Author: Zhang, S.
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THPMK108 Production of Magnetized Electron Beam from a DC High Voltage Photogun 4567
 
  • M.A. Mamun, P.A. Adderley, J. F. Benesch, D.B. Bullard, J.R. Delayen, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M. Poelker, R. Suleiman, M.G. Tiefenback, Y.W. Wang, S. Zhang
    JLab, Newport News, Virginia, USA
  • S.A.K. Wijethunga
    ODU, Norfolk, Virginia, USA
 
  Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177
Bunched-beam electron cooling is a key feature of all proposed designs of the future electron-ion collider, and a requirement for achieving the highest promised collision luminosity. At the Jefferson Lab Electron Ion Collider (JLEIC), fast cooling of ion beams will be accomplished via so-called 'magnetized cooling' implemented using a recirculator ring that employs an energy recovery linac. In this contribution, we describe the production of magnetized electron beam using a compact 300 kV DC high voltage photogun with an inverted insulator geometry, and using alkali-antimonide photocathodes. Beam magnetization was assessed using a modest diagnostic beamline that includes YAG view screens used to measure the rotation of the electron beamlet passing through a narrow upstream aperture. Magnetization results are presented for different gun bias voltages and for different laser spot sizes at the photocathode, using 532 nm lasers with DC and RF time structure. Photocathode lifetime was measured at currents up to 4.5 mA, with and without beam magnetization.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK108  
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THPMK110 300 kV DC High Voltage Photogun with Inverted Insulator Geometry and CsK2sb Photocathode 4571
SUSPF028   use link to see paper's listing under its alternate paper code  
 
  • Y.W. Wang, P.A. Adderley, J. F. Benesch, D.B. Bullard, J.M. Grames, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, G.A. Krafft, M.A. Mamun, G.G. Palacios Serrano, M. Poelker, R. Suleiman, M.G. Tiefenback, S. Zhang
    JLab, Newport News, Virginia, USA
  • G.A. Krafft, S.A.K. Wijethunga
    ODU, Norfolk, Virginia, USA
 
  Funding: This work is supported by the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC05-06OR23177
A compact DC high voltage photogun with inverted-insulator geometry was designed, built and operated reliably at 300 kV bias voltage using alkali-antimonide photocathodes. This presentation describes key electrostatic design features of the photogun with accompanying emittance measurements obtained across the entire photocathode surface that speak to field non-uniformity within the cathode/anode gap. A summary of initial photocathode lifetime measurements at beam currents up to 4.5 mA is also presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK110  
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THPMK111 Negative Electron Affinity Gallium Arsenide Photocathodes Based on Optically Resonant Nanostructure 4575
 
  • S. Zhang, M. Poelker, M.L. Stutzman
    JLab, Newport News, Virginia, USA
  • X. Peng, J. Zou
    East China University of Science and Technology, Shanghai, People's Republic of China
 
  Funding: DOE
We report the design and fabrication of a new type of negative electron affinity (NEA) gallium arsenide (GaAs) photocathode with optically resonant nanostructures. We observed a significant enhancement of the quantum effi-ciency (QE) from the GaAs photocathode with nanowire arrays (NWA) due to the Mie resonance effect within the intended wavelength range. Theoretical calculations of the expected reflectance behaviour together with experi-mental results of optical and photoemission characteris-tics are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK111  
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