Author: Meot, F.     [Méot, F.]
Paper Title Page
MOPAF03 Polarization Lifetime in an Electron Storage Ring, an Ergodic Approach in eRHIC EIC 140
 
  • F. Méot
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Electron polarization in a storage ring is subject to two very long term effects: Sokolov-Ternov polarization and depolarization by diffusion. This leads to an equilibrium state over a very long time scale, and, simulation-wise, is highly CPU-time and -memory consuming. Simulations aimed at determining optimal ring storage energy in an electron-ion collider in this context, are always based on tracking bunches with thousands of particles, and in addition for short time scales in comparison, due to HPC limitations. Based on considerations of ergodicity of electron bunch dynamics in the presence of synchrotron radiation, and on the very slow depolarization aimed at in a collider, tracking a single particle instead is investigated, here. This saves a factor of more than 2 orders of magnitudes in the parameter CPU-time*Memory-allocation, it allows much longer tracking and thus improved accuracy on the evaluation of polarization and time constants. The concept is illustrated with polarization lifetime and equilibrium polarization simulations at the eRHIC electron-ion collider.
 
slides icon Slides MOPAF03 [1.758 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-MOPAF03  
About • paper received ※ 23 October 2018       paper accepted ※ 27 January 2019       issue date ※ 26 January 2019  
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TUPAF04
Zgoubi: Recent Developments and Future Plans  
 
  • D.T. Abell
    RadiaSoft LLC, Boulder, Colorado, USA
  • I.B. Beekman
    ParaTools, Inc., Eugene, Oregon, USA
  • F. Méot
    BNL, Upton, Long Island, New York, USA
  • D.W.I. Rouson
    Sourcery Institute, Oakland, California, USA
 
  Funding: This work was supported in part by the US Department of Energy, Office of Science, Office of Nuclear Physics under Award No. DE-SC0017181.
The particle tracking code Zgoubi [*] has been used for a broad array of accelerator design studies, including FFAGs and EICs [**]. Zgoubi is currently being used to evaluate proposed designs for both JLEIC and eRHIC [***], and to prepare for commissioning the CBETA BNL-Cornell FFAG return loop ERL [****]. Moreover, Zgoubi is now the subject of a Phase II SBIR aimed at improving its speed, flexibility, and ease-of-use. In this paper, we describe our on-going work on several fronts: (i) parallelizing Zgoubi using new features of Fortran 2018, including coarrays [*****]; (ii) implementing a new particle update algorithm that requires significantly less memory and arithmetic; and (iii) developing symplectic tracking for field maps. In addition, we describe plans for a web-based graphical interface to Zgoubi.
*F Meot, FERMILAB-TM-2010
**F Lemuet, NIM-A, 547:638; F Lin, IPAC17:WEPIK114
***A Kondratenko, IPAC18:MOPML007; F Meot, IPAC18:MOPMF013
****G Hoffstaetter, IPAC18:TUYGBE2
*****J Reid, WG5 N2145
 
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TUPAF08 A Full Field-Map Modeling of Cornell-BNL CBETA 4-Pass Energy Recovery Linac 186
 
  • F. Méot, S.J. Brooks, D. Trbojevic, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • J.A. Crittenden
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Cornell-BNL Electron Test Accelerator (CBETA) is a four-pass, 150 MeV energy recovery linac (ERL), now in construction at Cornell. A single fixed-field alternating gradient (FFAG) beam line recirculates the four energies, 42, 78, 114 and 150 MeV. The return loop is comprised of 107 quadrupole-doublet cells, built using Halbach permanent magnet technology. Spreader and combiner sections (4 independent beam lines each) connect the 36 MeV linac to the FFAG loop. We present here a start-to-end simulation of the 4-pass ERL, entirely, and exclusively, based on the use of magnetic field maps to model the magnets and correctors. There are paramount reasons for that and this is discussed, detailed outcomes are presented, together with comparisons with regular beam transport (mapping based) techniques.
 
slides icon Slides TUPAF08 [2.568 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF08  
About • paper received ※ 23 October 2018       paper accepted ※ 07 December 2018       issue date ※ 26 January 2019  
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TUPAF09 Multi Pass Energy Recovery Linac Design With a Single Fixed Field Magnet Return Line 191
 
  • D. Trbojevic, J.S. Berg, S.J. Brooks, F. Méot, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • W. Lou
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  We present a new approach of the Energy Recovery Linac Design for the future projects: PERLE (Powerful Energy Recovery Linac for Experiments), LHeC/FCCeH and eR- HIC. The concept uses superconducting linacs and a single xed eld beam line with multiple energy passes of electron beams. This represents an update to the existing CBETA (Cornell University Brookhaven National Laboratory ERL Test Accelerator) where the superconducting linac uses a single xed eld magnet beam line with four energy passes during acceleration and four passes during the energy recov- ery. To match the single xed eld beam line to the linac the CBETA uses the spreaders and combiners on both sides of the linac, while the new concept eliminates them. The arc cells from the single xed eld beam line are connected to the linac with adiabatic transition arcs wher cells increase in length. The orbits of di erent energies merge into a sin- gle orbit through the interleaved linac within the straight sections as in the CBETA project. The betatron functions from the arcs are matched to the linac. The time of ight of di erent electron energies is corrected for the central orbits by additional correction magnet controlled induced beam oscillations.  
slides icon Slides TUPAF09 [3.935 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF09  
About • paper received ※ 22 October 2018       paper accepted ※ 27 January 2019       issue date ※ 26 January 2019  
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TUPAF13 Calculation of the AGS Optics Based on 3D Fields Derived From Experimentally Measured Fields on Median Plane 209
 
  • N. Tsoupas, J.S. Berg, S.J. Brooks, F. Méot, V. Ptitsyn, D. Trbojevic
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by the US Department of Energy
Closed orbit calculations of the AGS synchrotron were performed and the beam parameters at the extraction point of the AGS [1] were calculated using the RAYTRACE computer code [2] which was modified to generate 3D fields from the experimentally measured field maps on the median plane of the AGS combined function magnets. The algorithm which generates 3D fields from field maps on a plane is described in reference [3] which discusses the details of the mathematical foundation of this approach. In this presentation we will discuss results from studies [1,4] that are based on the 3D fields generated from the known field components on a rectangular grid of a plane. A brief overview of the algorithm used will be given, and two methods of calculating the required field derivatives on the plane will be presented. The calculated 3D fields of a modified Halbach magnet [5] of inner radius of 4.4 cm will be calculated using the two different methods of calculating the field derivatives on the plane and the calculated fields will be compared against the ’ideal’ fields as calculated by the OPERA computer code [6]. [1] N. Tsoupas et. al. ’Closed orbit calculations at AGS and Extraction Beam Parameters at H13 AD/RHIC/RD-75 Oct. 1994 [2] S.B. Kowalski and H.A. Enge ’The Ion-Optical Program Raytrace’ NIM A258 (1987) 407 [3] K. Makino, M. Berz, C. Johnstone, Int. Journal of Modern Physics A 26 (2011) 1807-1821 [4] N. Tsoupas et. al. ’Effects of Dipole Magnet Inhomogeneity on the Beam Ellipsoid’ NIM A258 (1987) 421-425 [5] ’The CBETA project: arXiv.org > physics > arXiv:1706.04245’’ [6] Vector Fields Inc. https://operafea.com/
 
slides icon Slides TUPAF13 [1.772 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF13  
About • paper received ※ 20 October 2018       paper accepted ※ 07 December 2018       issue date ※ 26 January 2019  
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