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Tauchi, T.

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.

 
MOPE035 Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor 1050
 
  • Y.I. Kim, A. Heo, E.-S. Kim
    Kyungpook National University, Daegu
  • S.T. Boogert
    Royal Holloway, University of London, Surrey
  • Y. Honda, T. Tauchi, N. Terunuma
    KEK, Ibaraki
  • J. May, D.J. McCormick, T.J. Smith
    SLAC, Menlo Park, California
 
 

Nanometer resolution Beam Position Monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam focused has to be measured within a few nanometer resolution at the interaction point. In order to achieve this performance, electronics for this BPM was developed. Every component of the electronics have been simulated and checked by local test and using beam signal. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal.

 
MOPE100 The Straightness Monitor System at ATF2 1218
 
  • M.D. Hildreth
    University of Notre Dame, Notre Dame
  • A.S. Aryshev
    Royal Holloway, University of London, Surrey
  • S.T. Boogert
    JAI, Egham, Surrey
  • Y. Honda, T. Tauchi, N. Terunuma
    KEK, Ibaraki
  • G.R. White
    SLAC, Menlo Park, California
 
 

The demonstration of the stability of the position of the focused beam is a primary goal of the ATF2 project. We have installed a laser interferometer system that will eventually correct the measurement of high-precision Beam Position Monitors used in the ATF2 Final Focus Steering Feedback for mechanical motion or vibrations. Here, we describe the installed system and present preliminary data on the short- and long-term mechanical stability of the BPM system.

 
WEOCMH01 First Beam Test of the Tilt Monitor in the ATF2 Beam Line 2402
 
  • D. Okamoto
    Tohoku University, Graduate School of Science, Sendai
  • Y. Honda, T. Tauchi
    KEK, Ibaraki
  • T. Sanuki
    Tohoku University, School of Scinece, Sendai
 
 

We have studied a beam orbit tilt monitor for stabilizing the beam orbit in ATF2. Once we can measure a beam orbit tilt with high precision at one point, we can relate this data with the beam position profile at the focal point. A tilt monitor is composed of a single rectangular sensor cavity and a waveguide to extract the signal. In the sensor cavity, there is the most basic resonant mode called monopole mode. This monopole mode is perpendicular to the nominal beam axis, and excited by the beam tilt. We extract this monopole mode. As the result, the amplitude of the extracted signal is proportional to the tilt angle. The tilt monitor is almost indepnedent with beam postion, so we can get the tilt date independently. According to our simulation, the sensitivity is estimated about 35nrad in the vertical direction. The prototype was completed and installed in the test area on the ATF2 beamline. The first beam test will be performed in December 2009. We will report this result and future update plan.

 

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MOPE070 Cavity Beam Position Monitor System for ATF2 1140
 
  • S.T. Boogert, G.E. Boorman, C. Swinson
    JAI, Oxford
  • R. Ainsworth, S. Molloy
    Royal Holloway, University of London, Surrey
  • A.S. Aryshev, Y. Honda, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • J.C. Frisch, J. May, D.J. McCormick, J. Nelson, T.J. Smith, G.R. White, M. Woodley
    SLAC, Menlo Park, California
  • A. Heo, E.-S. Kim, H.-S. Kim, Y.I. Kim
    Kyungpook National University, Daegu
  • A. Lyapin
    UCL, London
  • H.K. Park
    KNU, Deagu
  • M.C. Ross
    Fermilab, Batavia
  • S. Shin
    PLS, Pohang
 
 

The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (BPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance.

 
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

 
WEPE017 Beam Test Plan of Permanent Magnet Quadrupole Lens at ATF2 3380
 
  • Y. Iwashita, H. Fujisawa, M. Ichikawa, H. Tongu, S. Ushijima
    Kyoto ICR, Uji, Kyoto
  • M. Masuzawa, T. Tauchi
    KEK, Ibaraki
 
 

A prototype of a permanent magnet quadrupole lens for ILC final focus doublet is fabricated. In order to demonstrate the feasibility, it will be tested in a real beam line. Such practical experiences include its shipping, storage, handling, installation, alignment technique, and so on. Because permanent magnets cannot be switched off in contradistinction to electromagnets, they should be evacuated from beam lines when no interference is desired and the process should be quick with enough reproducibility. The magnetic center and strength stability including reproducibility are also important issues during the beam test. In order to reduce interferences with current ongoing testing items at ATF2, the magnet will be installed at a further upstream position of the ATF2 beam line. The installation and test plan will be described.

 
THPD080 Coupling Measurements in ATF2 Extraction Line 4467
 
  • C. Rimbault
    LAL, Orsay
  • S. Kuroda, T. Tauchi, N. Terunuma
    KEK, Ibaraki
  • G.R. White, M. Woodley
    SLAC, Menlo Park, California
 
 

The purpose of ATF2 is to deliver a beam with stable very small spotsizes as required for future linear colliders such as ILC or CLIC. To achieve that, precise controls of the aberrations such as dispersion and coupling are necessary. Theoretically, the complete reconstruction of the beam matrix is possible from the measurements of horizontal, vertical and tilted beam sizes, combining skew quadrupole scans at several wire-scanner positions. Such measurements were performed in the extraction line of ATF2 in May 2009. We present analysis results attempting to resolve the 4X4 beam matrix and discuss the experimental limitations of 4D emittance measurements with wire scanners.

 
THPE020 Scenarios for the ATF2 Ultra-Low Betas Proposal 4554
 
  • E. Marin, R. Tomás
    CERN, Geneva
  • P. Bambade
    LAL, Orsay
  • S. Kuroda, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • B. Parker
    BNL, Upton, Long Island, New York
  • A. Seryi, G.R. White, M. Woodley
    SLAC, Menlo Park, California
 
 

The current ATF2 Ultra-Low beta proposal was designed to achieve 20nm vertical IP beam size without considering the multipolar components of the FD magnets. In this paper we describe different scenarios that avoid the detrimental effect of these multipolar errors in the FD. The simplest approach consists in modifying the optics but other solutions are studied as the introduction of new higher order magnets or the replacement of the FD with SC technology. The practical aspects of such an upgrade are the tuning performance and the compatibility with existing devices and instrumentation. These are fully addressed in the paper.

 
WEPE041 A Superconducting Magnet Upgrade of the ATF2 Final Focus 3440
 
  • B. Parker, M. Anerella, J. Escallier, P. He, A.K. Jain, A. Marone, P. Wanderer, K.-C. Wu
    BNL, Upton, Long Island, New York
  • P. Bambade
    LAL, Orsay
  • B. Bolzon, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux
  • P.A. Coe, D. Urner
    OXFORDphysics, Oxford, Oxon
  • C. Hauviller, E. Marin, R. Tomás, F. Zimmermann
    CERN, Geneva
  • N. Kimura, K. Kubo, T. Kume, S. Kuroda, T. Okugi, T. Tauchi, N. Terunuma, T. Tomaru, K. Tsuchiya, J. Urakawa, A. Yamamoto
    KEK, Ibaraki
  • A. Seryi, C.M. Spencer, G.R. White
    SLAC, Menlo Park, California
 
 

The KEK ATF2 facility, with a well instrumented beam line and Final Focus (FF), is a proving ground for linear collider (LC) technology to demonstrate the extreme beam demagnification and spot stability needed for a LC FF*. ATF2 uses water cooled magnets but the baseline ILC calls for a superconducting FF**. Thus we plan to replace some ATF2 FF magnets with superconducting ones made via direct wind construction as planned for the ILC. With no cryogenic supply at ATF2, we look to cool magnets and current leads with a few cryocoolers. ATF2 FF coil winding is underway at BNL and production warm magnetic measurements indicate good field quality. Having FF magnets with larger aperture and better field quality than present FF might allow reducing the beta function at the FF for study of focusing regimes relevant to CLIC. Our ATF2 magnet cryostat will have laser view ports for cold mass movement measurement and FF support and stabilization requirements under study. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC R&D prototype at BNL. We want to be able to predict LC FF performance with confidence.


* ATF2 proposal, volumes 1 and 2 at http://lcdev.kek.jp/ILC-AsiaWG/WG4notes/atf2/proposal/index.html
** International Linear Collider Reference Design Report, ILC-REPORT-2007-001, August 2007.