04: Hadron Accelerators
Paper Title Page
MOOHC1
The Facility for Rare Isotope Beams Project: Motivation, Status, and Technical Challenges  
 
  • T. Glasmacher
    FRIB, East Lansing, Michigan, USA
 
  Funding: The design and establishment of FRIB are supported by the U.S. Department of Energy Office of Science under cooperative agreement DE-SC0000661, the State of Michigan, and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) is being designed and established by Michigan State University as a DOE Office of Science (DOE-SC) scientific user facility supporting the mission of the Office of Nuclear Physics in DOE-SC. Over 90% complete, FRIB will enable world-leading research opportunities with rare isotopes in nuclear physics, nuclear chemistry, and the application of rare isotopes for society. FRIB is centered on a superconducting radio-frequency linear accelerator, operating at 2 K and capable of delivering 400 kW of beam power, and a fragment separator consisting of superconducting magnets capable of selecting and identifying 1 in 1018 rare isotopes. This presentation reviews the physics motivation for FRIB, the project’s status, the major technical challenges, and some of the strategic choices supporting delivery of the project baseline with a high likelihood of success.
 
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MOYBB5 Characterization and Performance of Plasma Window for Gas Flow Restriction in Different Geometries 44
SUPLE17   use link to see paper's listing under its alternate paper code  
WEPLH05   use link to see paper's listing under its alternate paper code  
 
  • A. Lajoie
    NSCL, East Lansing, Michigan, USA
  • J. Gao, F. Marti
    FRIB, East Lansing, Michigan, USA
 
  Funding: This work is supported by NSF Award PHY-1565546.
The plasma window is a DC cascaded arc whose function is to restrict gas flow from a high pressure region to a low pressure region without the use of any solid separation*. As a result, the plasma window allows a greater pressure to be maintained than otherwise possible. This is a beneficial characteristic for gas charge strippers for ion accelerators, since the higher pressures enable the stripper to be shorter and allow the same amount of stripping interactions**. The flow rate reduction is established by the increase in gas temperature from the power deposited into the plasma via the cathodes, resulting in a dramatically increased viscosity. The flow rate reduction, depends on the properties of the plasma, including the electron density and temperature, pressure, and electrical conductivity. Understanding these properties in multiple arc geometries - in this work having either 6 mm or 10 mm channel diameter - provides a means optimizing the plasma window for a given design. Determinations of the properties for different conditions are shown, and results are compared with a PLASIMO simulation, which has been shown to yield comparable properties to measurements in an argon arc***.
*A. Hershcovitch, Phys. Plasma 5, 2130 (1998).
**J. A. Nolen and F. Marti, Rev. Accel. Sci. Tech. 6, 221 (2013).
***G. M. W. Kroesen et al., Plas. Chem. and Plas. Proc. 10, 531 (1990).
 
slides icon Slides MOYBB5 [4.132 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBB5  
About • paper received ※ 27 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEYBB1 ELENA Commissioning 626
WEPLH18   use link to see paper's listing under its alternate paper code  
 
  • D. Gamba, M.E. Angoletta, P. Belochitskii, L. Bojtár, F. Butin, C. Carli, B. Dupuy, Y. Dutheil, T. Eriksson, P. Freyermuth, C. Grech, M. Hori, J.R. Hunt, M. Jaussi, L.V. Jørgensen, B. Lefort, S. Pasinelli, L. Ponce, G. Tranquille
    CERN, Meyrin, Switzerland
  • R. Gebel
    FZJ, Jülich, Germany
  • C. Grech
    University of Malta, Information and Communication Technology, Msida, Malta
  • M. Hori
    MPQ, Garching, Munich, Germany
 
  The Extra Low ENergy Antiproton storage ring (ELENA) is an upgrade project at the CERN AD (Antiproton Decelerator). ELENA will further decelerate the 5.3 MeV antiprotons coming from the AD down to 100 keV. ELENA features electron cooling for emittance control during deceleration thus preserving the beam intensity and allowing to extract bright bunches towards the experiments. The lower energy will allow for increasing the antiproton trapping efficiency up to two orders of magnitude, which is typically less than 1% with the present beam from AD. The ring was completed with the installation of the electron cooler at the beginning of 2018. Decelerated beams with characteristics close to the design values were obtained before the start of CERN Long Shutdown 2 (LS2). During LS2 electrostatic transfer lines from the ELENA ring to the experimental zones will be installed, replacing the magnetic transfer lines from the AD ring. The latest results of commissioning with H and antiprotons and the first observation of electron cooling in ELENA will be presented, together with an overview of the project and status and plans for LS2 and beyond.  
slides icon Slides WEYBB1 [20.792 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB1  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEYBB2
Foil R&D and Temperature Measurements at the SNS  
 
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  The SNS uses charge exchange injection during the accumulation of the accelerated beam in the ring. At a beam power of 1.2 MW, the stripping foil lasts for many weeks, sometimes months. However, given the upgrade to 2.8 MW, it is important to know the current temperature of the foil in order to estimate its lifetime for the new beam power and beam size. This paper will discuss the foil R&D and experimental temperature measurements of a stripper foil, exposed to current operating conditions of the SNS accelerator.  
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WEYBB3 Foil Scattering Model for Fermilab Booster 632
WEPLH14   use link to see paper's listing under its alternate paper code  
 
  • C.M. Bhat, S. Chaurize, J.S. Eldred, V.A. Lebedev, S. Nagaitsev, K. Seiya, C.-Y. Tan, R. Tesarek
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
At the Fermilab Booster, and many other proton facilities, an intense proton beam is accumulated by injection an H beam through a stripping foil. The circulating beam scatters off the injection beam and large-angle Coulomb scattering leads to uncontrolled losses concentrated in the first betatron period. We measure the foil scattering rate in the Booster as a function of linac current, number of injection-turns, and time on injection foil. We find that current Booster operations has a 1% foil scattering loss rate and we make projections for the Proton Improvement Plan II (PIP-II) injector upgrade. We find that accurate modeling of the foil scattering loss must account for beam emittance in conjunction with the scattering rate and ring acceptance. Estimate of beam emittance at injection are discussed.
 
slides icon Slides WEYBB3 [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 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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WEYBB5 A Crab-Crossing Scheme for Laser-Ion Beam Applications 639
 
  • A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, Y. Liu, A. Rakhman, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
 
  Lasers have recently been used in many applications to H beams, including laser charge exchange, laser wire scanners, and laser temporal pulse patterning. The H beam in these applications has wide variation ofμpulse length width dependence on focusing of the RF cavities, energy spread of the beam, and space charge forces. Achieving the required laser pulse length for complete overlap with the H can be challenging in some scenarios when available laser power constrained. The scheme proposed here utilizes a crab-crossing concept between the laser and the ion beam to achieve overlap of a short laser pulse with an arbitrarily long H beam pulse. An experiment to test the hypothesis in the context of H charge exchange is described.  
slides icon Slides WEYBB5 [5.201 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBB5  
About • paper received ※ 30 August 2019       paper accepted ※ 02 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 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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WEPLH01 Longitudinal Beam Profile Measurement by Silicon Detector in Facility for Rare Isotope Beams at Michigan State University 799
 
  • T. Maruta, P.N. Ostroumov, Q. Zhao
    FRIB, East Lansing, Michigan, 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
The Facility for Rare Isotope Beams (FRIB) includes a continuous wave superconducting linear accelerator designed to deliver 400 kW ion beams with energies above 200 MeV/u. The beam commissioning of the first three cryomodules took place in the summer of 2018. A temporary diagnostic station installed after the first three cryomodules included a Silicon Detector (SiD) to measure absolute energy and bunch shape of 40Ar and 86Kr beams accelerated up to 2.3 MeV/u. The beam longitudinal emittance was evaluated by measuring bunch shapes while the bunching field amplitude of the upstream resonator was varied. In this paper, we will present the SiD setup and measurement results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH01  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLH02 Experience with Long-Pulse Operation of the PIP2IT Warm Front End 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 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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WEPLH04 Beam Envelope Reconstruction for FRIB-FS1 Transport Line Using Beam Position Monitors 810
 
  • T. Yoshimoto, S. Cogan, J.L. Crisp, K. Fukushima, S.M. Lidia, T. Maruta, P.N. Ostroumov, A.S. Plastun, T. Zhang, Q. Zhao
    FRIB, East Lansing, Michigan, USA
 
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The Facility for Rare Isotope Beam (FRIB) includes a heavy ion superconducting (SC) linac. Recently we completed beam commissioning of the Linac Segment 1 (LS1) and 45° bend section of the Folding Segment 1 (FS1). Four ion species, 40Ar9+, 20Ne6+, 86Kr17+ and 129Xe26+ were successfully accelerated to a beam energy of 20.3 MeV/u. We explored the possibility of non-invasive beam diagnostics for online beam envelope monitoring based on beam quadrupole moments derived from Beam Position Monitors (BPMs)*. In future operations, various ion beam species will be accelerated and minimization of beam tuning time is critical. To address this requirement, it is beneficial to use BPMs to obtain beam Twiss parameters instead of wire scanners. This paper reports the results of BPM-based beam Twiss parameters evolution in the FS1.
* R. E. Shafer, "Laser Diagnostic for High Current H beams", Proc. 1998 Beam Instrumentation Workshop (Stanford). A.I.P. Conf. Proceedings, (451), 191.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH04  
About • paper received ※ 27 August 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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WEPLH06 Commissioning Status of the FRIB Front End 813
 
  • H.T. Ren, J. Brandon, N.K. Bultman, K.D. Davidson, E. Daykin, T. Elkin, B. Galecka, P.E. Gibson, L. Hodges, K. Holland, D.D. Jager, M.G. Konrad, B.R. Kortum, S.M. Lidia, G. Machicoane, I.M. Malloch, H. Maniar, T. Maruta, G. Morgan, D.G. Morris, P. Morrison, A.C. Morton, P.N. Ostroumov, A.S. Plastun, E. Pozdeyev, X. Rao, T. Russo, J.W. Stetson, R. Walker, J. Wei, Y. Yamazaki, T. Yoshimoto, Q. Zhao, S. Zhao
    FRIB, East Lansing, Michigan, USA
  • S. Renteria
    NSCL, East Lansing, Michigan, USA
 
  Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The FRIB Front End was successfully commissioned in 2017 with commissioning goals achieved and Key Per-formance Parameters (KPP) demonstrated for both 40Ar9+ and 86Kr17+ beams. Two more ion species, 20Ne6+ and 129Xe26+, have been commissioned on the Front End and delivered to the superconducting linac during the beam commissioning of Linac Segment 1 (LS1) in March 2019. In August 2019, Radio Frequency Quadrupole (RFQ) conditioning reached the full design power of 100 kW continuous wave (CW) that is required to accelerate Ura-nium beams. Start-up/shutdown procedures and opera-tional screens were developed for the Front End subsys-tems for trained operators, and auto-start and RF fast re-covery functions have been implemented for the Front End RFQ and bunchers. In this paper, we will present the current commissioning status of the Front End, and per-formance of the main technical systems, such as the ECR ion source and RFQ.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH06  
About • paper received ※ 01 September 2019       paper accepted ※ 05 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 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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WEPLH08 Use of the Base-Band Tune Meter Kickers During the FY18 STAR Fixed Target Run at 3.85 GeV/u 820
 
  • P. Adams, N.A. Kling, C. Liu, G.J. Marr
    BNL, Upton, New York, USA
 
  The base-band tune meter (BBQ) kickers proved to be a useful tool in managing STAR trigger rates during the RHIC FY18 3.85GeV/u Fixed Target Run. The STAR collected over 3 times their original event goal, since it was possible to optimize the STAR trigger rates throughout the length of the physics store.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH08  
About • paper received ※ 16 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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WEPLH09 FRIB Driver Linac Integration to be ready for Phased Beam Commissioning 823
 
  • H. Ao, S. Beher, N.K. Bultman, F. Casagrande, C. Compton, J.C. Curtin, K.D. Davidson, K. Elliott, V. Ganni, A. Ganshyn, P.E. Gibson, I. Grender, W. Hartung, L. Hodges, K. Holland, A. Hussain, M. Ikegami, S. Jones, P. Knudsen, S.M. Lidia, G. Machicoane, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, J. Priller, T. Russo, K. Saito, S. Stanley, D.R. Victory, X. Wang, J. Wei, M. Xu, T. Xu, Y. Yamazaki, S. Zhao
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  • R.E. Laxdal
    TRIUMF, Vancouver, Canada
 
  Funding: Work supported by the U.S. Department of Energy (DOE) Office of Science under Cooperative Agreement DE-SC0000661
The driver linac for Facility for Rare Isotope Beams (FRIB) will accelerate all stable ion beams from proton to uranium beyond 200 MeV/u with beam powers up to 400 kW. The linac now consists of 104 superconducting quarter-wave resonators (QWR), which is the world largest number of low-beta SRF cavities operating at an accelerator facility. The first 3 QWR cryomodules (CM) (β = 0.041) were successfully integrated with cryogenics and other support systems for the 2nd Accelerator Readiness Review (ARR). The 3rd ARR scope that includes 11 QWR CM (β=0.085) and 1 QWR matching CM (β=0.085) was commissioned on schedule by January 2019, and then we met the Key Performance Parameters (KPP), accelerating Ar and Kr > 16 MeV/u at this stage, in a week upon the ARR authorization. We examine a variety of key factors to the successful commissioning, such as component testing prior to system integration, assessment steps of system/device readiness, and phased commissioning. This paper also reports on the integration process of the β=0.085 CMs including the test results, and the current progress on β=0.29 and 0.53 CMs in preparation for the upcoming 4th ARR.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH09  
About • paper received ※ 02 September 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLH10 Efficiency Estimation for Sequential Excitation Laser Stripping of H Beam 827
 
  • T.V. Gorlov, A.V. Aleksandrov, S.M. Cousineau, Y. Liu, A. Rakhman
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UTBattelle, LLC, under contract DEAC0500OR22725 for the U.S. Department of Energy.
A new laser stripping scheme for charge exchange injection of H beam is considered. The sequential scheme for the planned demonstration experiment includes two step excitation that requires much smaller laser power compared to the traditional 1-step excitation. The new scheme can be applied to a wider range of H beam energies and provides more flexibility on the choice of laser frequency. In this paper we discuss the two-step excitation method and estimate laser stripping parameters and stripping efficiency for the SNS accelerator and its future H energy upgrade to 1.3 GeV.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH10  
About • paper received ※ 22 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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WEPLH11 RHIC Quench Protection Diode Radiation Damage 831
 
  • K.A. Drees, O. Biletskyi, D. Bruno, A. Di Lieto, J. Escallier, G. Heppner, C. Mi, T. Samms, J. Sandberg
    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.
Each of RHIC’s superconducting magnets is protected by a silicon quench protection diode (QPD). In total, RHIC has over 800 diodes installed inside the cryostat close to the vacuum pipe~[RHICconfig]. After years of operation with high energy heavy ion beams we experienced a first permanently damaged QPD in the middle of our FY2016 Au Au run and a second damaged diode in the following year. In 2016 the run had to be interrupted by 19 days to replace the diode, in 2017 RHIC could still operate with a reduced ramping speed of the superconducting magnets. Both diodes were replaced and examined "cold" as well as "warm". This paper reports on what we have learned so far about the conditions leading up to the damage as well as the damage itself.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH11  
About • paper received ※ 23 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLH15 Light Ion Injector for NICA 834
 
  • H. Höltermann, H. Hähnel, B. Koubek, H. Podlech, U. Ratzinger, A. Schempp, D. Strehl, R. Tiede
    BEVATECH, Frankfurt, Germany
  • M. Busch, M. Schuett
    IAP, Frankfurt am Main, Germany
  • A.V. Butenko, D.E. Donets, A.D. Kovalenko, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, D.O. Ponkin, K.V. Shevchenko, I.V. Shirikov, A.O. Sidorin, G.V. Trubnikov
    JINR/VBLHEP, Dubna, Moscow region, Russia
  • B.V. Golovenskiy, A. Govorov, V.V. Kobets, E. Syresin
    JINR, Dubna, Moscow Region, Russia
 
  The Nuclotron ring of the NICA project will get a new light ion injector linac (LILac) for protons and ions with a mass to charge ratio up to 3. The LILac will consist of 2 sections: A 600 A keV RFQ followed by an IH-type DTL up to 7 AMeV, and a postaccelerator IH-cavity for protons only - up to 13 MeV. A switching magnet will additionally allow 13 MeV proton beam injection into a future superconducting testing section. The pulsed Linac up to 7 AMeV and including the postaccelerator for protons up to 13 MeV will be developed in collaboration between JINR and Bevatech GmbH. The technical design of that Linac is discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH15  
About • paper received ※ 29 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLH16 Tolerances on Energy Deviation in Microbunched Electron Cooling 837
 
  • P. Baxevanis, G. Stupakov
    SLAC, Menlo Park, California, USA
 
  The performance of microbunched electron cooling (MBEC)* is highly dependent on the quality of the hadron and cooler electron beams. As a result, understanding the influence of beam imperfections is very important from the point of view of determining the tolerances of MBEC. In this work, we incorporate a non-zero average energy offset into our 1D formalism (**,***), which allows us to study the impact of effects such as correlated energy spread (chirp). In particular, we use our analytical theory to calculate the cooling rate loss due to the electron beam chirp and discuss ways to minimize the influence of this effect on MBEC.
* D. Ratner, Phys. Rev. Lett. 111, 084802 (2013).
** G. Stupakov, Phys. Rev. AB, 21, 114402 (2018).
*** G. Stupakov and P. Baxevanis, Phys. Rev. AB, 22, 034401 (2019).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH16  
About • paper received ※ 28 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLH17 Diffusion and Nonlinear Plasma Effects in Microbunched Electron Cooling 841
 
  • P. Baxevanis, G. Stupakov
    SLAC, Menlo Park, California, USA
 
  The technique of michrobunched electron cooling (MBEC) is an attractive scheme for enhancing the brightness of hadron beams in future high-energy circular colliders (*). To achieve the required cooling times for a realistic machine configuration, it is necessary to boost the bunching of the cooler electron beam through amplification sections that utilize plasma oscillations. However, these plasma sections also amplify the intrinsic noise of the electron beam, leading to additional diffusion that can be very detrimental to the cooling. Moreover, they can exhibit nonlinear gain behavior, which reduces performance and limits the applicability of theory. In this paper, we study both of these important effects analytically with the aim of quantifying their influence and keeping them under control.
* D. Ratner, Phys. Rev. Lett. 111, 084802 (2013).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH17  
About • paper received ※ 28 August 2019       paper accepted ※ 03 September 2019       issue date ※ 08 October 2019  
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WEPLH19 Record Fast Cycling Accelerator Magnet Based on High Temperature Superconductor 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 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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WEPLO16 Energy Spread Measurements for 400 MeV LINAC Beam at Fermilab Booster using a LASER Notcher System 868
 
  • C.M. Bhat, D.E. Johnson
    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.
To mitigate 8 GeV beam losses at extraction in the Fermilab Booster synchrotron, a LASER notcher system for multi-turn injection that produces notches at 720 keV is used. These notches synchronize with the revolution period of the beam [ref. HB2018, page 416] at injection in the Booster. Recently, a dedicated notching pattern that keeps a single 201 MHz LINAC bunch untouched in the middle of a notch is developed to measure the beam energy spread by studying the time evolution of this bunch in the Booster. A complementary to this method, recently, it has been realized that one can also measure energy spread of the LINAC beam by injecting <2 Booster turn beam and studying the time evolution of the multiple 201 MHz LINAC bunches. In this paper we present the general principle of the method and results from our measurements.
 
poster icon Poster WEPLO16 [0.193 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO16  
About • paper received ※ 28 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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THZBA1
Physics Studies for High Intensity Proton Beams at the Fermilab Booster  
WEPLO10   use link to see paper's listing under its alternate paper code  
 
  • J.S. Eldred
    Fermilab, Batavia, Illinois, USA
 
  We present the results of the studies of the physics of high intensity proton seams at the 8 GeV Fermilab Booster RCS carried out in Spring 2019. The Booster studies span a variety of beam physics topics ’ The discovery of a new convective beam instability, an investigation of power-supply ripple in the Booster gradient dipoles, a characterization of space-charge induced emittance growth, optimization of adiabatic capture, a study of periodicity in the Booster, nonlinear chromaticity measurements, and transverse impedance measurements. The results will help prepare the Booster for the upcoming PIP-II intensity upgrades and inform next-generation RCS design.  
slides icon Slides THZBA1 [7.575 MB]  
poster icon Poster THZBA1 [1.856 MB]  
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THZBA2 The MYRRHA Project 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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THZBA3 Status of Beam Commissioning in FRIB Driver Linac 951
 
  • T. Maruta, S. Cogan, K. Fukushima, M. Ikegami, S.H. Kim, S.M. Lidia, G. Machicoane, F. Marti, D.G. Morris, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, J. Wei, T. Xu, T. Yoshimoto, T. Zhang, Q. Zhao, S. Zhao
    FRIB, East Lansing, Michigan, 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.
The beam commissioning of linac segment 1 (LS1) composed of fifteen cryomodules consisting of total 104 superconducting (SC) resonators and 36 SC solenoids was successfully completed. Four ion beam species, Ne, Ar, Kr and Xe were successfully accelerated up to 20.3 MeV/u. The FRIB driver linac in its current configuration became the highest energy continuous wave hadron linac. We will report a detailed study of beam dynamics in the LS1 prior to and after stripping with a carbon foil.
 
slides icon Slides THZBA3 [11.377 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA3  
About • paper received ※ 04 September 2019       paper accepted ※ 20 November 2019       issue date ※ 08 October 2019  
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THZBA4 Characterization and Modeling of High-Intensity Evolution in the SNS Beam Test Facility 954
 
  • K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau
    ORNL, Oak Ridge, Tennessee, USA
  • Z.L. Zhang
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Partial support by NSF Accelerator Science grant 1535312
Modern high-power accelerators are charged with delivering reliable beam with low losses. Resolving the complex dynamics arising from space charge and nonlinear forces requires detailed models of the accelerator and particle-in-cell simulation. There has historically been discrepancy between simulated and measured beam distributions, particularly at the low-density halo level. The Beam Test Facility (BTF) at the Spallation Neutron Source is outfitted to study beam evolution in a high-power linear accelerator MEBT. This includes capability for high-dimensional measurements of the post-RFQ beam distribution, including interplane correlations that may be the key to accurate simulation. Beam is transported through a 4.6 m FODO channel (9.5 cells) to a second distribution measurement stage. Plans for validating simulations against BTF measurements of beam evolution in the FODO channel are discussed.
 
slides icon Slides THZBA4 [8.316 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA4  
About • paper received ※ 27 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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THZBA5 First Electron Cooling of Hadron Beams Using a Bunched Electron Beam 957
 
  • A.V. Fedotov, Z. Altinbas, M. Blaskiewicz, J.M. Brennan, D. Bruno, J.C. Brutus, M.R. Costanzo, K.A. Drees, W. Fischer, J.M. Fite, M. Gaowei, D.M. Gassner, X. Gu, J. Halinski, K. Hamdi, L.R. Hammons, T. Hayes, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, Y.C. Jing, P.K. Kankiya, D. Kayran, J. Kewisch, D. Lehn, C.J. Liaw, C. Liu, J. Ma, G.J. Mahler, M. Mapes, A. Marusic, K. Mernick, C. Mi, R.J. Michnoff, T.A. Miller, M.G. Minty, S.K. Nayak, L.K. Nguyen, M.C. Paniccia, I. Pinayev, S. Polizzo, V. Ptitsyn, T. Rao, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, L. Smart, K.S. Smith, H. Song, A. Sukhanov, R. Than, P. Thieberger, S.M. Trabocchi, J.E. Tuozzolo, P. Wanderer, E. Wang, G. Wang, D. Weiss, B.P. Xiao, T. Xin, W. Xu, A. Zaltsman, H. Zhao, Z. Zhao
    BNL, Upton, New York, USA
 
  Funding: Work supported by the U.S. Department of Energy.
The Low Energy RHIC electron Cooler (LEReC) was recently constructed and commissioned at BNL. The LEReC is the first electron cooler based on the RF acceleration of electron bunches (previous electron coolers all used DC beams). Bunched electron beams are necessary for cooling hadron beams at high energies. The challenges of such an approach include generation of electron beams suitable for cooling, delivery of electron beams of the required quality to the cooling sections without degradation of beam emittances and energy spread, achieving required small angles between electrons and ions in the cooling sections, precise energy matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched beam cooling. Following successful commissioning of the electron accelerator in 2018, the focus of the LEReC project in 2019 was on establishing electron-ion interactions and demonstration of cooling process using electron energy of 1.6MeV (ion energy of 3.85GeV/n), which is the lowest energy of interest. Here we report on the first demonstration of Au ion cooling in RHIC using this new approach.
 
slides icon Slides THZBA5 [16.417 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA5  
About • paper received ※ 16 August 2019       paper accepted ※ 31 August 2019       issue date ※ 08 October 2019  
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