Author: Werin, S.
Paper Title Page
MOPAB266 Start-to-End Study on Laser and RF Jitter Effects for MAX-IV SXL 844
 
  • S.P. Pirani, B.S. Kyle
    MAX IV Laboratory, Lund University, Lund, Sweden
  • F. Curbis, M.A. Pop, S. Werin
    Lund University, Lund, Sweden
  • W. Qin
    DESY, Hamburg, Germany
 
  A Soft X-ray free electron laser (FEL) for the MAX IV Laboratory is currently in the design phase and it will use the existing 3 GeV linac. Present stability limits in the RF and the photocathode laser will affect the performance of the FEL. One of the critical elements for the design of a FEL is to have an estimation on jitter effects of the accelerator parameters on the X-ray radiation. In this regard, we implemented a start-to-end study using Astra, Elegant and Genesis in order to assess possible variations in pulse energy, photon pulse length and spectral width in the Soft X-ray Laser (SXL) radiation. This investigation provides insights on the final SXL performance variation due to RF and laser related jitter affecting the electron beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB266  
About • paper received ※ 19 May 2021       paper accepted ※ 26 July 2021       issue date ※ 24 August 2021  
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TUPAB082 Analysis of the Effect of Energy Chirp in Implementing EEHG at SXL 1566
 
  • M.A. Pop, F. Curbis, B.S. Kyle, S.P. Pirani, W. Qin, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
  • F. Curbis, S. Werin
    Lund University, Lund, Sweden
  • W. Qin
    DESY, Hamburg, Germany
 
  As a part of the efforts to improve the longitudinal coherence in the design of the Soft X-ray FEL (the SXL) at MAX IV, we present a possible implementation of the EEHG harmonic seeding scheme partly integrated into the second bunch compressor of the existing LINAC. A special focus is given to the effect of CSR on the resulting EEHG bunching and on how this unwanted effect might be controlled.  
poster icon Poster TUPAB082 [1.825 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB082  
About • paper received ※ 15 May 2021       paper accepted ※ 28 July 2021       issue date ※ 17 August 2021  
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TUPAB113 Highlights From the Conceptual Design Report of the Soft X-Ray Laser at MAX IV 1651
 
  • F. Curbis, J. Andersson, L. Isaksson, B.S. Kyle, F. Lindau, E. Mansten, H. Tarawneh, P.F. Tavares, S. Thorin, A.S. Vorozhtsov
    MAX IV Laboratory, Lund University, Lund, Sweden
  • S. Bonetti
    Stockholm University, Stockholm, Sweden
  • V.A. Goryashko, P.M. Salén
    Uppsala University, Uppsala, Sweden
  • P. Johnsson, S.P. Pirani, M.A. Pop, W. Qin, S. Werin
    Lund University, Lund, Sweden
  • M. Larsson
    Stockholm University, Department of Physics, Stockholm, Sweden
  • A. Nilsson
    FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
  • J.A. Sellberg
    KTH Physics, Stockholm, Sweden
 
  Funding: Knut and Alice Wallenberg Foundation
The SXL (Soft X-ray Laser) project developed a conceptual design for a soft X-ray Free Electron Laser in the 1–5 nm wavelength range, driven by the existing MAX IV 3 GeV linac. In this contribution we will focus on the FEL operation modes developed for the first phase of the project based on two different linac modes. The design work was supported by the Knut and Alice Wallenberg foundation and by several Swedish universities and organizations (Stockholm, Uppsala, KTH Royal Institute of Technology, Stockholm-Uppsala FEL center, MAX IV laboratory and Lund University).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB113  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 19 August 2021  
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TUPAB198 ESS DTL Tuning Using Machine Learning Methods 1872
 
  • J.S. Lundquist, N. Milas, E. Nilsson
    ESS, Lund, Sweden
  • S. Werin
    Lund University, Lund, Sweden
 
  The European Spallation Source, currently under construction in Lund, Sweden, will be the world’s most powerful neutron source. It is driven by a proton linac with a current of 62.5 mA, 2.86 ms long pulses at 14 Hz. The final section of its normal-conducting front-end consists of a 39 m long drift tube linac (DTL) divided into five tanks, designed to accelerate the proton beam from 3.6 MeV to 90 MeV. The high beam current and power impose challenges to the design and tuning of the machine and the RF amplitude and phase have to be set within 1% and 1 degree of the design values. The usual method used to define the RF set-point is signature matching, which can be a time consuming and challenging process, and new techniques to meet the growing complexity of accelerator facilities are highly desirable. In this paper we study the usage of Machine Learning to determine the RF optimum amplitude and phase. The data from a simulated phase scan is fed into an artificial neural network in order to identify the needed changes to achieve the best tuning. Our test for the ESS DTL1 shows promising results, and further development of the method will be outlined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB198  
About • paper received ※ 17 May 2021       paper accepted ※ 21 June 2021       issue date ※ 13 August 2021  
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TUPAB103 Discussion on CSR instability in EEHG Simulation 1622
 
  • D. Samoilenko, W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • F. Curbis, M.A. Pop, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
  • P. Niknejadi, G. Paraskaki
    DESY, Hamburg, Germany
  • F. Pannek
    University of Hamburg, Hamburg, Germany
 
  Echo-Enabled Harmonic Generation (EEHG) is an external seeding technique for XUV and soft X-ray Free Electron Lasers (FEL). It has recently been experimentally demonstrated and currently many facilities worldwide intend to incorporate it in user operation. The EEHG process relies on very accurate and complex transformations of electron beam phase space by means of a series of undulators coupled to lasers and dispersive chicanes. As a result of the phase space manipulation, electrons are bunched at a high harmonic of the seed laser wavelength allowing coherent emission at few nm wavelength. Dispersion occurring in strong chicanes is imperative for implementation of this scheme and effective electron bunching generation. However, strong chicanes at the same time can be source of beam instability effects, such as Coherent Synchrotron Radiation (CSR), that can significantly grow in these conditions and suppress the bunching process. Therefore, there is a common need to investigate such effects in detail. Here, we discuss their treatment with simulation codes applied to a typical EEHG setup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB103  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 12 August 2021  
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