Keyword: FEM
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MOPTS113 Sensitivity Analyses of All-Electric Storage Ring Designs alignment, closed-orbit, storage-ring, proton 1148
  • M.J. Syphers, A. Narayanan
    Northern Illinois University, DeKalb, Illinois, USA
  Funding: This work supported by the National Science Foundation Grant 1623691.
Future searches of electric dipole moments (EDMs) of fundamental particles can require electrostatic storage rings operating at the particle’s "magic momentum" whereby spin precessions out of the plane of the particle motion would be governed in principle only by the presence of an EDM. An EDM search for the proton, for example, requires a momentum of approximately 700 MeV/c and thus implies a half-kilometer circumference, where relatively modest electric fields are assumed. As no all-electric ring on this scale has been constructed before, the ability to produce precise radial fields for establishing a central orbit and precise electrostatic focusing fields about that orbit requires attention. Results of initial investigations into the feasibility of designing a proper system and the sensitivities of such a system to placement, mis-powering errors and other requirements on realistic electrostatic elements will be presented.
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About • paper received ※ 09 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUPGW017 Superconducting Undulator Coils with Period Length Doubling undulator, vacuum, operation, storage-ring 1426
  • S. Casalbuoni, N. Glamann, A.W. Grau, T. Holubek, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  Funding: Work supported by the German government in the BMBF-project Superconducting ’Insertion Device Technologies for Ultra-Low-Emittance Light Sources’ (05K12CK1)
Only since few years it has been demonstrated experimentally that NbTi based superconducting undulators (SCUs) have a higher peak field on axis for the same gap and period length in operation with electron beam with respect to permanent magnet undulators (even the ones in vacuum and cooled to cryogenic temperatures). Another advantage of NbTi based SCUs with respect to permanent magnet devices is radiation hardness, widely demonstrated for NbTi magnets, which is and will become an increasingly important issue with the small gaps in the newest machines as round beam storage rings and FELs. Moreover, SCU technology allows switching of the period length by changing the current direction in one of separately powered subset of winding packages of the superconducting coils. This feature further broadens the energy range of the emitted photons, required by the different beamlines. To this end 0.5 m long superconducting undulator coils with switchable period length between 17 mm and 34 mm have been developed. In this contribution we describe the design and report on the quench tests, as well as on the magnetic field measurements.
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About • paper received ※ 25 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW033 Status of Test-Accelerator as Coherent THz Source (t-ACTS) at ELPH, Tohoku University radiation, electron, undulator, polarization 1475
  • S. Kashiwagi, H. Hama, F. Hinode, K. Kanomata, S. Miura, N. M. Morita, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, H. Saito, K. Takahashi, H. Yamada
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  A test-Accelerator as Coherent Terahertz Source (t-ACTS) has been under development at the Research Center for Electron Photon Science (ELPH), Tohoku University, in which an intense coherent terahertz radiation is generated from the femtosecond electron pulses. Velocity bunching scheme in a traveling accelerating structure is employed to generate femtosecond electron pulses, and the generation of femtosecond electron pulses was confirmed by spectrum analysis of coherent transition radiation using Michelson interferometer. Coherent transition radiation and coherent undulator radiation in the terahertz (THz) region from the short electron pulses has been demonstrated, and their characteristics such as frequency spectrum, spatial distribution and polarization were measured and compared with theoretical calculations. We have succeeded to generate the coherent transition radiation up to approximately 5 THz and the coherent undulator radiation with narrow bandwidth from 2.6 to 3.4 THz. At present, development of a variable polarized THz light source using a crossed-undulator system is being carried out. In addition, we are developing a nondestructive beam monitor using Cherenkov radiation emitted from the electron pulses. The status of t-ACTS will be presented in this conference.  
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About • paper received ※ 17 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW055 Improving High Precision Cam Mover’s Stiffness alignment, interface, experiment, collider 3713
  • J. Kemppinen
    ETH, Zurich, Switzerland
  • H.M. Durand, A. Herty
    CERN, Meyrin, Switzerland
  Pre-alignment is a key challenge of the Compact Linear Collider (CLIC) study. The requirement for CLIC main beam quadrupole (MBQ) alignment is positioning to within 1 µm from target in 5 degrees of freedom (DOF) with ± 3 mm travel. After motion, the position should be kept passively while the system’s fundamental frequency is above 100 Hz. Cam movers are considered for the task. Traditionally they are used for the alignment of heavier magnets with lower accuracy and stiffness requirement. This paper presents a new CLIC prototype cam mover with design emphasis on the fundamental frequency. A finite element method (FEM) model predicts the mode shapes and eigenfrequencies of the system and can be used for further improving the design. Experimental modal analysis (EMA) of the prototype shows that the prototype’s fundamental frequency is at 44 Hz. It also validates the FEM model.
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About • paper received ※ 01 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW079 THz-Based Femtosecond MeV Electron Bunch Compression electron, GUI, experiment, focusing 3766
  • M. A. K. Othman, M.C. Hoffmann, M.E. Kozina, R.K. Li, E.A. Nanni, X. Shen, E.J. Snively, X.J. Wang
    SLAC, Menlo Park, California, USA
  Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
Probing structural dynamics at atomic spatial and ultrashort temporal scales reveals unprecedented details of fundamental behavior of nature, allowing for better understanding of intricate energy-matter interaction occurring at such scales. Developing state-of-the-art technology to access these details entails utilizing X-ray free-electron lasers (XFELs), ultrafast electron diffraction (UED), and advanced electron microscopes. In particular, ultrafast diffraction science received growing attention thanks to innovation in sources, detectors and instrumentation in general. Within this context, interest in laser-generated THz wave-matter interaction has recently emerged as a new regime for controlling electrons with high temporal precision. Previously, the SLAC UED team has demonstrated attosecond electron metrology using laser-generated single-cycle THz radiation, which is intrinsically phase locked to the optical drive pulses, to manipulate multi-MeV relativistic electron beams. Here we demonstrate further steps towards achieving ultrafast timing resolution that utilizes femtosecond electron bunches. The proposed setup allows for compressing electron beam bunches down to a femtosecond using interaction with high field single-cycle THz pulses. We demonstrate a novel design of a dispersion-free parallel-plate tapered waveguide that provides focusing of THz pulses achieving >100 MV/m field strength at the interaction point as measured by electro-optical sampling for ~7 μJ of incoming THz pulse energy. The structure is being designed and built for bunch compression experiments using the SLAC UED facility.
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About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB018 Large-Scale Optical Synchronization System of the European XFEL with Femtosecond Precision laser, FEL, electron, controls 3835
  • T. Lamb, M.K. Czwalinna, M. Felber, C. Gerth, T. Kozak, J.M. Müller, H. Schlarb, S. Schulz, C. Sydlo, M. Titberidze, F. Zummack
    DESY, Hamburg, Germany
  Femtosecond pulsed optical synchronization systems have evolved over the last few years and are now a mature technique to synchronize FELs. A large-scale femtosecond-precision synchronization system with up to 44 end-stations has been constructed at the European XFEL to meet the FEL synchronization stability requirements. The synchronization system is used to phase-lock various laser systems with femtosecond accuracy, to precisely measure the electron bunch arrival time along the accelerator for fast arrival time feedbacks and to locally phase stabilize the phase of the RF reference signals for the accelerator RF controls on a femtosecond level. The architecture of the large-scale synchronization system and design choices made to achieve the reliability, maintainability and performance requirements are presented together with measurement results from the past year of operation.  
DOI • reference for this paper ※  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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