WEYBB —  Wednesday Parallel Session 4   (04-Sep-19   10:30—12:30)
Chair: S.M. Cousineau, ORNL, Oak Ridge, Tennessee, USA
Paper Title Page
WEYBB1 ELENA Commissioning -1
WEPLH18   use link to see paper's listing under its alternate paper code  
  • D. Gamba, M.E. Angoletta, P. Belochitskii, L. Bojtár, F. Butin, C. Carli, B. Dupuy, Y. Dutheil, T. Eriksson, P. Freyermuth, C. Grech, M. Hori, J.R. Hunt, M. Jaussi, L.V. Jørgensen, B. Lefort, S. Pasinelli, L. Ponce, G. Tranquille
    CERN, Meyrin, Switzerland
  • R. Gebel
    FZJ, Jülich, Germany
  • C. Grech
    University of Malta, Information and Communication Technology, Msida, Malta
  • M. Hori
    MPQ, Garching, Munich, Germany
  The Extra Low ENergy Antiproton storage ring (ELENA) is an upgrade project at the CERN AD (Antiproton Decelerator). ELENA will further decelerate the 5.3 MeV antiprotons coming from the AD down to 100 keV. ELENA features electron cooling for emittance control during deceleration thus preserving the beam intensity and allowing to extract bright bunches towards the experiments. The lower energy will allow for increasing the antiproton trapping efficiency up to two orders of magnitude, which is typically less than 1% with the present beam from AD. The ring was completed with the installation of the electron cooler at the beginning of 2018. Decelerated beams with characteristics close to the design values were obtained before the start of CERN Long Shutdown 2 (LS2). During LS2 electrostatic transfer lines from the ELENA ring to the experimental zones will be installed, replacing the magnetic transfer lines from the AD ring. The latest results of commissioning with H and antiprotons and the first observation of electron cooling in ELENA will be presented, together with an overview of the project and status and plans for LS2 and beyond.  
slides icon Slides WEYBB1 [21.717 MB]  
Foil R&D and Temperature Measurements at the SNS  
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  The SNS uses charge exchange injection during the accumulation of the accelerated beam in the ring. At a beam power of 1.2 MW, the stripping foil lasts for many weeks, sometimes months. However, given the upgrade to 2.8 MW, it is important to know the current temperature of the foil in order to estimate its lifetime for the new beam power and beam size. This paper will discuss the foil R&D and experimental temperature measurements of a stripper foil, exposed to current operating conditions of the SNS accelerator.  
slides icon Slides WEYBB2 [12.022 MB]  
WEYBB3 Foil Scattering Model for Fermilab Booster -1
WEPLH14   use link to see paper's listing under its alternate paper code  
  • C.M. Bhat, S. Chaurize, J.S. Eldred, V.A. Lebedev, S. Nagaitsev, K. Seiya, C.-Y. Tan, R. Tesarek
    Fermilab, Batavia, Illinois, USA
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
At the Fermilab Booster, and many other proton facilities, an intense proton beam is accumulated by injection an H beam through a stripping foil. The circulating beam scatters off the injection beam and large-angle Coulomb scattering leads to uncontrolled losses concentrated in the first betatron period. We measure the foil scattering rate in the Booster as a function of linac current, number of injection-turns, and time on injection foil. We find that current Booster operations has a 1% foil scattering loss rate and we make projections for the Proton Improvement Plan II (PIP-II) injector upgrade. We find that accurate modeling of the foil scattering loss must account for beam emittance in conjunction with the scattering rate and ring acceptance. Estimate of beam emittance at injection are discussed.
slides icon Slides WEYBB3 [6.000 MB]  
WEYBB4 Progress of Liquid Lithium Stripper for FRIB -1
  • T. Kanemura, J. Gao, R. Madendorp, F. Marti, Y. Momozaki
    FRIB, East Lansing, Michigan, USA
  • M.J. LaVere
    MSU, East Lansing, Michigan, USA
  • Y. Momozaki
    ANL, Lemont, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) at Michigan State University is building a heavy ion linear accelerator (linac) to produce rare isotopes by the fragmentation method. At energies between 16 and 20 MeV/u ions are further stripped by a charge stripper increasing the energy gain downstream in the linac. The main challenges in the stripper design are high power deposited by the ions in the stripping media and radiation damage to the media itself. To overcome these challenges, self-recovering stripper media are the most suitable solutions. The FRIB baseline choice is a high-velocity thin film of liquid lithium*. Because liquid lithium is highly reactive with air, we have implemented rigorous safety measures. Since May 2018, the lithium stripper system has been operated safely at an offline test site to accumulate operational experience. Recently, we successfully completed a 10-day long unattended continuous operation without any issue, which proved the reliability of the system. The next step is to characterize the lithium film stability with diagnostics. In 2020, we plan to bring the lithium stripper into the accelerator tunnel and commission it with ion beams.
*Jie Wei, et al., TU1A04, Proceedings of LINAC 2012, Tel-Aviv, Israel
slides icon Slides WEYBB4 [6.777 MB]  
WEYBB5 A Crab-Crossing Scheme for Laser-Ion Beam Applications -1
  • A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A. Rakhman, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  Lasers have recently been used in many applications to H beams, including laser charge exchange, laser wire scanners, and laser temporal pulse patterning. The H beam in these applications has wide variation ofμpulse length width dependence on focusing of the RF cavities, energy spread of the beam, and space charge forces. Achieving the required laser pulse length for complete overlap with the H can be challenging in some scenarios when available laser power constrained. The scheme proposed here utilizes a crab-crossing concept between the laser and the ion beam to achieve overlap of a short laser pulse with an arbitrarily long H beam pulse. An experiment to test the hypothesis in the context of H charge exchange is described.  
slides icon Slides WEYBB5 [5.409 MB]  
WEYBB6 Design Considerations and Operational Features of the Collimators for the Fermilab Main Injector and Recycler -1
  • B.C. Brown, P. Adamson, R. Ainsworth, D. Capista, K.J. Hazelwood, I. Kourbanis, N.V. Mokhov, D.K. Morris, V.S. Pronskikh, I.L. Rakhno, I.S. Tropin, M. Xiao, M.-J. Yang
    Fermilab, Batavia, Illinois, USA
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Fermilab Main Injector system delivers 700 kW of 120 GeV Proton beam for neutrino experiments. Since 2013 this has been achieved using slip stacking accumulation in the Recycler with up to 12 batches from the Fermilab Booster per Main Injector Ramp Cycle. To control activation from beam loss, collimation systems in the Booster to Recycler transfer line, in the Recycler and in the Main Injector are employed. Residual radiation measurements around the ring with detailed studies at the collimators are required to maintain adequate loss control. We will review design considerations, operational parameters and activation results for more than ten years of operation. Simulations with MARS15 are used to explore the activation rates and the isotopic composition of the resulting activation.
slides icon Slides WEYBB6 [14.634 MB]