Author: Tennant, C.
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TUIACC001 LERF - New Life for the Jefferson Lab FEL 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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WEIACC003 ER@CEBAF, a 7 Gev, 5-Pass, Energy Recovery Experiment 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 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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