun and the magnetic measurements of the wiggler prototype. We describe current design status as well as near future plans.