Author: Wang, E.
Paper Title Page
MOPMA033 Modeling Electron Emission and Surface Effects from Diamond Cathodes 620
 
  • D.A. Dimitrov, J.R. Cary, D.N. Smithe, C.D. Zhou
    Tech-X, Boulder, Colorado, USA
  • I. Ben-Zvi, T. Rao, J. Smedley, E. Wang
    BNL, Upton, Long Island, New York, USA
  
  Funding: We are grateful to the U.S. DoE Office of Basic Energy Sciences for supporting this work under grants DE-SC0006246 and DE-SC0007577.
We developed modeling capabilities, within the Vorpal particle-in-cell code, for three-dimensional (3D) simulations of surface effects and electron emission from semiconductor photocathodes. They include calculation of emission probabilities using general, piece-wise continuous, space-time dependent surface potentials, effective mass and band bending field effects. We applied these models, in combination with previously implemented capabilities for modeling charge generation and transport in diamond, to investigate the emission dependence on applied electric field in the range from approximately 2 to 17 MV/m along the [100] direction. The simulation results were compared to experimental data when using different emission models, band bending effects, and surface-dependent electron affinity. Simulations using surface patches with different levels of hydrogenation lead to the closest agreement with the experimental data. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA033  
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TUPMA047 Multipacting-free Quarter-wavelength Choke Joint Design for BNL SRF 1935
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, C.J. Liaw, G.T. McIntyre, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  
  The BNL SRF gun cavity was operated well at CW mode up to 2 MV. However, the performance suffered due to multipacting in the quarter-wavelength choke-joint. A new multipacting-free cathode stalk was designed and will be conditioned. This paper will describes RF and thermal design of new cathode stalk and conditioning results.
This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA047  
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TUPMA049 First Beam Commissioning at BNL ERL SRF Gun 1941
 
  • W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, S. Deonarine, D.M. Gassner, H. Hahn, L.R. Hammons, T. Hayes, J.P. Jamilkowski, P. K. Kankiya, D. Kayran, N. Laloudakis, R.F. Lambiase, V. Litvinenko, L. Masi, G.T. McIntyre, K. Mernick, T.A. Miller, G. Narayan, D. Phillips, V. Ptitsyn, T. Rao, T. Seda, F. Severino, B. Sheehy, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, J.E. Tuozzolo, E. Wang, D. Weiss, M. Wilinski, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, V. Ptitsyn
    Stony Brook University, Stony Brook, USA
  
  Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz superconducting RF gun successfully generated the first photoemission beam on Nov. 17 2014. This paper will report the latest results of SRF beam commissioning, including the SRF cavity performance, cathode QE measurements, and beam parameter measurements. The beam commissioning setup is described in the paper as well. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA049  
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WEPJE023 Cathode Performance during Two Beam Operation of the High Current High Polarization Electron Gun for eRHIC 2720
 
  • O.H. Rahman
    Stony Brook University, Stony Brook, USA
  • M.A. Ackeret, J.R. Pietz
    Transfer Engineering and Manufacturing, Inc, Fremont, California, USA
  • I. Ben-Zvi, C. Degen, D.M. Gassner, R.F. Lambiase, A.I. Pikin, T. Rao, B. Sheehy, J. Skaritka, E. Wang
    BNL, Upton, Long Island, New York, USA
  • E. Dobrin, R.C. Miller, K.A. Thompson, C. Yeckel
    Stangenes Industries, Palo Alto, California, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Two electron beams from two activated bulk GaAs photocathodes were successfully combined during the recent beam test of the High Current High Polarization Electron gun for eRHIC. The beam test took place at Stangenes Industries in Palo Alto, CA, where the cathodes were placed in radially opposite locations inside the high voltage shroud. No significant cross talking between the cathodes were found for the pertinent vacuum and low average current operation, which is very promising towards combining multiple beams for higher average current. This paper describes the cathode preparation, transport and cathode performance in the gun for the combining test, including the QE and lifetimes of the photocathodes at various steps of the experiment. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE023  
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WEPJE033 The Progress of Funnelling Gun High Voltage Condition and Beam Test 2735
 
  • E. Wang, I. Ben-Zvi, D.M. Gassner, R.F. Lambiase, W. Meng, A.I. Pikin, T. Rao, B. Sheehy, J. Skaritka
    BNL, Upton, Long Island, New York, USA
  • M.A. Ackeret, J.R. Pietz
    Transfer Engineering and Manufacturing, Inc, Fremont, California, USA
  • E. Dobrin, R.C. Miller, K.A. Thompson, C. Yeckel
    Stangenes Industries, Palo Alto, California, USA
  • O.H. Rahman
    Stony Brook University, Stony Brook, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A prototype of a high average current polarized electron funneling gun as an eRHIC injector has been built at BNL. The gun was assembled and tested at Stangenes Incorporated. Two beams were generated from GaAs photocathodes and combined by a switched combiner field. We observed the combined beams on a YAG crystal and measured the photocurrent by a Faraday cup. The gun has been shipped to Stony Brook University and is being tested there. In this paper we will describe the major components of the gun and recent beam test results. High voltage conditioning is discussed as well. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE033  
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WEPWI049 Commissioning of the 112 MHz SRF Gun and 500 MHz Bunching Cavities for the CeC PoP Linac 3597
 
  • S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, V. Litvinenko, G. Narayan, P. Orfin, I. Pinayev, T. Rao, J. Skaritka, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, Q. Wu, B. P. Xiao, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, T. Xin
    Stony Brook University, Stony Brook, USA
  • P.A. McIntosh, A.J. Moss, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
The Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment at BNL includes a short electron linac. During Phase I a 112 MHz superconducting RF photoemission gun and two 500 MHz normal conducting bunching cavities were installed and commissioned. The paper describes the Phase I linac layout and presents commissioning results for the cavities and associated RF, cryogenic and other sub-systems. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI049  
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