MC2: Photon Sources and Electron Accelerators
A18 Energy Recovery Linacs
Paper Title Page
TUPGW008 PERLE: A High Power Energy Recovery Facility 1396
 
  • W. Kaabi, I. Chaikovska, A. Stocchi, C. Vallerand
    LAL, Orsay, France
  • D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S.A. Bogacz, A. Hutton, F. Marhauser, R.A. Rimmer, C. Tennant
    JLab, Newport News, Virginia, USA
  • S. Bousson, D. Longuevergne, G. Olivier, G. Olry
    IPN, Orsay, France
  • O.S. Brüning, R. Calaga, L. Dassa, F. Gerigk, E. Jensen, P.A. Thonet
    CERN, Geneva, Switzerland
  • B. Hounsell, M. Klein, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • E.B. Levichev, Yu.A. Pupkov
    BINP SB RAS, Novosibirsk, Russia
  
  PERLE is a proposed high power Energy Recovery Linac, designed on multi-turn configuration, based on SRF technology, to be hosted at Orsay-France in a col-laborative effort between local laboratories: LAL and IPNO, together with an international collaboration involv-ing today: CERN, JLAB, STFC ASTeC Daresbury, Liverpool University and BINP Novosibirsk. PERLE will be a unique leading edge facility designed to push advances in accelerator technology, to provide intense and highly flexible test beams for component development. In its final configuration, PERLE provides a 500 MeV elec-tron beam using high current (20 mA) acceleration during three passes through 801.6 MHz cavities. This presenta-tion outlines the technological choices, the lattice design and the main component descriptions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW008  
About • paper received ※ 19 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPGW023 Incorporation of a MESA Linac Modules into BERLinPro 1449
 
  • B.C. Kuske, W. Anders, A. Jankowiak, A. Neumann
    HZB, Berlin, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
  • F. Hug, T. Stengler, C.P. Stoll
    KPH, Mainz, Germany
  
  Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin, grants of the Helmholtz Association and grants of Helmholtz Association and the DFG within GRK 2128
BERLinPro is an Energy Recovery Linac (ERL) project, currently being set up at the Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany. BERLinPro is designed as - and for - experiments in accelerator physics and as a test bed for novel ERL components. MESA is an ERL project under construction at the Johannes Gutenberg-Universität, Mainz, Germany. MESA is designed as a user facility to perform experiments in dark matter physics and precision measurements of natural constants. Despite the diverse goals, the main linac, providing the larger part of the particles energy, is fairly compatible. It is planned to test and run the MESA linac module in BERLinPro, prior to its usage in MESA. The goals and benefits of this unique cooperation for both projects are outlined in this paper. The necessary adaptions in BERLinPro, including hardware aspects, the new optics, and the scope of performance are described. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW023  
About • paper received ※ 30 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW028 Low Energy Beam Transport System for MESA 1461
 
  • C. Matejcek, K. Aulenbacher, S. Friederich
    IKP, Mainz, Germany
  
  An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low energy beam transport system connecting the 100 keV electron source with the injector accelerator. The present setup includes the chopper- and bunching system. The devices are of most importance in order to achieve sufficient bunch compression particularely at higher bunch charges and currents. With the circular deflecting cavity of the chopper system it is possible to measure the longitudinal dimension of the bunches upstream of the buncher whereas downstream the longitudinal size will be measured by Smith Purcell radiation. Based on experimental results obtained from this setup we will discuss the beam parameter and compare them with simulations of the beamline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW028  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW036 1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance 1482
 
  • T. Obina, D.A. Arakawa, M. Egi, T. Furuya, K. Haga, K. Harada, T. Honda, Y. Honda, T. Honma, E. Kako, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, T. Konomi, H. Matsumura, T. Miura, T. Miyajima, S. Nagahashi, H. Nakai, N. Nakamura, K. Nakanishi, K.N. Nigorikawa, T. Nogami, F. Qiu, H. Sagehashi, H. Sakai, S. Sakanaka, M. Shimada, M. Tadano, T. Takahashi, R. Takai, O.A. Tanaka, Y. Tanimoto, T. Uchiyama, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • R. Hajima, R. Nagai, M. Sawamura
    QST, Tokai, Japan
  • N. Nishimori
    National Institutes for Quantum and Radiological Science and Technology (QST), Sayo-cho, Japan
  
  A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %.
* S. Sakanaka, et.al., Nucl. Instr. and Meth. A 877 (2017)197, https://doi.org/10.1016/j.nima.2017.08.051
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW036  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW037 Systematic Measurements of the Coherent THz Spectra by Magnetic Bunch Compression at the Compact ERL 1486
 
  • M. Shimada, Y. Honda, R. Kato, T. Miyajima, N. Nakamura, T. Obina, T. Uchiyama
    KEK, Ibaraki, Japan
  • T. Hotei
    Sokendai, Ibaraki, Japan
  
  Short electron bunch beam is one of the key elements of a Free Electron Laser (FEL) or intense THz coherent light source. The Energy Recovery Linac (ERL) has the strong advantage of operation of such an electron bunch at high repetition rate and is expected to increase the photon flux. At the Compact ERL in KEK site, we have demonstrated the magnetic bunch compression at the 180-degree return arc and measured the THz spectra of the Coherent Transition Radiation (CTR). This paper reports the revamped THz beamline and the improvement of the beam tuning as well as the systematic measurements of the THz spectra by magnetic bunch compression.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW037  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW084 Multi-pass ERL in a ’Dogbone’ Topology 1601
 
  • 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.
The main thrust of a multi-pass RLA is its very efficient usage of expensive linac structures. That efficiency can be further enhanced by configuring an RLA in a ’dogbone’ topology, which further boosts the RF efficiency by factor of two (compare to a corresponding racetrack). However, the ’dogbone’ configuration requires the beam to traverse the linac in both directions, while being accelerated. This can be facilitated by a special ’bisected’ linac Optics. Here, the quadrupole gradients scale up with momentum to maintain periodic FODO structure for the lowest energy pass in the first half of the linac and then the quadrupole strengths are mirror reflected in the second linac half. The virtue of this optics is the appearance of distinct nodes in the beta beat-wave at the ends of each pass (where the droplet arcs begin), which limits the growth of initial betas at the beginning of each subsequent droplet arc. Furthermore, ‘bisected’ linac optics naturally supports energy recovery in the ’dogbone’ topology. In this paper, we present a-proof-of-principle lattice design of a multi-pass ’dogbone’ ERL. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW084  
About • paper received ※ 08 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW086 Energy and RF Cavity Phase Symmetry Enforcement in Multi-Turn ERL Models 1606
 
  • R.M. Koscica, N. Banerjee, C.M. Gulliford, G.H. Hoffstaetter, W. Lou
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  In a multi-pass Energy Recovery Linac (ERL), each cavity must regain all energy expended from beam acceleration during beam deceleration, and the beam should achieve specific energy targets during each loop that returns it to the linac. For full energy recovery, and for every returning beam to meet loop energy requirements, we must optimize the phase and voltage of cavity fields in addition to selecting adequate flight times. If we impose symmetry in time and energy during acceleration and deceleration, fewer parameters are needed, simplifying the optimization. As an example, we present symmetric models of the Cornell BNL ERL Test Accelerator (CBETA) with solutions that satisfy the optimization targets of loop energy and zero cavity loading.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW086  
About • paper received ※ 14 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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TUPGW102 CBETA - Novel Superconducting ERL 1651
 
  • R.J. Michnoff, J.S. Berg, S.J. Brooks, J. Cintorino, Y. Hao, C. Liu, G.J. Mahler, F. Méot, S. Peggs, V. Ptitsyn, T. Roser, P. Thieberger, S. Trabocchi, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, F.J. Willeke, H. Witte
    BNL, Upton, Long Island, New York, USA
  • N. Banerjee, J. Barley, A.C. Bartnik, I.V. Bazarov, D.C. Burke, J.A. Crittenden, L. Cultrera, J. Dobbins, S.J. Full, F. Furuta, R.E. Gallagher, M. Ge, C.M. Gulliford, B.K. Heltsley, G.H. Hoffstaetter, D. Jusic, R.P.K. Kaplan, V.O. Kostroun, Y. Li, M. Liepe, W. Lou, J.R. Patterson, P. Quigley, D.M. Sabol, D. Sagan, J. Sears, C.H. Shore, E.N. Smith, K.W. Smolenski, V. Veshcherevich, D. Widger
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • D. Douglas
    Douglas Consulting, York, Virginia, USA
  • M. Dunham, C.E. Mayes
    SLAC, Menlo Park, California, USA
  
  Funding: New York State Research&Development Authority - NYSERDA agreement number 102192
We are successfully commissioning a unique Cornell University and Brookhaven National Laboratory Electron Recovery Linac (ERL) Test Accelerator ’CBETA’ [1]. The ERL has four accelerating passes through the supercon-ducting linac with a single Fixed Field Alternating Linear Gradient (FFA-LG) return beam line built of the Halbach type permanent magnets. CBETA ERL accelerates elec-trons from 42 MeV to 150 MeV, with the 6 MeV injec-tor. The novelties are that four electron beams, with ener-gies of 42, 78, 114, and 150 MeV, are merged by spreader beam lines into a single arc FFA-LG beam line. The elec-tron beams from the Main Linac Cryomodule (MLC) pass through the FFA-LG arc and are adiabatically merged into a single straight line. From the straight section the beams are brought back to the MLC the same way. This is the first 4 pass superconducting ERL and the first single permanent magnet return line. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW102  
About • paper received ※ 13 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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