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MOPCH160 |
A Beam-based High Resolution Phase Imbalance Measurement Method for the ILC Crab Cavities
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433 |
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- A. Kalinin, L. Ma, R.J. Smith
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
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A high resolution method of RF phase adjustment and test is proposed for the Crab Cavity system of the ILC. The method is based on beam as ultimate test instrument. To measure phase imbalance in the pair of crab cavities (<0.02deg at 1.3GHz is required), a low energy (~1GeV) beam is used. A bunch center-of-mass trajectory through the cavities spaced (n+1/2) RF wavelengths and excited as in the case of the ILC, is a straight line for phase-balanced cavities and gets a kick when unbalanced. The kick is measured by two spaced BPMs with reference to the initial trajectory angle measured by two other BPMs. The method is insensitive to a bunch arrival time jitter and RF phase Common Mode jitter. A prototype of the test bench based on the method, is proposed. Using a 10MeV beam, two simple dipole cavities and low RF power, the prototype can be utilized for mastering high resolution measurements, for adjustment and tests of low level electronics of the Crab Cavity system and RF systems of XFEL ERLs as well. The phase resolution of the prototype is estimated as 0.01deg and the amplitude resolution as 0.01%.
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MOPLS122 |
Design of the ILC Prototype FONT4 Digital Intra-train Beam-based Feedback System
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849 |
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- P. Burrows
Queen Mary University of London, London
- G.B. Christian, H. Dabiri Khah, A.F. Hartin, G.R. White
JAI, Oxford
- C.C. Clarke, C. Perry
OXFORDphysics, Oxford, Oxon
- A. Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- D.J. McCormick, S. Molloy, M.C. Ross
SLAC, Menlo Park, California
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We report on the design and initial testing of the 4th generation Feedback on Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). FONT4 comprises a fast-analogue front-end BPM signal processor, with an FPGA-based digital feedback processor and a fast-risetime kicker-driver amplifier. The system is being designed with a total latency budget (including signal propagation delays) of about 140ns. FONT4 will be deployed at the Accelerator Test Facility (ATF) at KEK, where it will be tested with the electron bunchtrain extracted from the ATF damping ring. The bunches will have a spacing of c. 150ns, chosen to match the ILC design. We report the results of initial beam tests of the system components. We aim to demonstrate feedback, with delay-loop operation, on this ILC-like bunchtrain.
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MOPLS123 |
Performance of the FONT3 Fast Analogue Intra-train Beam-based Feedback System at ATF
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852 |
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- P. Burrows
Queen Mary University of London, London
- G.B. Christian, A.F. Hartin, H.D. Khah, G.R. White
JAI, Oxford
- C.C. Clarke, C. Perry
OXFORDphysics, Oxford, Oxon
- A. Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- D.J. McCormick, S. Molloy, M.C. Ross
SLAC, Menlo Park, California
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We report on the design and testing of the 3rd generation Feedback On Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). The all-analogue FONT3 electronics was designed to have an ultra-short latency of c. 10ns. We describe the design of the BPM signal processor, feedback circuit and kicker-driver amplifier. We report on deployment of FONT3 at the Accelerator Test Facility (ATF) at KEK, where it was tested with the 56ns-long electron bunchtrain extracted from the ATF damping ring. Feedback, with delay-loop operation, on the beam was demonstrated with a latency close to design. We comment on the applicability of this technology to ILC, as well as future warm-RF based linear colliders, such as CLIC.
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THPCH088 |
A Possibility of Constant Energy Extraction at the KEK ATF2
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2994 |
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- A. Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
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Beam energy oscillations of the order of 0.02% take place at the KEK ATF. With extractions, the synchrotron oscillation amplitude and phase at the extraction turn randomly fluctuates. The energy jitter causes a position/angle jitter in the Diagnostic section of the Extraction Line. To reduce it, a feed forward energy stabilisation can be used done by extraction of the beam at the turn next to that turn at which the energy passes the equilibrium value. For this, the synchrotron oscillation is measured by a turn-by-turn BPM as a horizontal position oscillation. A fast turn-by-turn processor detects the turn where the oscillation passes zero, and generates an extraction permission signal that triggers the existing ATF Extraction system. Stability improvement by factor of 10 can be obtained even when the extraction is done with uncertainty up to three turns after the trigger.
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THPCH089 |
The Electromagnetic Background Environment for the Interaction-point Beam Feedback System at the International Linear Collider
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2997 |
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- G.B. Christian, P. Burrows, G.B. Christian, C.C. Clarke, A.F. Hartin, C. Swinson, G.R. White
OXFORDphysics, Oxford, Oxon
- R. Arnold, C. Hast, S. Smith, M. Woods
SLAC, Menlo Park, California
- A. Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
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The Interaction Point (IP) feedback system is essential for maintaining the luminosity at the International Linear Collider (ILC). It is necessary to demonstrate the performance of the feedback beam position monitor (BPM) in an electron-positron pair background similar to that expected in the ILC interaction region (IR). We have simulated the ILC beam-beam interactions and used a GEANT model of the IR to evaluate the pair and photon flux incident on the BPM, for both the 2 mrad and 20 mrad crossing angle geometries. We present results as a function of the proposed machine parameter schemes, as well as for various system layouts within the IR. We plan to study the degradation of BPM resolution, and the long term survivability, in beam tests at End Station A at SLAC. To simulate the background environment of the ILC a 'spray beam' will be produced, which will scatter from a mechanical mock-up of the forward region of the IR, and irradiate the BPM with realistic flux of secondary pairs. We present the proposed experimental layout and planned beam tests.
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MOPLS067 |
Test Beam Studies at SLAC's End Station A, for the International Linear Collider
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700 |
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- M. Woods, C. Adolphsen, R. Arnold, G.B. Bowden, G.R. Bower, R.A. Erickson, H. Fieguth, J.C. Frisch, C. Hast, R.H. Iverson, Z. Li, T.W. Markiewicz, D.J. McCormick, S. Molloy, J. Nelson, M.T.F. Pivi, M.C. Ross, S. Seletskiy, A. Seryi, S. Smith, Z. Szalata, P. Tenenbaum
SLAC, Menlo Park, California
- D. Adey, M.C. Stockton, N.K. Watson
Birmingham University, Birmingham
- M. Albrecht, M.H. Hildreth
Notre Dame University, Notre Dame, Iowa
- W.W.M. Allison, V. Blackmore, P. Burrows, G.B. Christian, C.C. Clarke, G. Doucas, A.F. Hartin, B. Ottewell, C. Perry, C. Swinson, G.R. White
OXFORDphysics, Oxford, Oxon
- D.A.-K. Angal-Kalinin, C.D. Beard, J.L. Fernandez-Hernando, F. Jackson, A. Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R.J. Barlow, A. Bungau, G.Yu. Kourevlev, A. Mercer
UMAN, Manchester
- S.T. Boogert
Royal Holloway, University of London, Surrey
- D.A. Burton, J.D.A. Smith, R. Tucker
Lancaster University, Lancaster
- W.E. Chickering, C.T. Hlaing, O.N. Khainovski, Y.K. Kolomensky, T. Orimoto
UCB, Berkeley, California
- C. Densham, R.J.S. Greenhalgh
CCLRC/DL, Daresbury, Warrington, Cheshire
- V. Duginov, S.A. Kostromin, N.A. Morozov
JINR, Dubna, Moscow Region
- G. Ellwood, P.G. Huggard, J. O'Dell
CCLRC/RAL, Chilton, Didcot, Oxon
- F. Gournaris, A. Lyapin, B. Maiheu, S. Malton, D.J. Miller, M.W. Wing
UCL, London
- M.B. Johnston
University of Oxford, Clarendon Laboratory, Oxford
- M.F. Kimmitt
University of Essex, Physics Centre, Colchester
- H.J. Schriber, M. Viti
DESY Zeuthen, Zeuthen
- N. Shales, A. Sopczak
Microwave Research Group, Lancaster University, Lancaster
- N. Sinev, E.T. Torrence
University of Oregon, Eugene, Oregon
- M. Slater, M.T. Thomson, D.R. Ward
University of Cambridge, Cambridge
- Y. Sugimoto
KEK, Ibaraki
- S. Walston
LLNL, Livermore, California
- T. Weiland
TEMF, Darmstadt
- M. Wendt
Fermilab, Batavia, Illinois
- I. Zagorodnov
DESY, Hamburg
- F. Zimmermann
CERN, Geneva
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The SLAC Linac can deliver to End Station A a high-energy test beam with similar beam parameters as for the International Linear Collider for bunch charge, bunch length and bunch energy spread. ESA beam tests run parasitically with PEP-II with single damped bunches at 10Hz, beam energy of 28.5 GeV and bunch charge of (1.5-2.0)·1010 electrons. A 5-day commissioning run was performed in January 2006, followed by a 2-week run in April. We describe the beamline configuration and beam setup for these runs, and give an overview of the tests being carried out. These tests include studies of collimator wakefields, prototype energy spectrometers, prototype beam position monitors for the ILC Linac, and characterization of beam-induced electro-magnetic interference along the ESA beamline.
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