WEPLH —  Wednesday Poster Session-Lake Huron   (04-Sep-19   16:30—18:00)
Paper Title Page
WEPLH01 Longitudinal Beam Profile Measurement by Silicon Detector in Facility for Rare Isotope Beams at Michigan State University -1
  • 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.
WEPLH02 Experience with Long-Pulse Operation of the PIP2IT Warm Front End -1
  • 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.
WEPLH03 Redesign of ReA3 4-Rod RFQ -1
  • 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.
WEPLH04 Beam Envelope Reconstruction for FRIB-FS1 Transport Line Using Beam Position Monitors -1
  • 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.
Characterization and Performance of Plasma Window for Gas Flow Restriction in Different Geometries  
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  • 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 WEPLH05 [4.252 MB]  
WEPLH06 Commissioning Status of the FRIB Front End -1
  • 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.
WEPLH07 Commissioning of the FRIB/NSCL New ReA3 4-Rod Radio Frequency Quadrupole Accelerator -1
  • 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.
WEPLH08 Use of the Base-Band Tune Meter Kickers During the FY18 STAR Fixed Target Run at 3.85 GeV/u -1
  • 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.  
WEPLH09 FRIB Driver Linac Integration to be ready for Phased Beam Commissioning -1
  • H. Ao, S. Beher, N.K. Bultman, F. Casagrande, C. Compton, J. 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.
WEPLH10 Efficiency Estimation for Sequential Excitation Laser Stripping of H Beam -1
  • 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.
WEPLH11 RHIC Quench Protection Diode Radiation Damage -1
  • 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.
ReA3 Accelerator: From Design, Commissioning to Operation and Upgrade  
  • Q. Zhao
    NSCL, East Lansing, Michigan, USA
  Funding: Work supported by the National Science Foundation under Grant PHY-15-65546, National Science Foundation under Cooperative Agreement PHY-1102511, the State of Michigan and Michigan State University.
ReA3 facility at Michigan State University is a state-of-the-art reaccelerator that delivers both rare and stable isotope beams for nuclear physics research with energy of 0.3 to 6 MeV/u. It consists of an Electron Beam Ion Source, a Radio Frequency Quadrupole with an external buncher, a superconducting quarter wave resonator linac, and high energy beamlines to three user stations. ReA3 not only acted as a prototype to provide valuable experience for the FRIB development, but also will reaccelerate rare isotopes from FRIB. The voltage of each resonator was calibrated with beams, so resonator setups can be pre-calculated to obtain desired output energy. Performance degradation of superconducting resonators was recovered by rf conditioning. Linac stability and availability were improved with new rf controllers and newly-developed automatic turn-on scripts. Current upgrades include development of a high performance EBIS, improved design of RFQ, and double output energy with one more cryomodule. We will present the beam measurement results with comparison of designs, discuss lessons learned from beam commissioning and operation, and describe the ongoing energy and performance upgrade.
Experimental and Simulation Studies of Cooling of a Bunched Ion Beam in a Storage Ring by a Bunched Electron Beam  
  • Y. Zhang
    JLab, Newport News, Virginia, USA
  Cooling of high energy ion beams is essential for future electron-ion colliders to reach high luminosity. It is critical to demonstrate experimentally cooling by a bunched electron beam and to benchmark the experimental data with simulations. Such experimental and simulation studies were carried out by a collaboration of Jefferson Lab and Institute of Modern Physics (IMP), utilizing a DC cooler at IMP. The thermionic gun of the DC cooler was modified by pulsing its grid voltage to produce cooling electron pulses in a pulse length range of 0.07 - 3.5 µs, with a 250 kHz repetition frequency. The performed experiments clearly demonstrated cooling of a RF focused ion bunches by this pulsed electron beam. The simulation results agree with measurements qualitatively. In this paper, we present a brief overview of the experiments and also show the main experimental and simulation results.  
Foil Scattering Model for Fermilab Booster  
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  • 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 WEPLH14 [6.000 MB]  
WEPLH15 Light Ion Injector for NICA -1
  • 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.  
WEPLH16 Tolerances on Energy Deviation in Microbunched Electron Cooling -1
  • 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).
WEPLH17 Diffusion and Nonlinear Plasma Effects in Microbunched Electron Cooling -1
  • 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).
ELENA Commissioning  
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  • 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 WEPLH18 [21.717 MB]  
WEPLH19 Record Fast Cycling Accelerator Magnet Based on High Temperature Superconductor -1
  • 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.
WEPLH20 Modeling of H Ion Source at LANSCE -1
  • 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.