Author: Ha, G.
Paper Title Page
TUA2IO02
 DWFA Staging Results at the Argonne Wakefield Accelerator Facility (AWA)  
 
  • M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, Q. Gao, G. Ha, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.Q. Qiu, C. Whiteford, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • S.P. Antipov, C.-J. Jing, J.Q. Qiu
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • Q. Gao
    TUB, Beijing, People's Republic of China
  • G. Ha
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
We report on recent Two-Beam-Acceleration (TBA) experiments conducted at the Argonne Wakefield Accelerator Facility (AWA), which used 70 MeV electron bunches to accelerate a 0.5 nC witness bunch in gradients of up to 150 MV/m. The wakefields were generated by the passage of the 15 - 45 nC drive bunches through iris-loaded metallic structures operating at 11.7 GHz. No indication of witness beam quality degradation was observed, and bunch charge was preserved during the acceleration process. Another series of experiments was conducted using two TBA stages, demonstrating acceleration of the witness beam in these two subsequent stages by means of two independent drive bunch trains. 		 
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TUPOB16 A Simple Method for Measuring the Electron-Beam Magnetization 521
SUPO15   use link to see paper's listing under its alternate paper code  
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • G. Ha
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • J.G. Power, E.E. Wisniewski
    ANL, Argonne, Illinois, USA
  • G. Qiang
    TUB, Beijing, People's Republic of China
  
  There are a number of projects that require magnetized beams, such as electron cooling or aiding in flat beam transforms. Here we explore a simple technique to characterize the magnetization, observed through the angular momentum of magnetized beams. These beams are produced through photoemission. The generating drive laser first passes through microlens arrays (fly-eye light condensers) to form a transversely modulated pulse incident on the photocathode surface. The resulting charge distribution is then accelerated from the photocathode. We explore the evolution of the pattern via the relative shearing of the beamlets, providing information about the angular momentum. This method is illustrated through numerical simulations and preliminary measurements carried out at the Argonne Wakefield Accelerator (AWA) facility are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOB16  
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WEPOB20 Multiple Scattering Effects on a Short Pulse Electron Beam Travelling Through Thin Beryllium Foils 937
 
  • E.E. Wisniewski, S.P. Antipov, M.E. Conde, D.S. Doran, W. Gai, Q. Gao, C.-J. Jing, W. Liu, J.G. Power, C. Whiteford
    ANL, Argonne, Illinois, USA
  • S.P. Antipov, C.-J. Jing
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • Q. Gao
    TUB, Beijing, People's Republic of China
  • G. Ha
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  Funding: Argonne, a U.S.A. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.
The Argonne Wakefield Accelerator beamlines have stringent vacuum requirements (100 picotorr) necessitated by the Cesium telluride photoinjector. In direct conflict with this, the structures-based wakefield accelerator research program sometimes includes worthy but complex experimental installations with components or structures unable to meet the vacuum standards. A proposed chamber to sequester such experiments safely behind a thin beryllium (Be) window is described and the results of a study of beam-quality issues due to the multiple scattering of the beam through the window are presented and compared to GEANT4 simulations via G4beamline. Three thicknesses of Be foil were used: 30, 75 and 127 micron, probed by electron beams of three different energies: 25, 45, and 65 MeV. Multiple scattering effects were evaluated by comparing the measured transverse rms beam size for the scattered vs. unscattered beam. The experimental results are presented and compared to simulations. Results are discussed along with the implications and suggestions for the future sequestered vacuum chamber design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB20  
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THPOA46 Benchmark of RF Photoinjector and Dipole Using ASTRA, GPT, and OPAL 1194
SUPO31   use link to see paper's listing under its alternate paper code  
 
  • N.R. Neveu
    IIT, Chicago, Illinois, USA
  • A. Adelmann
    PSI, Villigen PSI, Switzerland
  • G. Ha
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • C.J. Metzger-Kraus
    HZB, Berlin, Germany
  • N.R. Neveu, J.G. Power
    ANL, Argonne, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S.J. Russell
    LANL, Los Alamos, New Mexico, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: Grant no. DE-SC0015479, and contract No. DE-AC02-06CH11357.
With the rapid improvement in computing resources and codes in recent years, accelerator facilities can now achieve and rely on accurate beam dynamics simulations. These simulations include single particle effects (e.g. particle tracking in a magnetic field) as well as collective effects such as space charge (SC), and coherent synchrotron radiation (CSR). Using portions of the Argonne Wakefield Accelerator (AWA) as the benchmark model, we simulated beam dynamics with three particle tracking codes. The AWA rf photoinjector was benchmarked, primarily to study SC, in ASTRA, GPT, and OPAL-T using a 1 nC beam. A 20° dipole magnet was used to benchmark CSR effects in GPT and OPAL-T by bending a 1nC beam at energies between 2 MeV and 100 MeV. In this paper we present the results, and discuss the similarities and differences between the codes. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA46  
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