Paper |
Title |
Page |
TUPCH048 |
A Study of Emittance Measurement at the ILC
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1115 |
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- G.A. Blair, I.V. Agapov, J. Carter, L. Deacon
Royal Holloway, University of London, Surrey
- D.A.-K. Angal-Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- L.J. Jenner
Cockcroft Institute, Warrington, Cheshire
- M.C. Ross, A. Seryi, M. Woodley
SLAC, Menlo Park, California
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The measurement of the ILC emittance in the ILC beam delivery system and the linac is simulated. Estimates of statistical and machine-related errors are discussed and implications for related diagnostics R&D are inferred.
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WEPCH062 |
Precision Measurement and Improvement of Optics for e+, e- Storage Rings
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2065 |
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- Y.T. Yan, Y. Cai, W.S. Colocho, F.-J. Decker, J. Seeman, M.K. Sullivan, J.L. Turner, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California
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Through horizontal and vertical excitations, we have been able to make a precision measurement of linear geometric optics parameters with a Model-Independent Analysis (MIA). We have also been able to build up a computer model that matches the real accelerator in linear geometric optics with an SVD-enhanced Least-square fitting process. Recently, with the addition of longitudinal excitation, we are able to build up a computer virtual machine that matches the real accelerators in linear optics including dispersion without additional fitting variables. With this optics-matched virtual machine, we are able to find solutions that make changes of many normal and skew quadrupoles for machine optics improvement. It has made major contributions to improve PEP-II optics and luminosity. Examples from application to PEP-II machines will be presented.
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MOPLS045 |
Achieving a Luminosity of 1034/cm2/s in the PEP-II B-factory
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643 |
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- J. Seeman, J. Browne, Y. Cai, W.S. Colocho, F.-J. Decker, M.H. Donald, S. Ecklund, R.A. Erickson, A.S. Fisher, J.D. Fox, S.A. Heifets, R.H. Iverson, A. Kulikov, A. Novokhatski, V. Pacak, M.T.F. Pivi, C.H. Rivetta, M.C. Ross, P. Schuh, K.G. Sonnad, M. Stanek, M.K. Sullivan, P. Tenenbaum, D. Teytelman, J.L. Turner, D. Van Winkle, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky
SLAC, Menlo Park, California
- M.E. Biagini
INFN/LNF, Frascati (Roma)
- W. Kozanecki
CEA, Gif-sur-Yvette
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For the PEP-II Operation Staff: PEP-II is an asymmetric e+e- collider operating at the Upsilon 4S and has recently set several performance records. The luminosity has exceeded 1x1034/cm2/s and has delivered an integrated luminosity of 728/pb in one day. PEP-II operates in continuous injection mode for both beams, boosting the integrated luminosity. The peak positron current has reached 2.94 A and 1.74 A of electrons in 1732 bunches. The total integrated luminosity since turn on in 1999 has reached over 333/fb. This paper reviews the present performance issues of PEP-II and also the planned increase of luminosity in the near future to over 2 x 1034/cm2/s. Upgrade details and plans are discussed.
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MOPLS052 |
Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation
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661 |
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- Y. Cai, W.S. Colocho, F.-J. Decker, Y. Nosochkov, P. Raimondi, J. Seeman, K.G. Sonnad, M.K. Sullivan, J.L. Turner, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky
SLAC, Menlo Park, California
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The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x1034cm-2s-1 as the beam currents increased.
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MOPLS066 |
Direct Measurement of Geometric and Resistive Wakefields in Tapered Collimators for the International Linear Collider
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697 |
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- N.K. Watson, D. Adey, M.C. Stockton
Birmingham University, Birmingham
- D.A.-K. Angal-Kalinin, C.D. Beard, J.L. Fernandez-Hernando, F. Jackson
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R. Arnold, R.A. Erickson, C. Hast, T.W. Markiewicz, S. Molloy, M.C. Ross, S. Seletskiy, A. Seryi, Z. Szalata, P. Tenenbaum, M. Woodley, M. Woods
SLAC, Menlo Park, California
- R.J. Barlow, A. Bungau, R.M. Jones, G.Yu. Kourevlev, A. Mercer
UMAN, Manchester
- D.A. Burton, J.D.A. Smith, A. Sopczak, R. Tucker
Lancaster University, Lancaster
- C. Densham, G. Ellwood, R.J.S. Greenhalgh, J. O'Dell
CCLRC/RAL, Chilton, Didcot, Oxon
- Y.K. Kolomensky
UCB, Berkeley, California
- M. Kärkkäinen, W.F.O. Müller, T. Weiland
TEMF, Darmstadt
- N. Shales
Microwave Research Group, Lancaster University, Lancaster
- M. Slater
University of Cambridge, Cambridge
- I. Zagorodnov
DESY, Hamburg
- F. Zimmermann
CERN, Geneva
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Precise collimation of the beam halo is required in the ILC to prevent beam losses near the interaction region that could cause unacceptable backgrounds for the physics detector. The necessarily small apertures of the collimators lead to transverse wakefields that may result in beam deflections and increased emittance. A set of collimator wakefield measurements has previously been performed in the ASSET region of the SLAC LINAC. We report on the next phase of this programme, which is carried out at the recently commissioned End Station A test facility at SLAC. Measurements of resistive and geometric wakefields using tapered collimators are compared with model predictions from MAFIA and GdfidL and with analytic calculations.
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WEPCH150 |
The Accelerator Markup Language and the Universal Accelerator Parser
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2278 |
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- D. Sagan, M. Forster
Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
- D.A. Bates, A. Wolski
LBNL, Berkeley, California
- T. Larrieu, Y. Roblin
Jefferson Lab, Newport News, Virginia
- T.A. Pelaia
ORNL, Oak Ridge, Tennessee
- S. Reiche
UCLA, Los Angeles, California
- F. Schmidt
CERN, Geneva
- P. Tenenbaum, M. Woodley
SLAC, Menlo Park, California
- N.J. Walker
DESY, Hamburg
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A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.
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