Keyword: linac
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MOIDCC006 ERL Mode of S-DALINAC: Design and Status ion, recirculation, operation, dipole 40
  • M. Arnold, C. Burandt, J. Pforr, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • C. Eschelbach, M. Lösler
    Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
  • T. Kürzeder
    HIM, Mainz, Germany
  Funding: *Work supported by DFG through RTG 2128, INST163/383-1/FUGG and INST163/384-1/FUGG
Recently, the S-DALINAC was extended by an additional recirculation beam line to a thrice-recirculating linear accelerator. This upgrade enables an increase of the maximum achievable energy close to its design value of 130 MeV as well as an operation as an ERL. The new beam line features a path-length adjustment system which is capable of changing the phase of the beam by a full RF phase and, thus, allowing to shift the timing of the electron bunches to the decelerating phase. The project comprises different aspects concerning the design (magnets, beam dynamics, lattice, etc.) and the construction work including the alignment done at the accelerator. This contribution presents a rough overview on the design, installation and status.
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TUIACC001 LERF - New Life for the Jefferson Lab FEL ion, target, operation, solenoid 45
  • C. Tennant, S.V. Benson, J.R. Boyce, J.L. Coleman, D. Douglas, S.L. Frierson, J. Gubeli, C. Hernandez-Garcia, K. Jordan, C. Keith, R.A. Legg, M.D. McCaughan, T. Satogata, M. Spata, M.G. Tiefenback, S. Zhang
    JLab, Newport News, Virginia, USA
  • R. Alarcon, D. Blyth, R.A. Dipert, L. Ice, G. Randall, B.N. Thorpe
    Arizona State University, Tempe, USA
  • J. Balewski, J.C. Bernauer, J.C. Bessuille, R. Corliss, R.F. Cowan, C. Epstein, P.F. Fisher, I. Friščić, D.K. Hasell, E. Ihloff, J. Kelsey, Y.-J. Lee, R. Milner, P. Moran, D. Palumbo, S. Steadman, C. Tschalär, C. Vidal, Y. Wang
    MIT, Cambridge, Massachusetts, USA
  • T. Cao, B. Dongwi, P. Guèye, N. Kalantarians, M. Kohl, A. Liyanage, J. Nazeer
    Hampton University, Hampton, Virginia, USA
  • R. Cervantes, A. Deshpande, N. Feege
    Stony Brook University, Stony Brook, USA
  • K. Dehmelt
    SUNY SB, Stony Brook, New York, USA
  • P.E. Evtushenko
    HZDR, Dresden, Germany
  • M. Garçon
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  • B. Surrow
    Temple University, Philadelphia, USA
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In 2012 Jefferson Laboratory's energy recovery linac (ERL) driven Free Electron Laser successful completed a transmission test in which high current CW beam (4.3 mA at 100 MeV) was transported through a 2 mm aperture for 7 hours with beam losses as low as 3 ppm. The purpose of the run was to mimic an internal gas target for DarkLight* - an experiment designed to search for a dark matter particle. The ERL was not run again until late 2015 for a brief re-commissioning in preparation for the next phase of DarkLight. In the intervening years, the FEL was rebranded as the Low Energy Recirculator Facility (LERF), while organizationally the FEL division was absorbed into the Accelerator division. In 2016 several weeks of operation were allocated to configure the machine for Darklight with the purpose of exercising - for the first time - an internal gas target in an ERL. Despite a number of challenges, including the inability to energy recover, beam was delivered to a target of thickness 1018 cm-2 which represents a 3 order of magnitude increase in thickness from previous internal target experiments. Details of the machine configuration and operational experience will be discussed.
* J. Balewski et al., A Proposal for the DarkLight Experiment at the Jefferson Laboratory Free Electron Laser, May 2012.
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TUIDCC001 PERLE - Beam Optics Design ion, injection, optics, cryomodule 49
  • S.A. Bogacz
    JLab, Newport News, Virginia, USA
  Funding: Work has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
PERLE (Powerful ERL for Experiments) is a novel ERL test facility, initially proposed to validate design choices for a 60 GeV ERL needed for a future extension of the LHC towards a hadron-electron collider, the LHeC. Its main goal is to test the limits of a high current, CW, multi-pass operation with superconducting cavities at 802 MHz (and perhaps exploring other frequencies of interest). PERLE optics features Flexible Momentum Compaction (FMC) lattice architecture for six vertically stacked return arcs and a high current, 5 MeV photo-injector. With only one pair of 4-cavity cryomodules, 400 MeV beam energy can be reached in three re-circulation passes, with beam currents in excess of 15 mA. This unique quality beam is intended to perform a number of experiments in different fields reaching from uncharted tests of accelerator components via elastic ep scattering to laser-Compton backscattering for photon physics. Following the experiment, the CW beam is decelerated in three consecutive passes back to the injection energy, transferring virtually stored energy back to the RF.
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TUIDCC004 CBETA FFAG Beam Optics Design ion, focusing, quadrupole, resonance 52
  • J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • J.A. Crittenden, Y. Li, C.E. Mayes
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
CBETA is an Energy Recovery Linac (ERL) accelerating an electron beam to 150 MeV in four linac passes. Instead of having four separate return loops to the linac, it instead has a single fixed field alternating gradient (FFAG) beamline with nearly a factor of 4 energy acceptance. While ideally the FFAG would be circular with identical cells all around, space and cost considerations dictate that small radius of curvature FFAGs should be used near the linac, connected by a straight beamline. To ensure good orbit matching over the entire energy range, adiabatic transitions are inserted between the arcs and the straight. After briefly introducing basic principles of FFAG optics, we describe how we choose the parameters of the arc cell, the basic building block of the lattice. We then describe how the straight cell is chosen to work well with the arc. Finally we describe the design process for the transition that ensures orbits over the entire energy range end up very close to the axis of the straight. We discuss how the realization of this lattice design with physical magnets impacts the design process.
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WEIACC003 ER@CEBAF, a 7 Gev, 5-Pass, Energy Recovery Experiment ion, extraction, optics, hardware 58
  • F. Méot, I. Ben-Zvi, Y. Hao, C. Liu, M.G. Minty, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Thieberger, N. Tsoupas, C. Xu, W. Xu
    BNL, Upton, Long Island, New York, USA
  • M.E. Bevins, S.A. Bogacz, D. Douglas, C.J. Dubbé, T.J. Michalski, Y. Roblin, T. Satogata, M. Spata, C. Tennant, M.G. Tiefenback
    JLab, Newport News, Virginia, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract DE-AC02-98CH10886 with the U.S. DOE, Jefferson Science Associates, LLC under Contract DE-AC05-06OR23177 with the U.S. DOE.
A multiple-pass, high energy Energy Recovery Linac experiment at the JLab CEBAF will be instrumental in providing necessary information and technology testing for a number of possible future applications and facilities such as Linac-Ring based colliders, which have been designed at BNL (eRHIC) and CERN (LHeC), and also drivers for high-energy FELs and 4th GLS. The project has been submitted to, and has received approval from, JLab Program Advisory Committee (PAC 44) in July 2016. Since it was launched 2+ years ago, it has progressed in defining the experimental goals, including for instance multiple-beam instrumentation, ER efficiency, BBU, and the necessary modifications to CEBAF lattice, including for instance a 4-dipole phase chicane in recirculation Arc A, a dump line, and new linac optics. End-to-end simulations have been undertaken and software tools are under development. A next major objective in demonstrating readiness is a technical review as mandated by PAC 44. This paper gives a status of the project and its context, and presents plans for the near future.
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WEIBCC004 Studies of CSR and Microbunching at the Jefferson Laboratory ERLs ion, bunching, emittance, electron 59
  • C. Tennant, S.V. Benson, D. Douglas, R. Li
    JLab, Newport News, Virginia, USA
  • C.-Y. Tsai
    SLAC, Menlo Park, California, USA
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One attractive feature of energy recovery linacs (ERLs) is they are source limited. However as beam brightness increases so too do the effects of coherent synchrotron radiation (CSR) and the microbunching instability. The Low Energy Recirculator Facility at Jefferson Laboratory provides a test bed to characterize aspects of CSR's effect on the beam by measuring the energy extraction via CSR as a function of bunch compression. Data was recorded with acceleration occuring on the rising part of the RF waveform while the full compression point was moved along the backleg of the machine and the response of the beam measured. Acceleration was moved to the falling part of the RF waveform and the experiment repeated. Initial start-to-end simulations using a 1D CSR model show good agreement with measurements. The experiment motivated the design of a modified Continuous Electron Beam Accelerator Facility style arc with control of CSR and the microbunching gain. Insights gained from that study informed designs for recirculation arcs in an ERL-driven electron cooler for Jefferson Laboratory's Electron Ion Collider. Progress on the design and outstanding challenges of the cooler are discussed.
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