Keyword: free-electron-laser
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MOPC144 Autocorrelation Function and Power Spectrum of a Train of Quasiperiodic Sequence of Pulses electron, FEL, wakefield, optics 415
 
  • E.M. Laziev, B. Grigoryan, V.M. Tsakanov
    CANDLE, Yerevan, Armenia
  • M. Movsisyan, D.L. Oganesyan
    YSU, Yerevan, Armenia
 
  The statistical relationship of the autocorrelation function and spectrum of a train of quasi-periodic sequence of pulses having a time jitter of the repetition rate is obtained. Presented the accordance of autocorrelation function as well as power spectrum of the bounded quasi-periodic sequence of pulses and timing jitter of their repetition rate. The results can be used at the measurements of timing jitter of a train of electron bunches.  
 
TUPC076 Realization of a High Bandwidth Bunch Arrival-time Monitor with Cone-shaped Pickup Electrodes for FLASH and XFEL pick-up, electron, laser, coupling 1177
 
  • A. Angelovski, M. Hansli, R. Jakoby, A. Kuhl, A. Penirschke, S. Schnepp
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, H. Schlarb
    DESY, Hamburg, Germany
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA
In the Free Electron Laser in Hamburg (FLASH) an electro-optical system is used as a Bunch Arrival time Monitor (BAM). The time-of-arrival resolution is proportional to the steepness of the beam pick-up signal at the first zero-crossing*. Future experiments will be conducted using significantly lower bunch charges resulting in a reduced signal steepness. This requires BAM pickup electrodes with increased bandwidth as introduced in **. This paper presents the implementation and measurement results of a high bandwidth cone-shaped pickup capable of operating in the frequency range up to 40 GHz. The slope steepness at the zero crossing is investigated for a simplified equivalent circuit model. RF-measurements have been performed using a non-hermetic prototype of the BAM pickups for assessing the influence of manufacturing tolerances on the sensor performance. The measurements are compared to simulation results obtained by CST PARTICLE STUDIO®.
* F. Loehl et al., Proc. of DIPAC2007, WEPB15, p. 262 (2007).
** A. Angelovski et al., "Pickup design for a high resolution Bunch Arrival time Monitor for FLASH and XFEL", DIPAC2011.
 
 
TUPC079 Sensitivity and Tolerance Analysis of a New Bunch Arrival-time Monitor Pickup Design for FLASH and XFEL pick-up, simulation, laser, electron 1186
 
  • A. Kuhl, A. Angelovski, R. Jakoby, A. Penirschke, S. Schnepp
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, H. Schlarb
    DESY, Hamburg, Germany
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Funding: Supported by the Graduate School of Computational Engineering at TU Darmstadt and the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free Electron Laser in Hamburg (FLASH) is equipped with Bunch Arrival Time Monitors (BAM)*, which provide for a time resolution of less than 10 fs for bunch charges higher than 0.2 nC. Future experiments, however, will aim at generating FEL light pulses from a broad range of bunch charges down to 10 pC. In these circumstances the requirements on the time resolution will no longer be fulfilled, which demands for a larger bandwidth of the pickup system. A new cone-shaped pickup, which has a bandwidth greater than 40 GHz has been proposed**. At high frequencies, small manufacturing tolerances might have great influence on the pickup signal. A sensitivity analysis of several manufacturing tolerances in the pickup design regarding their influence on the output signal was carried out (by means of CST PARTICLE STUDIO®). These results are utilized for setting limits to the manufacturing tolerances.
* M.K. Bock et al., IPAC2010, WEOCMH02, Kyoto, Japan, 2010.
** A. Kuhl et al., "Design eines hochauflösenden Ankunftszeitmonitor für FLASH", DPG Frühjahrstagung 2011, Karlsruhe, Germany.
 
 
TUPS014 Vacuum Performance Simulation of C-band Accelerating Structures vacuum, cavity, linac, simulation 1548
 
  • H. Lee, M.-H. Cho, S.H. Kim, C.H. Yi
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  • W. Namkung, C.D. Park
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  Funding: This work is partly supported by the MEST and POSTECH Physics BK21 program.
A C-band accelerating structure has a higher accelerating gradient than that of the S-band structure. It provides a good advantage of a shorter machine length. In order to effectively use RF power and for cost reduction, the accelerating structure should be as long as possible. We propose a 2.2-m long structure compared to 1.8-m at SACLA (SPring-8 Angstrom Compact free electron LAser). However, a longer accelerating structure has worse vacuum performance than a shorter accelerating structure. Thus, the vacuum conductance of 2.2-m long structure has to be checked. We calculate vacuum performance of the accelerating structure by 1-D analytical method and 3-D finite element method (FEM). It is shown that the vacuum performance for the 2.2-m long accelerating structure is safe enough for the XFEL LINAC.
 
 
TUPS056 Synchronizing GEANT and 3D CAD - A Collaborative Engineering Study at ILD simulation, laser, electron 1659
 
  • L. Hagge, S. Eucker, B. List, S. Sühl, N. Welle
    DESY, Hamburg, Germany
 
  The design of a detector for a high-energy physics experiment is a complex task, driven by two different communities: The scientists aim to optimize the detector performance, while engineers are tasked to provide a design that can actually be built. Both groups have their own specific tools (e.g. GEANT versus 3D CAD systems) that are employed to model the detector and improve its design. The ensuing models need to be compared and synchronized at regular intervals, so that optimizations made to the physics simulation model are propagated to the engineering world, and engineering solutions are reflected properly in the physics simulation. Based on experience from the European XFEL project, DESY is providing tools and processes for establishing this synchronization at a very early stage in the design of the International Large Detector (ILD) for the International Linear Collider (ILC). They have been used to analyze compliance and differences of the ILD engineering design and physics simulation models. The poster introduces tools and process and presents first results and lessons learned.  
 
WEPZ016 Generation and Characterization of Electron Bunches with Ramped Current Profiles at the FLASH Facility electron, laser, wakefield, linac 2805
 
  • P. Piot
    Fermilab, Batavia, USA
  • C. Behrens, C. Gerth, M. Vogt
    DESY, Hamburg, Germany
  • F. Lemery, D. Mihalcea
    Northern Illinois University, DeKalb, Illinois, USA
 
  Funding: This work was supported the Defense Threat Reduction Agency, Basic Research Award # HDTRA1-10-1-0051, to Northern Illinois University and the German's Bundesministerium f\"ur Bildung und Forschung
We report on the successful generation of electron bunches with current profiles that have a quasi-linear dependency on the longitudinal coordinate. The technique relies on impressing nonlinear correlations in the longitudinal phase space using a linac operating at two frequencies (1.3 and 3.9 GHz) and a bunch compressor. Data taken for various accelerator settings demonstrate the versatility of the method. The produced bunches have parameters well matched to drive high-gradient accelerating field with enhanced transformer ratio in beam-driven accelerators based on sub-mm-sizes dielectric or plasma structures.
 
 
THPC174 Manufacturing and Testing of the First Phase Shifter Prototypes Built by CIEMAT for the European-XFEL controls, undulator, electron, laser 3308
 
  • I. Moya, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, L.M. Martinez Fresno, T. Martínez de Alvaro, E. Molina Marinas, A.L. Pardillo, L. Sanchez, S. Sanz, F. Toral, C. Vazquez, J.G.S. de la Gama
    CIEMAT, Madrid, Spain
 
  Funding: Work partially supported by the Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009.
The European X-ray Free Electron Laser (EXFEL) will be based on a 10 to 17.5 GeV electron linac. Its beam will be used in three undulator systems to obtain ultra-brilliant X-ray flashes from 0.1 to 6 nanometres for experimentation. The undulator systems are formed by 5m long undulator segments and 1.1m long intersections in between. They accommodate a quadrupole on top of a precision mover, a beam position monitor, two air coil correctors and a phase shifter. The function of the phase shifter is to adjust the phase of the electron beam with respect to that of the radiation field when the wavelength is changed by tuning the gap. In this context, CIEMAT will deliver 92 phase shifters, as part of the Spanish in-kind contribution to the EXFEL project. This paper describes the engineering design, the manufacturing techniques and the mechanical and magnetic tests realized on the first prototypes.