Author: Prost, L.R.
Paper Title Page
WEP113 Low-Energy Run of Fermilab Electron Cooler's Beam Generation System 1695
 
  • L.R. Prost, A.V. Shemyakin
    Fermilab, Batavia, USA
  • A.V. Fedotov, J. Kewisch
    BNL, Upton, Long Island, New York, USA
 
  Funding: FNAL is operated by FRA, LLC under Contract No.DE-AC02-07CH11359 with US DoE. BNL is operated by BSA, LLC under Contract No.DE-AC02-98CH10886 with US DoE.
In the context of the evaluation of possibly using the Fermilab Electron Cooler for the proposed low-energy RHIC run at BNL, operating the cooler at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main conclusion of this feasibility study is that the cooler's beam generation system is suitable for BNL needs. The beam recirculation was stable for all tested parameters. In particular, a beam current of 0.38 A was achieved with the cathode magnetic field up to the maximum value presently available of 250 G. The energy ripple was measured to be 40 eV. A striking difference with running the 4.3 MeV beam (nominal for operation at FNAL) is that no unprovoked beam recirculation interruptions were observed.
 
 
WEP114 Transverse Instability of the Antiproton Beam In the Recycler Ring 1698
 
  • L.R. Prost, C.M. Bhat, A.V. Burov, J.L. Crisp, N. Eddy, M. Hu, A.V. Shemyakin
    Fermilab, Batavia, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The brightness of the antiproton beam in Fermilab’s 8 GeV Recycler ring is limited by a transverse instability. This instability has occurred during the extraction process to the Tevatron for large stacks of antiprotons even with dampers in operation. This paper describes observed features of the instability, introduces the threshold phase density to characterize the beam stability, and finds the results to be in agreement with a resistive wall instability model. Effective exclusion of the longitudinal tails from Landau damping by decreasing the depth of the RF potential well is observed to lower the threshold density by up to a factor of two.
 
 
WEP228 Effect of Transverse Electron Velocities on the Longitudinal Cooling Force in the Fermilab Electron Cooler 1915
 
  • A. Khilkevich
    BSU, Minsk, Belarus
  • L.R. Prost, A.V. Shemyakin
    Fermilab, Batavia, USA
 
  Funding: FNAL is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
In Fermilab’s electron cooler, a 0.1A, 4.3MeV DC electron beam propagates through the 20 m cooling section, which is immersed in a weak longitudinal magnetic field. A proper adjustment of 200 dipole coils, installed in the cooling section for correction of the magnetic field imperfections, can create a helix-like trajectory with the wavelength of 1-10 m. The longitudinal cooling force is measured in the presence of such helices at different wavelengths and amplitudes. The results are compared with a model calculating the cooling force as a sum of collisions with small impact parameters, where the helical nature of the coherent angle is ignored, and far collisions, where the effect of the coherent motion is neglected. A qualitative agreement is found.
 
 
THP082 Design Aspects of an Electrostatic Electron Cooler for Low-energy RHIC Operation 2288
 
  • A.V. Fedotov, I. Ben-Zvi, J. Brodowski, X. Chang, D.M. Gassner, L.T. Hoff, D. Kayran, J. Kewisch, B. Oerter, A. Pendzick, S. Tepikian, P. Thieberger
    BNL, Upton, Long Island, New York, USA
  • L.R. Prost, A.V. Shemyakin
    Fermilab, Batavia, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Electron cooling was proposed to increase the luminosity of RHIC operation for heavy ion beam energies below 10 GeV/nucleon. The electron cooling system needed should be able to deliver an electron beam of adequate quality in a wide range of electron beam energies (0.9-5 MeV). An option of using an electrostatic accelerator for cooling heavy ions in RHIC was studied in detail. In this paper, we describe the requirements and options to be considered in the design of such a cooler for RHIC, as well as the associated challenges. The expected luminosity improvement and limitations with such electron cooling system are also discussed.