Keyword: recirculation
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TUPWA067 Status of Higher Bunch Charge Operation in Compact ERL operation, optics, space-charge, emittance 1583
 
  • T. Miyajima, K. Harada, Y. Honda, T. Miura, N. Nakamura, T. Obina, F. Qiu, H. Sakai, S. Sakanaka, M. Shimada, R. Takai, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • R. Hajima, R. Nagai, N. Nishimori
    JAEA, Ibaraki-ken, Japan
  • D. Lee
    KNU, Deagu, Republic of Korea
  
  In the KEK compact ERL (cERL), machine studies toward higher bunch charge operation is one of the most important issues. From January 2015 to April 2015, we carried out a higher bunch charge operation with an bunch charge of 0.5 pC for the experiment of laser compton scattering. After the study of space charge effect and optics tuning, we succeeded in the recirculation operation with the emittance, which was close to the design value. Moreover, a test operation in the injector section with the bunch charge of 7.7 pC was carried out as a preparation toward the recirculation operation with the average current of 10 mA.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA067  
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TUPMA034 Control of Synchrotron Radiation Effects During Recirculation with Bunch Compression emittance, controls, lattice, simulation 1910
 
  • D. Douglas, S.V. Benson, R. Li, C. Tennant
    JLab, Newport News, Virginia, USA
  • G.A. Krafft, B. Terzić
    ODU, Norfolk, Virginia, USA
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Studies of beam quality preservation during recirculation * have been extended to generate a design of a compact arc providing bunch compression with positive momentum compaction ** and control of both incoherent and coherent synchrotron radiation (ISR and CSR) effects using the optics balance methods of diMitri et al.***. In addition, the arc/compressor generates very little micro-bunching gain. We detail the beam dynamical basis for the design, discuss the design process, give an example solution, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of micro-bunching effects ****.
* D. Douglas et al., these proceedings
** S. Benson et al., these proceedings
*** S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013
**** C.Y. Tsai et al., these proceedings 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA034  
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TUPMA035 Control of Synchrotron Radiation Effects during Recirculation emittance, controls, lattice, synchrotron 1913
 
  • D. Douglas, S.V. Benson, A.S. Hofler, R. Kazimi, R. Li, Y. Roblin, C. Tennant
    JLab, Newport News, Virginia, USA
  • G.A. Krafft, B. Terzić
    ODU, Norfolk, Virginia, USA
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Numerous proposals invoke recirculation and/or energy recovery for cost-performance optimization. These often encounter challenges with the beam-quality-degrading effects of incoherent and coherent synchrotron radiation (ISR and CSR). We describe a means of controlling of this degradation. The approach utilizes results by diMitri et al. *, and invokes behavior observed during simulations of the recirculation process. The method is based on the use of periodically isochronous 2nd-order achromats; this not only insures that the conditions for the suppression of CSR-driven emittance growth are met*, it also suppresses micro-bunching gain over a broad range of parameter space **. Details of specific designs will be presented, and a reference to an analysis of micro-bunching effects ** provided. A planned test of the CSR suppression mechanism in CEBAF will be described.
*S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013.
**C.Y. Tsai et al., these proceedings.
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA035  
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WEPMA055 The Magnet and Power Supply System for the Compact-ERL quadrupole, power-supply, extraction, operation 2899
 
  • K. Harada, T. Kume, S. Nagahashi, N. Nakamura, S. Sakanaka, A. Ueda
    KEK, Ibaraki, Japan
  
  The recirculation loop of the cERL (compact Energy Recovery LINAC) was constructed in 2013. In this paper, we show the magnet and the power supply system for the recirculation loop of the cERL. The recirculation loop consists of the eight main bending magnets, sixty quadrupole magnets and ten small bending magnets for the three chicanes of the injection, extraction and circumference adjuster. The four power supplies are used for the chicane bending magnets, sixty for the quadrupoles, forty-eight for the horizontal correctors, and thirty-three for the vertical correctors. The EPICS (Experimental Physics and Industrial Control System) was used for the control of the power supplies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA055  
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