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Kamiya, Y.

Paper Title Page
MOPE022 Development of Shintake Beam Size Monitor for ATF2 1011
 
  • Y. Kamiya
    ICEPP, Tokyo
  • S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • S. Komamiya, M. Oroku, T.S. Suehara, Y. Yamaguchi, T. Yamanaka
    University of Tokyo, Tokyo
 
 

In this paper, we describe a system design and current status of Shintake beam size monitor. Shintake monitor is a laser-based beam diagnostics tool, which provides a non-invasive measurement of transverse beam sizes. The interaction target probing the electron beam is interference fringes build up by the two coherent lasers that have narrow bandwidth and long coherent length. A scale of the target structure corresponds to approximately one fourth of the laser wave length, and the smallest measurable size reaches down to several tens of nanometers. The monitor we described here is installed at the virtual interaction point of the ATF2 beam line, which is built to confirm the proposed final focus system for Future Linear Colliders. We adopt second harmonics of Nd:YAG laser of 532 nm wavelength, and phase stabilization feedback system to allow to measure the designed beam size of about 37 nm. To widen a measurable range up to about 5 microns (wire scanner's range), we also prepare three crossing modes that change an effective wavelength for the fringes. The monitor is used to measure a focus size during the tuning process. The system is based on the Shintake monitor for FFTB.

 
MOPE023 Evaluation of Expected Performance of Shintake Beam Size Monitor for ATF2 1014
 
  • Y. Yamaguchi, S. Komamiya, M. Oroku, T.S. Suehara, T. Yamanaka
    University of Tokyo, Tokyo
  • S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • Y. Kamiya
    ICEPP, Tokyo
 
 

ATF2 is the final focus test facility for ILC to realize and demonstrate nanometer focusing. One of the goals of the ATF2 is a demonstration of a compact final focus system based on the local chromaticity correction. A designed beam size at the focal point is to be 37 nm in vertical. To achieve the goal, a beam size monitor capable of nanometer beam size measurement is inevitably needed. Shintake monitor satisfies the demands, and is installed at the virtual interaction point of the ATF2. Shintake monitor is a beam size monitor which uses laser interference fringe pattern to measure beam size. The beam test for the Shintake monitor was successful in measurement of signal modulation with the laser interference fringe pattern in November 2009. In April 2010, beam size of less than 1 micron was achieved. We have studied the error sources, and evaluated the total error to be less than 10% for 1 minute measurement. This paper is about the evaluation of the Shintake monitor performance by analyzing beam tests data. Most systematic error sources are well understood, so that we can estimate accuracy of beam size measurement when the beam size reaches 37nm.

 
WEOBMH01 Operational Experiences Tuning the ATF2 Final Focus Optics Towards Obtaining a 37nm Electron Beam IP Spot Size 2383
 
  • G.R. White, A. Seryi, M. Woodley
    SLAC, Menlo Park, California
  • S. Bai
    IHEP Beijing, Beijing
  • P. Bambade, Y. Renier
    LAL, Orsay
  • B. Bolzon
    IN2P3-LAPP, Annecy-le-Vieux
  • Y. Kamiya
    ICEPP, Tokyo
  • S. Komamiya, M. Oroku, Y. Yamaguchi, T. Yamanaka
    University of Tokyo, Tokyo
  • K. Kubo, S. Kuroda, T. Okugi, T. Tauchi
    KEK, Ibaraki
  • E. Marin
    CERN, Geneva
 
 

The primary aim of the ATF2 research accelerator is to test a scaled version of the final focus optics planned for use in next-generation linear lepton colliders. ATF2 consists of a 1.3 GeV linac, damping ring providing low-emittance electron beams (<12pm in the vertical plane), extraction line and final focus optics. The design details of the final focus optics and implementation at ATF2 are presented elsewhere* . The ATF2 accelerator is currently being commissioned, with a staged approach to achieving the design IP spot size. It is expected that as we implement more demanding optics and reduce the vertical beta function at the IP, the tuning becomes more difficult and takes longer. We present here a description of the implementation of the overall tuning algorithm and describe operational experiences and performances


* Beam-Based Alignment, Tuning and Beam Dynamics Studies for the ATF2 Extraction Line and Final Focus System. Glen R. White , S. Molloy, M. Woodley, (SLAC). EPAC08-MOPP039, SLAC-PUB-13303.

 

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Slides

 
TUPEA008 An Ultra-low Emittance Design for Energy Recovery Linac (ERL) Injector 1342
 
  • J. Yamazaki, A. Enomoto, Y. Kamiya
    KEK, Ibaraki
 
 

One of the most important issues for ERL injectors is to generate electron beams with ultra-low emittance and to accelerate the beams through the injector without emittance growth. For this purpose, we have developed an efficient simulation code to investigate the mechanism of emittance growth due to space charge effect and to exploit its suppression method. In this code, the longitudinal motion is treated by the one-dimensional difference equations for macro-particles, while the radial motion is solved by the envelope equations for the pieces of sliced bunch. We find that the total emittance takes a minimum when all ellipses of sliced envelope have the same direction on the a-a' plane, where a is the amplitude of sliced envelope and a' its derivative along the longitudinal direction. The parameters of a 5 MeV injector were optimized by this code, assuming that the voltage of the DC electron gun is 330 kV and the initial particle distribution at the exit of the gun has a uniform ellipse. Even for such a low voltage gun, we obtained a minimum value of the rms normalized emittance, 0.10 mm, and the rms bunch length, 0.83 mm, the values of which were calculated by using PARMELA.