WEM1 —  E-Cooling III   (20-Sep-17   09:00—11:00)
Chair: A. Wolf, MPI-K, Heidelberg, Germany
Paper Title Page
WEM11
 Status of Bunched Beam Electron Cooler LEReC  
 
  • A.V. Fedotov
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy.
The Low Energy RHIC electron Cooler (LEReC) system is presently under construction and commissioning at BNL. Although required energies of electron beam (few MeV) are not very high, an approach based on RF acceleration of electron beams was chosen. Required electron beam and its acceleration will be provided by the photoemission electron gun and the RF linear accelerator. As a result, cooling will be accomplished by using bunched electron beams produced by high-brightness high-current electron linear accelerator. Here, we describe design aspects and challenges of such an approach, as well as summarize status of the LEReC project. First commissioning results of the LEReC injector are also presented.
on behalf of the LEReC team. 		 
slides icon Slides WEM11 [4.363 MB]  
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WEM12 Development of a Bunched Beam Electron Cooler Based on ERL and Circulator Ring Technology for the Jefferson Lab Electron-Ion Collider 72
 
  • S.V. Benson, Y.S. Derbenev, D. Douglas, F.E. Hannon, A. Hutton, R. Li, R.A. Rimmer, Y. Roblin, C. Tennant, H. Wang, H. Zhang, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Jefferson Lab is in the process of designing an electron ion collider with unprecedented luminosity at a 45 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires the novel use of bunched-beam cooling. There are two designs for such a bunched beam cooler. The first uses a conventional Energy Recovery Linac (ERL) with a magnetized beam while the second uses a circulating ring to enhance both the peak and average current experienced by the ion beam. This presentation will describe the design of both the Circulator Cooling Ring (CCR) design and that of the backup option using the stand-alone ERL operated at lower charge but higher repetition rate than the ERL injector required by the CCR-based design. 		 
slides icon Slides WEM12 [5.124 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-WEM12  
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WEM13
 Electron Cooling of Bunched Ion Beams and Recent Results at the Heidelberg Cryogenic Storage Ring (CSR)  
 
  • P. Wilhelm
    MPI-K, Heidelberg, Germany
  
  The cryogenic storage ring CSR is an electrostatic machine of 35 m circumference for positive and negative ions at up to 300 keV kinetic energy per charge. Vacuum chambers and ion optics are cooled to well below 10 K by a closed-cycle He system. Rest gas densities down to a room-temperature equivalent pressure of <10-14 mbar and 1/e ion-beam lifetimes up to ~45 min were observed*. With rotationally cold diatomic ions, photodissociation Feshbach resonances of CH+ (J=0,1,2) were reported**. By time-dependent laser photodetachment, free-space radiative lifetimes of OH− ions (J=1,2) up to ~190 s were measured***. An electron cooling device with a cryogenic (high-temperature superconducting) magnet and beam-merging system was taken into operation with an electron beam of ~40 eV from the TSR GaAs photocathode system****. It was applied to perform bunched-beam electron cooling of 1200 keV F(6+) ions. Future research will be devoted to interaction studies between stored atomic, molecular and cluster ions and laser, electron and neutral particle beams. Electron-beam studies (meV relative energies) will focus on dissociative recombination and state-changing collisions of molecular ions.
*R. von Hahn et al., Rev. Sci. Instr. 87, 063115 (2016)
**A. O'Connor et al., PRL 116, 113002 (2016)
***C. Meyer et al., PRL 119, 023202 (2017)
****D. Orlov et al., J. Appl. Phys. 106, 054907(2009) 		 
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