Author: Chase, B.E.
Paper Title Page
MOPWI021 The LCLS-II LLRF System 1195
 
  • C. Hovater, R. Bachimanchi
    JLab, Newport News, Virginia, USA
  • S. Babel, B. Hong, D. Van Winkle
    SLAC, Menlo Park, California, USA
  • B.E. Chase, E. Cullerton, P. Varghese
    Fermilab, Batavia, Illinois, USA
  • L.R. Doolittle, G. Huang, A. Ratti, C. Serrano
    LBNL, Berkeley, California, USA
 
  Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515.
The SLAC National Accelerator Laboratory is planning an upgrade (LCLS-II) to the Linear Coherent Light Source with a 4 GeV CW superconducting (SCRF) linac. The SCRF linac consists of 35 ILC style cryomodules (eight cavities each) for a total of 280 cavities. Expected cavity gradients are 16 MV/m with a loaded QL of ~ 4x107. The RF system will have 3.8 kW solid state amplifiers driving single cavities. To ensure optimum field stability a single source single cavity control system has been chosen. It consists of a precision four channel cavity receiver and RF stations (Forward, Reflected and Drive signals). In order to regulate the resonant frequency variations of the cavities due to He pressure, the tuning of each cavity is controlled by a Piezo actuator and a slow stepper motor. In addition the system (LLRF-amplifier-cavity) is being modeled and cavity microphonic testing has started. This paper describes the LLRF system under consideration, including recent modeling and cavity tests.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI021  
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MOPWI028 Initial Experimental Results of a Machine Learning-Based Temperature Control System for an RF Gun 1217
 
  • A.L. Edelen, S. Biedron, S.V. Milton
    CSU, Fort Collins, Colorado, USA
  • B.E. Chase, D.J. Crawford, N. Eddy, D.R. Edstrom, E.R. Harms, J. Ruan, J.K. Santucci, P. Stabile
    Fermilab, Batavia, Illinois, USA
 
  Colorado State University (CSU) and Fermi National Accelerator Laboratory (Fermilab) have been developing a control system to regulate the resonant frequency of an RF electron gun. As part of this effort, we present experimental results for a benchmark temperature controller that combines a machine learning-based model and a predictive control algorithm for improved settling time, overshoot, and disturbance rejection relative to conventional techniques. Such improvements have implications for machine up-time and management of reflected power. This work is part of an on-going effort to develop adaptive, machine learning-based tools specifically to address control challenges found in particle accelerator systems.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI028  
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TUPJE080 First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab 1831
 
  • D.J. Crawford, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B.E. Chase, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, C.D. Joe, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P. Piot, P.S. Prieto, J. Reid, J. Ruan, J.K. Santucci, W.M. Soyars, G. Stancari, D. Sun, R.M. Thurman-Keup, A. Valishev, A. Warner, S.J. Wesseln
    Fermilab, Batavia, Illinois, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE080  
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WEPWI044 High-Power Magnetron Transmitter for the Electron Collider Ring of the MEIC Facility 3587
 
  • G.M. Kazakevich
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • B.E. Chase, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • Y.S. Derbenev
    JLab, Newport News, Virginia, USA
 
  Operation of the 3-12 GeV electron collider 8-shape ring of the MEIC facility causes a Synchrotron Radiation (SR) of electrons in arcs with energy loss of ~20 kW/m at beam current of ~3 A. The total SR loss up to 2 MW per a revolution is presumed to compensate by Superconducting RF (SRF) accelerating cavities. To minimize the beam emittance, each individual SRF cavity is proposed to feed by an individual and independent RF source allowing a wide-band control in phase and power. Most efficient and less expensive in capital and maintenance costs the high-power transmitters based on magnetrons, injection-locked by phase-modulated signals, controlled in wide-band are proposed as the RF sources. The magnetron RF sources utilizing 2-cascade magnetrons allowing a wide-band phase and power control by the injection-locking phase-modulated signals were experimentally modelled by 2.45 GHz, CW, 1 kW magnetrons. Results of the modelling and adequacy of the transmitters for the SRF cavities are discussed in the presented article.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI044  
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THPF113 Energy Spread of the Proton Beam in the Fermilab Booster at Its Injection Energy 3979
 
  • C.M. Bhat, B.E. Chase, S. Chaurize, F.G. Garcia, W. Pellico, K. Seiya, T. Sullivan, A.K. Triplett
    Fermilab, Batavia, Illinois, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
We have measured the total energy spread (99% energy spread) of the Booster beam at its injection energy of 400 MeV by three different methods - 1) creating a notch of about 40 nsec wide in the beam immediately after multiple turn injection and measuring the slippage time required for high and low momentum particles for a grazing touch in line-charge distribution, 2) injecting partial turn beam and letting it to debunch, and 3) comparing the beam profile monitor data with predictions from MAD simulations for the 400 MeV injection beam line. The measurements are repeated under varieties of conditions of RF systems in the ring and in the beam transfer line.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF113  
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