Keyword: operation
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MOYBA1 LHC Status and Plans luminosity, electron, experiment, proton 8
 
  • X. Buffat
    CERN, Geneva, Switzerland
  
  Performance and accelerator physics challenges from LHC Run 2 are reviewed, along with the ongoing preparation and plans for LHC Runs 3 and 4.  
slides icon Slides MOYBA1 [13.269 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA1  
About • paper received ※ 26 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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MOYBA6 Accelerator Performance During the Beam Energy Scan II at RHIC in 2019 electron, luminosity, cavity, MMI 26
 
  • C. Liu, I. Blacker, M. Blaskiewicz, K.A. Brown, D. Bruno, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, D. Kayran, N.A. Kling, Y. Luo, D. Maffei, G.J. Marr, B. Martin, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, S. Polizzo, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, A. Zaltsman, K. Zeno, I.Y. Zhang, W. Zhang
    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.
RHIC provided Au-Au collisions at beam energies of 9.8, 7.3, 4.59 and 3.85 GeV/nucleon during the first year of the Beam Energy Scan II in 2019. The physics goals at the first two higher beam energies were achieved. At the two lower beam energies, bunched electron beam cooling has been demonstrated successfully. The accelerator performance was improved compared to when RHIC was operated at these energies in earlier years. This article will introduce the challenges to operate RHIC at low energies and the corresponding countermeasures, and review the improvement of accelerator performance during the operation in 2019. 		 
slides icon Slides MOYBA6 [6.579 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBA6  
About • paper received ※ 21 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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MOYBB2 Recent Advance in ECR Ion Sources ECR, ion-source, plasma, electron 31
 
  • G. Machicoane, N.K. Bultman, P. Morrison, M. Omelayenko, X. Rao
    FRIB, East Lansing, Michigan, USA
  • D. Arbelaez, R.R. Hafalia, P. Pan, S. Prestemon
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
High continuous wave (cw) current of highly charged ion beams are required for several heavy ion accelerator facilities including the Facility for Rare Isotope Beams (FRIB). In most cases, Electron-Cyclotron-Resonance (ECR) ion sources remain the only ion source capable to meet the beam intensity requirement for these facilities. Performances of ECR ion source have increased by several order of magnitude since their inception in the 1970s mostly driven by increasing the resonance frequency with today current state of the art ECR ion source operating from 24 to 28 GHz. This paper provides an overview of recent advance in the design and operation of ECR ion source including plans to develop the next generation of ion source capable of operating above 40 GHz. A detailed account of the design and status of the new superconducting ECR ion source in construction for FRIB will also be reported. 		 
slides icon Slides MOYBB2 [9.483 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBB2  
About • paper received ※ 02 September 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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MOZBA2 Operational Experience with Superconducting Undulators at APS undulator, photon, vacuum, radiation 57
 
  • K.C. Harkay, L.E. Boon, M. Borland, J.C. Dooling, L. Emery, V. Sajaev, Y.P. Sun
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by U. S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
APS has been developing superconducting undulators for over a decade. Presently, two planar and one helical device are in operation in the APS storage ring, and a number of devices will be installed in the APS Upgrade ring. All superconducting devices perform with very high reliability and have very minor effect on the storage ring operation. To achieve this, a number of storage ring modifications had to be done, such as introduction of the beam abort system to eliminate device quenches during beam dumps, and lattice and orbit modifications to allow for installation of the small horizontal aperture helical device with magnet coils in the plane of synchrotron radiation. 		 
slides icon Slides MOZBA2 [3.424 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBA2  
About • paper received ※ 02 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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MOPLM04 First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization experiment, quadrupole, storage-ring, emittance 98
 
  • S.C. Leemann, Ph. Amstutz, W.E. Byrne, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini
    LBNL, Berkeley, USA
  
  Funding: This research is funded by the US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM04  
About • paper received ※ 26 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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MOPLS06 Mu*STAR: An Accelerator-Driven Subcritical Modular Reactor target, site, neutron, SRF 163
 
  • R.P. Johnson, R.J. Abrams, M.A. Cummings, T.J. Roberts
    Muons, Inc, Illinois, USA
  
  We present a conceptual design for a new modular, accelerator-driven subcritical reactor based on a molten salt. Mu*STAR is a reactor, that without re-design, can burn a variety of nuclear fuels, with the beam tuned to that fuel. We will discuss the elements of this system: the accelerator, the reactor, the spallation target, and the fractional distillation to separate volatile fission products. Our GAIN project with ORNL is successfully completed, with a design of the Fuel Processing Plant that will convert spent nuclear fuel into the molten-salt fuel for Mu*STAR.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLS06  
About • paper received ※ 01 September 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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MOPLH08 Tests of Cs-Free Operation of the SNS RF H− Ion Sources ion-source, plasma, neutron, power-supply 184
 
  • B. Han, S.M. Cousineau, S.N. Murray, T.R. Pennisi, M.P. Stockli, R.F. Welton
    ORNL, Oak Ridge, Tennessee, USA
  • T.M. Sarmento, O.A. Tarvainen
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • C. Stinson
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This work was performed at Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract number DE-AC05-00OR22725 for the United States Department of Energy.
Tests were performed at SNS in collaboration with visiting colleagues from ISIS, UK to evaluate the uncesiated beam performance of the SNS RF H− ion sources. Two spare experimental sources, one with internal antenna and one with external antenna were used for the tests. The beam currents achieved with Cs-free operations accounted for about 1/3 to 1/2 of the beam currents produced with cesiated operations. ~17 mA uncesiated H− current was demonstrated within the tested RF power range up to 65 kW with the internal antenna source and ~15 mA with up to 40 kW RF with the external antenna source. In Cs-free operations, the power supply for the electron dumping electrode was loaded down below its set voltage but was not too drastic to tamper the operation. 		 
poster icon Poster MOPLH08 [0.949 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH08  
About • paper received ※ 27 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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MOPLH13 STARRE Lab: The Sub-THz Accelerator Research Laboratory laser, electron, experiment, GUI 199
 
  • J.F. Picard, S.C. Schaub, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts, USA
  
  Funding: Department of Energy, Office of HEP, DE- SC0015566; Office of Fusion Energy Sciences, DE-FC02-93ER54186; National Institutes of Health, NIBIB, EB004866 and EB001965;
This work presents the development of the STARRE Lab, a facility at MIT for testing breakdown in high gradient accelerator structures at 110 GHz. The system utilizes a Laser-Driven Semiconductor Switch (LDSS) to modulate the output of a megawatt gyrotron, which generates 3 μs pulses at up to 6 Hz. The LDSS employs silicon (Si) and gallium arsenide (GaAs) wafers to produce nanosecond-scale pulses at the megawatt level from the gyrotron output. Photoconductivity is induced in the wafers using a 532 nm Nd:YAG laser, which produces 6 ns, 230 mJ pulses. A single Si wafer produces 110 GHz RF pulses with 9 ns width, while under the same conditions, a single GaAs wafer produces 24 ns 110 GHz RF pulses. In dual-wafer operation, which uses two active wafers, pulses of variable length down to 3 ns duration can be created at power levels greater than 300 kW. The switch has been successfully tested at incident 110 GHz RF power levels up to 720 kW.* The facility has been used to successfully test an advanced 110 GHz accelerator structure built by SLAC to gradients in excess of 220 MV/m.
*J.F. Picard et al., Appl. Phys. Lett. 114, 164102 (2019); doi: https://doi.org/10.1063/1.5093639
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLH13  
About • paper received ※ 24 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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MOPLO09 A Pulsed, Current Regulated Magnet Power Supply for Small Magnets quadrupole, injection, controls, timing 252
 
  • G.D. Wyche, B.L. Beaudoin, L. Dovlatyan, D.F. Sutter
    UMD, College Park, Maryland, USA
  
  Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) has two pulsed quadrupoles in the injection section that must be current regulated to the same precision as the other DC quadrupoles in the ring, as well as accurately synchro-nized to the ring operating cycle. To meet this need, a practical pulsed current, regulated power supply has been designed and built using a commercial power operational amplifier for output, standard operational amplifiers for feedback control and monitoring, and matched resistor pairs to produce the desired transfer function of 10 Volts to 6 Amperes. For other applications the circuit can be modified to produce a range of transfer functions by varying the appropriate resistor pair ratios. Output pulse width and timing are generated by a standardized TTL pulse from the control system that gates the output of the amplifier. Installed safety circuitry detects the absence of a proper control pulse, an open circuit or shorted output, and measures and returns to the control system the actual operating amplitude of the current pulse. In this paper we present the design, implementation, and operational results of the prototyped pulsed current source. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO09  
About • paper received ※ 28 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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MOPLO13 Field Quality Analysis of Interaction Region Quadrupoles for JLEIC quadrupole, electron, collider, interaction-region 259
 
  • G.L. Sabbi
    LBNL, Berkeley, California, USA
  • B.R. Gamage, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, M. Wiseman
    JLab, Newport News, Virginia, USA
  • Y.M. Nosochkov, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the US Department of Energy Office of Science.
The JLEIC physics goals of high luminosity and a full acceptance detector result in significant design challenges for the Interaction Region quadrupoles. Key requirements include large aperture, high field, compact transverse and longitudinal dimensions, and tight control of the field errors. In this paper, we present and discuss field quality estimates for the IR Quadrupoles of both electron and ion beamlines, obtained by integrating experience from pre-vious projects with realistic designs consistent with the specific requirements of the JLEIC collider. 		 
poster icon Poster MOPLO13 [0.847 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO13  
About • paper received ※ 27 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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MOPLO15 Engineering and Fabrication of the High Gradient Structure for Compact Ion Therapy Linac linac, vacuum, proton, coupling 267
 
  • O. Chimalpopoca, R.B. Agustsson, S.V. Kutsaev, A.Yu. Smirnov, A. Verma
    RadiaBeam, Santa Monica, California, USA
  • A. Barcikowski, R.L. Fischer, B. Mustapha
    ANL, Lemont, Illinois, USA
  
  RadiaBeam is fabricating a novel ultra-high gradient linear accelerator for the Advanced Compact Carbon Ion LINAC (ACCIL) project. The ACCIL is an Argonne National Laboratory (ANL) led project, in collaboration with RadiaBeam, designed to be capable of delivering sufficiently energized carbon ions and protons while maintaining a 50 m footprint. This is made possible by the development of S-Band 50 MV/m accelerating structures for particles with beta of 0.3 or higher. Such high gradient accelerating structures require particular care in their engineering details and fabrication process to limit the RF breakdown at the operating gradients. The details of fabrication and engineering design of the accelerating structure will be presented.  
poster icon Poster MOPLO15 [1.050 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO15  
About • paper received ※ 28 August 2019       paper accepted ※ 12 September 2019       issue date ※ 08 October 2019  
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MOPLO24 A Novel Technique for Pulsed Operation of Magnetrons without Modulation of Cathode Voltage controls, cathode, cavity, injection 290
 
  • G.M. Kazakevich, R.P. Johnson
    Muons, Inc, Illinois, USA
  • T.N. Khabiboulline, V.A. Lebedev, G.V. Romanov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Modern pulsed superconducting accelerators of megawatt beams require efficient RF sources controllable in phase and power. For each Superconducting RF (SRF) cavity is desirable a separate RF source with power up to hundreds of kW with pulse duration in the millisecond range. The efficiency of the traditional RF sources (klystrons, IOTs, solid-state amplifiers) is lower than that of the magnetrons, while the cost of a unit of RF power is much higher. Therefore the magnetron-based RF sources would significantly reduce the capital and operation costs in comparison with the traditional RF sources. A recently developed an innovative technique makes possible the pulsed generation of magnetrons powered below the self-excitation threshold voltage. This technique does not require pulse modulators to form RF pulses. The magnetron operation in this regime is stable, low noise, controllable in phase and power, and provides higher efficiency than other types of RF power sources. It allows operation in pulsed modes with large duty factor. The developed technique and its experimental verification are considered and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO24  
About • paper received ※ 29 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUZBA1 Commissioning of the Electron Accelerator LEReC for Bunched Beam Cooling electron, cavity, cathode, gun 330
 
  • D. Kayran, Z. Altinbas, D. Bruno, M.R. Costanzo, K.A. Drees, A.V. Fedotov, W. Fischer, M. Gaowei, D.M. Gassner, X. Gu, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, Y.C. Jing, J. Kewisch, C.J. Liaw, C. Liu, J. Ma, K. Mernick, T.A. Miller, M.G. Minty, L.K. Nguyen, M.C. Paniccia, I. Pinayev, V. Ptitsyn, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, L. Smart, K.S. Smith, A. Sukhanov, P. Thieberger, J.E. Tuozzolo, E. Wang, G. Wang, W. Xu, A. Zaltsman, H. Zhao, Z. Zhao
    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 brand-new state of the art electron accelerator, LEReC, was built and commissioned at BNL. LEReC accelerator includes a photocathode DC gun, a laser system, a photocathode delivery system, magnets, beam diagnostics, a SRF booster cavity, and a set of Normal Conducting RF cavities to provide sufficient flexibility to tune the beam in the longitudinal phase space. Electron beam quality suitable for cooling in the Relativistic Heavy Ion Collider (RHIC) was achieved [1], which lead to the first demonstration of bunched beam electron cooling of hadron beams [2]. This presentation will discuss commissioning results, achieved beam parameters and performance of the LEReC systems.
[1] D.Kayran et al., First results from Commissioning of LEReC, in Proc of IPAC2019
[2] A.Fedotov et al., First electron cooling of hadron beams using a bunched electron beam, presented at NAPAC2019 		 
slides icon Slides TUZBA1 [18.343 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA1  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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TUPLM29 Current Status and Prospects of FRIB Machine Protection System LLRF, machine-protect, FPGA, controls 437
 
  • Z. Li, D. Chabot, S. Cogan, S.M. Lidia
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) is designed to accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Fast response of the machine protection system is critical for FRIB beam commissioning and operation to prevent damage to equipment. The beam commissioning of the first linac segment, including fifteen cryomodules, has been completed. Four ion species were accelerated to a beam energy of 20.3 MeV/u with duty factors from 0.05 percent to continuous wave. The peak beam current exceeded 10 percent of the final requirements. This paper summarizes the status of the machine protection system deployed in the production, Machine interlock response time of ~8 μs was achieved. Incentives for future development include being able to achieve smooth and reliable beam operation, faster machine protection response time and real time data analysis of failure mode. 		 
poster icon Poster TUPLM29 [2.067 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM29  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLS03 Advanced Photon Source Upgrade vacuum, photon, storage-ring, undulator 453
 
  • M.E. Szubert, E.R. Anliker, T.J. Bender, J.E. Lerch
    ANL, Lemont, Illinois, USA
  
  The Advanced Photon Source Upgrade (APS-U) in-cludes four straight sections equipped with full length Superconducting Undulators (SCUs). These sections require vacuum systems that must span 5.383 meters at nominal length, accommodate the SCU device, and ac-commodate additional magnets for the canted configura-tions. In the direction of the beam, the upstream portion of the vacuum system is a copper chamber doubling as a photon absorber with a design that is manufactured to allow a 13.5 mm canting magnet gap. This portion of the vacuum system operates at room temperature and shad-ows the length of the vacuum chamber that operates within the cryostat at 20K. The vacuum chamber inside the cryostat is a weldment including a machined alumi-num extrusion allowing for an 8mm magnetic gap, stain-less steel thermal insulators, copper shields, and bel-lows/flange assembly. The vacuum system includes an-other room temperature copper chamber and absorber on the downstream end of the straight section. The vacuum system provides Ultra-high Vacuum (UHV) continuity through the straight section, connecting the storage ring vacuum systems.  
poster icon Poster TUPLS03 [0.974 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS03  
About • paper received ※ 26 August 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLS10 Troubleshooting and Characterization of Gridded Thermionic Electron Gun cathode, electron, gun, controls 474
 
  • M.S. Stefani
    ODU, Norfolk, Virginia, USA
  • F.E. Hannon
    JLab, Newport News, Virginia, USA
  
  Jefferson National Laboratory has, in collaboration with Xelera research group, designed and built a gridded thermionic election gun with the potential for magnetization; in an effort to support research towards electron sources that may be utilized for the electron cooling process in the Jefferson Laboratories Electron Ion collider design. Presented here is the process and result of troubleshooting the electron gun components and operation to ensure functionality of the design.  
poster icon Poster TUPLS10 [10.691 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS10  
About • paper received ※ 27 August 2019       paper accepted ※ 13 September 2019       issue date ※ 08 October 2019  
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TUPLS11 NEG-Coated Copper Vacuum Chambers for the APS-Upgrade Storage Ring Vacuum System vacuum, storage-ring, photon, radiation 477
 
  • O.K. Mulvany, B. Billett, B. Brajuskovic, J.A. Carter, A. McElderry, K.J. Wakefield
    ANL, Lemont, Illinois, USA
  
  Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
The APS-Upgrade (APS-U) storage ring features a diverse group of vacuum chambers including seven distinctive, non-evaporable getter (NEG)-coated copper vacuum chambers per each of the 40 sectors. These chambers feature a 22-millimeter diameter aperture along the electron-beam path, with two vacuum chambers permitting photon extraction through a keyhole-shaped extension to this aperture. The chambers range from 0.3-meters to 1.7-meters in length and fit within the narrow envelope of quadrupole and sextupole magnets. Six of the seven copper vacuum chambers intercept significant heat loads from synchrotron radiation; five of these designs are fabricated entirely from OFS copper extrusions and are equipped with a compact Glidcop® photon absorber. A hybrid vacuum chamber, fabricated from OFS copper extrusion and a copper chromium zirconium (CuCrZr) keyhole transition, also intercepts synchrotron radiation. The seventh vacuum chamber design features a keyhole aperture across its length and is entirely fabricated from CuCrZr. This paper details the careful balance of vacuum chamber functionality, manufacturability, and the overall design process followed to achieve the final designs. 		 
poster icon Poster TUPLS11 [4.941 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS11  
About • paper received ※ 27 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLS14 Analyzing Accelerator Operation Data with Neural Networks injection, storage-ring, network, booster 487
 
  • F.Y. Wang, X. Huang, Z. Zhang
    SLAC, Menlo Park, California, USA
  
  Funding: Work is supported by DOE contract DE-AC02-76SF00515 (SLAC) and DOE contracts 2018-SLAC-100469 and 2018-SLAC-100469ASCR.
Accelerator operation history data are used to train neural networks in an attempt to understand the underly-ing causes of performance drifts. In the study, injection efficiency of SPEAR3 [1] over two runs is modelled with a neural network (NN) to map the relationship of the injection efficiency with the injected beam trajectory and environment variables. The NN model can accurately predict the injection performance for the test data. With the model, we discovered that an environment parameter, the ground temperature, has a big impact to the injection performance. The ideal trajectory as a function of the ground temperature can be extracted from the model. The method has the potential for even larger scale application for the discovery of deep connections between machine performance and environment parameters. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS14  
About • paper received ※ 29 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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TUPLH01 Status of the Superconducting Undulator Program at the Advanced Photon Source undulator, storage-ring, alignment, photon 490
 
  • M. Kasa, E.R. Anliker, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, W.G. Jansma, I. Kesgin, Y. Shiroyanagi
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Since 2013 there has been at least one superconducting undulator (SCU) in operation at the Advanced Photon Source (APS), currently there are two planar SCUs and one helical SCU. The combined operational experience of SCUs at the APS is more than 11 years and counting. Through all these years, APS SCUs operated with the predicted or better than predicted radiation performance and with 99% availability. With this demonstrated reliability and experimentally confirmed spectral performance, the APS upgrade project is planning on leveraging the advantages of SCU technology. The present planar SCUs are comprised of ~1.1-m-long magnets, each operated within a 2-m-long cryostat, while the planar SCUs for the upgrade will have two ~1.8-m-long magnets operating within a 5-m-long cryostat. Progress is also being made in other areas of SCU development with work on an arbitrary polarizing SCU, referred to as SCAPE, and a planar SCU wound with Nb3Sn superconductor. A Nb3Sn SCU is being designed with two 1.3-m-long magnets within a 5-m-long cryostat, and installation is planned for 2021. Also under development are the alignment and magnetic measurement systems for use with the 5-m-long cryostat. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH01  
About • paper received ※ 26 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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TUPLH18 NSLS-II Inject Linac RF Control Electronics Upgrade controls, linac, klystron, network 516
 
  • H. Ma
    BNL, Upton, New York, USA
  
  Funding: US DOE
The electron LINAC injector of NSLS-II synchrotron light-source runs both Single-Bunch beam and long Multi-Bunch beam of up to 150 bunches. The key component for achieving this dual injector beam mode support capability is a high-speed rf modulator (or RFM) in the LINAC RF electronics front-end, which performs the necessary rf control and the beam loading compensation of different injection beams. The original LINAC rf electronics front-end successfully supported the machine commissioning and meets the basic needs of the machine operation. The upgrade being pursued is focused on improving the RFM control performance through replacing the current analog implementation in the RFM with a much more capable digital implementation, while still maintaining the necessary control bandwidth that is required for long and short Multi-Bunch beams. A variety of modern COTS rf transmission/reception DSP technology will be incorporated in the new design. The improvement in the reliability of network connection between the RFM’s and their host server is another focus in the upgrade, and the solution includes the adoption of the COTS TCP/IP and other communication protocol offload engines. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH18  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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TUPLH19 Upgrade and Operation Experience of Solid-State Switching Klystron Modulator in NSLS-II Linac klystron, linac, high-voltage, injection 519
 
  • H. Ma, J. Rose
    BNL, Upton, New York, USA
  
  Funding: US DOE
The NSLS-II synchrotron light-source at BNL uses three S-band, 45MW klystrons in its injector LINAC. At the core of the klystron station design is the novel solid-state switching modulators (or SSM). Compared to the conventional PFN klystron modulators, the main advantages of the SSM include the compact size requiring a smaller footprint in the LINAC, and a very flat top in the produced klystron HV pulses. The flatness of the HV pulses is very important for NSLS-II LINAC that runs multi-bunch beams to keep the beam energy dispersion within the tolerance. The principle of the SSM is fairly simple. It uses a large number of relatively low-voltage switched charging capacitor cells (or SU’s) in parallel. A specially designed, high step-up ratio, pulse transformer in the oil-tank with the same number of primary windings (as SU’s) combines the power from all the SU’s, and steps up to the required ~300kV klystron beam voltage. The operation experience at NSLS-II has proven the performance and reliability of the SSM’s. The BNL Model K2 SSM’s are currently being upgraded to Model K300 to run more powerful, and more cost-effective Canon’s E37302A klystrons. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH19  
About • paper received ※ 27 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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TUPLO03 RHIC Beam Abort System Upgrade Options kicker, vacuum, proton, heavy-ion 536
 
  • W. Fischer, M. Blaskiewicz, M. Mapes, M.G. Minty, C. Montag, S.K. Nayak, V. Ptitsyn, J. Sandberg, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, K. Yip
    BNL, Upton, New York, USA
  
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The RHIC ion (polarized proton) beam intensity has increased to 4x (1.1x) of the original design specifications. In 2013 proton beam currents overcame the eddy current reduction design features in the RHIC beam abort system kicker magnets causing ferrite heating and resulting in a reduction of the kicker strength. In 2014, the abort kicker ferrites were changed, the eddy current reduction design was upgraded, and an active ferrite cooling loop installed to prevent heating. For ions the beam dump vacuum window was changed from stainless steel to a titanium alloy and the adjacent beam diffuser block carbon material was changed to allow for higher ion intensities. A thicker beam pipe was installed to prevent secondaries from quenching the adjacent superconducting quadrupole. With these upgrades there is at least a factor 2 of safety margin for the demonstrated intensities to date. For a further increase in the intensity for RHIC and eRHIC we evaluate upgrade options for the beam abort system. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO03  
About • paper received ※ 26 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLO04 The Latest Code Development Progress of JSPEC electron, simulation, emittance, collider 539
 
  • H. Zhang, S.V. Benson, Y. Roblin, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
The JLab Simulation Package on Electron Cooling (JSPEC) is an open source software developed at Jefferson Lab for electron cooling and intrabeam scattering (IBS) simulations. IBS is an important factor that leads to the growth of the beam emittance and hence the reduction of the luminosity in a high density ion collider ring. Electron cooling is an effective measure to overcome the IBS effect. Although JSPEC is initiated to fulfill the simulation needs in JLab Electron Ion Collider project, it can be used as a general design tool for other accelerators. JSPEC provides various models of the ion beam and the electron beam and it calculates the expansion rate and simulates the evolution of the ion beam under the IBS and/or electron cooling effect. In this report, we will give a brief introduction of JSPEC and then present the latest code development progress of JSPEC, including new models, algorithms, and the user interface. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO04  
About • paper received ※ 20 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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TUPLO05 Fixed Target Operation at RHIC in 2019 target, experiment, controls, kicker 542
 
  • C. Liu, I. Blacker, M. Blaskiewicz, K.A. Brown, D. Bruno, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, D. Kayran, N.A. Kling, Y. Luo, D. Maffei, G.J. Marr, B. Martin, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, I. Pinayev, S. Polizzo, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, S. Tepikian, P. Thieberger, A. Zaltsman, K. Zeno, I.Y. Zhang, W. Zhang
    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.
RHIC operated in fixed target mode at beam energies 4.59, 7.3, and 31.2 GeV/nucleon in 2019 as a part of the Beam Energy Scan II program. To scrape beam halo effectively at the fixed target which is 2.05 m away from the center of the STAR detectors, lattice design with relative large beta function at STAR was implemented at the two lower energies. The kickers of the base-band tune (BBQ) measurement system were engaged to dilute the beam transversely to maintain the event rate except for 31.2 GeV/nucleon. In addition, beam orbit control, tune and chromaticity adjustments were used to level the event rate. This paper will review the operational experience of RHIC in fixed target mode at various energies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO05  
About • paper received ※ 21 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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TUPLE07 Overview of FRIB’s Diagnostics Controls System controls, EPICS, diagnostics, software 576
 
  • B.S. Martins, S. Cogan, M.G. Konrad, S.M. Lidia, D.O. Omitto, P.J. Rodriguez
    FRIB, East Lansing, Michigan, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
In this work we will present an overview of the diagnostics systems put in place by FRIB’s Beam Instrumentation and Measurements department. We will focus on the controls and integration aspects for different kinds of equipment, such as pico ammeters and motor controllers, used to drive and readback the devices deployed on the beamline, such as profile monitors, Faraday cups, etc. In particular, we will discuss the controls software used in our deployment and how we make use of continuous integration and deployment systems to automate certain tasks and make the controls system in production more robust. 		 
poster icon Poster TUPLE07 [2.302 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE07  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLE13 Analytical Thermal Analysis of Thin Diamond in High-Intensity High-Repetition-Rate Application laser, FEL, electron, free-electron-laser 587
 
  • Y. Hong, B. Yang
    University of Texas at Arlington, Arlington, USA
  • J. Wu, G. Zhou
    SLAC, Menlo Park, California, USA
  
  Thin diamond plates are used in monochromator for X-ray Free-Electron Laser self-seeding scheme. To function properly, they must endure high-intensity and high-repetition-rate laser pulses without crossing thresholds set by various adverse effects, such as thermal strain-induced diffraction distortion and graphitization. In this work, a theoretical model is developed, and an analytical solution is derived to elucidate potential thermal runaway under edge cooling condition. It is shown that the crystal edge cooling can effectively mitigate the issue to a certain extent. The analytical solution can be used as an efficient tool for XFEL operation parameter setup.  
poster icon Poster TUPLE13 [0.939 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE13  
About • paper received ※ 27 August 2019       paper accepted ※ 06 September 2019       issue date ※ 08 October 2019  
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WEYBB3 Foil Scattering Model for Fermilab Booster scattering, injection, booster, proton 632
 
  • 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 [5.690 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB3  
About • paper received ※ 28 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEYBB4 Progress of Liquid Lithium Stripper for FRIB vacuum, MMI, electron, gun 636
 
  • 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 [6.012 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB4  
About • paper received ※ 03 September 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEYBB6 Design Considerations and Operational Features of the Collimators for the Fermilab Main Injector and Recycler collimation, proton, radiation, controls 642
 
  • 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 [12.713 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB6  
About • paper received ※ 30 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEZBA5 Development of a Marx Modulator for FNAL Linac controls, flattop, power-supply, high-voltage 653
 
  • T.A. Butler, F.G. Garcia, M.R. Kufer, K.S. Martin, H. Pfeffer
    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.
A Marx-topology modulator has been designed and developed at the Fermi National Accelerator Laboratory under the Proton Improvement Plan (PIP). This modulator replaces the previous triode hard-tube design, increasing reliability, lowering operational costs, and maintaining waveform accuracy. The Marx modulator supplies the anode of the 7835 VHF power triode tube with a 35 kV, 375 Amp, 460 µs pulse at 15 Hz. It consists of 54 individual Marx cells, each containing a 639 µF capacitor charged to 900 Volts, combined in series with IGBT switches to create the desired output waveform. This requires variable rise and fall times, flattening of capacitive droop, and feedforward beam loading compensation. All five 201.25 MHz RF systems have been upgraded to Marx modulators to ensure continued operation of the linear accelerator. 		 
slides icon Slides WEZBA5 [15.252 MB]  
poster icon Poster WEZBA5 [3.029 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA5  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM05 Continuous Monitoring of Spectral Features of Electron Beam Orbit Motion at NSLS-II undulator, controls, feedback, cavity 673
 
  • B. Podobedov, A.A. Derbenev, K. Ha, T.V. Shaftan
    BNL, Upton, New York, USA
  
  NSLS-II ring is equipped with state-of-the art beam position monitors (BPMs) which are indispensable in all aspects of machine studies and operations. Among other data, they can provide, on demand, up to 10 seconds of fast-acquisition (FA) data, sampled at ~10 kHz. Analysis of these data in time, frequency and spatial domains provides valuable insights into orbit stability, locations of residual noise sources, performance of feedback systems, etc. In addition, changes in FA signal spectral features are often the earliest indicators of potential equipment problems. This is why we recently implemented an Input / Output Controller (IOC) software that runs during regular user operation, and, once a minute, acquires 10 second buffers of FA data from 180 BPMs around the ring. These buffers are processed to determine the amplitudes and frequencies of the strongest spectral peaks as well as some other measures of fast beam orbit noise. Processed results can be monitored in real time and are also archived for offline analysis and troubleshooting. In this paper we discuss the implementation of this system and the insights we gained from it over about two years of operations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM05  
About • paper received ※ 31 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEPLM64 High Dynamic Voltage Range Studies of Piezoelectric Multilayer Actuators at Low Temperatures linac, cavity, SRF, vacuum 739
 
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  • Y.M. Pischalnikov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  
  Piezo actuators are used for resonance control in superconducting linacs. In high accelerating gradients linacs, such as those operated in a pulsed mode, the piezos require a large operating voltage. This is due to the Lorentz forced detuning which causes a large frequency shift and is compensated with an active piezo-tuning system. In this high dynamic voltage range the piezo is expected to warm up drastically due to it being in an insulated vacuum. This study characterizes the dielectric properties (capacitance, dielectric losses), the piezo stroke (from geophone), and thermal properties such as heating. Results obtained in the temperature range of 20K to 300K will be presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM64  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLM71 Thermal Performance of FRIB Cryomodules cryomodule, cryogenics, cavity, solenoid 759
 
  • M. Xu, W. Chang, C. Compton, A. Ganshyn, S.H. Kim, S.J. Miller, J.T. Popielarski, K. Saito, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511.
Now SRF cavity development is advancing high-Q/high gradient by nitrogen doping, infusion, or the new low temperature bake recipe. Once cavity dynamic loss is reduced, the static heat load of the cryomodule will be of concern from the cryogenic plant capability point of view. FRIB gives us a good chance to statistically compare the cryogenic plant design and the measured results, along with a thought for future updated cryomodule design using a low/medium beta cryomodule. FRIB cryomodules have two cooling lines: 4.5 K for solenoids and 2K for cavities. The boil-off liquid helium method was used to measure the cryomodule’s heat load. So far, FRIB has completed certification testing (bunker tests) on 39 of 49 cryomodules (80%). This paper reports the static heat load measurement results, which are important for future FRIB upgrades to estimate remaining cryogenic capability. The cryomodule’s evolution related to heat load is introduced too. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM71  
About • paper received ※ 05 September 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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WEPLM72 Design of a High-Gradient S-Band Annular Coupled Structure coupling, cavity, linac, Windows 762
 
  • B. Mustapha, A. Abogoda, A. Barcikowski, R.L. Fischer, A. Nassiri
    ANL, Lemont, Illinois, USA
  
  Funding: This work was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357 through ANL’s LDRD program.
At Argonne, we have recently developed a conceptual design for a compact linear accelerator for ion beam therapy named ACCIL [1]. A linac-based ion-beam therapy facility offers many advantages over existing synchrotron based facilities. In addition to the reduced footprint, ACCIL offers more flexibility in beam tuning, including pulse-per-pulse energy and intensity modulation and fast switching between ion species. Essential to the compactness of the ACCIL linac are high-gradient structures for low to intermediate velocity ions, capable of accelerating fields of ~ 50 MV/m. For this purpose, we have designed an S-band annular-coupled structure (ACS). An ACS has the desired qualities of high electric field limit, high shunt-impedance, large area for magnetic coupling and good cooling capacity, making it a very promising candidate for high-gradient operations. We here present the optimized RF design for a β ~ 0.4 ACS.
* P. Ostroumov, et al., "Compact Carbon Ion Linac", Proceedings of NAPAC2016, Oct 10-14 2016, Chicago, IL
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM72  
About • paper received ※ 04 October 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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WEPLS10 Modeling of Space-Charge Effects in the ORISS MRTOF Device for Applications to FRIB focusing, space-charge, optics, linac 786
 
  • R. Hipple
    MSU, East Lansing, Michigan, USA
  • S.M. Lund
    FRIB, East Lansing, Michigan, USA
  
  The Oak Ridge Isotope/Isomer Spectrometer and Separator (ORISS) is an electrostatic multiply reflecting time-of-flight (MRTOF) mass separator constructed by the University Radioactive Ion Beam Consortium (UNIRIB) and Louisiana State University. The device was never fully commissioned, and was eventually shipped to Michigan State University for use at the Facility for Rare Isotopes and Beams (FRIB). The separation process is sensitive to space-charge effects due to the reflection of ions at both ends of the trap, as well as nonlinearities in the optics. In this study we apply the time-based particle-in-cell code Warp to model the effects of intense space-charge during the separation process. We find that the optics can be tuned for isochronous operation and focusing in the presence of intense space-charge to enable separation of bunches with high particle counts. This suggests the device may be effectively utilized at FRIB as a separator, spectrograph and spectrometer.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS10  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLS14 A C++ TPSA/DA Library With Python Wrapper multipole, simulation, framework, collective-effects 796
 
  • H. Zhang, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Truncated power series algebra (TPSA) or differential algebra (DA) is often used by accelerator physicists to generate a transfer map of a dynamic system. The map then can be used in dynamic analysis of the system or in particle tracking study. TPSA/DA can also be used in some fast algorithms, eg. the fast multipole method, for collective effect simulation. This paper reports a new TPSA/DA library written in C++. This library is developed based on Dr. Lingyun Yang’s TPSA code, which has been used in MAD-X and PTC. Compared with the original code, the updated version has the following changes: (1) The memory management has been revised to improve the efficiency; (2) A new data type of DA vector is defined and supported by most frequently used operators; (3) Support of inverse trigonometric functions and hyperbolic functions for the DA vector has been added; (4) function composition is revised for better efficiency; (5) a python wrapper is provided. The code is hosted at github and available to the public. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS14  
About • paper received ※ 20 September 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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WEPLH02 Experience with Long-Pulse Operation of the PIP2IT Warm Front End rfq, MEBT, kicker, LEBT 803
 
  • A.V. Shemyakin, J.-P. Carneiro, A.Z. Chen, D. Frolov, B.M. Hanna, R. Neswold, L.R. Prost, G.W. Saewert, A. Saini, V.E. Scarpine, A. Warner, J.Y. Wu
    Fermilab, Batavia, Illinois, USA
  • C.J. Richard
    NSCL, East Lansing, Michigan, 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 warm front end of the PIP2IT accelerator, assembled and commissioned at Fermilab, consists of a 15 mA DC, 30 keV H− ion source, a 2-m long Low Energy Beam Transport (LEBT) line, a 2.1-MeV, 162.5 MHz CW RFQ, followed by a 10-m long Medium Energy Beam Transport (MEBT) line. A part of the commissioning efforts involves operation in regimes where the average beam power in this front end emulates the operation of the proposed PIP-II accelerator, which will have a duty factor of 1.1% or above. The maximum achieved power is 5 kW (2.1 MeV x 5 mA x 25 ms x 20 Hz). This paper describes the difficulties encountered and some of the solutions that were implemented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH02  
About • paper received ※ 20 August 2019       paper accepted ※ 01 September 2019       issue date ※ 08 October 2019  
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WEPLH03 Redesign of ReA3 4-Rod RFQ rfq, MMI, simulation, linac 807
 
  • A.S. Plastun, P.N. Ostroumov, A.C.C. Villari, Q. Zhao
    FRIB, East Lansing, Michigan, USA
  • A.C.C. Villari, Q. Zhao
    NSCL, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. DoE Office of Science under Cooperative Agreement DE-SC0000661 and the NSF under Cooperative Agreement PHY-1102511, the State of Michigan and Michigan State University.
The present RFQ of ReA3 reaccelerator at Michigan State University (MSU) has been commissioned in 2010. This 4-rod RFQ was designed to accelerate the prebunched 80.5 MHz beams with the lowest Q/A = 1/5. However, the lack of proper cooling limited the RFQ performance to the pulsed operation with the lowest Q/A = 1/4. The design voltage for Q/A = 1/5 has never been reached even in a pulsed mode due to the sparking. In 2016 we initiated the upgrade of ReA3 RFQ to support high duty cycle (up to CW) operation with Q/A = 1/5 beams. The upgrade included the new rods with trapezoidal modulation, and new stems with improved cooling. The redesigned 80.5 MHz RFQ will consume only 65% rf power of the present RFQ for Q/A = 1/5 beam. It will provide the transmission up to 78% for 16.1 MHz beams and 89% for 80.5 MHz beams. High reliability and efficiency of the RFQ are very important for the going-on reaccelerator upgrade to ReA6 and for future operation as a part of FRIB. The electrodes have been manufactured and are being installed. The RF and beam tests are scheduled to summer 2019. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH03  
About • paper received ※ 27 August 2019       paper accepted ※ 01 September 2019       issue date ※ 08 October 2019  
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WEPLH07 Commissioning of the FRIB/NSCL New ReA3 4-Rod Radio Frequency Quadrupole Accelerator rfq, vacuum, MMI, cavity 817
 
  • S. Nash, J.F. Brandon, D.B. Crisp, T. Summers, A.C.C. Villari, Q. Zhao
    NSCL, East Lansing, Michigan, USA
  • P.N. Ostroumov, A.S. Plastun
    FRIB, East Lansing, Michigan, USA
  
  Funding: This work was supported by the National Science Foundation under Grant PHY-15-65546
The reaccelerator facility ReA3 at the National Superconducting Cyclotron Laboratory is a state-of-the-art accelerator for ions of rare and stable isotopes. The first stage of acceleration is provided by a 4-rod radio-frequency quadrupole (RFQ) at 80.5 MHz, which accelerates ions from 12 keV/u to 530 keV/u. The internal copper acceleration structure of the RFQ was re-designed. The goal was to improve transmission while allowing to operate the RFQ in CW and accelerating ions with A/Q from 2 to 5. In this paper, we summarize the steps involved in the disassembly of the existing structure, preparation work on the retrofitted vacuum vessel, installation of the new components, acceptance testing, and commissioning of the completed RFQ. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH07  
About • paper received ※ 29 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLH19 Record Fast Cycling Accelerator Magnet Based on High Temperature Superconductor cryogenics, proton, booster, collider 845
 
  • H. Piekarz, J.N. Blowers, S. Hays, V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359
We report on the prototype High Temperature Superconductor (HTS) based accelerator magnet capable to operate at 12 T/s B-field ramping rate with a very low supporting cryogenic cooling power thus indicating a feasibility of its application in large accelerator requiring high repetition rate and high average beam power. The magnet is designed to simultaneously accelerate two particle beams in the separate beam gaps energized by a single conductor. The design, construction and the power test arrangement of a prototype of this fast-cycling HTS based accelerator magnet are presented. As example, the cryogenic power loss limit measured in the magnet power test is discussed in terms of feasibility of application of such a magnet for the construction of an 8 GeV dual-beam proton booster accelerator. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH19  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLH20 Modeling of H− Ion Source at LANSCE ion-source, experiment, plasma, electron 848
 
  • N.A. Yampolsky, I. Draganić, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Work supported by the US Department of Energy under Contract Number DE-AC52-06NA25396
We report on the progress in modeling performance of the H− ion source at LANSCE. The key aspect we address is the lifetime of the tungsten filament. The lifetime depends on multiple parameters of the ion source and can dramatically vary in different regimes of operation. We use the multiphysics approach to model the performance of the ion source. The detailed analysis has been made to recognize key physical processes, which affect the degradation of the filament. The analysis resulted in the analytical model, which includes relevant processes from the first principles. The numerical code based on this model has been developed and benchmarked. The results of the modeling show good agreement with experimental data. As a result, the developed model allows predicting the performance of the ion source in various regimes of operation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH20  
About • paper received ※ 28 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLO20 High Gradient High Efficiency C-Band Accelerator Structure Research at LANL simulation, experiment, cavity, electron 882
 
  • E.I. Simakov, A.W. Garmon, T.C. Germann, M.F. Kirshner, F.L. Krawczyk, J.W. Lewellen, D. Perez, G. Wang
    LANL, Los Alamos, New Mexico, USA
  • A. Fukasawa, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  
  Funding: Los Alamos National Laboratory LDRD Program
This poster will report on the status of the new high gradient C-band accelerator project at LANL. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. Our goal is to use a multi-disciplinary approach that includes accelerator design, molecular dynamics simulations, and advanced manufacturing to develop high gradient, high efficiency RF structures for both compact and facility-size accelerator systems. We considered common operation frequencies for accelerators and identified C-band as the optimal frequency band for high gradient operations based on achievable gradients and means to control wakefields. We are putting together a high gradient C-band test facility that includes a 50 MW Toshiba klystron and cryo-coolers for operating copper NCRF accelerator cavities at long pulse duration. We plan to conduct high gradient testing of the optimized RF structures made of copper and novel copper alloys. LANL modeling capabilities will be used to systematically study the formation of breakdown precursors at high fields to develop basic theoretical understanding of the breakdown. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO20  
About • paper received ※ 27 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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THYBA6 Active Pointing Stabilization Techniques Applied to the Low Energy RHIC Electron Cooling Laser Transport at BNL laser, electron, controls, cathode 938
 
  • 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 [3.426 MB]  
poster icon Poster THYBA6 [1.299 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THYBA6  
About • paper received ※ 27 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THZBA2 The MYRRHA Project cavity, linac, rfq, proton 945
 
  • H. Podlech, P. Britten, K. Kümpel, S. Lamprecht, N.F. Petry
    IAP, Frankfurt am Main, Germany
  • M. Abs, J. Brison
    IBA, Louvain-la-Neuve, Belgium
  • C. Angulo, J. Belmans, F. Doucet, A. Gatera, F. Pompon, A. Ponton, D. Vandeplassche
    SCK•CEN, Mol, Belgium
  • A. Apollonio, J.A. Uythoven
    CERN, Meyrin, Switzerland
  • A. Bechtold
    NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
  • J.-L. Biarrotte, C. Joly, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • P. Fernandez Ramos, A.E. Pitigoi
    Empresarios Agrupados, Madrid, Spain
  • H. Höltermann, U. Ratzinger
    BEVATECH, Frankfurt, Germany
  • T. Junquera
    Accelerators and Cryogenic Systems, Orsay, France
  • R. Modic
    Cosylab, Ljubljana, Slovenia
  • F. Senée, D.U. Uriot
    CEA-IRFU, Gif-sur-Yvette, France
  • C. Zhang
    GSI, Darmstadt, Germany
  
  The main objective of the MYRRHA project at SCK•CEN, the Belgian Nuclear Research Centre, is to demonstrate the feasibility of nuclear waste transmutation using an Accelerator Driven System (ADS). It is based on a High Power CW operated 600 MeV proton Linac with an average beam power of 2.4 MW. Due to the coupling of the accelerator with a subcritical reactor, a major concern is reliability and availability of the accelerator. The MYRRHA Linac consists of a room temperature 17 MeV Injector based on CH-cavities and the superconducting main Linac using different RF structures as Single Spokes, Double-Spokes and elliptical cavities. In 2017, it has been decided to stage the project and to start with the construction of a 100 MeV Linac (Injector and Single Spoke section) including a 400 kW proton target station. This facility (MINERVA) will be operational in 2026 aiming to evaluate the reliability potential of the 600 MeV Linac. The Front-End consisting of an ECR source, LEBT and 1.5 MeV RFQ is already operational while the first 7 CH-cavities are under construction. The presentation gives an overview about the MYRRHA Project, its challenges and the status of construction and testing.  
slides icon Slides THZBA2 [27.209 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA2  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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THZBB5 Present Status and Upgrades of the SNS Ion Beam Bunch Shape Monitors electron, controls, power-supply, high-voltage 968
 
  • V. Tzoganis, A.V. Aleksandrov, R.W. Dickson
    ORNL, Oak Ridge, Tennessee, USA
  
  Six interceptive Feschenko-style longitudinal bunch profile monitors have been deployed in the normal conducting part of the SNS linac and HEBT. They have been operational for more than 10 years and although their performance has been satisfactory, reliability and parts obsolescence must be addressed. The upgrade plan focuses in mainly two areas, electronics architecture modernization and improvement of measurement resolution. In the first phase that is presented here the objective is to improve the control and readout electronics taking advantage of more recent technology. This will primarily address the obsolescence issues with older components, the frequent RF power failures, the non-trivial maintenance and troubleshooting and will lead to a simpler and more reliable system. This contribution describes in detail the implemented upgrades and presents the first experimental data.  
slides icon Slides THZBB5 [4.926 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB5  
About • paper received ※ 29 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THAHC2 The Future Circular Collider and Physical Review Accelerators & Beams collider, hadron, luminosity, lepton 975
 
  • F. Zimmermann
    CERN, Geneva, Switzerland
  
  The proposed integrated program of the Future Circular Collider(FCC) takes a huge step beyond LEP and LHC. The FCC consists, in a first stage, of an energy- and luminosity-frontier electron-positron collider, which will operate at center-of-mass (c.m.) energies from about 90 to 365 GeV, and serve as electroweak factory. The second stage of the FCC will be a 100 TeV proton collider based on novel high-field magnets. A similar project is being proposed in China. In parallel to the development of future colliders, also the field of publications is undergoing profound changes. Physical Review Accelerators and Beams (PRAB) was founded in 1997 as a pioneering all-electronic diamond open-access journal, far ahead of its time. For many years PRAB was the fastest growing journal in the Physical Review family. Authors, editors and referees are highly internationalized. In this paper, on the occasion of the acceptance of the 2019 USPAS Prize for Achievement in Accelerator Science and Technology, I sketch the history, status, and challenges of FCC and PRAB.  
slides icon Slides THAHC2 [10.458 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THAHC2  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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