Author: Kazimi, R.
Paper Title Page
MOPOTK012 Concept of a Polarized Positron Source for CEBAF 457
SUSPMF058   use link to see paper's listing under its alternate paper code  
 
  • S.H. Habet, R.M. Bodenstein, S.A. Bogacz, J.M. Grames, A.S. Hofler, R. Kazimi, F. Lin, M. Poelker, Y. Roblin, A. Seryi, R. Suleiman, A.V. Sy, D.L. Turner
    JLab, Newport News, Virginia, USA
  • A. Ushakov
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • C.A. Valerio-Lizárraga
    ECFM-UAS, Culiacan, Sinaloa, Mexico
  • E.J-M. Voutier
    LPSC, Grenoble Cedex, France
  
  Funding: Laboratoire de Physique des 2 Infinis Irène Joliot-Curie Université Paris-Saclay -> Eric Voutier : eric.voutier@ijclab.in2p3.fr.
Positron beams would provide new and meaningful probes for the experimental program at the Thomas Jefferson National Accelerator Facility (JLab), including but not limited to future hadronic physics and dark matter experiments. Critical requirements involve generating positron beams with a high degree of spin polarization, sufficient intensity and a continuous-wave (CW) bunch train compatible with acceleration to 12 GeV at the Continuous Electron Beam Accelerator Facility (CEBAF). To address these requirements, a polarized positron injector based upon the bremsstrahlung of an intense CW spin polarized electron beam is considered*. First a polarized electron beam line provides >1 mA of polarized electrons at ~120 MeV to a high-power target for positron production. Next, a second beam line collects, shapes and aligns the spin of positrons for users. Finally, the positron beam is matched into the CEBAF acceptance for acceleration and transport to the end stations with energies up to 12 GeV. An optimized layout to provide positrons beams with intensity >100 nA (polarized) or intensity >3 µA (unpolarized) will be discussed in this poster.
* D. Abbott et al., "Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies", Phys. Rev. Lett., 116, 214801 (2016) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK012  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 06 July 2022
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MOPOTK052 CEBAF Injector Model for KL Beam Conditions 580
 
  • S. Pokharel, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • M.W. Bruker, J.M. Grames, A.S. Hofler, R. Kazimi, G.A. Krafft, S. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
The Jefferson Lab KL experiment will run at the Continuous Electron Beam Accelerator Facility with a much lower bunch repetition rate (7.80 or 15.59 MHz) than nominally used (249.5 or 499 MHz). While the proposed average current of 2.5 - 5.0 muA is relatively low compared to the maximum CEBAF current of approximately 180 muA, the corresponding bunch charge is atypically high for CEBAF injector operation. In this work, we investigated the evolution and transmission of low-rep-rate, high-bunch-charge (0.32 to 0.64 pC) beams through the CEBAF injector. Using the commercial software General Particle Tracer, we have simulated and analyzed the beam characteristics for both values of bunch charge. We performed these simulations with the existing injector using a 130 kV gun voltage. We have calculated and measured the transmission as a function of the photocathode laser spot size and pulse length. We report on the findings of these simulations and optimum parameters for operating the experiment. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK052  
About • Received ※ 07 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 26 June 2022  
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