Author: Douglas, D.
Paper Title Page
MOPAB216 20-24 GeV FFA CEBAF Energy Upgrade 715
 
  • S.A. Bogacz, J.F. Benesch, R.M. Bodenstein, B.R. Gamage, G.A. Krafft, V.S. Morozov, Y. Roblin
    JLab, Newport News, Virginia, USA
  • J.S. Berg, S.J. Brooks, D. Trbojevic
    BNL, Upton, New York, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, 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
A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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TUPAB036 The Accelerator Design Progress for EIC Strong Hadron Cooling 1424
 
  • E. Wang, S. Peggs, V. Ptitsyn, F.J. Willeke, W. Xu
    BNL, Upton, New York, USA
  • S.V. Benson
    JLab, Newport News, Virginia, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • C.M. Gulliford, G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • C.E. Mayes
    Xelera Research LLC, Ithaca, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy,
The Electron-Ion Collider will achieve a luminosity of 1034 cm-2 s−1 by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB036  
About • paper received ※ 16 May 2021       paper accepted ※ 11 June 2021       issue date ※ 01 September 2021  
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MOPAB240 Estimates of Damped Equilibrium Energy Spread and Emittance in a Dual Energy Storage Ring 774
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring design consists of two loops at markedly different energies. As in a single-energy storage ring, the linear optics in the ring design may be used to determine the damped equilibrium emittance and energy spread. Because the individual radiation events in the two rings are different and independent, we can provide analytical estimates of the damping times in a dual energy storage ring. Using the damping times, the values of damped energy spread, and emittance can be determined for a range of parameters related to lattice design and rings energies. We present analytical calculations along with simulation results to estimate the values of damped energy spread and emittance in a dual energy storage ring. We note that the damping time tends to be dominated by the damping time of the high energy ring in cases where the energy of the high energy rings is significantly greater than that of the low energy ring.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB240  
About • paper received ※ 17 May 2021       paper accepted ※ 27 May 2021       issue date ※ 13 August 2021  
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TUXA07 Beam Dynamics Study in a Dual Energy Storage Ring for Ion Beam Cooling* 1290
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
 
  Funding: * Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring designed for beam cooling consists of two closed rings with significantly different energies: the cooling and damping rings. These two rings are connected by an energy recovering superconducting RF structure that provides the necessary energy difference. In our design, the RF acceleration has a main linac and harmonic cavities both running at crest that at first accelerates the beam from low energy EL to high energy EH and then decelerates the beam from EH to EL in the next pass. The purpose of the harmonic cavities is to extend the bunch length in a dual energy storage ring as such a longer bunch length may be very useful in a cooling application. Besides these cavities, a bunching cavity running on zero-crossing phase is used outside of the common beamline to provide the necessary longitudinal focusing for the system. In this paper, we present a preliminary lattice design along with the fundamental beam dynamics study in such a dual energy storage ring.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA07  
About • paper received ※ 19 May 2021       paper accepted ※ 07 June 2021       issue date ※ 28 August 2021  
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TUPAB079 Using ER@CEBAF to Show that a Multipass ERL Can Drive an XFEL 1555
 
  • G. Perez-Segurana
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • I.R. Bailey, P.H. Williams
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • I.R. Bailey
    Lancaster University, Lancaster, United Kingdom
  • R.M. Bodenstein, S.A. Bogacz, D. Douglas, Y. Roblin, T. Satogata
    JLab, Newport News, Virginia, USA
  • T. Satogata
    ODU, Norfolk, Virginia, USA
  • P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility as an option for a potential UK-XFEL. Energy Recovery enables multi-MHz FEL sources, for example, an X-ray FEL oscillator or regenerative amplifier FEL. Additionally, combining with external lasers and/or self-interaction would provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power for nuclear and particle physics applications. An opportunity exists to demonstrate the necessary point-to-parallel longitudinal matches to drive an XFEL and successfully energy recover at the upcoming 5-pass up, 5-pass down Energy Recovery experiment on CEBAF at JLab termed ER@CEBAF. We show candidate matches and simulations supporting the minimal necessary modifications to CEBAF this will require. This includes linearisation of the longitudinal phase space in the injector and a reduction in the dispersion of the arcs, both of which increase the energy acceptance of CEBAF. We expect to commence initial tests of these adaptations on CEBAF during 2021.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB079  
About • paper received ※ 17 May 2021       paper accepted ※ 27 July 2021       issue date ※ 17 August 2021  
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