Keyword: bunching
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MOPO040 Coherent Synchrotron Radiation Monitor for Microbunching Instability in XFEL radiation, laser, electron, FEL 115
 
  • J.H. Ko, I.S. Ko
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • H.-S. Kang, C. Kim, G. Kim
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  The microbunching instability is an important issue in an X-ray Free Electron Laser (XFEL). The intensity of the FEL can be reduced significantly by the microbunching instability so that the laser heater is widely used to reduce it. In the X-ray Free Electron Laser of the Pohang Accelerator Laboratory (PAL-XFEL), to directly monitor the microbunching instability, a visible CCD camera was included into the coherent radiation monitor (CRM) which uses a pyroelectric detector. It enabled us to measure the microbunching instability more clearly and optimize the FEL lasing in the PAL-XFEL.  
slides icon Slides MOPO040 [1.125 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO040  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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MOPO092 A 3-gap Booster Cavity to Match Ion Source Potential to RFQ Acceptance booster, rfq, ISAC, space-charge 196
 
  • R.E. Laxdal, Z.T. Ang, T. Au, S. Kiy, S.D. Rädel, O. Shelbaya, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
 
  The ISAC RFQ can accelerate ions with A/Q ration from 1 to 30 and requires an input energy of 2.04keV/u. The harsh environment of the ISAC on-line ISOL target facility makes it difficult to meet the energy for the heaviest masses. For these cases we have designed and installed a short three gap device that accelerates the beams produced at source potential to match the required energy for RFQ acceptance. The booster cavity operates at 11.7MHz, the RF frequency of the pre-buncher. The device can also be used as a second buncher to augment the acceptance in the RFQ or to improve the acceptance of higher space charge beams. The device will be described and the results of beam measurements will be given.  
slides icon Slides MOPO092 [7.627 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO092  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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TU1P01 Extreme High Brightness Electron Beam Generation in a Space Charge Regime cavity, emittance, electron, space-charge 314
 
  • A. Bacci
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • L. Faillace, M. Rossetti Conti
    Universita’ degli Studi di Milano & INFN, Milano, Italy
 
  The generation of ultra-short, low emittance and low energy spread electron bunches is nowadays a critical requirement for accelerators in plasma wave or for femto-second light sources. A new longitudinal compression scheme, based on velocity and ballistic bunching tech-niques in presence of space charge forces, allows to enter in a peculiar regime, so-called laminar bunching (LB). In this regime, the bunch is longitudinally compressed, at the expense of its transverse size, and the over-bunching is forbidden by the laminarity: going to the minimal longi-tudinal dimension the bunch is adiabatically frozen and transversally refocused. Furthermore this technique heats slightly the uncorrelated energy spread resulting in elec-tron distributions that, in case of bending paths, does not require Laser Heater devices.  
slides icon Slides TU1P01 [1.720 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1P01  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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THPO042 An Optimization Method of the Nose-cone Buncher Cavity cavity, simulation, proton, radiation 778
 
  • W.L. Liu, P.T. Cong, Z.M. Wang
    NINT, Shannxi, People’s Republic of China
  • H. Jiang, S.X. Zheng
    TUB, Beijing, People’s Republic of China
 
  The nose-cone buncher cavity is widely used on proton accelerators. It’s important to properly optimize the cavity geometry for fine RF performance. Howev-er, currently the optimization is usually carried out manually and the criteria are not objective enough. In this paper, an optimization method using the multi-objective, multi-variable optimization approach is presented. The geometry and RF parameters are con-sidered as the variables and objectives respectively. The goal function is defined as the weighted sum of multiple RF parameters. The multi-variable functions are approximately derived from the single-variable functions based on electromagnetic simulation. And an optimization code is developed accordingly which has been applied to the XiPAF debuncher optimization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO042  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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