Keyword: undulator
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MOPA09 Overview of Beam Instrumentation and Commissioning Results from the Coherent Electron Cooling Experiment at BNL* electron, cathode, laser, optics 43
  • T.A. Miller, J.C.B. Brutus, W.C. Dawson, D.M. Gassner, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, V. Litvinenko, C. Liu, R.J. Michnoff, M.G. Minty, P. Oddo, M.C. Paniccia, I. Pinayev, Z. Sorrell, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  Funding: *Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Coherent Electron Cooling (CeC) Proof-of-Principle experiment [1], installed in the RHIC tunnel at BNL, has completed its second run. In this experiment, an FEL is used to amplify patterns imprinted on the cooling electron beam by the RHIC ion bunches and then the imprinted pattern is fed back to the ions to achieve cooling of the ion beam. Diagnostics for the CeC experiment have been fully commissioned during this year's run. An overview of the beam instrumentation is presented, this includes devices for measurements of beam current, position, profile, bunch charge, emittance, as well as gun photocathode imaging and FEL infra-red light emission diagnostics. Design details are discussed and beam measurement results are presented.
[1] I. Pinayev, et al, 'First Results of Proof-of-Principle Experiment of Coherent Electron Cooling at BNL' proceedings from IPAC 2018, Vancouver, CANADA
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MOPB08 Evaluation of the Transverse Impedanse of Pf in-Vacuum Undulator Using Local Orbit Bump Method factory, betatron, impedance, simulation 89
  • O. Tanaka, M. Adachi, K. Harada, R. Kato, N. Nakamura, T. Obina, R. Takai, Y. Tanimoto, K. Tsuchiya, N. Yamamoto
    KEK, Ibaraki, Japan
  When a beam passes through insertion devices (IDs) with narrow gap or beam ducts with small aperture, it receives a transverse kick from the impedances of those devices. This transverse kick depends on the beam trans-verse position and beam parameters such as the bunch length and the total bunch charge. In the orbit bump method, the transverse kick factor of an ID is estimated through the closed orbit distortion (COD) measurement at many BPMs for various beam currents [1]. In the present study, we created an orbit bump of 1 mm using four steering magnets, and then measured the COD for two cases: when the gap is opened (the gap size is 42 mm) and when the gap is closed (the gap size is 3.83 mm). The ID's kick factors obtain by these measurements are compared with those obtain by simulations and analytical evaluations.  
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MOPC17 On-line Crosstalk Measurement and Compensation Algorithm Study of SXFEL Digital BPM System FEL, cavity, experiment, background 150
  • F.Z. Chen, L.W. Lai, Y.B. Leng, T. Wu, L.Y. Yu
    SSRF, Shanghai, People's Republic of China
  • J. Chen, R.X. Yuan
    SINAP, Shanghai, People's Republic of China
  Shanghai soft X-ray Free Electron Laser (SXFEL) has acquired the custom designed Digital BPM processor used for signal processing of cavity BPMs and stripline BPMs. In order to realize monitor the beam position accurately, it has high demand for DBPM system performance. Considering the crosstalk may introduce distortion and influence beam position resolution, it is important to analyze and compensate the crosstalk to improve the resolution. We choose the CBPM signal to study the crosstalk for its narrowband and sensitive for phase. The main experiment concept is successive accessing four channels to form a signal transfer matrix, which including amplitude frequency response and phase response information. And the compensation algorithm is acquire four channel readouts, then using the signal transfer matrix to reverse the true signal to ensure the accurate beam position measurement. This concept has already been tested at SXFEL and hopeful to compensate the crosstalk sufficiently.  
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WEOB03 The European XFEL Beam Loss Monitor System FEL, electron, high-voltage, controls 357
  • T. Wamsat, T. Lensch
    DESY, Hamburg, Germany
  The European XFEL MTCA based Beam Loss Monitor System (BLM) is composed of about 470 monitors, which are part of the Machine Protection System (MPS). The BLMs detect losses of the electron beam, in order to protect accelerator components from damage and excessive activation, in particular the undulators, since they are made of permanent magnets. Also each cold accelerating module is equipped with a BLM to measure the sudden onset of field emission (dark current) in cavities. In addition some BLMs are used as detectors for wire- scanners. Experience from the already running BLM system in FLASH2 which is developed for XFEL and tested here, led to a fast implementation of the system in the XFEL. Further firmware and server developments related to alarm generation and handling are ongoing. The BLM systems structure, the current status and the different possibilities to trigger alarms which stop the electron beam will be presented.  
slides icon Slides WEOB03 [3.631 MB]  
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WEPB01 Photon Beam Imager at SOLEIL radiation, vacuum, operation, insertion 425
  • M. Labat, J. Da Silva, N. Hubert, F. Lepage
    SOLEIL, Gif-sur-Yvette, France
  In one of the long straight sections of SOLEIL is installed a pair of canted in-vacuum undulators for the ANATOMIX and NANOSCOPIUM beamlines. Since the upstream undulator radiation can potentially damage the downstream undulator magnets, an accurate survey of the respective alignment of the two devices is mandatory. An XBPM has been initially installed for this purpose in the beamline frontend. For redundancy and further analysis, an X-ray imager was then designed and added just downstream the XBPM. It is made of a diamond plate that can be inserted into the upstream beamline frontend at low current. Fluorescence of the Nitrogen impurities in the diamond is imaged on a CCD to check that the upstream radiation is not hitting the downstream insertion device. We present the commissioning of this new device together with its first results in operation.  
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WEPB09 Wire Scanner Measurements at the PAL-XFEL FEL, electron, emittance, controls 445
  • G. Kim, H.-S. Kang, C. Kim, B.G. Oh, D.C. Shin
    PAL, Pohang, Kyungbuk, Republic of Korea
  The PAL-XFEL, an X-ray Free electron laser user facility based on a 10 GeV normal conducting linear accelerator, have been operational at Pohang, South Korea. The wire scanners are installed for transverse beam profile measurement of the Linac and the Hard X-ray undulator section. The wire scanner is a useful device for emittance measurements in the Hard X-ray undulator section. In this paper, we describe the details of the wire scanner and the results of the measurements.  
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WEPC05 The European XFEL Wire Scanner System detector, FEL, optics, electron 498
  • T. Lensch, S. Liu, M. Scholz
    DESY, Hamburg, Germany
  The European-XFEL (E-XFEL) is an X-ray Free Electron Laser facility located in Hamburg (Germany). The superconducting accelerator for up to 17.5 GeV electrons will provide photons simultaneously to several user stations. Currently 12 Wire Scanner units are used to image transverse beam profiles in the high energy sections. These scanners provide a slow scan mode which is currently used to measure beam emittance and beam halo distributions. When operating with long bunch trains (>100 bunches) also fast scans are planned to measure beam sizes in an almost nondestructive manner. Scattered electrons can be detected with regular Beam Loss Monitors (BLM) as well as dedicated wire scanner detectors. Latter are installed in different variants at certain positions in the machine. Further developments are ongoing to optimize the sensitivity of the detectors to be able to measure both, beam halo and beam cores within the same measurement with the same detector. This paper describes the current status of the system and examples of different slow scan measurements.  
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THOA03 Progress on Transverse Beam Profile Measurement Using the Heterodyne Near Field Speckles Method at ALBA radiation, scattering, target, experiment 538
  • S. Mazzoni, F. Roncarolo, G. Trad
    CERN, Geneva, Switzerland
  • U. Iriso, C. Kamma-Lorger, A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • M.A.C. Potenza
    Universita' degli Studi di Milano & INFN, Milano, Italy
  • M. Siano
    Università degli Studi di Milano, Milano, Italy
  We present the recent developments of a study aiming at measuring the transverse beam profile using the Heterodyne Near Field Speckles (HNFS) method. The HNFS technique consists of a suspension of nanoparticles suspended in a liquid and illuminated by synchrotron radiation (either in the visible or in X-ray wavelength range). The transverse coherence of the source, and therefore, under the conditions of validity of the Van Cittert and Zernike theorem, the transverse electron beam size is retrieved from the interference between the transmitted beam and the spherical waves scattered by each nanoparticle. We here describe the fundamentals of this technique, as well as the recent experimental results obtained with 12 keV radiation at the NCD beamline at ALBA. The applicability of such technique for future accelerators (e.g. CLIC or FCC) is also discussed.  
slides icon Slides THOA03 [2.414 MB]  
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