Author: Nichols, K.E.
Paper Title Page
TUPTS073 Analysis of Electron Beam Divergence in Diamond Field Emitter Array Cathodes 2090
 
  • D. Kim, H.L. Andrews, R.L. Fleming, C. Huang, J.W. Lewellen, K.E. Nichols, V.N. Pavlenko, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • B.K. Choi
    Cheju Halla University, Jeju-si, Republic of Korea
  
  Funding: Los Alamos National Laboratory (LANL) Laboratory Directed Research and Development (LDRD) program (Contract DE-AC52-06NA25396) and Sandia National Laboratories (Contract DE-NA-0003525).
At Los Alamos National Laboratory (LANL), we have recently established a capability to fabricate diamond array cathodes for electron beam sources. Our fabricated diamond field emitter arrays (DFEAs) are the arrays of micrometer-scale diamond pyramids with nanometer-scale sharp tips and produce high per-tip current (> 15 μA per-tip) in DC testing. For the beam divergence measurements, we designed and assembled a test stand consisting of a DFEA cathode, a mesh aperture of 0.375-inch for an anode, and AZO (ZnO:Al2O3) screen coated on a sapphire substrate for beam visualization. A negative voltage of about 40 kV is applied to the cathode, and the mesh and the screen are kept at ground. We measure a size of the electron beam on the AZO screen at different mesh to screen distances at a fixed cathode-mesh gap in order to calculate the beam divergence angles. We also perform the beam dynamics simulations with Computer Simulation Technology (CST) Studio and General Particle Tracer (GPT) using a single pyramidal shape with a nanowire tip model. In this presentation, the measured experimental results of the beam divergences will be compared to the beam dynamic simulations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS073  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPTS090 Experimental Results of Dense Array Diamond Field Emitters in RF Gun 2134
 
  • K.E. Nichols, H.L. Andrews, D. Kim, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • S.P. Antipov
    Euclid Beamlabs LLC, Bolingbrook, USA
  • G. Chen
    IIT, Chicago, Illinois, USA
  • M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.F. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  
  We present experimental emission results from arrays of diamond field emitter tips operating in an RF gun at the Argonne Cathode Test-stand. Results from various arrays will be presented with different spacing between array elements. Very high charge densities were produced at various field gradients. The maximum field gradient for a particular geometry was discovered and break-down effects will be presented. Cathode lifetime was preliminarily studied. Further experiments are being planned and work on the cathode design optimization to produce higher quality beams will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS090  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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