Keyword: alignment
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MOPC13 Design of Cold Beam Position Monitor for CADS Injector II Proton LINAC BPM, linac, cryogenics, proton 75
 
  • Y. Zhang, X.C. Kang, M. Li, J.X. Wu, G. Zhu
    IMP, Lanzhou, People's Republic of China
  
  Cold beam position monitor based on capacitive buttons are designed for Chinese Accelerator Driven System (CADS) Injector II proton LINAC. This LINAC is aiming to produce a maximum design current of 15 mA at the 10 MeV energy with an operating frequency of 162.5 MHz. Cold button BPM will be installed in the Cryomodule, which will be in the middle of the superconductor cavity and the superconductor magnet. Some special issues must be considered when designing a cold BPM: low-beta beam in the cryogenic environment, strong rf-field from the superconductor cavity and high magnetic field from the superconductor magnet. In this contribution, the status of cold BPM will be presented, focusing on the electromagnetic response for low-beta beams and mechanical design in the cryogenic environment.  
 
TUPC31 New Design of High Order Modes Electronics in MTCA.4 Standard for FLASH and the European XFEL XFEL, DESY, beam-position, monitoring 443
 
  • S. Bou Habib, A. Abramowicz
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • N. Baboi, H. Schlarb
    DESY, Hamburg, Germany
  
  At free-electron linear accelerators, various High Order Modes (HOM) - both monopole and dipole - are excited. Extensive studies at DESY have shown that monitoring and analysis of some of these modes can be used for different applications including Beam Position Monitors (BPMs) and the reduction of wake-fields, the measurement of the beam phase with-respect-to RF signal in cavities, and the measurement of cavity alignment in the 1.3 GHz cryo-modules. Three frequencies were chosen for further experiments: the 1.3 GHz base frequency from the klystron, the 1.7 GHz dipole mode and the 2.4 GHz monopole mode. In order to realize the monitoring and analysis requirements, very high resolution measurements in amplitude, phase and shape (time resolution) are required for all three frequencies simultaneously. In this paper, we present the new HOM electronics prototype including a microstrip and stripline RF tri-passband filter design and measurements and the specialized MTCA.4 Rear Transition Module for HOM measurements with an ultra-fast high-resolution AMC digitizer.  
poster icon Poster TUPC31 [1.226 MB]  
 
TUPC41 A Femtosecond Resolution Electro-Optic Diagnostic Using a Nanosecond-Pulse Laser laser, diagnostics, CLIC, longitudinal 474
 
  • S.P. Jamison
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • W.A. Gillespie, D.A. Walsh
    University of Dundee, Nethergate, Dundee, Scotland, United Kingdom
  
  Funding: We gratefully acknowledge support under CERN collaboration agreement KE1865/TE
Electro-optic longitudinal profile diagnostic systems with intrinsically improved reliability and a time resolution of 20 fs rms are being developed for CLIC. Exploiting the electro-optic effect, the bunch electric field 'pulse carves' an optical replica from a narrow bandwidth nanosecond duration laser probe. All-optical characterisation of the optical replica is via spectrally resolved auto-correlation, providing a sub-20fs resolution capability. An optical parametric amplification stage following the pulse carving, and driven by same nanosecond laser that provides the probe, enables sufficient intensity for single-shot measurement. In basing the optical system on nanosecond Q-switched lasers, bypassing complex femtosecond laser systems, the potential for robust instrumentation development is enhanced. The bandwidth limitations of the electro-optic materials are being addressed through investigations into multiple crystal detectors, and THz induced second harmonic generation on metal surfaces. Experimental results on the optical subsystems, using laser-produced THz as an electron bunch mimic, are presented together with performance projections for the integrated system. 		 
 
TUPF09 Commissioning Experience and First Results From the New SLS Beam Size Monitor SLS, polarization, emittance, optics 519
 
  • V. Schlott, M. Rohrer, A. Saá Hernández, A. Streun
    PSI, Villigen PSI, Switzerland
  • Å. Andersson, J. Breunlin
    MAX-lab, Lund, Sweden
  • N. Milas
    LNLS, Campinas, Brazil
  
  Funding: The presented work has received funding from the European Commission under FP-7-INFRASTRUCTURES-2010-1/INFRA-2010- 2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
In the context of the TIARA work package “SLS vertical emittance tuning” (SVET), an extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, was verified using an optical monitor based on imaging of pi-polarized light. Since the existing beam size monitor reached its limit of resolution, a new monitor beam line was designed and installed at the 08BD bending magnet of the storage ring of the Swiss Light Source SLS. Larger magnification and operation at shorter wavelength provide improved spatial resolution. Reflective optics enables convenient switching between different wavelengths. An optical table is located in a hutch outside the storage ring tunnel to provide access during operation. Movable obstacles in the beam path create interference patterns and thus provide redundancy of model based analysis of the images. In this paper we report on our commissioning experience and provide a comparison of the different measurement methods at different wavelengths. 		 
poster icon Poster TUPF09 [0.292 MB]  
 
WEBL3 Wake Field Monitors in a Multi Purpose X Band Accelerating Structure CERN, dipole, longitudinal, emittance 634
 
  • M.M. Dehler, S. Bettoni, B. Beutner, G. De Michele
    PSI, Villigen PSI, Switzerland
  • G. De Michele
    EPFL, Lausanne, Switzerland
  • G. De Michele
    CERN, Geneva, Switzerland
  
  In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. These feature integrated wake field monitors (WFMs), which are used to measure the alignment (offset and tilt) between structure and beam. One structure has recently been installed in the SwissFEL Injector Test facility (SITF) at PSI. The WFM front end electronics will be developed within the EuCard2 framework, so for the measurements described in this paper we used the raw WFM signals. We compare these measurements to the theoretical results obtained via an equivalent circuit model used in the design and numerical calculations. The beam tests show that by minimizing the WFM signals, the emittance dilution given by the transverse wakes, crucial because of the small aperture of the structure, is minimized as well.  
slides icon Slides WEBL3 [1.668 MB]  
 
WEPF01 Alignment of a Nozzle-Skimmer System for a Non Invasive Gas Jet Based Beam Profile Monitor laser, vacuum, electron, ion 803
 
  • V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by EU under contract 215080, Helmholtz Association and GSI under contract VH-BG-328, STFC under the Cockcroft Institute Core Grant No.ST/G008248/1 and a Liverpool - Riken fellowship.
A non-invasive gas jet-based beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This shall allow monitoring ultra-low energy, as well as high energy particle beams in a way that causes least disturbance to both, primary beam and accelerator vacuum. In this setup a nozzle-skimmer system is used to generate a thin supersonic curtain-shaped gas jet. However, very small diameters of both, the gas inlet nozzle and subsequent skimmers, required to shape the jet, have caused problems in monitor operation in the past. Here, an image processing based technique is presented which follows after careful manual initial alignment using a laser beam. An algorithm has been implemented in Labview and offers a semi-automated and straightforward solution for all previously encountered alignment issues. The procedure is presented in detail and experimental results are shown. 		 
poster icon Poster WEPF01 [0.863 MB]  
 
WEPF21 Scanning Wire Beam Position Monitor for Alignment of a High Brightness Inverse-Compton X-ray Source laser, electron, scattering, free-electron-laser 856
 
  • M.R. Hadmack, E.B. Szarmes
    University of Hawaii, Honolulu, HI, USA
  
  Funding: US Department of Homeland Security DNDO ARI program GRANT NO. 2010-DN-077-ARI045-02
The Free-Electron Laser Laboratory at the University of Hawaii has constructed and tested a scanning wire beam position monitor to aid the alignment and optimization of a high spectral brightness inverse-Compton scattering X-ray source. X-rays are produced by colliding the 40 MeV electron beam from a pulsed S-band LINAC with infrared laser pulses from a mode-locked free-electron laser driven by the same electron beam. The electron and laser beams are focused to 60 micron diameters at the interaction point to achieve high scattering efficiency. This wire-scanner allows for high resolution measurements of the size and position of both the laser and electron beams at the interaction point to verify spatial coincidence. Time resolved measurements of secondary emission current allow us to monitor the transverse spatial evolution of the e-beam throughout the duration of a 4 microsecond macropulse while the laser is simultaneously profiled by pyrometer measurement of the occulted infrared beam. Using this apparatus we have demonstrated that the electron and laser beams can be co-aligned with a precision better than 10 microns as required to maximize X-ray yield. 		 
poster icon Poster WEPF21 [14.675 MB]