THYBA —  Thursday Parallel Session 3   (05-Sep-19   10:30—12:30)
Chair: P. Raimondi, ESRF, Grenoble, France
Paper Title Page
THYBA1 Status of the CBETA Cornell-BNL ERL Prototype -1
  • K.E. Deitrick, N. Banerjee, A.C. Bartnik, J.A. Crittenden, L. Cultrera, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, W. Lou, P. Quigley, D. Sagan, K.W. Smolenski, D. Widger
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J.S. Berg, S.J. Brooks, R.L. Hulsart, R.J. Michnoff, S. Peggs, D. Trbojevic
    BNL, Upton, New York, USA
  CBETA, the Cornell-BNL ERL Test Accelerator, is an SRF multi-turn ERL which has been commissioned in the one-turn configuration from March to July 2019. During this time, the project has demonstrated an energy acceptance of 1.5 in the FFA arc, high-transmission energy recovery performance, and increased the CBETA energy-recovered maximum average current.  
slides icon Slides THYBA1 [11.598 MB]  
Multi-Pulse Scorpius Linear Induction Accelerator for Flash X-Ray Radiography  
  • N. Pogue, Y.-J. Chen
    LLNL, Livermore, California, USA
  • M.T. Crawford, D.J. Funk
    LANL, Los Alamos, New Mexico, USA
  The Scorpius electron linear induction accelerator is currently being developed for NNSA stockpile stewardship’s Enhanced Capabilities for Subcritical Experiments (ECSE) Program. The purpose is to provide multiple x-ray pulses for flash radiography of large hydrodynamic experiments driven by high explosive. The Scorpius accelerator is designed to produce four 90-ns, 2-kA, 20-MeV electron pulses with the inter-pulse separation varying from 100 ns to 900 ns. The exiting electron pulses will be focused onto a high-Z target to produce the needed radiographic x-ray sources. The ECSE Scorpius project is managed at Los Alamos National Laboratory with cooperation from Lawrence Livermore National Laboratory, Sandia National Laboratory and Nevada National Security Site. Currently, the project completion date is set for 2024. This presentation will cover Scorpius accelerator’s development status.  
THYBA3 Use of Solid Xenon as a Beam Dump Material for 4th-Generation Storage Rings -1
  • M. Borland, H. Cease, J.C. Dooling
    ANL, Lemont, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Damage to tungsten beam dumps has been observed in the Advanced Photon Source due to the high charge (368 nC/store), high energy (7 GeV), and short loss time (about 15 microseconds). Owing to the higher charge (736 nC/store) and much lower emittance (42 pm vs 2.5 nm), this issue is expected to be much more severe in the APS Upgrade. This strongly suggests that such dumps are necessary in 4th-generation electron storage rings to prevent catastrophic damage to vacuum systems when, for example, rf systems trip. However, it also implies that the dump will be damaged by each strike and will thus need to be "refreshed," perhaps by moving the dump surface vertically to expose undamaged material. Xenon, a gas that solidifies at 161K, is an intriguing possibility for a beam dump material. Calculations suggest that as the beam spirals in toward a dump in a high-dispersion area the tails of the electron beam would vaporize sufficient xenon to rapidly diffuse the beam and render it harmless. The dump surface could be periodically reformed without breaking vacuum. Issues with the concept include the need to protect the frozen xenon from wakefield heating.
slides icon Slides THYBA3 [2.447 MB]  
THYBA4 Status of the Magnetized Thermionic Electron Source at Jefferson Lab -1
  • F.E. Hannon, D.B. Bullard, C. Hernandez-Garcia, M.A. Mamun, M. Poelker, R. Suleiman
    JLab, Newport News, Virginia, USA
  • J.V. Conway, B.M. Dunham, R.G. Eichhorn, C.E. Mayes, K.W. Smolenski, N.W. Taylor
    Xelera Research LLC, Ithaca, New York, USA
  • C.M. Gulliford, V.O. Kostroun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • M.S. Stefani
    ODU, Norfolk, Virginia, USA
  A 125kV DC gridded thermionic gun has been de-signed and constructed through a collaboration between Jefferson Lab and Xelera Research LLC. The gun has been recently installed at the Gun Test Stand diagnostic line at Jefferson Lab where transverse and longitudinal parameter space will be experimentally explored. The status and results characterizing the commissioning and trouble-shooting the thermionic gun are presented.  
slides icon Slides THYBA4 [13.603 MB]  
THYBA5 Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab -1
SUPLH03   use link to see paper's listing under its alternate paper code  
TUPLH13   use link to see paper's listing under its alternate paper code  
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • K. Kim
    ANL, Lemont, Illinois, USA
  • V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A.Y. Murokh
    RadiaBeam, Marina del Rey, California, USA
  • T.V. Shaftan
    BNL, Upton, New York, USA
  We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab, with an InGaAs PIN photodiode and an integrating circuit. In this paper, we present a theoretical model for the experimental data from previous similar experiments and in our present experiment, we attempt to verify the model in an independent and a more systematic way. Moreover, in our experiment we consider the regime of very small fluctuation when the contribution from the photon shot noise is significant, whereas we believe it was negligible in the previous experiments. Accordingly, we present certain critical improvements in the experimental setup that let us measure such a small fluctuation.  
slides icon Slides THYBA5 [8.044 MB]  
poster icon Poster THYBA5 [3.004 MB]  
THYBA6 Active Pointing Stabilization Techniques Applied to the Low Energy RHIC Electron Cooling Laser Transport at BNL -1
MOPLM22   use link to see paper's listing under its alternate paper code  
SUPLH07   use link to see paper's listing under its alternate paper code  
  • L.K. Nguyen, A.J. Curcio, W.J. Eisele, A.V. Fedotov, A. Fernando, W. Fischer, P. Inacker, J.P. Jamilkowski, D. Kayran, K. Kulmatycski, D. Lehn, T.A. Miller, M.G. Minty, A. Sukhanov
    BNL, Upton, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The electron beam for the Low Energy RHIC electron Cooler (LEReC) at Brookhaven National Laboratory (BNL) is generated by a high-power fiber laser illuminating a photocathode. The pointing stability of the electron beam, which is crucial given its long transport, is highly dependent on the center-of-mass (CoM) stability of the laser spot on the photocathode. For reasons of accessibility during operations, the laser is located outside the accelerator tunnel, and the laser beam is propagated over a total distance of 34 m via three laser tables to the photocathode. The challenges to achieving the required CoM stability of 10 microns RMS on the photocathode include mitigation of the effects of vibrations along the transport and of weather- and season-related environmental effects, while preserving accessibility and diagnostic capabilities. Due to the insufficiency of infrastructure alone in overcoming these challenges, two active laser transport stabilization systems aimed at addressing specific types of position instability were installed during the 2018 Shutdown. After successful commissioning of the full transport in 2018/19, we report on our solutions to these design challenges.
slides icon Slides THYBA6 [3.421 MB]  
poster icon Poster THYBA6 [1.336 MB]