Keyword: linac
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MOYBB4 Large-Scale Dewar Testing of FRIB Production Cavities: Statistical Analysis cavity, SRF, multipactoring, cryomodule 41
 
  • C. Zhang, W. Chang, W. Hartung, S.H. Kim, J.T. Popielarski, K. Saito, J.F. Schwartz, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  The Facility for Rare Isotope Beams (FRIB) requires a driver linac with 324 superconducting cavities to deliver ion beams at 200 MeV per nucleon. About 1/3 of the cavities are quarter-wave resonators (QWRs, 805. MHz); the rest are half-wave resonators (HWRs, 322 MHz). FRIB cavity production is nearly complete, with more than 90% of the required cavities certified for installation into cryomodules (as of May 2019). We have accumulated a large data set on performance of production QWRs and HWRs during Dewar certificating testing of jacketed cavities. In this paper, we will report on the data analysis, including statistics on the BCS resistance, residual resistance, energy gap, and Q-slope. Additionally, we will discuss performance limitations and conditioning (multipacting, field emission).  
slides icon Slides MOYBB4 [1.200 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBB4  
About • paper received ※ 01 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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MOYBB6 X-Ray Detector Array for Spatial and Temporal Diagnostic at the LANSCE Linac cavity, detector, shielding, photon 47
 
  • M. Sanchez Barrueta, G.O. Bolme, J.T.M. Lyles, J.E. Zane
    LANL, Los Alamos, New Mexico, USA
  • R.Z. Pinsky
    NERS-UM, Ann Arbor, Michigan, USA
  
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract 89233218CNA000001
A recent industrial development has made possible the use of chip-scale radiation detectors by combining a Cerium-doped Lutetium based scintillator crystal optically coupled with a Silicon Photomultiplier (SiPM) as a detector. At the Los Alamos Neutron Science Center (LANSCE), there has been an ongoing effort to determine the location of high voltage breakdowns of the accelerating radio-frequency field inside of an evacuated resonant cavity. Tests were conducted with an array of 8 X-ray detectors with each detector observing a cell of the Drift Tube Linac (DTL) cavity. The array can be moved along the DTL cavity and record X-ray emissions from a section of the cavity and their timing with respect to the RF field quench using a fast 8 channel mixed-signal oscilloscope. This new diagnostic allowed us to map the most energetic emissions along the cavity and reduce the area to investigate. A thorough visual inspection revealed that one of the ion pump grating welds in the suspected area was exposing a small gap and melting copper on both sides. Sparking across this discontinuity is believed to be a source of electrons that drive the high voltage breakdowns in the drift tube cells. 		 
slides icon Slides MOYBB6 [39.283 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOYBB6  
About • paper received ※ 28 August 2019       paper accepted ※ 12 September 2019       issue date ※ 08 October 2019  
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MOZBA1 LCLS-II SC Linac: Challenges and Status cavity, cryomodule, SRF, FEL 51
 
  • M.C. Ross
    SLAC, Menlo Park, California, USA
  
  Funding: ∗ This work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515
The Linac Coherent Light Source II (LCLS-II) project requires the assembly, test, and installation of 37 cry-omodules (CM) in order to deliver a 4 GeV CW electron beam to the FEL undulators for production of both hard and soft X-ray pulses at a repetition rate of up to 1 MHz. All of the cryomodules will operation in continuous wave mode, with 35 operating at 1.3 GHz for acceleration and 2 operating at 3.9 GHz to linearize the longitudinal beam profile. The assembly and testing of the 1.3 GHz cry-omodules is nearing completion and the 3.9 GHz cry-omodules work is entering to assembly and testing phase. Roughly 60% of the cryomodules have been shipped to SLAC for installation in the accelerator enclosure. The status and challenges of these efforts will be reported in this paper. 		 
slides icon Slides MOZBA1 [80.533 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBA1  
About • paper received ※ 02 September 2019       paper accepted ※ 12 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 vacuum, proton, operation, 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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MOPLO17 Large-Scale Dewar Testing of FRIB Production Cavities: Results cavity, cryomodule, SRF, MMI 270
 
  • W. Hartung, W. Chang, S.H. Kim, D. Norton, J.T. Popielarski, K. Saito, J.F. Schwartz, T. Xu, C. Zhang
    FRIB, East Lansing, Michigan, USA
  
  The Facility for Rare Isotope Beams (FRIB), under construction at Michigan State University (MSU), includes a superconducting driver linac to deliver ion beams at 200 MeV per nucleon. The driver linac requires 104 quarter-wave resonators (QWRs, β = 0.041 and 0.085) and 220 half-wave resonators (HWRs, β = 0.29 and 0.54). The jacketed resonators are Dewar tested at MSU before installation into cryomodules. The cryomodules for β = 0.041, 0.085, and 0.29 have been completed and certified; 89% of the β = 0.54 HWRs have been certified (as of May 2019). The Dewar certification tests have provided valuable information on the performance of production QWRs and HWRs at 4.3 K and 2 K and on performance limits. Results will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO17  
About • paper received ※ 08 November 2019       paper accepted ※ 26 November 2019       issue date ※ 08 October 2019  
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MOPLO18 Thermal Analysis of the LANSCE H+ RFQ Test Stand Faraday Cup rfq, LEBT, MEBT, interface 274
 
  • E.N. Pulliam, I. Draganić, J.L. Medina, J.P. Montross, J.F. O’Hara, L. Rybarcyk
    LANL, Los Alamos, New Mexico, USA
  
  The Los Alamos Neutron Science Center (LANSCE) op-erates one of the nation’s most powerful linear accelera-tors (LINAC). Currently the facility utilizes two 750 keV Cockcroft-Walton (CW) based injectors for transporting H+ and H− beams into the 800 MeV accelerator. A Radio Frequency Quadrupole (RFQ) design is being proposed to replace the aged CW injectors. An important component of the RFQ Test Stand is the Faraday cup that is assem-bled at the end of the Low Energy Beam Transport (Phase 1 LEBT) and Medium Energy Beam Transport (Phase 3 MEBT). The Faraday cup functions simultaneously as both a beam diagnostic and as a beam stop for each of the three project phases. This paper describes various aspects of the design and analysis of the Faraday cup. The first analysis examined the press fit assembly of the graphite cone and the copper cup components. A finite element analysis (FEA) evaluated the thermal expansion proper-ties of the copper component, and the resulting material stress from the assembly. Second, the beam deposition and heat transfer capability were analyzed for LEBT and MEBT beam power levels. Details of the calculations and analysis will be presented.  
poster icon Poster MOPLO18 [3.399 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO18  
About • paper received ※ 27 August 2019       paper accepted ※ 25 November 2019       issue date ※ 08 October 2019  
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TUZBA3 A High-Energy Design for JLEIC Ion Complex booster, electron, proton, collider 341
 
  • B. Mustapha, J.L. Martinez Marin
    ANL, Lemont, Illinois, USA
  • Y.S. Derbenev, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: This work was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
A recent assessment of the scientific merit for a future Electron Ion Collider (EIC) in the US, by the National Academy of Sciences, found that such a facility would be unique in the world and would answer science questions that are compelling, fundamental, and timely. This assessment confirmed the recommendations of the 2015 Nuclear Science Advisory Committee for an EIC with highly polarized beams of electrons and ions, sufficiently high luminosity and variable center-of-mass (CM) energy. The baseline design of Jefferson Lab Electron-Ion Collider (JLEIC) has been updated to 100 GeV CM energy, corresponding to 200 GeV proton energy. We here present a high-energy design for the JLEIC ion complex. It consists of a 135 MeV injector linac, a 6-GeV non figure-8 pre-booster ring and a 40-GeV large ion booster, which could also serve as electron storage ring (e-ring). The energy choice in the accelerator chain is beneficial for a future upgrade to 140 GeV CM energy. The large booster is designed with the same shape and size of the original e-ring allowing for the option of building separate electron and ion rings by stacking them in the same tunnel along with the ion collider ring. 		 
slides icon Slides TUZBA3 [5.435 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA3  
About • paper received ※ 03 September 2019       paper accepted ※ 25 November 2019       issue date ※ 08 October 2019  
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TUPLS07 Helical Transmission Line Test Stand for Non-Relativistic BPM Calibration impedance, simulation, network, resonance 463
 
  • C.J. Richard
    NSCL, East Lansing, Michigan, USA
  • S.M. Lidia
    FRIB, East Lansing, Michigan, USA
  
  Measurements of non-relativistic beams by coupling to the fields are affected by the properties of the non-relativistic fields. The authors propose calibrating for these effects with a test stand using a helical line which can propagate pulses at low velocities. Presented are simulations of a helical transmission line for such a test stand which propagates pulses at 0.033c. A description of the helix geometry used to reduce dispersion is given as well as the geometry of the input network.  
poster icon Poster TUPLS07 [3.469 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS07  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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TUPLH17 Design Study of Low-Level RF Control System for CW Superconducting Electron Linear Accelerator in KAERI controls, SRF, LLRF, cavity 512
 
  • S.H. Lee, J.Y. Lee
    Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
  • P. Buaphad, I.G. Jeong, Y.J. Joo, H.R. Lee
    University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
  • M.-H. Chun, I.H. Yu
    PAL, Pohang, Republic of Korea
  • Y. Kim
    KAERI, Jeongeup-si, Republic of Korea
  
  Korea Atomic Energy Research Institute (KAERI) has been operating a 20 MeV superconducting RF linear accelerator (SRF LINAC) to conduct research on atom/nuclear reaction using neutron Time-Of-Flight (nTOF). It can accelerate electron beams up to 20 MeV with 1 kW continuous wave (CW) operation mode. Unfortunately, this machine has been aged over 15 years that brings about considerably difficulty in normal operation due to the performance degradation of sub-systems. To improve the operation condition of 20 MeV SRF LINAC, we has been carrying out an upgrade project with replacement and repair of old sub-systems from 2018. This paper describes a design study of Low-Level RF (LLRF) feedback system to raise the stability and acceleration efficiency of the electric field generated in the superconducting RF cavity structure in 20 MeV SRF LINAC.  
poster icon Poster TUPLH17 [0.644 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH17  
About • paper received ※ 30 August 2019       paper accepted ※ 04 September 2019       issue date ※ 08 October 2019  
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TUPLH18 NSLS-II Inject Linac RF Control Electronics Upgrade controls, klystron, network, operation 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, operation, 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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TUPLO02 Spin Dynamics in the JLEIC Ion Injector Linac solenoid, proton, rfq, focusing 533
 
  • J.L. Martinez Marin, B. Mustapha
    ANL, Lemont, Illinois, USA
  • L.K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois, USA
  
  Funding: This work was supported by the U.S. DOE, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the requirements for the future Electron Ion Col-lider (EIC) is to collide polarized electrons and light ions with at least 70% polarization for each beam. For light ions, polarized ion sources are used for injection to a linac, which is usually the first accelerator in the collider chain. The Jefferson Lab EIC (JLEIC) ion injector linac consists of a low-energy room-temperature section with quadrupole focusing followed by a superconducting linac with solenoid focusing inside long cryomodules. These two sections have different effects on the spin. Spin dy-namics simulation studies are carried out for the JLEIC injector linac in order to preserve and maintain a high degree of polarization for light ion beams for delivery to the booster. The different options to maintain and restore the spin in the different sections of the linac for hydrogen, deuterium and helium ions are presented and discussed. Results from both the Zgoubi and COSY-Infinity codes are presented and compared for every section of the ion linac but the radio-frequency quadrupole (RFQ). Current-ly, a method to simulate the RFQ using Zgoubi is being investigated. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO02  
About • paper received ※ 28 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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TUPLE01 Python Scripts for RF Commissioning at FRIB cavity, EPICS, LLRF, controls 563
 
  • H. Maniar, E. Daykin, D.G. Morris, A.S. Plastun, H.T. Ren, S. Zhao
    FRIB, East Lansing, Michigan, USA
  
  Abstract RF commissioning at FRIB involves QWR cavities (β=0.085 and β=0.041), HWR cavities (β=0.29 and β=0.53) and few room temperature devices. Each RF system has many process variables for LLRF and amplifier control located on different pages of CS-Studio. Efficient handling of all these PVs can be challenging for RF experts. Several scripts using Python have been developed to facilitate this process. User interface application has been developed using Qt Designer and PyQt package of Python, for ease of access of all scripts. These scripts are useful for mass ac-tions (for multiple systems) including turning on/ off LLRF controllers and amplifiers, resetting interlocks/ errors, chang-ing a PV value, etc. Python scripts are also used to quickly prototype the auto-start procedure for QWR cavities, which eventually is implemented on IOC driver. The application sends commands to IOC driver with device name, PV name and value to be changed. Future developments can be con-verting to state-notation language on IOC to add channel access security. This application intends to reduce time and efforts for RF commissioning at FRIB.  
poster icon Poster TUPLE01 [0.429 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE01  
About • paper received ※ 27 August 2019       paper accepted ※ 16 November 2020       issue date ※ 08 October 2019  
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TUPLE11 Proposed Enhanced Imaging Station in the 6-GeV Booster-to-Storage Ring Transport Line for APS Upgrade radiation, booster, emittance, electron 583
 
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • W. Berg, J.C. Dooling, K.P. Wootton, C. Yao
    ANL, Lemont, Illinois, USA
  
  Funding: This manuscript has been authored by FRA, LLC under Contract No.DE-AC02-07CH11359 with the U.S.DoE, Office of HEP. Work supported by U.S.DoE, Office of Science, under Contract No.DE-AC02-06CH11357.
One of the challenges of the injector for the Advanced Photon Source Upgrade (APS-U) is the measurement and monitoring of the required high charge electron beam at 6 GeV between the Booster synchrotron and the storage ring in the transport line (BTS. In APS-U charges of up to 17 nC per micropulse are specified with a beam geometrical horizontal emittance of 60 nm rad. Vertical beam sizes at the imaging station of ~80 µm (σ) are expected so system resolutions of <30 µm are warranted. A phased approach to enhance the imaging station performance has been initiated. Recently, the 20-year-old Chromox screen oriented at 45 degrees to the beam was replaced by a 100-micron thick YAG:Ce screen which gave an improved screen resolution of <10 micron(σ. However, the optical magnification of the system still needs to be increased. In addition, the high areal charge densities are expected to exceed the scintillator mechanism’s saturation threshold so an optical transition radiation (OTR) screen will be added to the station for high-charge studies. A final phase would be the use of optical diffraction radiation (ODR) as a non-intercepting, beam-size monitor during top-up injections. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE11  
About • paper received ※ 22 August 2019       paper accepted ※ 02 September 2019       issue date ※ 08 October 2019  
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WEXBA3 CSR Phase Space Dilution in CBETA simulation, lattice, radiation, shielding 605
 
  • W. Lou, G.H. Hoffstaetter, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • C.E. Mayes
    SLAC, Menlo Park, California, USA
  
  CBETA, the Cornell BNL ERL Test Accelerator, will be the first multi-turn Energy Recovery Linac (ERL) with SRF accelerating cavities and Fixed Field Alternating gradient (FFA) beamline. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving varying phase advances are being investigated.  
slides icon Slides WEXBA3 [6.121 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEXBA3  
About • paper received ※ 28 August 2019       paper accepted ※ 15 September 2019       issue date ※ 08 October 2019  
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WEYBB5 A Crab-Crossing Scheme for Laser-Ion Beam Applications laser, experiment, cavity, injection 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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WEZBA2 Experience and Lessons in FRIB Superconducting Quarter-Wave Resonator Commissioning cavity, cryomodule, MMI, controls 646
 
  • S.H. Kim, H. Ao, F. Casagrande, W. Chang, C. Compton, A. Facco, V. Ganni, E. Gutierrez, W. Hartung, N. Hasan, P. Knudsen, T.L. Larter, H. Maniar, S.J. Miller, D.G. Morris, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, H.T. Ren, K. Saito, M. Thrush, D.R. Victory, J. Wei, M. Xu, T. Xu, Y. Yamazaki, C. Zhang, S. Zhao
    FRIB, East Lansing, Michigan, USA
  
  The superconducting (SC) linear accelerator (linac) for the Facility for Rare Isotope Beams (FRIB) has one quarter-wave resonator (QWR) segment and two half-wave resonator (HWR) segments. The first linac segment (LS1) contains twelve β = 0.041 and ninety-two β = 0.085 QWRs operating at 80.5 MHz, and thirty-nine SC solenoids. Superconducting radiofrequency (SRF) commissioning and beam commissioning of LS1 was completed in April 2019. The design accelerating gradients (5.1 MV/m for β = 0.041 and 5.6 MV/m for β = 0.085) were achieved in all cavities with no multipacting or field emission issues. The cavity field met the design goals: peak-to-peak stability of ±1% in amplitude and ±1° in phase. We achieved 20.3 MeV/u ion beams of Ar, Kr, Ne, and Xe with LS1. In this paper, we will discuss lessons learned from the SRF commissioning of the cryomodules and methods developed for efficient testing, conditioning, and commissioning of more than 100 SC cavities, each with its own independent RF system.  
slides icon Slides WEZBA2 [2.841 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA2  
About • paper received ※ 03 September 2019       paper accepted ※ 05 December 2019       issue date ※ 08 October 2019  
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WEZBA3 No Beam-Loss Quadrupole Scan for Transverse Phase Space Measurements quadrupole, emittance, cryomodule, beam-losses 650
 
  • K. Fukushima, T. Maruta, P.N. Ostroumov, T. Yoshimoto
    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.
Facility for Rare Isotope Beams (FRIB) at Michigan State University is based on a high power heavy ion linac and beam commissioning is under way. For evaluation of beam Twiss parameters and rms emittance, we routinely use multiple profile measurements while the strength of an upstream quadrupole is varied. The change of the quadrupole strength results in a beam mismatch downstream of the profile monitor which can cause beam losses. This is not acceptable in a high energy beamline. To avoid this transverse mismatch, we developed a beam matching procedure by optimization of quadrupoles’ setting downstream of the profile monitor. Using this procedure we were able to eliminate beam losses during the quadrupole scan, and evaluate beam Twiss parameters and rms emittance. Examples of using this procedure in the folding segment of the FRIB linac will be reported. 		 
slides icon Slides WEZBA3 [7.964 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA3  
About • paper received ※ 27 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM02 Finding Beam Loss Locations in a Linac with Oscillating Dipole Correctors dipole, DTL, betatron, radiation 663
 
  • A.V. Shemyakin, K. Seiya
    Fermilab, Batavia, Illinois, USA
  • R. Prakash
    RRCAT, Indore, India
  
  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 paper proposes a method of finding the beam loss locations in a linac. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync produces a line at the corresponding frequency in spectra of current-sensitive devices downstream of the loss point. The phase of this signal contains information about the location of the beam loss. Similar lines appear also in the position signals of Beam Position Monitors (BPMs). The phases of the BPM position lines change monotonically (within each 2π) along the linac and can be used a reference system. The phase of the loss signal compared with this reference system pinpoints the beam loss location, assuming that longitudinal coordinates of the BPMs are known. If the correctors deflection amplitudes and the phase offset between their waveforms are chosen optimally and well calibrated, the same measurement provides values of the β-function and the betatron phase advance at the BPM locations. Optics measurements of this type can be made parasitically, with negligible effect on the emittance, if a long measurement time is acceptable. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM02  
About • paper received ※ 27 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLM23 Updated Applications of Advanced Compact Accelerators electron, radiation, laser, site 694
 
  • M. Uesaka
    The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
  
  We are working for downsizing of RF accelerators from room-size to portable and table-top sizes and applying them to industril and social uses. We have developed portable 950 keV / 3.95 MeV X-band (9.3 GHz) electron linac based X-ray/neutron sources and successfully applied to on-site nondestructive inspection of industrial and social infrastructures such as chemical reaction chambers and bridges following the radiation safety law and regulation in Japan. By using the portable 950 keV / 3.95 MeV X-band electron linac based X-ray sources for on-site actual bridge inspection, we visualize inner reinforcement iron structure. The information of of the iron states is used for the structural analysis of the a bridge in order to evaluate its residual strength and sustainability. Table-topμelectron / ion beam sources using laser dielectric accelerating techniques are under development. The beam energy is ~ 1 MeV, the beam size is ~1 micron. We aim to apply them to 3D dynamic observation of radiation-induced DNA damage / repair for basic research of radiation therapy and low dose effect.  
poster icon Poster WEPLM23 [0.778 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM23  
About • paper received ※ 30 August 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLM51 Ka-Band High Power Harmonic Amplifier for Bunch Phase-Space Linearization cavity, klystron, bunching, simulation 710
 
  • X. Chang, Y. Jiang, S.V. Shchelkunov
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  • J.L. Hirshfield
    Omega-P, Inc., New Haven, Connecticut, USA
  
  Funding: Supported by USA National Science Foundation, Award #1632588
Abstract: A future European light source CompactLight is being proposed to extend FEL operation further into the x-ray region than other light sources by using a linac operating at X-band (12 GHz) with a short Ka-band (36 GHz) section for linearizing bunch phase space. The Ka-band system requires a high-power RF amplifier, synchronized with the main X-band source. We report here on design of a third-harmonic klystron amplifier for this application. Our design employs a four-cavity system with a multi-cell extended interaction output cavity. Initial simulation results indicate that more than 10 MW of 36-GHz power can be obtained with an efficiency exceeding 20%, and with 12-GHz drive power of 30 W. A preliminary design for a proof-of-principal experimental test of this concept is described 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM51  
About • paper received ※ 23 August 2019       paper accepted ※ 05 September 2019       issue date ※ 08 October 2019  
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WEPLM62 First Cold Test Results of a Medium-Beta 644 MHz Superconducting 5-Cell Elliptical Cavity for the FRIB Energy Upgrade cavity, target, pick-up, accelerating-gradient 731
 
  • K.E. McGee, B.W. Barker, K. Elliott, A. Ganshyn, W. Hartung, S.H. Kim, P.N. Ostroumov, J.T. Popielarski, A. Taylor, C. Zhang
    FRIB, East Lansing, Michigan, USA
  • M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  
  Funding: Work supported by Michigan State University.
The superconducting linac for the Facility for Rare Isotope Beams (FRIB) will accelerate ions to 200 MeV per nucleon, with the possibility of a future energy upgrade to 400 MeV per nucleon via additional cavities. A 5-cell superconducting β = 0.65 elliptical cavity was designed for this purpose. Two unjacketed 5-cell niobium cavities were fabricated; the first of these was Dewar tested in February 2019. The surface preparation was bulk electropolishing (EP, 150 µm), hydrogen degassing (600°C, 10 hours), light EP (20 µm), clean-room high-pressure water rinsing, and in-situ baking (120°C, 48 hours). We achieved Q0 = 2·1010, equivalent to Rs = 10 nΩ, at the design gradient of 17.5 MV/m. The cavity was tested in a newly refurbished FRIB test Dewar, equipped with a variable input coupler. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM62  
About • paper received ※ 02 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLM64 High Dynamic Voltage Range Studies of Piezoelectric Multilayer Actuators at Low Temperatures cavity, operation, 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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WEPLM70 FRIB Tuner Performance and Improvement cavity, cryomodule, controls, MMI 755
 
  • J.T. Popielarski, W. Chang, C. Compton, W. Hartung, S.H. Kim, E.S. Metzgar, S.J. Miller, K. Saito, J.F. Schwartz, 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
The Facility for Rare Isotope Beams (FRIB) is under construction at Michigan State University (MSU). The FRIB superconducting driver linac will accelerate ion beams to 200 MeV per nucleon. The driver linac requires 104 quarter-wave resonators (QWRs, β = 0.041 and 0.085) and 220 half-wave resonators (HWRs, β = 0.29 and 0.54). The cryomodules for β = 0.041, 0.085, and 0.29 have been completed and certified; 32 out of 49 cryomodules are certified via bunker test (as of March 2019). FRIB QWR cavities have a demountable niobium tuning plate which uses a warm external stepper motor and the FRIB HWR cavities use pneumatic actuated bellows. Progress on the preparation and performance of the tuners is presented in this paper along with improvements made to ensure meeting frequency specification. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM70  
About • paper received ※ 26 September 2019       paper accepted ※ 19 November 2019       issue date ※ 08 October 2019  
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WEPLM72 Design of a High-Gradient S-Band Annular Coupled Structure coupling, cavity, Windows, operation 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, operation 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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WEPLH01 Longitudinal Beam Profile Measurement by Silicon Detector in Facility for Rare Isotope Beams at Michigan State University detector, timing, emittance, rfq 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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WEPLH03 Redesign of ReA3 4-Rod RFQ rfq, MMI, operation, simulation 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 quadrupole, MMI, diagnostics, emittance 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 rfq, MMI, cavity, ECR 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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WEPLH09 FRIB Driver Linac Integration to be ready for Phased Beam Commissioning MMI, SRF, cryomodule, cavity 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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WEPLH15 Light Ion Injector for NICA cavity, rfq, DTL, proton 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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WEPLO06 Start-to-End Simulation of the Drive-Beam Longitudinal Dynamics for Beam-Driven Wakefield Acceleration laser, simulation, electron, wakefield 858
 
  • W.H. Tan, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  • A. Zholents, A. Zholents
    ANL, Lemont, Illinois, USA
  
  Funding: This work is supported by the U.S. Department of Energy, Office of Science under contracts No. DE-AC02-06CH11357 (via a laboratory- directed R&D program at ANL) and No. DE-SC0018656 at NIU.
Collinear beam-driven wakefield acceleration (WFA) relies on shaped driver beam to provide higher accelerating gradient at a smaller cost and physical footprint. This acceleration scheme is currently envisioned to accelerate electron beams capable of driving free-electron laser *. Start-to-end simulation of drive-bunch beam dynamics is crucial for the evaluation of the design of accelerators built upon WFA. We report the start-to-end longitudinal beam dynamics simulations of an accelerator beamline capable of producing high charge drive beam. The generated wakefield when it passes through a corrugated waveguide results in a transformer ratio of 5. This paper especially discusses the challenges and criteria associated with the generation of temporally-shaped driver beam, including the beam formation in the photoinjector, and the influence of energy chirp control on beam transport stability.
A. Zholents et al., "A Conceptual Design of a Compact Wakefield Accelerator for a High Repetition Rate Multi User X-ray Free-Electron Laser Facility" 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO06  
About • paper received ※ 27 August 2019       paper accepted ※ 03 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 booster, injection, laser, experiment 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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THZBA2 The MYRRHA Project cavity, rfq, proton, operation 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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THZBB4 Beam Loss in the First Segment of the FRIB Linac detector, monitoring, radiation, beam-losses 965
 
  • R. Shane, S. Cogan, S.M. Lidia, T. Maruta
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Beam loss in accelerators is an unavoidable and often unwanted reality, but it is not without its use. Information from beam loss can be leveraged to optimize the tune and improve beam quality, in addition to monitoring for machine fault and failure conditions. The folded geometry at the Facility for Rare Isotope Beams (FRIB) presents a unique challenge in the detection of radiative losses, resulting in the introduction of non-traditional measurement schemes. In addition to neutron detectors and pressurized ionization chambers, FRIB will utilize halo ring monitors, fast thermometry within the cryomodules, and differential beam-current measurements. This paper will present an analysis of beam-loss measurements from commissioning the first segment of the FRIB accelerator, and a discussion of ways to evaluate and monitor the health of the beam loss monitoring system. 		 
slides icon Slides THZBB4 [2.477 MB]  
poster icon Poster THZBB4 [0.584 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB4  
About • paper received ※ 04 September 2019       paper accepted ※ 17 November 2020       issue date ※ 08 October 2019  
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THZBB6 Error Minimization in Transverse Phase-Space Measurements Using Quadrupole and Solenoid Scans quadrupole, focusing, emittance, solenoid 971
 
  • C.Y. Wong
    NSCL, East Lansing, Michigan, USA
  • S.M. Lund
    FRIB, East Lansing, Michigan, USA
  
  Quadrupole and solenoid scans are common techniques where a series of beam profile measurements are taken under varying excitation of the linear focusing elements to unfold second-order phase-space moments of the beam at an upstream location. Accurate knowledge of the moments is crucial to machine tuning and understanding the underlying beam dynamics. The scans have many sources of errors including measurement errors, field errors and misalignments. The impact of these uncertainties on the moment measurement is often not analyzed. This study proposes a scheme motivated by linear algebra error bounds that can efficiently select a set of scan parameters to minimize the errors in measured initial moments. The results are verified via a statistical error analysis. These techniques are being applied at the Facility for Rare Isotope Beams (FRIB). We find that errors in initial moments can be large under conventional scans but are greatly reduced using the procedures described.  
slides icon Slides THZBB6 [2.153 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB6  
About • paper received ※ 04 September 2019       paper accepted ※ 04 December 2019       issue date ※ 08 October 2019  
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FRXBB1 Rare Isotope Beams and High-power Accelerators target, proton, heavy-ion, neutron 993
 
  • J. Wei
    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.
Facilities for rare isotope beams provide tools for nuclear science research and tools for applications ranging from fundamental nuclear structure and dynamics to societal benefits in medicine, energy, material sciences and national security. State-of-the-art rare isotope facilities can be based on an isotope separation on-line (ISOL) approach using mostly high-power proton beams striking a thick target where the isotopes are produced in the target, or an in-flight fragment separation (IF) approach using high-power heavy ion beams striking upon a thinner target where the isotopes continue out of the target followed by fragment separation. This tutorial class introduces high power hadron accelerators as driver machines for rare isotope production, summarizing the key design philosophy, physical and technical challenges, and current world-wide development status. As an example, the Facility for Rare Isotope Beams (FRIB) project is used to illustrate the process of establishing such facilities. 		 
slides icon Slides FRXBB1 [41.291 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBB1  
About • paper received ※ 02 September 2019       paper accepted ※ 17 November 2020       issue date ※ 08 October 2019  
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