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.
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.
LAL, Orsay
KEK, Ibaraki
SLAC, Menlo Park, California
Funding: CNRS-IN2P3, ANR
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 aberrations such as dispersion and coupling are necessary. Initially, coupling correction upstream of the final focus line of the ATF2 will be performed with only two skew quadrupoles (SQ) in the extraction line (EXT). We thus first examine the feasability of coupling correction in the EXT with those two SQ, considering several possible coupling error sources. The correction is first based on an algorithm of minimisation of vertical emittance with successive skew scans, implemented in the Flight Simulator code*. We will then investigate new methods to measure and extract the first order four coupling parameters of the beam matrix in order to perform a more direct and accurate coupling correction.
*G. White et al., "A flight simulator for ATF2…", TUPP016 EPAC08
SLAC, Menlo Park, California
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
KEK, Ibaraki
LAL, Orsay
UMAN, Manchester
CERN, Geneva
Funding: Work supported in part by Department of Energy Contract DE-AC02-76SF00515
Using a new extraction line currently being commissioned, the ATF2 experiment plans to test a novel compact final focus optics design using a local chromaticity correction scheme, such as could be used in future linear colliders*. Using a 1.3 GeV beam of ~30nm normalised vertical emittance extracted from the ATF damping ring, the primary goal is to achieve a vertical IP waist of 35nm. We discuss our planned strategy, implementation details and early experimental results for tuning the ATF2 beam to meet the primary goal. These optics require uniquely tight tolerances on some magnet strengths and positions, we discuss efforts to re-match the optics to meet these requirements using high-precision measurements of key magnet elements. We simulated in detail the tuning procedure using several algorithms and different code implementations for comparison from initial orbit establishment to final IP spot-size tuning. Through a Monte Carlo study of 100's of simulation seeds we find we can achieve a spot-size within 10% of the design optics value in at least 90% of cases. We also ran a simulation to study the long-term performance with the use of beam-based feedbacks.
*"ATF2 Proposal", ATF2 Collaboration (Boris Ivanovich Grishanov et al.)., KEK-REPORT-2005-2, Aug 23, 2005.
SLAC, Menlo Park, California
IHEP Beijing, Beijing
Funding: Work supported in part by the DOE Contract DE-AC02-76SF00515. This work was performed in support of the LCLS project at SLAC.
XAL, a high-level application framework originally developed by Spallation Neutron Source (SNS), has been adapted by the Linac Coherent Light Source (LCLS) project. The work includes proper relational database schema modification to better suit XAL configuration data requirement, addition of new device types for LCLS online modeling purpose, longitudinal coordinate system change to better represent the LCLS electron beam rather than proton or ion beam in the original SNS XAL design, intensively benchmark with MAD and present SLC modeling system for the online model, and various new features to the XAL framework. Storing online model data in a relational database and providing universal access methods for other applications is also described here.
SLAC, Menlo Park, California
LAL, Orsay
The Flight Simulator is a tool used for international collaboration in the writing and deployment of online beam dynamics algorithms. Written as an add-on to the Lucretia tracking software, it allows simulation of a beamline in a control system environment identical to that in the control room. This allows the testing and development of monitoring and correction tools by an international collaboration by making the control system transparent to the user. The native beamline representation are those adopted by Lucretia, so, in order to allow third party software, to interface with this system, it was necessary to develop functionality to convert the lattice to a universal representation. Accelerator Markup Language (AML), and its associated Universal Accelerator Parser (UAP), were used for this purpose. This paper describes the use of the UAP to convert the internal beamline representation to AML, and the testing of this conversion routine using the lattice description of the ATF2 final focus experiment at KEK, Japan. Also described are the inclusion of PLACET and SAD based algorithms using appropriate converters, and tests of these on the ATF2 extraction line.
SLAC, Menlo Park, California
The Flight Simulator is a Matlab middleware layer which uses the Lucretia beam tracking engine and a lower level EPICS control system to allow the development of beam control and monitoring algorithms in a simulation environment that appears identical to the that of the control room. The goal of ATF2 is to test a novel compact final final focus optics design intended for use in future linear colliders. The newly designed extraction line and final focus system will be used to produce a 37nm vertical waist from the extracted beam. Alignment of the magnetic elements is of vital importance for this goal and it is expected that beam-based alignment (BBA) techniques will be necessary to achieve the necessary tolerances. This paper describes a package for the beam-based alignment of quadrupole and sextupole magnets in the ATF2 damping ring, extraction line, and final focus system. It brings together several common techniques for the alignment of magnetic elements, and has been implemented as a GUI-based tool that may be used on its own, or integrated with other routines. The design of this package is described, and simulation and beam results are shown.
SLAC, Menlo Park, California
Funding: Department of Energy contract DE-ACO3-76SF00515
We describe an integrated relational database for beamline element configuration and online accelerator modelling for LCLS. It is hosted in Oracle, from which online controls software, optimization applications and feedback, use a programming interface to acquire the element data and model. Database population is by an automated process starting with a MAD deck, which is processed in Matlab to derive text files that describe the beamline elements whose data are uploaded using Oracle Loader, and the resulting Oracle APEX applications and reports are used for survey, cabling, metrology and other facilities. An automated facility for online model generation creates an XAL online model beamline description file using a database query; the resulting model is then tracked, and results can be loaded back into the database. As such, both the design or extant machine model, of the present and all previous model runs are available, and linked to the relevant element configuration. We present the process flow from the MAD design to the database, the database schema, the database applications, the process of generating a machine model, and some scientific software which uses the database.
Kyungpook National University, Daegu
Royal Holloway, University of London, Surrey
KEK, Ibaraki
PAL, Pohang, Kyungbuk
UCL, London
SLAC, Menlo Park, California
Fermilab, Batavia
CHEP, Daegu
University of Cambridge, Cambridge
The ATF2 international collaboration is intending to demonstrate nanometer beam sizes required for the future Linear Colliders. The position of the electron beam focused down at the end of the ATF2 extraction line to a size as small as 35 nm has to be measured with nanometer resolution. For that purpose a special Interaction Point(IP) beam position monitor (BPM) was designed. In this paper we report on the features of the BPM and electronics design providing the required resolution. We also consider the results obtained with BPM triplet which was installed in the ATF beamline and the first data from ATF2 commissioning runs.
UCL, London
Royal Holloway, University of London, Surrey
Kyungpook National University, Daegu
KEK, Ibaraki
SLAC, Menlo Park, California
Fermilab, Batavia
University of Cambridge, Cambridge
The ATF2 international collaboration is intending to demonstrate nanometre beam sizes required for the future Linear Colliders. An essential part of the beam diagnostics needed to achieve this goal is the high resolution cavity beam position monitors (BPMs). In this paper we report on the S-band system installed in the final focus region of the new ATF2 extraction beamline. It only includes 4 BPMs, but they are mounted on the most critical final focus magnets squeezing the beam down to 35 nm. We discuss both the design and the first operational experience with the system.
Royal Holloway, University of London, Surrey
Kyungpook National University, Daegu
KEK, Ibaraki
UCL, London
SLAC, Menlo Park, California
Fermilab, Batavia
University of Cambridge, Cambridge
The ATF2 international collaboration is intending to demonstrate nanometre beam sizes required for the future Linear Colliders. An essential part of the beam diagnostics needed to achieve that goal is the high resolution cavity beam position monitors (BPMs). In this paper we report on the C-band system consisting of 32 BPMs spread over the whole length of the new ATF2 extraction beamline. We discuss the design of the BPMs and electronics, main features of the DAQ system, and the first operational experience with these BPMs.
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.
