WEPAF —  Wednesday Parallel Fiesta Key   (24-Oct-18   09:00—10:00)
Paper Title Page
WEPAF01 A Compact Permanent Magnet Spectrometer for CILEX 320
  • M. Khojoyan, A. Cauchois, J. Prudent, A. Specka
    LLR, Palaiseau, France
  Laser Wakefield acceleration experiments make exten- sive use of small permanent magnets or magnet assemblies for analyzing and focusing electron beams produced in plasma accelerators. Besides being compact, these magnets have to have a large angular acceptance for the divergent laser and electron beams which imposes constraint of the gap size. We will present the optimized design and charac- terization of a 100 mm long, 2.1 Tesla permanent magnet dipole. Furthermore, we will present the performance of such a magnet as a spectrometer in the CILEX/APOLLON 10PW laser facility in France.  
slides icon Slides WEPAF01 [6.898 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-WEPAF01  
About • paper received ※ 15 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPAF02 Simulations of Beam Chopping for Potential Upgrades of the SNS LEBT Chopper 325
  • B. Han, S.N. Murray, T.R. Pennisi, V.V. Peplov, M.P. Stockli, R.F. Welton
    ORNL, Oak Ridge, Tennessee, USA
  • R.B. Saethre, C. Stinson
    ORNL RAD, Oak Ridge, Tennessee, USA
  Funding: This work was performed at Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract number DE-AC05-00OR22725 for the United States Department of Energy.
The LEBT chopper is a critical element of the SNS accelerator system. In this work, the benefit of increasing the chopping voltage amplitude for the present chopping pattern is shown with beam simulations, and an ongoing hardware upgrade of the chopper pulser units is discussed. In addition, with the prospect of higher voltage capability of the new pulser design, two alternative chopping patterns which reduce the switching frequency of the chopper pulsers down to 1/2 or 1/4 of the present chopping pattern, are also explored with beam simulations.
slides icon Slides WEPAF02 [7.431 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-WEPAF02  
About • paper received ※ 31 October 2018       paper accepted ※ 07 December 2018       issue date ※ 26 January 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
Magnetized Electron Cooling Simulations for JLEIC  
  • I.V. Pogorelov, D.T. Abell, D.L. Bruhwiler, J.A. Carlsson, Y.I. Eidelman, C.C. Hall, S.D. Webb
    RadiaSoft LLC, Boulder, Colorado, USA
  • J. Gerity, P.M. McIntyre
    Texas A&M University, College Station, USA
  • H. Zhang, Y. Zhang
    JLab, Newport News, Virginia, USA
  Funding: This work is supported by the U.S. DOE Office of Science, Office of Nuclear Physics, under Award Number DE-SC0015212.
Relativistic magnetized electron cooling in untested parameter regimes is essential to achieve the ion luminosity requirements of proposed electron-ion collider (EIC) designs. Therefore, accurate calculations of magnetized dynamic friction are required, with the ability to include all relevant physics that might increase the cooling time, including space charge forces, field errors and complicated phase space distributions of imperfectly magnetized electron beams. We present simulations relevant to the JLEIC design, using the BETACOOL and JSPEC codes. We also present recent work on Warp simulations of the electron beam through the solenoid field. Space charge neutralization is provided by impact ionization of a background hydrogen gas. For optimal cooling it is essential that space charge be sufficiently neutralized. We also present recent work on a new analytic treatment of momentum transfer from a single magnetized electron to a drifting ion, and its use for calculations of dynamic friction.
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
WEPAF04 Longitudinal Beam Dynamics in FRIB and ReA Linacs 330
  • A.S. Plastun, P.N. Ostroumov, A.C.C. Villari, Q. Zhao
    FRIB, East Lansing, USA
  The Front-End and first three cryomodules of the Facility for Rare Isotope Beam (FRIB) at Michigan State University (MSU) commissioned in July, 2018. The paper describes the online tuning procedures of the longitudinal beam dynamics through the FRIB linac. These procedures include tuning of the accelerating field phases and amplitudes in the cavities. We developed an automated simulation-based tuning procedure for the multi-harmonic buncher. In order to tune the radio-frequency quadrupole (RFQ) we measured and calculated its threshold voltage and scanned its longitudinal acceptance. Tuning of the rebunchers and superconducting accelerating cavities is per-formed by means of the phase scans and Time-Of-Flight (TOF) beam energy measurements with beam position and phase monitors. While FRIB is being commissioned, the re-accelerator (ReA3) for rare isotope beams (RIBs) is being upgraded. We redesigned the ReA3 RFQ to improve its cooling system and provide reliable operation with 16.1 MHz prebunched ion beams with A/Q = 5. In order to provide matching of any ReA3 beam both to the following upgrade cryomodules and physics experiments’ requirements, room temperature rebuncher/debuncher is being designed. The design procedure includes the beam dynamics, electromagnetic, thermal and mechanical simulations and optimizations.  
slides icon Slides WEPAF04 [2.406 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-WEPAF04  
About • paper received ※ 19 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)