KEK, Ibaraki
The kicker of the damping ring for the International linear collider(ILC) requires fast rise/fall times(3 or 6ns) and high repetition rate(3 MHz). A multiple strip-line kicker system is developing to realize the specification*. We present results of the beam test at KEK-ATF by the strip-line kicker**. The multi-bunch beam, which has 5.6ns bunch spacing in the damping ring, is extracted with 308ns duration. Two units of the strip-line electrodes are used to extract the beam. The scheme of the beam extraction is same as the kicker of the ILC. A bump orbit and an auxiliary septum magnet are used with the kicker to clear the geometrical restriction.
*T. Naito et. al., Proc. of PAC07, pp2772-2274
**T. Naito et. al., Proc. of EPAC08, pp601-603
CERN, Geneva
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
IHEP Beijing, Beijing
LAL, Orsay
KEK, Ibaraki
UMAN, Manchester
SLAC, Menlo Park, California
The CLIC Final Focus System has considerably larger chromaticity than those of ILC and its scaled test machine ATF2. We propose to reduce the IP betas of ATF2 to reach a CLIC-like chromaticity. This would also allow to study the FFS tuning difficulty as function of the IP beam spot size. Both the ILC and CLIC projects will largely benefit from the ATF2 experience at these ultra-low IP betas.
KEK, Ibaraki
IN2P3-LAPP, Annecy-le-Vieux
ICEPP, Tokyo
University of Tokyo, Tokyo
The ATF2, accelerator test facility has been developed confirming techniques for obtaining super low emittance beam for future particle accelerators. Here, the converged beam size is designed to be 37 nm, and a precision beam size monitor using interference fringes as a reference called Shintake monitor is used for measuring it. In order to measure the beam size with resolution of better than 10%, relative position between the beam and the interference fringes should be stabilized within few nanometers. Highly rigid tables and mounts for the Shintake monitor and final focusing magnets are adopted with highly rigid floor to ensure relative position stability. Then, the Shintake monitor can be stabilized against the beam, since the beam fluctuates coherently with the final focusing magnets. On the other hand the interference fringes are stabilized against the Shintake monitor with precise phase control system. As a result, relative position between the beam and the interference fringes is stabilized based on rigidity of tables, mounts, and floor between them. We will present our conception for stabilization and results of vibration measurements for the Shintake monitor.
IHEP Beijing, Beijing
JAI, Egham, Surrey
KEK, Ibaraki
ICEPP, Tokyo
SLAC, Menlo Park, California
University of Tokyo, Tokyo
Funding: NSFC 10525525 and 10775154. CNRS-IN2P3 and ANR.
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. We report on techniques developed based on simulation studies to adjust the horizontal and vertical beam waists independently in the presence of errors, at two different IP locations where the beam size can be measured with different accuracies. During initial commissioning, we will start 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. The first measurements in such intermediate β-configurations are reported.
University of Tokyo, Tokyo
KEK, Ibaraki
ICEPP, Tokyo
Commissioning of the ATF/ATF2 project will start in the winter of 2008 to 2009, with the aim of studying beam optics, diagnostic instrumentations, and tuning processes for around 35 nm beam size. The project is the realistic scaled down model of the ILC final focus system, and also, studies in the project offered important findings for future accelerator physics. In this presentation, we will present about the status of the first commissioning of the Shintake monitor for ATF2. The monitor is located at the virtual interaction point of the ATF2 (the focus point) to measure beam size. A measurable ranges as a design are from 6 micron down to 20 nm in vertical and down to several microns in horizontal. That wide range allows us to used the detector from the beginning of the beam tuning process. The monitor scheme was originally proposed by T. Shintake and verified using around 60 nm beam at FFTB project. We upgraded the detector system for ATF2 of smaller beam size and implemented a laser wire scheme for horizontal beam size measurement. These additional capabilities are also presented.
KEK, Ibaraki
The University of Liverpool, Liverpool
SLAC, Menlo Park, California
One of the goals of the Accelerator Test Facility (ATF) at KEK is to demonstrate ultra-low vertical emittance for linear colliders. Highly precise correction of the vertical dispersion and betatron coupling will be needed to achieve the target of 2 pm (which will be required for ILC). Optics correction and tuning must be supported by an accurate model, which can be developed from a variety of beam measurements, including orbit response to dipole kicks, beta functions at the quadrupoles, etc. Here, we report experimental data and the status of the model and low-emittance tuning.
LAL, Orsay
IN2P3-LAPP, Annecy-le-Vieux
KEK, Ibaraki
UMAN, Manchester
SLAC, Menlo Park, California
Funding: CNRS/IN2P3 ANR (Programme Blanc, Project ATF2-IN2P3-KEK, contract ANR-06-BLAN-0027)
The orbit in the ATF2 extraction line has to be accurately controlled to allow orbit and optics corrections to work well downstream. The Final Focus section contains points with large beta function values which amplify incoming beam jitter, and few correctors since the steering is performed using quadrupole movers, and so good orbit stability is required. It is also essential because some magnets are non-linear and can introduce position-dependent coupling of the motion between the two transverse planes. First experience monitoring the orbit in the extraction line during the ATF2 commissioning is described, along with a simulation of the planned steering algorithm.
SLAC, Menlo Park, California
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
JAI, Oxford
KEK, Ibaraki
IHEP Beijing, Beijing
LAL, Orsay
Royal Holloway, University of London, Surrey
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
ATOMKI, Debrecen
CERN, Geneva
DESY, Hamburg
Fermilab, Batavia
Kyungpook National University, Daegu
PAL, Pohang, Kyungbuk
Kyoto ICR, Uji, Kyoto
ICEPP, Tokyo
University of Tokyo, Tokyo
UCL, London
BNL, Upton, Long Island, New York
Tohoku University, Graduate School of Science, Sendai
UMAN, Manchester
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
Cockcroft Institute, Warrington, Cheshire
ATF2 is a final-focus test beam line that attempts to focus the low-emittance beam from the ATF damping ring to a beam size of about 37 nm, and at the same time to demonstrate nm beam stability, using numerous advanced beam diagnostics and feedback tools. The construction is well advanced and beam commissioning of ATF2 has started in the second half of 2008. ATF2 is constructed and commissioned by ATF international collaborations with strong US, Asian and European participation.