Abstracts Brochure - CERN

WEPCH — Poster Session 28-Jun-06 16:00 - 18:00
around 13 meters from the interaction point. In this new configuration we present the performance improvements
and the hardware requirements.
Sorting Strategies for the Arc Quadrupoles of the LHC
The variation in the field gradient of the LHC
arc quadrupoles can not be corrected inde- Y. Papaphilippou, A.M. Lombardi (CERN)
pendently by the dedicated trim quadrupole
circuits. This may result to a beta function beating larger than the one accepted by the machine budget. In this respect,
sorting strategies for the installation of these magnets were implemented in order to eliminate this effect, as locally
as possible. Special care was taken for quadrupoles whose warm measurements showed large gradient errors due to
an excessive magnetic permeability. The figures of merit used in the sorting and the results obtained for all 8 sectors
of the LHC are detailed. The global optics function beating foreseen, as computed by both analytical estimates and
simulations with MAD-X are finally presented.
Design and Validation with Measurements of the LEIR Injection Line
The CERN Low Energy Ion Ring (LEIR) commissioning
started in the year 2005. O F. Roncarolo, C. Carli, M. Chanel, L.D. Dumas, R. Scrivens (CERN)
4+ and
Pb 54+ 4.2 MeV/nucleon ion beams are transferred
from Linac 3 to LEIR through a low energy transfer line, for which the constraints and the resulting optics design
are presented. First trajectory and dispersion measurements agreed only poorly with the theoretical model. Iterations
of a refined optics model and further measurements improved the agreement between experimental observations
and expectations. In particular, the effect of quadrupolar errors in the line dipole magnets is discussed.
Procedures and Accuracy Estimates for Beta-beat Correction in the LHC
The LHC aperture imposes a tight tolerance
of 20% on the maximum acceptable beta-beat R. Tomas, O.S. Brüning (CERN) R. Calaga, S. Peggs (BNL)
in the machine. An accurate knowledge of
the transfer functions for the individually powered insertion quadrupoles and techniques to compensate beta-beat
are key prerequisites for successful operation with high intensity beams. We perform realistic simulations to predict
quadrupole errors in LHC and explore possible ways of correction to minimize beta-beat below the 20% level.
Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors
The Large Hadron Collider, now under construction
at CERN, relies heavily on superconducting
magnets for its optics layout: besides
the main magnets, almost all the cor-
W. Venturini Delsolaro, L. Bottura, Y. C. Chaudhari, M. Karppinen
(CERN) N.J. Sammut (University of Malta, Faculty of Engineering)
recting magnets are superconducting. Along with clear advantages, this brings about complications due to the
effects of persistent currents in the superconducting filaments. Correcting magnets that trim key beam parameters
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