Author: Edstrom, D.R.
Paper Title Page
TUXGBF2 Higher-Order-Mode Effects in Tesla-Type Superconducting RF Cavities on Electron Beam Quality 612
 
  • A.H. Lumpkin, N. Eddy, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • K. Bishofberger, B.E. Carlsten
    LANL, Los Alamos, New Mexico, USA
  • O. Napoly
    CEA/DSM/IRFU, France
 
  Funding: *Work at Fermilab supported by FRA, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy. **Work at LANL supported by U.S. Dept. of Energy through the LANL/LDRD Program.
We report the direct observations of the correlation of higher order modes (HOMs) generated by off-axis electron beam steering in TESLA-type SCRF cavities and sub-macropulse beam centroid shifts (with the concomitant effect on averaged beam size and emittance). The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility using its unique configuration of a PC rf gun injecting beam into two separated 9-cell cavities in series with corrector magnets and beam position monitors (BPMs) located before, between, and after them. The ~100-kHz oscillations with up to 300-µm amplitudes at downstream locations were observed in a 3-MHz micropulse repetition rate beam with charges of 500 and 1000 pC/b, although the effects were much reduced at 100 pC/b. The studies were based on HOM detector circuitry targeting the first and second dipole passbands, rf BPM bunch-by-bunch data, and imaging cameras viewing multi-slit images for emittance assessments at 33 MeV. Initial calculations reproduced a key feature of the phenomena. In principle, these results may be scaled to cryomodule configurations of major accelerator facilities.
 
slides icon Slides TUXGBF2 [3.636 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF2  
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THYGBE2
Results and Discussion of Recent Applications of Neural Network-Based Approaches to the Modeling and Control of Particle Accelerators  
 
  • A.L. Edelen
    CSU, Fort Collins, Colorado, USA
  • S. Biedron
    University of New Mexico, Albuquerque, USA
  • D.L. Bowring, B.E. Chase, D.R. Edstrom, J. Steimel
    Fermilab, Batavia, Illinois, USA
  • J.P. Edelen
    RadiaSoft LLC, Boulder, Colorado, USA
  • P.J.M. van der Slot
    Mesa+, Enschede, The Netherlands
 
  Here we highlight several examples from our work in applying neural network-based modeling and control techniques to particle accelerator systems, through a combination of simulation and experimental studies. We also discuss where the specific approaches used fit into the state of the art in deep learning for control, including limitations of the present state of the art (for example in efficiently dealing with noisy, time-varying, many-parameter systems, like those found in accelerators). We will also briefly clarify some of the terminology/taxonomy of artificial intelligence, and describe how the neural network approaches used here relate to other classes of algorithms that are familiar to the accelerator community. The particle accelerator applications discussed include resonant frequency control of Fermilab's PIP-II RFQ, fast switching between beam parameters in a compact THz FEL, modeling of the FAST low energy beamline at Fermilab, temperature control for the FAST RF gun, and trajectory control for the Jefferson Laboratory FEL.  
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THPAK061 Magnetized and Flat Beam Generation at the Fermilab's FAST Facility 3364
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • D.J. Crawford, D.R. Edstrom, D. Mihalcea, S. Nagaitsev, P. Piot, A.L. Romanov, J. Ruan, V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work is supported by the DOE contract No.DEAC02-07CH11359 to the Fermi Research Alliance LLC. A.H. is supported by the DOE under contract No. DE-SC0011831 with Northern Illinois University.
Canonical angular momentum (CAM) dominated beams can be formed in photoinjectors by applying an axial magnetic field on the photocathode surface. Such a beam possess asymmetric eigenemittances and is characterized by the measure of its magnetization. CAM removal using a set skew-quadrupole magnets maps the beam eigenemittances to the conventional emittance along each transverse degree of freedom thereby yielding flat beam with asymmetric transverse emittance. In this paper we report on the experimental generation of CAM dominated beam and their subsequent transformation into flat beams at the Fermilab Accelerator Science and Technology (FAST) facility. Our results are compared with numerical simulations and possible applications of the produced beams are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK061  
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THPAK062 Bunch Compression of Flat Beams 3368
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • D.J. Crawford, D.R. Edstrom, D. Mihalcea, S. Nagaitsev, P. Piot, A.L. Romanov, J. Ruan, V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work is supported by the DOE contract No.DEAC02-07CH11359 to the Fermi Research Alliance LLC. A.H. is supported by the DOE under contract No. DE-SC0011831 with Northern Illinois University.
Flat beams can be produced via a linear manipulation of canonical angular momentum (CAM) dominated beams using a set of skew-quadrupole magnets. Recently such beams were produced at Fermilab Accelerator Science and Technology (FAST) facility. In this paper, we report the results of flat beam compression study in a magnetic chicane at an energy of E~32 MeV. Additionally, we investigate the effect of energy chirp in the round-to-flat beam transform. The experimental results are compared with numerical simulations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK062  
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THPMF024 Commissioning and Operation of FAST Electron Linac at Fermilab 4096
 
  • A.L. Romanov, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, D.J. Crawford, N. Eddy, D.R. Edstrom, E.R. Harms, J. Hurd, M.J. Kucera, J.R. Leibfritz, I.L. Rakhno, J. Reid, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari, R.M. Thurman-Keup, A. Valishev, A. Warner
    Fermilab, Batavia, Illinois, USA
 
  We report results of the beam commissioning and first operation of the 1.3 GHz superconducting RF electron linear accelerator at Fermilab Accelerator Science and Technology (FAST) facility. Construction of the linac was completed and the machine was commissioned with beam in 2017. The maximum total beam energy of about 300 MeV was achieved with the record energy gain of 250 MeV in the ILC-type SRF cryomodule. The pho-toinjector was tuned to produce trains of 200 pC bunches with a frequency of 3 MHz at a repetition rate of 1 Hz. This report describes the aspects of machine commission-ing such as tuning of the SRF cryomodule and beam optics optimization. We also present highlights of an experimental program carried out parasitically during the two-month run, including studies of wake-fields, and advanced beam phase space manipulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF024  
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THPMF025 Emittance Measurements at FAST Facility 4100
 
  • J. Ruan, D.R. Broemmelsiek, D.J. Crawford, A.L. Edelen, J.P. Edelen, D.R. Edstrom, A.H. Lumpkin, P. Piot, A.L. Romanov, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
 
  Funding: *Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The FAST facility at Fermilab recently been commissioned has demonstrated the generation of electron beam within a wide range of parameter (energy, charge) suitable for accelerator-science and beam-physics experiments. This accelerator consists of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. It will mainly serve as injector for the upcoming Integrable Optical Test Accelerator (IOTA). At the same time we will also carry out a LINAC based intense gamma ray experiment based on the Inverse Compton scattering. It is essential to understand the beam emittance for both experiments. A number of techniques are used to characaterizing the beam emittance including slit based method and quad scan method. An on-line emittance measurement based on multi-slit method is developed so the emittance measured will be immediately available to support further beam optimization. In this report we will present the results from the emittance studies using this tool. We will also present the emittance measurement based on quads scan technique for the high energy beam line.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF025  
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THPML063 Micro-Bunched Beam Production at FAST for Narrow Band THz Generation Using a Slit-Mask 4784
 
  • J. Hyun
    Sokendai, Ibaraki, Japan
  • D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, T. Sen, J.C.T. Thangaraj, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
 
  We discuss simulations and experiments on creating micro-bunch beams for generating narrow band THz radiation at the Fermilab Accelerator Science and Technology (FAST) facility. The low-energy electron beamline at FAST consists of a photoinjector-based RF gun, two L-band superconducting accelerating cavities, a chicane, and a beam dump. The electron bunches are lengthened with cavity phases set off-crest for better longitudinal separation and then micro-bunched with a slit-mask installed in the chicane. We carried out the experiments with 30 MeV electron beams and detected signals of the micro-bunching using a skew quadrupole magnet in the chicane. In this paper, the details of micro-bunch beam production, the detection of micro-bunching and comparison with simulations are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML063  
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