Paper |
Title |
Page |
TUPZ006 |
Aperture Determination in the LHC Based on an Emittance Blowup Technique with Collimator Position Scan |
1810 |
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- R.W. Assmann, R. Bruce, M. Giovannozzi, G.J. Müller, S. Redaelli, F. Schmidt, R. Tomás, J. Wenninger, D. Wollmann
CERN, Geneva, Switzerland
- M. Alabau
IFIC, Valencia, Spain
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A new method to determine the LHC aperture was proposed. The new component is a collimator scan technique that refers the globally measured aperture limit to the shadow of the primary collimator, expressed in σs of rms beam size. As a by-product the BLM response to beam loss is quantified. The method is described and LHC measurement results are presented.
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WEPC032 |
First Measurements of Higher Order Optics Parameters in the LHC |
2073 |
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- G. Vanbavinckhove
NIKHEF, Amsterdam, The Netherlands
- M. Aiba
PSI, Villigen, Switzerland
- R. Bartolini
Diamond, Oxfordshire, United Kingdom
- R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
- M. Giovannozzi, F. Schmidt, R. Tomás
CERN, Geneva, Switzerland
- E.H. Maclean
JAI, Oxford, United Kingdom
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Higher order effects can play an important role in the performance of the LHC. Lack of knowledge of these parameters can increase the tune footprint and compromise the beam lifetime. First measurements of these parameters at injection and flattop have been conducted. Detailed simulations are compared to the measurements together with discussions on the measurement limitations.
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WEPC078 |
Non-linear Chromaticity Studies of the LHC at Injection |
2199 |
|
- E.H. Maclean, M. Giovannozzi, F. Schmidt, R.J. Steinhagen, E. Todesco, R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland
- R. Bartolini
JAI, Oxford, United Kingdom
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The non-linear chromaticity of the LHC has been studied. Measurements of variation in tune with dp/p on both beams at injection optics are being compared with Q'' and Q''' as calculated with the LHC effective model. This model uses the best currently available measurements of magnetic field harmonics. An attempt is being made to optimize the b4 and b5 pool-pieces corrections in view of the corresponding chromaticity terms.
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WEPC079 |
Beta-beating in the Effective Model of the LHC Using PTC |
2202 |
|
- M.C. Alabau Pons, F. Schmidt, R. Tomás
CERN, Geneva, Switzerland
- E.H. Maclean
JAI, Oxford, United Kingdom
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An effective model of the LHC optics has been developed based on measurements of magnetic field, alignment errors and closed orbit. This model utilizes the Polymorphic Tracking Code with MAD-X as front-end to allow the inclusion of harmonics to an arbitrary order in thick lattice elements. Beta-beating calculations have been performed with this model at injection optics and at 3.5 TeV squeezed optics to 3.5 m beta-function at the interaction point. The model predictions are in remarkable agreement with the measurements performed in the 2010 LHC commissioning run.
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