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Bambade, P.

Paper Title Page
THPD077 Linear Collider Test Facility: Twiss Parameter Analysis at the IP/Post-IP location of the ATF2 beam line 4458
 
  • B. Bolzon, A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux
  • S. Bai
    IHEP Beijing, Beijing
  • P. Bambade
    KEK, Ibaraki
  • G.R. White
    SLAC, Menlo Park, California
 
 

At the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3um at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used (βx=4cm and βy=1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that beta functions and emittances were within errors of measurements when no rematching and coupling corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously αx, αy and the horizontal dispersion (Dx). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the αy knob were successfully performed.

 
THPD096 Simulation of Multiknobs Correction at ATF2 4512
 
  • S. Bai, J. Gao
    IHEP Beijing, Beijing
  • P. Bambade
    KEK, Ibaraki
  • B. Bolzon
    IN2P3-LAPP, Annecy-le-Vieux
 
 

The ATF2 project is the final focus system prototype for ILC and CLIC linear collider projects, with a purpose to reach a 37nm vertical beam size at the interaction point. During initial commissioning, we started with larger than nominal β-functions at the IP, to reduce the effects from higher-order optical aberrations and thereby simplify the optical corrections needed. We report on simulation studies at two different IP locations developed based on waist scan, dispersion, coupling and β function multiknobs correction in the large β optics of ATF2, in the presence of two kinds of magnet inaccuracies (quadrupole gradient and roll errors) to generate all possible linear optics distortions at the IP. A vertical beam size which is very close to the nominal beam size is obtained based on the simulation study.

 
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

 
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.

 
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.