| Paper |
Title |
Page |
| MOPLT005 |
An Improved Collimation System for the LHC
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536 |
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- R.W. Assmann, O. Aberle, A. Bertarelli, H.-H. Braun, M. Brugger, L. Bruno, O.S. Brüning, S. Calatroni, E. Chiaveri, B. Dehning, A. Ferrari, B. Goddard, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, V. Kain, M. Lamont, M. Mayer, E. Métral, R. Perret, S. Redaelli, T. Risselada, G. Robert-Demolaize, S. Roesler, F. Ruggiero, R. Schmidt, D. Schulte, P. Sievers, V. Vlachoudis, L. Vos, G. Vossenberg, J. Wenninger
CERN, Geneva
- I.L. Ajguirei, I. Baishev, I.L. Kurochkin
IHEP Protvino, Protvino, Moscow Region
- D. Kaltchev
TRIUMF, Vancouver
- H. Tsutsui
SHI, Tokyo
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The LHC design parameters extend the maximum stored beam energy 2-3 orders of magnitude beyond present experience. The handling of the high-intensity LHC beams in a super-conducting environment requires a high-robustness collimation system with unprecedented cleaning efficiency. For gap closures down to 2mm no beam instabilities may be induced from the collimator impedance. A difficult trade-off between collimator robustness, cleaning efficiency and collimator impedance is encountered. The conflicting LHC requirements are resolved with a phased approach, relying on low Z collimators for maximum robustness and hybrid metallic collimators for maximum performance. Efficiency is further enhanced with an additional cleaning close to the insertion triplets. The machine layouts have been adapted to the new requirements. The LHC collimation hardware is presently under design and has entered into the prototyping and early testing phase. Plans for collimator tests with beam are presented.
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| MOPLT006 |
The New Layout of the LHC Cleaning Insertions
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539 |
| |
- R.W. Assmann, O. Aberle, O.S. Brüning, S. Chemli, D. Gasser, J.-B. Jeanneret, J.M. Jimenez, V. Kain, E. Métral, G. Peon, S. Ramberger, C. Rathjen, T. Risselada, F. Ruggiero, L. Vos
CERN, Geneva
- D. Kaltchev
TRIUMF, Vancouver
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The improved LHC collimation system required significant changes in the layout and design of the warm insertion IR7. Requirements for collimation, optics, impedance, vacuum, and additional infrastructure are described and the adopted layout is discussed. Various design principles have been explored during the re-design, ranging from a regular 90 degree lattice and special low impedance lattices to an option with additional warm quadrupole units that could have extended the usable space for collimator installations in the insertion. The various constraints for the optics and cleaning design in the LHC cleaning insertions are summarized. Magnet positions and collimators were moved significantly, such that a good cleaning efficiency was maintained while impedance was reduced by a factor of two. Metallic phase 2 collimators allow a better efficiency than originally achievable and additional scrapers were allocated. The required infrastructure was specified, including a powerful cooling system for the collimators.
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| MOPLT025 |
Status and Plans for the SPS to LHC Beam Transfer Lines TI 2 and TI 8
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593 |
| |
- V. Mertens, B. Goddard, T. Risselada
CERN, Geneva
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Beam transfer from the CERN Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) will be done through the two transfer lines TI 2 and TI 8, presently under construction, with a combined length of about 5.6 km. The final layout, optics design and correction scheme for these lines will be presented. The requirement of simultaneously matching their geometry and optics with that of the LHC will be treated, including the methodology for alignment of the elements along the line and a proposed solution in the final matching section. After the commissioning of the short transfer line TT40 just upstream of TI 8 in 2003, beam tests of the whole of TI 8 are scheduled for autumn 2004, with the aim to validate many of the new features and mechanisms involved in the future control and operation of these lines. The status of the installation will be described, comprising the progress with infrastructure, services and line elements. An outlook will be given for the work remaining until 2007.
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| WEPLT017 |
Numerical Studies of the Impact of the Separation Dipoles and Insertion Quadrupoles Field Quality on the Dynamic Aperture of the CERN LHC
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1855 |
| |
- M. Giovannozzi, O.S. Brüning, S.D. Fartoukh, T. Risselada, F. Schmidt
CERN, Geneva
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A wide range of magnets, both warm and superconducting, will be used in the LHC. In addition to main dipoles, quadrupoles are used to focus the beam in regular arcs. Special dipoles separate or merge the two beams in insertion regions. A few very strong superconducting quadrupoles squeeze the beam to achieve the required luminosity, while warm quadrupoles are used in the collimation insertions. At injection the main dipoles largely dominate beam dynamics, but contributions from smaller classes of magnets should not be neglected. Peculiar optical configurations may dramatically enhance beam dynamics effects of few magnetic elements. This paper will focus on the effect of insertion quadrupoles, e.g. wide-aperture, and warm quadrupoles, as well as separation dipoles presenting on the dynamic aperture of the LHC machine.
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| WEPLT026 |
Dynamic Aperture Reduction from the Dodecapole Component in the LHC Main Quadrupoles and its Mechanism.
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1882 |
| |
- A.M. Lombardi, O.S. Brüning, S.D. Fartoukh, T. Risselada, F. Schmidt, A. Verdier
CERN, Geneva
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The systematic dodecapole component in the Main Quadrupoles of the LHC lattice has a strong influence on the machine dynamic aperture at injection. In this paper we quantify this effect with the help of tracking studies, explain the mechanism for the loss in dynamic aperture and look into potential correction schemes. Finally, we provide an estimate for the maximum allowed systematic dodecapole component in the MQ.
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