Keyword: linac
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SAPLG01 Advances in Simulation of High Brightness/High Intensity Beams emittance, simulation, controls, electron 1
 
  • J. Qiang
    LBNL, Berkeley, California, USA
 
  High brightness/high intensity beams play an important role in accelerator based applications by driving x-ray free electron laser (FEL) radiation, producing spallation neutrons and neutrinos, and generating new particles in high energy colliders. In this paper, we report on recent advances in modeling the high brightness electron beam with application to the next generation FEL light sources and in modeling space-charge effects in high intensity proton accelerators.  
slides icon Slides SAPLG01 [3.914 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-SAPLG01  
About • paper received ※ 02 November 2018       paper accepted ※ 19 November 2018       issue date ※ 26 January 2019  
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TUPAF08 A Full Field-Map Modeling of Cornell-BNL CBETA 4-Pass Energy Recovery Linac FFAG, optics, dipole, simulation 186
 
  • F. Méot, S.J. Brooks, D. Trbojevic, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • J.A. Crittenden
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Cornell-BNL Electron Test Accelerator (CBETA) is a four-pass, 150 MeV energy recovery linac (ERL), now in construction at Cornell. A single fixed-field alternating gradient (FFAG) beam line recirculates the four energies, 42, 78, 114 and 150 MeV. The return loop is comprised of 107 quadrupole-doublet cells, built using Halbach permanent magnet technology. Spreader and combiner sections (4 independent beam lines each) connect the 36 MeV linac to the FFAG loop. We present here a start-to-end simulation of the 4-pass ERL, entirely, and exclusively, based on the use of magnetic field maps to model the magnets and correctors. There are paramount reasons for that and this is discussed, detailed outcomes are presented, together with comparisons with regular beam transport (mapping based) techniques.
 
slides icon Slides TUPAF08 [2.568 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF08  
About • paper received ※ 23 October 2018       paper accepted ※ 07 December 2018       issue date ※ 26 January 2019  
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TUPAF09 Multi Pass Energy Recovery Linac Design With a Single Fixed Field Magnet Return Line electron, cavity, lattice, betatron 191
 
  • D. Trbojevic, J.S. Berg, S.J. Brooks, F. Méot, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • W. Lou
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  We present a new approach of the Energy Recovery Linac Design for the future projects: PERLE (Powerful Energy Recovery Linac for Experiments), LHeC/FCCeH and eR- HIC. The concept uses superconducting linacs and a single xed eld beam line with multiple energy passes of electron beams. This represents an update to the existing CBETA (Cornell University Brookhaven National Laboratory ERL Test Accelerator) where the superconducting linac uses a single xed eld magnet beam line with four energy passes during acceleration and four passes during the energy recov- ery. To match the single xed eld beam line to the linac the CBETA uses the spreaders and combiners on both sides of the linac, while the new concept eliminates them. The arc cells from the single xed eld beam line are connected to the linac with adiabatic transition arcs wher cells increase in length. The orbits of di erent energies merge into a sin- gle orbit through the interleaved linac within the straight sections as in the CBETA project. The betatron functions from the arcs are matched to the linac. The time of ight of di erent electron energies is corrected for the central orbits by additional correction magnet controlled induced beam oscillations.  
slides icon Slides TUPAF09 [3.935 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF09  
About • paper received ※ 22 October 2018       paper accepted ※ 27 January 2019       issue date ※ 26 January 2019  
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TUPAF10 Experience With CBETA Online Modeling Tools EPICS, simulation, lattice, MMI 196
 
  • C.M. Gulliford, A.C. Bartnik, J. Dobbins, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J.S. Berg
    BNL, Upton, Long Island, New York, USA
  • A. Nunez-delPrado
    UCF, Orlando, USA
 
  Funding: NYSERDA, the New York StateEnergy Research and Development Agency
The Cornell-Brookhaven CBETA machine is a four pass Energy Recovery Linac (ERL) with a Non-scaling Fixed-Field Alternating gradient (NS-FFA) arc. For online modeling of single particle dynamics in CBETA, a customized version of the Tao program, which is based upon the Bmad toolkit, has been developed. This online program, called CBETA-V, is interfaced to CBETA’s EPICS control system. This paper describes the online modeling system and initial experience during machine running.
 
slides icon Slides TUPAF10 [4.227 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF10  
About • paper received ※ 17 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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TUPAG04 Statistical Analysis of the Eigenmode Spectrum in the SRF Cavities with Mechanical Imperfections cavity, HOM, SRF, cryomodule 265
 
  • A. Lunin, T.N. Khabiboulline, N. Solyak, A.I. Sukhanov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work is supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
The superconducting radio frequency (SRF) technology is progressing rapidly over last decades toward high accelerating gradients and low surface resistance making feasible the particle accelerators operation with high beam currents and long duty factors. However, the coherent RF losses due to high order modes (HOMs) excitation becomes a limiting factor for these regimes. In spite of the operating mode, which is tuned separately, the parameters of HOMs vary from one cavity to another due to finite mechanical tolerances during cavities fabrication. It is vital to know in advance the spread of HOM parameters in order to predict unexpected cryogenic losses, overheating of beam line components and to keep stable beam dynamics. In this paper we present the method of generating the unique cavity geometry with imperfections while preserving operating mode frequency and field flatness. Based on the eigenmode spectrum calculation of series of randomly generated cavities we can accumulate the data for the evaluation the HOM statistics. Finally, we describe the procedure for the estimation of the probability of the resonant HOM losses in the SRF resonators. The study of these effects leads to specifications of SC cavity and cryomodule and can significantly impact on the efficiency and reliability of the machine operation
 
slides icon Slides TUPAG04 [1.810 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAG04  
About • paper received ※ 15 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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TUPAG20 Computational Beam Dynamics Requirements for FRIB ECR, simulation, emittance, controls 303
 
  • P.N. Ostroumov, Y. Hao, T. Maruta, A.S. Plastun, T. Yoshimoto, T. Zhang, Q. Zhao
    FRIB, East Lansing, USA
 
  Funding: Work supported by the U.S. DOE of Science under Cooperative Agreement DE-SC0000661 and the NSF under Cooperative Agreement PHY-1102511, the State of Michigan and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) being built at Michigan State University moved to the commissioned stage in the summer of 2017. There were extensive beam dynamics simulations in the FRIB driver linac during the design stage. Recently, we have used TRACK and IMPACT simulation codes to study dynamics of ion beam contaminants extracted from the ECR together with main ion beam. The contaminant ion species can produce significant losses after the stripping. These studies resulted in development of beam collimation system at relatively low energy of 16 MeV/u and room temperature bunchers instead of originally planned SC cavities. Commissioning of the Front End and the first 3 cryomodules enabled detailed beam dynamics studies experimentally which were accompanied with the simulations using above-mentioned beam dynamics codes and optimization code FLAME. There are significant challenges in understanding of beam dynamics in the FRIB linac. The most computational challenges are in the following areas: (1) Simulation of the ion beam formation and extraction from the ECR; (2) Development of the virtual accelerator model available on-line both for optimization and multi-particle simulations. The virtual model should include realistic accelerator parameters including device misalignments; (3) Large scale simulations to support high-power ramp up of the linac with minimized beam losses; (4) Interaction of the beam with the gas stripper which is the backup option for high power operation of the linac.
 
slides icon Slides TUPAG20 [5.721 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAG20  
About • paper received ※ 02 November 2018       paper accepted ※ 10 December 2018       issue date ※ 26 January 2019  
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WEPAF04 Longitudinal Beam Dynamics in FRIB and ReA Linacs rfq, cavity, emittance, simulation 330
 
  • A.S. Plastun, P.N. Ostroumov, A.C.C. Villari, Q. Zhao
    FRIB, East Lansing, USA
 
  The Front-End and first three cryomodules of the Facility for Rare Isotope Beam (FRIB) at Michigan State University (MSU) commissioned in July, 2018. The paper describes the online tuning procedures of the longitudinal beam dynamics through the FRIB linac. These procedures include tuning of the accelerating field phases and amplitudes in the cavities. We developed an automated simulation-based tuning procedure for the multi-harmonic buncher. In order to tune the radio-frequency quadrupole (RFQ) we measured and calculated its threshold voltage and scanned its longitudinal acceptance. Tuning of the rebunchers and superconducting accelerating cavities is per-formed by means of the phase scans and Time-Of-Flight (TOF) beam energy measurements with beam position and phase monitors. While FRIB is being commissioned, the re-accelerator (ReA3) for rare isotope beams (RIBs) is being upgraded. We redesigned the ReA3 RFQ to improve its cooling system and provide reliable operation with 16.1 MHz prebunched ion beams with A/Q = 5. In order to provide matching of any ReA3 beam both to the following upgrade cryomodules and physics experiments’ requirements, room temperature rebuncher/debuncher is being designed. The design procedure includes the beam dynamics, electromagnetic, thermal and mechanical simulations and optimizations.  
slides icon Slides WEPAF04 [2.406 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-WEPAF04  
About • paper received ※ 19 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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