Author: Benson, S.V.
Paper Title Page
MOCOZBS01
The Use of ERLs to Cool High Energy Ions in Electron-Ion Colliders  
 
  • S.V. Benson, A. Seryi, C. Tennant, Y. Zhang
    JLab, Newport News, Virginia, USA
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  • F.J. Willeke
    BNL, Upton, New York, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Future electron-ion colliders collide high-intensity ion beams with high current electron beams. The electron beams take advantage of synchrotron radiation to damp emittances but the ion beams must be cooled via a beam cooling mechanism, including electron cooling. The ion energies are typically a few hundreds of GeV per nucleon, for an electron-ion collider envisioned to be built in US. At this energy, DC coolers powered by electrostatic accelerators, are not useful. The ERL, in principle, can provide the high current and brightness to cool these high-brightness ion beams. The beam quality requirements are much different from previous ERLs designs used for FELs. The cooling bunch must be much longer than in an FEL and the relative energy spread must be very small. Incoherent cooling can be enhanced with magnetized beams, but the magnetization must be maintained throughout the ERL. An alternate cooling mechanism, the so-called Coherent Electron Cooling, is, in principle, stronger and can be done with non-magnetized beams. We will present several applications of ERLs to high energy electron cooling and describe the technical challenges that must be overcome to build such an ERL.
 
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TUCOWBS01
Longitudinal Phase Space Dynamics in ERLs  
 
  • S.V. Benson, C. Tennant
    JLab, Newport News, Virginia, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • P.E. Evtushenko
    HZDR, Dresden, Germany
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Both the dynamics and the architecture of an energy recovery linac are primarily determined by the longitudinal match. This match can be manipulated by both the magnetic lattice and the RF systems. Here we will present a few examples of systems and the longitudinal solutions found for each. The first application is a free-electron laser application where a short bunch and high peak current are required. The laser increases the energy spread and lowers the energy and this must be compensated in the ERL design. The second application is for an internal target experiment where the need was for small energy spread rather than a short bunch. The third example is for an electron cooler where the bunch must be very long with extremely small energy spread. The beam disruption due to cooling is small but CSR and microbunching effects are a real challenge. In the FEL, the longitudinal matching is mainly accomplished via lattice matching while in the cooler application the RF system is the dominant method to control the phase space. The internal target can be addressed either way.
 
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THCOZBS03
Magnetized Beam Generated from DC Gun for JLEIC Electron Cooler  
 
  • S.V. Benson, P.A. Adderley, J.F. Benesch, D.B. Bullard, J.M. Grames, J. Guo, F.E. Hannon, J. Hansknecht, C. Hernandez-Garcia, R. Kazimi, G.A. Krafft, M.A. Mamun, M. Poelker, R. Suleiman, M.G. Tiefenback, Y.W. Wang, S. Zhang
    JLab, Newport News, Virginia, USA
  • J.R. Delayen
    ODU, Norfolk, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Bunched-beam electron cooling is a key feature of all proposed designs of the future electron-ion collider, and a requirement for achieving the specified collision luminosity of the order 1034 cm-2s−1. For the Jefferson Lab Electron Ion Collider (JLEIC), fast cooling of ion beams will be accomplished via so-called ’magnetized electron cooling’, where the cooling process will occur inside a long solenoid field, which will be part of the collider ring and facilitated using a circulator ring and Energy Recovery Linac (ERL). In this contribution, we describe recent achievements that include the generation of picosecond-bunch magnetized beams at average currents up to 28 mA with exceptionally long photocathode lifetime, and independent demonstrations of magnetized beam with high bunch charge up to 700 pC at 10s of kHz repetition rates using a compact 300 kV DC high voltage photogun with an inverted insulator geometry and alkali-antimonide photocathodes. Magnetization characterization including beam rotation and drift emittance were also presented for various gun bias voltages and laser spot sizes at the photocathode using 532 nm lasers with DC and RF time structure. These accomplishments mark important steps toward demonstrating the feasibility of a technically challenging JLEIC cooler design using magnetized beams.
 
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